| Author | Message | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 587 Registered: 1-2003 Posted From: 208.178.75.194 Rating: N/A |
Once again I need to call on the collected wisdom of the list. My 8V92TA (DDEC-II) is acting up again. I am noticing a increased amount of black smoke under load, especially moving from a dead stop. Subjectively, I am suffering a loss of power as well, with low acceleration off the line. And, under load, such as pulling a 6% or so grade, temperatures are skyrocketing, and I am having to stop periodically to let the engine cool down. Turbo boost pressure and fuel delivery rates seem normal, and the cooling system looks normal (fans spinning, coolant level OK, etc.). Someone has already suggested dragging brakes, but I have temperature sensors in the wheels and all read normal. Yesterday I replaced the air filter, on the chance that it was restricted. No change. I also have a reader (Silverleaf VMS200) on my DDEC -- there are no codes and no abnormal readings, as far as I can tell. Fuel filters were just changed, and my primary is a Davco FuelPro 380 so I can see that it is not restricted. I am looking for suggestions on other things to check before I take it in to the shop for professional diagnosis. Thanks. -Sean http://OurOdyssey.BlogSpot.com | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 68 Registered: 8-2006 Posted From: 74.33.52.83 Rating: N/A |
Sean, check your bypass valve if your engine has a bypass blower it maybe stuck open (Message edited by luvrbus on July 15, 2007) | ||
| Pete/RTS Daytona (Pete_rtsdaytona)
Registered Member Username: Pete_rtsdaytona Post Number: 365 Registered: 1-2005 Posted From: 208.118.14.63 Rating: N/A |
Do you have a Catalytic converter IT COULD BE CLOGGED many mufflers can be opened and the Catalytic converter insert removed IIRC - Bubba Jef - RTS Va. had the same problem on his 6V92TA DDEC-iv Hopefully he will chim in - I believe his symptoms were Black smoke - poor acceleration - no top end (Message edited by pete RTS/Daytona on July 15, 2007) | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 57 Registered: 3-2007 Posted From: 76.4.143.219 Rating: N/A |
hey pete; when did they start putting catalytic converters on diesels. Am I living in the wrong age? | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 68 Registered: 10-2005 Posted From: 71.212.53.189 Rating: N/A |
Black smoke is excess fuel, lack of power and black smoke would point to incomplete combustion. The air filters on these buses are about 1/2 the size they should be, hotter air is thinner and if you are at any altitude at all I would not be shocked. Stuck open thermostat allowing the water to pass the rad too quickly, hornets nest on the rad preventing air flow, slipping fan clutch, not enough coolant causing boiling, etc. Aftercooler plugged stopping air flow - smoke. Plugged on the coolant side - high air inlet temps, thinner, hotter air. So many possiblities. Try driveing at night when it is cool and see if there is a difference. | ||
| Ed Jewett (Kristinsgrandpa)
Registered Member Username: Kristinsgrandpa Post Number: 326 Registered: 2-2003 Posted From: 64.24.214.161 Rating: N/A |
Check your air intake for critters nesting (4 legged and winged), if it is possible for them to get in there. This kinda sounds like the problem Belfert had with his Dina, and that was his problem. Good luck, Ed | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 588 Registered: 1-2003 Posted From: 208.178.75.194 Rating: N/A |
Good suggestions, everyone. I've pulled the air filter (and mine is HUGE -- probably plenty of flow for this motor). No critters in there. The engine was in-framed only 40,000 ago, so it's hard to believe I could have a plugged aftercooler, unless (gulp) my intake has come apart *again*. It's hard to get a look, without disassembling half the bedroom. Luvrbus -- I have to ask, what's a bypass valve? I thought I knew my engine pretty well, but this one's over my head. I'll check it, if you tell me where to look. (This isn't the turbo waste gate, is it?) -Sean http://OurOdyssey.BlogSpot.com | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 70 Registered: 10-2005 Posted From: 71.212.53.189 Rating: N/A |
I have seen pretty good nests built in a weekend, the 4 legged variety of critter seems to love wire insulation as well... "mine is HUGE" don't brag, it makes people question you. If your intake has come apart then it does not take much oil and dust to clog things up. | ||
| Steve N. (N4rsn)
Registered Member Username: N4rsn Post Number: 109 Registered: 2-2005 Posted From: 75.105.156.215 Rating: N/A |
Check the turbo, and see if it is spinning. #2 check the top of the blower, the screen could be clogged. Remove the turbo intake hose, and see if the smoking stops, as that will elimnate the air filter. | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 55 Registered: 1-2007 Posted From: 65.61.96.82 Rating: N/A |
Sean, Did symptoms suddenly start or come on gradually? If sudden, was it after fueling? Could be some bad fuel. Good luck sorting it out. | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 759 Registered: 11-2004 Posted From: 24.129.157.205 Rating: N/A |
