BNO BBS - BNO's Bulletin Board System
TOPICS => THE BOARD => Topic started by: pixmanbus on March 25, 2014, 04:48:11 PM
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Hi Guys! and Gals?!
Here is a fun topic.
Can you list for me any vehicle that would have run with a Detroit 6v92 using DDEC1.
I have an '87 MCI Crusader II converted that I just bought. The DDEC 1 is bad on it. The engine is good. I like the bus and want to keep it. I can't afford to upgrade to DDEC II,III, etc because my mechanic's labor would be too much. So I am desperately looking for any way to come up with a good DDEC 1. I'll buy an engine or a whole vehicle to get one. Then re-sell the vehicle or scrap it. It can be anything up to another bus if it's the right price and can be driven. Rusty, crashed, I don't care.
Please let me have your ideas and advice. I got stuck on this purchase and am trying to dig my way out.
Thanks in advance,
Robert
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I think you should read this.
http://prevostcommunity.com/forum/threaddetails.asp?Category=Chassis&ThreadID=2089
Ken
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Buying a DDEC I on purpose would be like cutting you finger off because of a hang nail 8) buy a mechanical if the III is out of your range,the DDEC I is easy to convert back to a mechanical it has the standard cams fwiw
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I am in total agreement for going with the mechanical DDC, first that is the only setup I am familiar with as I do not speak computer lingo, while I do enjoy my computerized ISM CUmmins, I am clueless to its many things as I am clueless to the DDC computer DDEC's, yes I am sure they are great WHEN they work, know of several very happy campers with the 6V-92 DDEC what ever version, 350 hp.
If I had a6V-92, it would be a 450 hp, we have done many of that setup for generators, and load bank (Dyno) at the 450 hp level for a few hours, no issues.
Some things improve with newer methods, but I am stuck in the DDC mechanical game, too old to change now. ;D
Dave M
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Dont know if they still need a DDEC1 but I know where there is a good one he would sell for 1/2 price of a new one.. it on a 6v92 they have removed..
Thanks
Steve
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There are 2 boxes for the DDEC 1 does he have both ?
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Dont know... but if he as the engine I would think it would be complete.. it will be monday before I can talk to him... but will post on what he has..
Thanks
Steve
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Well I found a DDEC 1 EDU which is what I was looking for. My mechanic is getting bad readings that seem to say the EDU is bad. I have found one now and can swap it out. If the codes don't change I will know the problem is somewhere else. Then I will have one to sell for someone else who needs one and still have a broken bus.
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Pixman,
I have read the entire thread, both here, and on the Prevost board, and I would like to offer the following as a way to figure this out.
1. Turbos work by having their impeller blades in the exhaust gas stream, and using that energy to turn the compressor blades on the other end of the same shaft, to force more air into the engine, so more fuel can be injected, and PROPERLY burned.
2. At lower engine speeds, and throttle settings, there isn't enough exhaust gas produced to turn the turbo fast enough to show pressure in the intake manifold.
3. Maximum turbo pressure is produced only at full fuel injection rate, at very near maximum engine RPM, which are the conditions required to produce maximum exhaust gas flow! So, if you floor the throttle with the trans in neutral, the engine will go to max RPM, but you will have NO turbo pressure, because the fuel injection rate is only the few percent necessary to run the unloaded engine.
4. DDEC's whole purpose is to reduce emissions, and it does this by regulating the fuel injection rate and timing, and it also watches engine temperature and oil pressure, turbo pressure, RPM, throttle setting, AND listens to electronic transmissions.
5. Black smoke is unburned fuel, which is usually the result of too much fuel being injected for the amount of air available to burn it. It can also be the result of improper injection timing, low compression due to mechanical problems, or worn injectors not atomizing fuel properly.
6. ELECTRONIC INJECTION SYSTEMS RELY ON ELECTRIC SIGNALS! Does that mean that faulty signals will result in poor performance? Don't bother answering...
What if the DDEC thinks you don't have enough turbo pressure? It will only allow a reduced fuel injection rate to avoid smoke and smog until the pressure comes up. Yes, I know you have changed the turbo and the boost sensor, but have you checked the voltage level of the boost sensor AT the DDEC? And specifically the voltage level between the turbo pressure input wire and the ground reference the DDEC boxes are using!!!!!
Throttle position is by wire... Same thing, if any of the connections between the TPS and the DDEC box have a high resistance, DDEC won't be told that you have your foot flat on the floor, and you won't get full turbo boost because of less than full fuel inj. Sound like your problem?
