| Author |
Message |
Mark R. Obtinario (Cowlitzcoach) (204.245.228.236)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 10:16 am: | |
Hi all,
I have a Thomas Saf-T-Liner ER with a CAT 3208T that I am having fuel problems. What is going on I am not real sure so any suggestions are greatly appreciated.
Four times now the engine has quit and has refused to restart. Three times I have removed the stop solenoid and was able to restart the engine. Two of the times has required repriming of the injection system.
Now the fourth time I am really stumped because the stop solenoid was removed when the engine quit running. With the stop solenoid removed I can't think of any reason that would cause the engine to stop (Yes the tank has fuel. The tank has at least thirty gallons in it.) In all cases, hand pumping the primer pump had fuel running out of the bypass within a couple of pumps.
Normally, the engine starts right up. Rarely does the starter even have to make a full revolution to get the engine started. Now when you crank it over you get nothing. Not even a breath of smoke out of the exhaust.
Does anyone have any ideas?
Thanks for you help.
Mark O. |
Mark R. Obtinario (Cowlitzcoach) (204.245.228.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 11:50 am: | |
P.S. The bus is pre-electronic. With the stop solenoid removed the bus should keep running even if the key is turned off. Right now, even with the key on the bus doesn't want to run.
Also, the first time the bus quit the bus was going down a steep hill. The second time it was running on the flat. The third time it wouldn't restart in a level parking lot. The fourth time it was going up hill.
The fuel filters have been changed.
The air filters are not restricted.
The solenoid has been changed twice.
Any ideas?
Thanks.
Mark O. |
John that newguy (199.232.240.182)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 12:12 pm: | |
Hmmm.... Would you like an opinion from a guy that knows little?
"(Yes the tank has fuel. The tank has at least thirty gallons in it.)
In all cases, hand pumping the primer pump had fuel running out of
the bypass within a couple of pumps. "
First, I'd fill the tank. Second, I'd see why I have to pump the primer
so many times after the start sequence didn't prime it.
With the absence of the auto-shutdown system, the only thing
left is the supply of fuel. If it's getting air bound (drawing air),
you should see it in the exhaust as white smoke while running
normally. If it's being choked up due to a plugged line, or some
obstruction floating in the tank, it would do as you are describing.
Or at least, that's what -I- would assume.. |
Mark R. Obtinario (Cowlitzcoach) (204.245.250.143)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 12:30 pm: | |
The hand primer only brings fuel up to the pump.
If you get air in the lines between the pump and the injectors you have to bleed the air out at every injector.
While running normally it rarely has any smoke after start up except for when you are running really hard and get some black smoke.
I am beginning to think you may be right about something in the tank. I hope so because that is bound to be less expensive than a new pump.
Thanks for the input.
Mark O. |
jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 1:36 pm: | |
you have a fuel line/filter base/something between the fuel supply and the fuel transfer pump that is allowing air to enter the lines.... the 3208's fuel transfer pump is an internal gear-rotor type pump, located in the front part of the fuel injection pump...something is allowing air to enter the fuel system on the suction side of the transfer pump...like a bad seal on line connection, a cracked line, maybe some of the flexible hoses have a crack that is open only once in a while...btw, i worked for cat, now i'm at an independent... you can email me at jimcat2@webtv.net if you want... |
Gary McFarland (Gearheadgary) (68.250.96.41)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 1:56 pm: | |
It's common to have an additional "Lift Pump" at the tank that "Pushes" fuel to the engine.
this is a commond add-on for bluebirds.
Glad to see I'm not the only one with a kittymotor on the list.
Gary |
John that newguy (199.232.240.182)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 2:12 pm: | |
Hmmmmmm.... "Lift Pump"
If that silly thing goes sour, wouldn't that cause the engine to
be starved to death if the tank was 1/3 full? |
Gary McFarland (Gearheadgary) (68.250.96.41)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 2:18 pm: | |
If you have a flat tire you'll be stuck too.
Gary |
John that newguy (199.232.240.182)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 3:25 pm: | |
Yeah - really, Gary.
Leave it to you.