Sean - since you obviously have figured in almost every scenario and your past history of maintenance/repairs is well documented on this board - my only guess that would fit ALL the symptoms leads me back to the fuel system and a possible low fuel pressure problem - HTH | ||
| Chris Peters (Chris_85_rts)
Registered Member Username: Chris_85_rts Post Number: 36 Registered: 11-2006 Posted From: 66.194.150.45 Rating: N/A |
To back up what Pete said, my 85 6V92TA had a cat in the muffler, and it was pretty clogged up, though I had no symptoms yet. See pics here: http://www.flickr.com/photos/79505093@N00/830971328/ | ||
| Debbie and Joe Cannarozzi (Joe_camper)
Registered Member Username: Joe_camper Post Number: 5 Registered: 10-2006 Posted From: 76.237.140.211 Rating: N/A |
Is there any soot accumulating around the exhaust ports, maifolds or clamps? Check all for tightness. You could also have a leaky aftercooler. On a straight 6 4stroke loss of power and black smoke is a turbo related issue. Haven't owned an 8V long enough to know for sure. Deb and Joe 86XL | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 589 Registered: 1-2003 Posted From: 71.129.84.239 Rating: N/A |
OK, I'm going to do the following, and see where it gets me: 1. Double-check the exhaust for any kind of restriction. Taking the muffler out will require a shop with a lift, so this will be a down-on-my-knees visual only. 2. Get the inspection cover over the turbo off, and make sure the intake has not come apart. That requires partial disassembly of my bedroom cabinetry and removal of the carpet, so I'll need to get to a place where I have some time to do it all in one shot -- can't be driving around with that stuff undone. 3. Look at the bypass valve, if I can get to it. Can someone help me to identify this? Is it attached to the blower, and what side/end of the engine is it on? Getting any further into the motor, like taking the turbo off to see the blower, or worse, taking the blower off to see the aftercooler, is a major undertaking. If that needs to be done, I will likely take it back to Pedco, who did an in-frame on this engine 40,000 miles ago. (I'll have to sneak up on them, so they don't see me coming. My engine bay is *really* tight.) Answering the questions that have come up: I can't say for sure if the problem is sudden-onset or has been building. I have a vague sense that the smoking and power loss have been developing over time (and the heavy grades/thin air coming into Tahoe just brought it into sharp relief), on the other hand, it has not seemed this bad until the last week. I will have to see how it behaves back down at sea level. My exhaust does not have a catalytic in it -- it's a 6" diameter exhaust with a Cowl spiral muffler in it. I have one follow-on question for Niles: you mentioned possible fuel pressure problems -- but I thought black smoke was generally over-fueling, not under-fueling? Do you think it would make sense to change the secondary and see if that helps? I do carry spares for the primary (FuelPro cartidge) and secondary (spin-on) with me (but I don't have a priming pump, which always makes me nervous changing my own secondary). Thanks, everyone. I'll keep you posted here as to what I find. -Sean http://OurOdyssey.BlogSpot.com | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 69 Registered: 8-2006 Posted From: 74.33.52.83 Rating: N/A |
Sean,if your engine is equipped with one it will be on the back of the blower with a 1/4 in hose If you have a manual you can see it at sec 3.4.1 page 3 i will send you a photo if i can make it work | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 71 Registered: 10-2005 Posted From: 67.40.193.222 Rating: N/A |
You can put a ball valve on the inlet to the fuel strainer, pre fuel pump. Close that ball valve to prevent fuel from draining back to the tank, then just change the filter and strainer and fill the new ones with clean fuel before installing them. This will prevent cavitating the fuel pump on the motor and running the batteries flat trying to get fuel back to the heads. | ||
| James Stacy (Jimstacy)
Registered Member Username: Jimstacy Post Number: 70 Registered: 1-2001 Posted From: 75.41.2.78 Rating: N/A |
I don't think it's your smoke problem but doesn't Davco reccomend eliminating both primary and secondary fuel filters when installing a Fuelpro? No priming pump or even priming fuel needed when changing the filter on a Fuelpro. When I had a bad fuel problem I changed mine several times in rest areas with no tools, just a catch bottle, a ziplock bag and a pair of latex gloves. I was told the bottom section replaces the primary filter function and the top filter is comparable to an oem secondary. Jim Stacy | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 592 Registered: 1-2003 Posted From: 71.129.84.239 Rating: N/A |
Jim, I've heard it both ways. I settled on keeping the secondary -- it's cheap insurance. -Sean http://OurOdyssey.BlogSpot.com | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 760 Registered: 11-2004 Posted From: 72.91.107.56 Rating: N/A |
Sean - although your injectors don't rely on 'true' pressure to function - a lack of sufficient fuel pressure to ALL the injectors might cause fuel starvation to ALL the injectors resulting in poor atomization of the fuel at ALL of the injectors - I know this would be as rare as T*ts on a boar hog but it would certainly explain all of your symptoms - I know you have worked this over in your head a thousand times, and this is just ONE shot in the dark - but I have run it around a few times myself and this is the ONLY thing that makes sense to me - or if not there may be some other fuel supply problem - FWIW | ||