Your installation of a vacuum sensor on the intake was a good idea. It indicates the amount of air the turbo is moving, and now it shows that the turbo is not doing as much as it once was. Turbos are quite obedient, they do what they're told, when they get lots of exhaust gas, they put out lots of boost.
When you don't inject as much fuel as you did, or it is not injected at exactly the right time, you don't get as much exhaust gas, the turbo doesn't turn as fast, you don't get as much boost, the boost sensor reads low, AND THE DDEC DOESN'T INJECT ANYWHERE NEAR AS MUCH FUEL, because it thinks it is preventing smoke!
DDEC looks at your engine temperature, if it thinks it is getting too warm, it will reduce the fuel, (fuel makes heat right?)
DDEC also measures oil pressure in relation to engine speed. At idle it will let the engine keep running at 8-10 psi, at full speed, it will want at least 30 psi, our Detroit gurus here can tell you exactly what the minimum pressures are.
There are fuses in the injection circuit in the cylinder heads. Have they been checked, and are the connections clean?
JAKE, which is the slang for Jacobs Engine Brake, will raise engine temperature slightly when it is being used. On an electronic engine, the JAKE timing is by the DDEC, so if it is not retarding like it was, it is not getting the proper signal from the DDEC. Black smoke during JAKE operation would indicate fuel being injected during braking.
My area of expertise is locomotives, a new EMD is just a 16V710, instead of a 6V92, but it won't work right with an open ground either. I feel very strongly that your problem will be another open or high resistance ground, besides the one mentioned on the Prevost Board, or an open or high resistance sensor circuit. I feel very strongly that you are giving your DDEC bad information, and it is responding accordingly. If the loose or high resistance connection is at the box, changing it would fix the problem by accident, but I don't feel that throwing expensive parts at it without a reason is the answer.
It takes fuel to make power, when was the last time the fuel filters were changed, and what is the fuel pressure under full load? You will have to put a tee on the output line of the fuel pump, and run a piece of fuel pressure tubing up inside the bus with a mechanical gauge so you can read the pressure at full throttle under full load.
It is my understanding that some electronically controlled transmissions send an instantaneous power reduction signal to the ECM during a shift to save wear on the clutches, what if your ATEC Trans is sending the wrong signal?
With your DDEC giving you the dash gauge readings, you know some of what the DDEC is seeing. Does the oil pressure increase properly with engine speed, and does the temperature warm up to the thermostat setting, and not go up too much more when going uphill?
A quality digital volt-ohmmeter is an absolute necessity, along with a small screwdriver and nutdrivers, etc to remove ALL of the electrical connections to your DDEC boxes, one at a time. Sand and clean all of the terminal rings and the washers, then pull on the wires to make sure the connection is good between the wire and the terminal, then replace it and go to the next one. Pull the large plugs out, and scrape the pins carefully with a small screwdriver to improve the connections. Pull the battery switch first!
Write back and tell us what you find, please.
G
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My money is on he got a shot of 24 v the 1 and 2 or 12 volt only,I doubt the ATEC is a problem like the DDEC 1 it requires a cab translator to work with the DDEC 1 it doesn't have much control if any unlike the WTEC
His biggest problem is having a DDEC 1 not much you can do with that beast it has no clock so just disconnect the power supply it will reset if it has a code problem I feel for the DDEC 1 owners they can be a nightmare
good luck
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I would convert back to a mechanical engine. As you've found, all the neat features of an electronic engine will negate any fuel benefit if you let out the smoke from the electronics.
When I had my old truck, my alternator went. I was able to run for two days without the alternator (never shut off the engine) without worry about running out of battery.
450hp for a generator 6V-92TA running at a constant 1800rpm is totally different then trying to run that kind of power in a bus that is pulling down in the RPM towards 1200rpm before shifting. On a mechanical, I wouldn't go above 90 injectors. With DDEC, Detroit built Jay Leno an engine for his Flx at 435hp and 1350lb/ft torque. Good Luck, TomC
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Agree 1200 rpm with the 450 hp setup would be stupid, would use the 10 speed and normal DDC 2 stroker 1800-2400 rm range.
Gotta know everone is crazy, its just who is judging who ;D
Dave M
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On the DDEC1 he showed me the box and it has 5 or 6 plug-in on it. He said it only had one box... That all the info I have at this time.
Steve