I meant... If that pump fails to do what it should, couldn't his
problem be with that pump and wouldn't the problem be
more pronounced with 1/3 tank?
(friggin tough audience here!) |
Dave (65.199.159.123)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 4:58 pm: | |
it could be a bad check valve,I had that same problem when I bought my coach.Dave |
Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 7:05 pm: | |
On our old cat engine(3160 IIRC), we didn't have to crack the injector lines to bleed them.
When we operated the hand pump with the fuel solenoid on, the hand pump got rid of enough air that the engine would start right up.
That was one feature I really liked about the engine. By the way, it was not in a bus; this was in an old concrete boom pumper.
I remember that if the fuel solenoid was turned off, the hand pump would build up enough pressure in the filter that the solenoid would not open the fuel valve when it was turned on. One time, it even blew the fuel filter gasket loose.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
For what it's worth. |
jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 7:33 pm: | |
beg pardon tom, but cat doesn't use a "fuel solenoid" like cummins does... caterpillar design uses a plunger-type solenoid (either electric, oil, air, or manual) to move the fuel rack to or from "no fuel" in order to either kill or allow the engine to run... and the 3100 family (3116, 3126, 3176, 3196) doesn't have individual external lines like the 3200, 3300 and 3400 engine families have...the hand primer pump is used to prime the fuel system (filters, lines, injection pump body, and transfer pump).... the individual external fuel injection lines are "cracked" open to allow trapped air to escape...so if mark's engine is getting air in the fuel system, its because of a leak on the suction side of the fuel transfer pump...the leak can be in many forms-- suction tube in the tank, loose lines, fittings, filter bases.. lotsa stuff to look at and check out... |
Soulin Heath (66.82.50.1)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 9:22 pm: | |
I have a Cat 3208 in my 65 gillig. There is an electric fuel pump that draws the fuel from the tank. It is after the first (primary fuel filter) check to see if your bus has an`electric fuel pump somewhere between the fuel tank & the engine. If your bus has 2 fuel tanks than odds are it has 2 electric fuel pumps, 2 primary fuel filters, 2 seprate return lines & a switching valve. Any air whatsoever and well you know the results. check all conections @ fuel lines, & filter connections, are they tight enough? any flaws, kinks or cracks in any of the fuel lines? any water or crud in the fuel tank? 2 tanks = 2 X the liklyhood of water,air, leaks & crud. If you have an electric fuel pump (I don't mean the injector pump) than it is best to turn it on before primeing the delivery system. Also a couple of times my bus wold not start after parking it when it got a little hot (not overheated). After 3-4 times of that I discovered that I was not tightening the prime-pump quite hard enough it was drawing air when the fuel cooled & contracted just enuogh to draw some air. although I don't think that is what is hapening in your case but, You might be in the same siduation sometime down the road. Just speaking from my tiny bit of knowlage. S.M.H. |
Gary McFarland (Gearheadgary) (68.250.96.41)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 17, 2004 - 9:50 pm: | |
I would consider rigging a small daytank to feed the engine supply.
If the problem dissapears, you can stop looking at the engine, and concentrate upstream I think.
Divide and conquer
Gary |
Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 19, 2004 - 12:12 am: | |
Jim, I just broke out the shop manual on our 3160, and it does show a solenoid operated fuel valve, all right. After looking at the drawings for a bit, I remembered why that engine doesn't easily get airlocked.
It doesn't have delivery check valves at the fuel pump, so hand priming pressure is enough to make fuel flow right by all the plungers that are down in their bores.
Once the bores are clear of air, they have no problem pumping air out of the injector lines and that's why that engine can be bled by hand pump alone, at least enough to start it easily.
The engine does have individual fuel lines until they reach the cylinder heads, where they tee together for the return flow.
I notice that you did not mention the engine model that I was referring to. Could you have been thinking of a different engine?
Tom Caffrey PD4106-2576
Suncatcher |
jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, September 19, 2004 - 10:55 am: | |
i'm not realy sure what a 3160 is...the 1160 was a predecesor to the 3208..and i've not seen a cat engine (one really made by cat, not something like a perkins that cat bought the rights to) that had return lines on the individual injectors...i sent you a email..let's visit sometime..jim |