| Jack Campbell (Blue_goose)
Registered Member Username: Blue_goose Post Number: 28 Registered: 5-2007 Posted From: 71.101.55.168 Rating: N/A |
One of my friends with a bluebird had the very same sympton and his problem was blown gaskets on the exhaust manifold. New gaskets and all good now for the last 3 years. Problems were not enough turbo boust. It was building boost but not enough for the ecm. If I remeber the boost should be a max of about 26 in. Jack | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 762 Registered: 11-2004 Posted From: 24.129.157.205 Rating: N/A |
Sean to clarify my 'early' morning post - the black smoke your seeing is not necessarily "overfueling" as that would not account for your "loss of power" - the situation that I'm refering to is incomplete combustion due to low fuel pressure/volume in the system (and therefore each injector)which causes each injector to malfunction at less than required pressure/volume and not completely atomize the fuel resulting in black smoke, heat (just watch your pyros), and certainly a loss of power as your DDEC is sending the correct signal for the right amount of fuel but it's not getting fully combusted - Hope this clarifies the nature of my GUESS | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 72 Registered: 10-2005 Posted From: 67.40.193.222 Rating: N/A |
I have sold about 200 Davco units and have at least 8 in my shop that I had to warranty, I am not a big fan I must admit. The 382 does not suffer from the compression seal of the lower bowl like the 234 which was a major weakness, but still had a plastic collar holding on the fuel bowl (tends to cross thread easily and crack with time) and the top port tends to become an air leak. Another issue I have had is when a filter loads up the small buna ball in the check valve can get sucked into the housing completely preventing fuel flow, I have seen this 3 times and each time resulted in the vehicle being towed in.... | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 593 Registered: 1-2003 Posted From: 71.129.206.247 Rating: N/A |
Thanks, Niles. I also got a comment on the blog suggesting clogged fuel filters, so it looks like I will change out the secondary and see if that helps. I know the primary's good, because I can see the restriction (and element) on that one. I don't have exhaust pyrometers -- wish I did. -Sean http://OurOdyssey.BlogSpot.com | ||
| Dale and LaShawn Hendricks (Lamichelle37)
Registered Member Username: Lamichelle37 Post Number: 5 Registered: 1-2004 Posted From: 72.178.75.83 Rating: |
Sean, this may or may not help but, I had a similar problem a few months back on a cummins diesel. I have a raycor fuel filter with a clear bowl. Everything looked good but lost power and would not accelerate past 40 mph. I thought injector pump was bad and had it replaced. Put rebuilt on and had the same problem. Bypassed the filter and everything worked great. Put in new fiter and now it works great. Moral of the story . Even if I have a flat tire, I change the filter. It is the cheapest fix. Rebuilt injector pump was 1300 dollars. A new filter was 10 dollars. | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 42 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
Check turbo fuction as well as by pass low power and black smoke sounds to me like turbo shaft may be coked up . When you shut her down do you let her idle for some time first or just shut it off? Many a good turbo Ive seen were the oil burns on the turbo shaft slowly kills free rotation of the turbo . Take the hose off the turbo inlet and the turbo should spin free . As for some of the other stuff people suggest well chances being filter ect slim | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 43 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
As well all of you that have a bus with a cat converter drill a hole in the pipe leading to the muffler tap it with a pipe tap ,find appropate guage ,stick in this hole . If you have excesive back presssure it will read . Must be very sensitive guage bellow ten psi good luck people | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 595 Registered: 1-2003 Posted From: 71.129.206.247 Rating: N/A |
Dale, Thanks for the additional info. I will definitely change filters as a next step. Hans: Hard to imagine that the turbo shaft is fouled. First off, I have normal boost readings. Secondly, the turbo's only got 40k miles on it. In any case, getting to the turbo is not easy, so I can't just pull the intake hose to check. The "let her idle for some time" advice is out of date. You only need to wait until the turbo has spun down before turning off the engine (and thus the oil supply). That takes at most four or five seconds, and, unless you've pulled into your parking space under heavy load, then hit the kill switch, your turbo will have already spun down by the time you apply the parking brakes. This, by the way, comes direct from Detroit Diesel (Mike Meloche). I always make sure the engine has been at idle for a few seconds before shutting it down -- but that's it. Anything more is a waste of fuel and just adds wear to the engine. -Sean http://OurOdyssey.BlogSpot.com | ||
| Steve N. (N4rsn)
Registered Member Username: N4rsn Post Number: 110 Registered: 2-2005 Posted From: 75.105.156.215 Rating: N/A |
( ------------(The "let her idle for some time" advice is out of date. You only need to wait until the turbo has spun down before turning off the engine (and thus the oil supply). That takes at most four or five seconds, and, unless you've pulled into your parking space under heavy load, then hit the kill switch, your turbo will have already spun down by the time you apply the parking brakes. This, by the way, comes direct from Detroit Diesel (Mike Meloche). I always make sure the engine has been at idle for a few seconds before shutting it down -- but that's it. Anything more is a waste of fuel and just adds wear to the engine.--------------) Why not give Mike Meloche a call? Sounds like he will know everything about Detroits. Steve | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 652 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
The idea to let it idle for a few minutes is if you have been climbing a grade, mountain, or whatever, and then stopping, say at an overview, or rest stop. where the turbo has been working hard and getting real hot. The idle cool down is for the oil to cool down the bearing and cast iron surrounding the bearing enough to keep the oil from coking from the intense heat. eventually the coking builds up enough to block proper lubrication to the bearing. some auto turbos have water cooled bearing assys to avoid this problem. Normal driving shouldn't be a concern, as you usually idle a few minutes before shutting off to get parked or run slow before being parked. People with pyrometers can see that turbos don't run that hot when cruising at reasonable speeds. Maybe 600 degrees normal running, but 1000 to 1100 degrees when climbing a long grade. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 653 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Usually black smoke is from restricted intake or exhaust, or excess fuel, not starving for fuel- exhaust should not black smoke if it can't get enough fuel; should run clean with loss of power. Turbo could be bad, but you said boost is normal or leak in pipes to or out of turbo. Since it is a DDEC, malfunctioning throttle delay, although excessive delay shouldn't make it smoke, since fuel is being held back. Retarded timing could cause these symtoms. I don't know how the timing is controlled on a DDEC, but if the computer controls it. I would definately check that If you can't find anything, you could check what the back pressure is in the exhaust.I think the back pressure is supposed to be no more than 1.8 HG on a turbo engine If this " acts up again " like you said- could be a connection problem in your DDEC wiring. A lot of times poor connections don't throw codes. | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 44 Registered: 2-2007 Posted From: 199.60.181.9 Rating: N/A |
Not meaning to argue apoint but if the turbo is hot the shaft will coke . We have had numerous failures for this . Its not a matter of lubrication its heat . It maybe old advice to you but its still sound advice to an old mechanic | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 763 Registered: 11-2004 Posted From: 24.129.157.205 Rating: N/A |
"Usually black smoke is from restricted intake or exhaust, or excess fuel, not starving for fuel- exhaust should not black smoke if it can't get enough fuel; should run clean with loss of power" Absolutely John - but I have made assumptions that all the USUAL suspects have been rounded up, as Sean has previously had this problem and it has been to some reputable shops, and they are still stumped. The fuel pressure/starvation is the only thing that I could think of that MIGHT account for all the symptoms - let's see if I can give you a visual of what I'm guessing; Go take a standard garden hose, turn the hose bib on wide open, hold your thumb over the end until you can produce a fine "mist", now without changing your thumb position start closing the hose bib. What starts to happen to your fine mist? If you did the same thing with a unit injector what would happen? Sean - as I think about it, isn't there an ECU parameter for low fuel pressure and a signal that is sent to prolong the flow to compensate for the lower pressure? Might be another possibility (Message edited by niles500 on July 19, 2007) | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 596 Registered: 1-2003 Posted From: 67.142.130.18 Rating: N/A |
Update: OK, first off, thanks for straightening me out on the turbo cool-down issue. Rest assured I never turn the engine off when it's hot -- I always park and high-idle it until all temps come down to normal, then turn high-idle off, then shut down a few seconds later. That being said, I've seen guys idle for five minutes before shutting down after normal driving because someone told them the turbo would be damaged otherwise. The suggestion to call Mike Meloche would be a great one -- I know few people who know more about two-stroke Detroits, especially in coach applications. For a long time, Mike was the go-to guy for us bus nuts. Unfortunately, he retired a few years back (AFAIK), and I have not seen or heard from him since. Too bad, really, because this kind of thing was right up his alley. Now I don't have any contacts at Detroit that I can call who know anything at all about two strokes or early DDEC. Anyway, on to the update: yesterday I changed out the secondary filter. I pre-filled the new one with fuel (something that engine mfrs generally advise against) and made the swap as quick as I could, and did not lose prime. The bad news is that it does not look to have helped with the problem. Upon further inspection, I can see that there is perhaps more restriction in the exhaust than is good. A 6" round exhaust is roughly 28 square inches of cross-section, and, on my coach, that transitions to a rectangular duct about 15" x 2" (30 square inches). Part of that duct is flattened in the center and I would estimate that the cross-section at the narrow spot might be as small as 21-22 square inches. That would be almost as small as a 5" round exhaust, which was not uncommon on this size motor, but it does represent a 25% reduction from "normal" on my bus. I guess that the combination of that 25% restriction and the thinner air up here at 6,200' could be the whole issue, but, subjectively, it "feels" worse than that. Opinions? -Sean http://OurOdyssey.BlogSpot.com | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 655 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Interesting thought Niles, but I still stand by my opinion. Also, I live near two steep short hills that I pass every day on the way back and forth to work for 22 years. I've probably seen 10 or 12 trucks over those years only make it about 1/2 to 2/3's of the way up the hill before dying; never saw black smoke when they quit. Now they may have had some other problem, but I doubt it as the scenario was always the same. The two hills ARE short and steep on US route 22 near Huntingdon, Pa. Now as I don't have familarity with DDEC. MAYBE you could be right. Just my opinion, of course. Also, I've driven diesel cars and trucks, and since 84 and have changed many fuel filters when needed. Always didn't blow black smoke when plugged. I was cheap- waited till they got pretty bad till I changed them since the commute wasn't that long. Had a couple of times a bicycle could have beat me home because I thought could go one more day. | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 45 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
So now let me say everyone belives in the almighty code reader . Well lets take it a throw it out for a moment . The only thing that case black smoke is to much fuel and incomplete combustion . So lets see chances being fuell system related since the computer meters the fuel chances are slim this is the cause . So this could be two things timming related , the comp takes its signal from the timming reference sensor . If its late (after tdc) then the fuel is injected it will have an incomplete burn due to lack of compression . So baring that the other is turbo boost (air volume in the combustion chamber) So what could cause this ,plugged exhaust , plugged air filter, turbo malfuction ,blower bypassing . The first place id look is the blower by pass . then filters , exhaust restriction . then turbo . You state it new ,well its been my experance that new parts fail too . Changing fuell filters is awaste of time and money . Check your fuel pressure not with a code reader with a manual guage . remember those tools ? | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 601 Registered: 1-2003 Posted From: 67.142.130.19 Rating: N/A |
Hans, I think I have now ruled out plugged intake and plugged exhaust -- I've put a new air filter in place, and spread open the slight restriction in the exhaust duct. I can't get to the turbo, so that will have to wait. But the computer says I am getting ~21psi of boost under load up here at 6,000', so the turbo "looks" good, at least to the computer. So that leaves the bypass, which I am still looking for (anyone have a photo?). Since I see black smoke mostly before the turbo spins up, that suggests the valve is stuck open, rather than closed, right? I don't have a fuel pressure gauge (hey, I'm not a diesel mechanic -- just an operator), nor does the DDEC report this parameter (only rate, in GPH). But help me out: what would I learn from reading the fuel pressure? -Sean http://OurOdyssey.BlogSpot.com | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 46 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
Hey look for the by pass at the bell hosing side of the blower . There is usally a line running to it small diameter hose . Ninety percent of the times its the small rubber hose that runs to this . We use a small diamater I beleve One Quauter inch dia hose silicone of a high heat restance to replce it . If I remeber it comes from the turbo back side to the blower as well there is a second one there for the map sensor I will look in my book tommorrow .see if I can find a picture for you . Fuell gage tells you if your pump is doing what it should so get a oil presure gage any thing and plum it in your fuell system . sorry about the spelling mistakes | ||
| Christopher Goodwin (Cgoodwin)
Registered Member Username: Cgoodwin Post Number: 83 Registered: 10-2005 Posted From: 71.212.87.83 Rating: N/A |
I do not know this motor and can only speculate. ON other diesel turbo motors I do know black smoke pre spool-up is common if the atmospheric compensator is out of adjustment, called the ALDA on mercedes motors it raises or lowers the volume of metered fuel dependant on atmospheric pressure. I do not know what system the DDEC uses to compensate for thinner air. Typically above 4000' I see a 20-30% loss of performance in the early IDI engines I work on, not pretty. Leaking air in the intake can also cause these issues, any leak of charge air after the turbo will cause lack of power and black smoke. I do not know how your boost is regulated but on the motors I work on the turbo spools and creates charge air or boosst, when this reaches a limit which can be adjusted the waste gate opens and spills exhaust to atmosphere limiting the turbo. Often the waste gate is controlled by a pressure line from the intake manifold usually with an adjustment. I have seen these lines clogged with crud, I have seen waste gates stuck open or partially open and have seen them stuck closed where boot increased until it blew the intake open at a clamp, then there was insufficinet boost for the motor and the turbo was spinning so fast the bearing went out... So in my opinion either the boost is too low due to a leak, worn turbo or imroper turbo control. You may be overfueling due to some lack of communication between the DDEC controler and whatever it uses to sense air OR you are simply driving a vehicle at high altitude which is adjusted for lower altitude and is not capable of adjusting itself due to its design or a malfunction. Of course none of this really helps... | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 47 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
Sorry sean its not a map sensor its the turbo boost sensor your looking for it goes from 0 to 5 volts and tell the computor what boost figure you got so it can set the fuel . Hope this helps | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 48 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
test | ||
| Hans (Buellhans)
Registered Member Username: Buellhans Post Number: 49 Registered: 2-2007 Posted From: 205.250.41.167 Rating: N/A |
MY BUS  (Message edited by buellhans on July 22, 2007) | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 606 Registered: 1-2003 Posted From: 67.142.130.48 Rating: N/A |
As I promised, I am posting an update here on our problems with low power, excess heat, and black smoke. Today we visited W. W. Williams in North Las Vegas. Unsurprisingly, they are now down to only two technicians qualified on two-stroke products. We got Hank, who seems to really know his stuff. While I was standing around, the maintenance supervisor for Clark County Fire came over to chat with me about the coach (he was there to pick up a fire apparatus), and had good things to say about Hank's familiarity with 8V92's (which were very popular in fire apparatus prior to Series 60). Hank could find nothing wrong with our coach, except for a dirty radiator. I have to confess to some embarrassment about not having noticed this myself (and no one here mentioned it either), and the price I paid for that gaff was to pay Williams over a C-note per hour to pressure-wash the radiator, which I could have done myself for free. And, while that may have accounted for some of the temperature issues, I don't think it fully explains the low power or excessive smoke. Hank also tried disabling injectors one by one to see if the smoke changed at all, but it did not. Otherwise, his assessment was that the engine was mechanically sound. He did not feel there could be a turbo problem with the boost readings we had, nor did he think it could be the bypass valve without other symptoms. I did have them pull an oil sample for analysis, which should come back tomorrow or maybe Thursday. That will, at least, tell me if I've sucked any dirt into the engine. With no further diagnostics to run, they buttoned us back up and we escaped for less than $300. I feel a little better about continuing to drive it in this condition, but I don't think we've solved the problem. Before I spend any more money in the shop, though, I am going to try to burn through the last 170 gallons of this batch of fuel, and see if things improve after taking on a fresh load. It's possible that the fuel I've got now has the wrong cetane number, or some other non-obvious deficiency. I'll post more if I learn anything from the oil sample, or if we get any closer to solving this. -Sean http://OurOdyssey.BlogSpot.com | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 667 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Are those oil sampling people able to do a sample check on the fuel? | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 612 Registered: 1-2003 Posted From: 67.142.130.11 Rating: N/A |
And the answer is (drum roll, please): The engine is dirted out, for the second time in less than 100,000 miles. More detail is on our blog at this post: http://ourodyssey.blogspot.com/2007/07/good-bad-and-ugly.html (Read the sections labeled "The Bad" and "The Ugly"). The short story is that the oil sample came back, and it looks like we have dirt in the engine, as I was beginning to suspect. Our oil consumption has gone up, and the low power/white smoke on start/black smoke on load is consistent with blow-by past the rings. We'll need eight new cylinder kits, a turbo, rod bearings, and any number of miscellaneous parts. I am guessing around $10,000 to get us back on the road. We'll be going either to Stewart & Stevenson in Pueblo, if we can even make it that far, or back to Pedco, who in-framed our engine the last time it was dirted out. I won't know until they start tearing into it where the problem occurred -- either something wore a hole in the intake, or the intake plumbing just came apart somehow. If you are curious, I will be posting follow-ups on our blog (not here). -Sean http://OurOdyssey.BlogSpot.com | ||
| niles steckbauer (Niles500)
Registered Member Username: Niles500 Post Number: 764 Registered: 11-2004 Posted From: 72.91.107.56 Rating: N/A |
Sean - I'd be asking for a CREDIT on your previous bill - from who? - you'd have to decide - but that is BS - you've gone what 40K? - there's no reason for this - I would never have guesed this - what if a rebuild doesn't work? - I'd want a second opinion - JMO | ||
| Sean Welsh (Sean)
Registered Member Username: Sean Post Number: 615 Registered: 1-2003 Posted From: 67.142.130.11 Rating: N/A |
Well, Niles, the last folks to even touch the intake system (other than filter changes, which I do myself) was Pedco. That was during the last in-frame. When I talked with Pedco owner Virgil Cooley this evening to ask how this could have happened after his crew took pains to put it on correctly, he suggested that (1) something as simple as a braided hose might have fallen against the intake plumbing and abraded through it or (2) off-road driving (of which we have done some, but not much) might have worked a clamp loose, causing the intake to come apart. The problem is that the whole intake system, other than the air cleaner housing, is buried in a very tight engine bay -- it's impossible to even see it without dismantling part of the bedroom and removing an access panel. Until we get in there, we won't know how it came apart. If I take the coach back to Pedco to have the new work done, I would hope that Virgil will step up to the plate to cover at least part of it, if it looks at all like the problem was related to workmanship issues on the last rebuild. But, as you know, that can be very hard to determine. If the intake hose is just loose, with the clamp dangling, is it because the mechanic that installed it didn't tighten the clamp properly, or is it because the air cleaner bounced around in its mount when I plowed through "the big puddle"? It will likely be impossible to say. In any case, it's a good bet that if I don't take it back to Pedco, there won't be any possibility for any credit, so that's one factor weighing in favor of going back there. OTOH, if I felt certain that this was a screw-up on their part, then I would be foolish to want to go back there to have them do it again. Anyone else here feel the same way Niles does? -Sean http://OurOdyssey.BlogSpot.com | ||
| Debbie and Joe Cannarozzi (Joe_camper)
Registered Member Username: Joe_camper Post Number: 11 Registered: 10-2006 Posted From: 76.223.67.232 Rating: N/A |
I often wonder how much of a discount or deal DD gave prevost, the whole industry for that matter, to exclusivly run these boat ankers for as long as they did, and continue this with the 60 series. Being a trucker by trade it was amazing to me at the lack of miles a 2-stroke could go on average, pittiful at best. Our 86XL had a factory rebuild at 110000, by the previous owner, and that is not uncommon for these from what I have seen. We have 214000 on it now and other than loosing some oil out the smaller down tubes when cold, even on high idle,, significantly more on one side than the other, we experiance no loss of power yet. I have come to the conclusion, and hoping, that a novice owner, that is also the biggest percentage of owners, seeing those tubes leaking, panics, and does a rebuild where a 2-stroke that is doing this could probably go a LONG LONG way after this point. I intend on finding out and will be happy to take back all bad comments about the DD if this is the case. When we turn Chicago to Fla. in December I'll warm it up and before leaving, shut it down, and drain the canisters we've instaled on those tubes. It will produce no more than a trace of oil after that point. Another thing that kills me is the soot that RAPIDLY accumulates in the oil on ANY detriot motor. I can change oil in a cat motor and it still looks like honey 7 and 8 thousand miles later. The Detriot motors turn BLACK instantly. To make a comparison we own a Cat 3406 with better than 900000 on it and it doesn't go through 1 gal. in 10000 and has never been apart, this is not uncommon, it is the norm. Once again, I will be happy to admit my ignorance, how many folks out there have gotton over 300000 on a 2-stroke without having it apart, how many have gone a million? We bought our bus cause it was the most camper we could get for our money and we really like the way it looks. We are going to keep it because of the way it rides and the quality of the construction of the shell, and by the converter. We will be putting up with the long list of shortfalls, by the manufacturer, with the motor being near the top of that list. Did I forget to mention the wonderfully LOW oil pressure at idle? Newel has it figured out, the Cat C-15, that's the ticket laddy. With an attempt to end this post on a good note, the 8-V is the best sounding deisel out there, at speed. | ||
| Henry 96A3 (Hank)
Registered Member Username: Hank Post Number: 107 Registered: 11-2005 Posted From: 69.129.126.133 Rating: N/A |
Joe_Camper, I've wondered the same thing. Why were 2 stokers so popular on buses? It seems that if there was an engine out there that could reliably give you up to a million miles, why would anyone use a 2 stroke that gives you 350K and uses gallons of oil? I know this has been addressed a little in the repower discussions but in terms of why they were originally spec'd, what gives? Was it reliability maybe? I'm curious too. | ||
| Debbie and Joe Cannarozzi (Joe_camper)
Registered Member Username: Joe_camper Post Number: 12 Registered: 10-2006 Posted From: 76.223.67.232 Rating: N/A |
I'm tellin ya detroit was almost giving these things to the manufacturer for the HUGE potential for future parts and service revenues they knew would be comming. | ||
| Henry 96A3 (Hank)
Registered Member Username: Hank Post Number: 108 Registered: 11-2005 Posted From: 69.129.126.133 Rating: N/A |
If that was their strategy how is it that they've been around so long with so much apparent success? You'd think that people would catch on after a couple of decades and switch to something else once they realized the long term economics weren't in their favor. It wouldn't be that big of a deal to spec a different engine? It still doesn't make sense. They were widely used throughout the industry-boats, generators, heavy equipment and are still the standard for DE locomotives. Many here have speculated that were it not for the EPA, they'd still be used. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 674 Registered: 10-2003 Posted From: 71.58.117.21 Rating: |
Joe Camper- I think that you should rip out your worthless boat anchor Detroit and replace it with one of those wonderful Cats. | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 77 Registered: 8-2006 Posted From: 74.32.88.185 Rating: N/A |
Joe,Newell needs that 600hp Cat because their p2000i weighs 54000# and averages 4.9 miles to the gallon and i do not know about other buses but you could get other engines in the Eagle model 10 and 15 the model 20 was a 6v92 only | ||
| Debbie and Joe Cannarozzi (Joe_camper)
Registered Member Username: Joe_camper Post Number: 13 Registered: 10-2006 Posted From: 76.223.67.232 Rating: N/A |
Hank, surplus is what your describing, makin my point. John, Don't have the time or recources to do that engine swap. It is not my intent to offend or anger with opinion, just throwing them out there. We take care of that 8-V with the same passion as the rest of our stuff. Luvrbus, You do not need 600hp to pull 54000. In fact I think that IS a little overkill. They should offer the C-13 or even the C-11, especially with the trends of fuel prices. Our 3406B is 350hp and it pulls 72000, our legal max gross, just fine. That 6V is still a detriot 2-stroke. I only get 5mpg at 65mph with my 8V(a very liberal estimate) and our XL is only 42000 loaded with gear full of fuel and water. The folks I know with that C-15 motor in trucks are getting better than that at 80000. Where did you hear of those low numbers? Still no responce from anyone with a 2-stroke that got 300000 without having it apart. (Message edited by Joe camper on July 27, 2007) | ||
| Luvrbus (Luvrbus)
Registered Member Username: Luvrbus Post Number: 78 Registered: 8-2006 Posted From: 74.32.88.185 Rating: N/A |
Tom C on the Mak board posted he got 500,000 from a 8v92 in his truck and i know people that have over 300,000 on 92 series.i got my information on the C15 in Newells from the Feb family motor coaching magazine on testing of the Newell.i am sure if you started a new thread on the subject you would get a lot of diffrent answers (Message edited by luvrbus on July 27, 2007) | ||
| Debbie and Joe Cannarozzi (Joe_camper)
Registered Member Username: Joe_camper Post Number: 14 Registered: 10-2006 Posted From: 76.223.67.232 Rating: N/A |
Hopefully we will be able to boast of the same results. I will be happy to eat my comments if so. What is the Mak board? | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 677 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Just how many of these guys do you think put 300,000 miles on their coaches? I've never seen a diesel engine that doesn't turn oil black in time. | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1110 Registered: 5-2001 Posted From: 65.74.67.130 Rating: N/A |
Joe Camper, the black oil issue is not all that hard to deal with. A half micron toilet paper filter does the job on ours. Our boat anchor gives us 10 mpg a good part of the time, so I think that there are some other things involved in the low mileage that you are getting. Driving one of these for economy can take some getting used to. Tom Caffrey PD-4106-2576 Suncatcher Ketchikan, Alaska | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 80 Registered: 5-2007 Posted From: 64.40.223.242 Rating: N/A |
Joe, The MAK Board is one of the other main bus conversion discussion groups. Go to www.busconversions.com you will find it there. Paul |
