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safehaven · 12-20-2013, 09:30 PM

Newby here folks. We have a 1996 Allegro when I start the engine it runs for a few minutes and then just shuts down. Gauges all show normal. Is there some kind of interlock safety device or something shutting me down. How can I troubleshoot this problem. Appreciate any and all advice. Thanks

spike45 · 12-20-2013, 10:07 PM

Quote:

Originally Posted by safehaven

Newby here folks. We have a 1996 Allegro when I start the engine it runs for a few minutes and then just shuts down. Gauges all show normal. Is there some kind of interlock safety device or something shutting me down. How can I troubleshoot this problem. Appreciate any and all advice. Thanks

Does the start immediately after this? Or do you have to crank for awhile before it fires?

Genset · 12-21-2013, 01:42 AM

Also, I would assume a 96 model might be a mechanical, non electronic engine and the engine model would help me get on the right page.
Dave M

safehaven · 12-21-2013, 02:23 AM

Thanks gentlemen, it is a 300 cummins 6 turbo the model for the coach is vc-26 29 rdrr. It starts and runs for a couple of minutes then just quits no matter if you pump accelerator or not. Then immediately starts again and does the same thing again, and again and again. Thanks

NHRA225 · 12-21-2013, 04:47 AM

Start by looking at the Fuel Shutoff Solenoid, at that age it could be weak.If your not mechanically inclined have someone with experience look at it.
Your Engine Model would be helpful !

Wizard · 12-21-2013, 05:42 AM

When was the last time the fuel filters was changed. Sounds like one of them may be clogged

94-Newmar · 12-21-2013, 05:52 AM

I'm with NHRA225 on this one. Being a '96 it's most likely an (94-95) 8.3C all mechanical. The fuel solenoids are a common item to fail with that much age on them. The solenoid is vertically mounted/located at the injection pump itself with a linkage attached to pump's fuel lever - you can't miss it. There are 2 different electrical coils in them (3 wires; 2 hot, 1 ground), 1 for START and 1 for RUN - when you turn the key to START one stronger coil is used to initially pull the solenoid closed and when you release the key to RUN another weaker coil is used to actually hold the solenoid closed.

To prove one faulty you'll need two people, one to start the engine and another to watch the solenoid operate. Watch it carefully as the key is moved from RUN to START and from START to RUN. You'll see the actuator move the fuel lever on the injection pump. Watch it closely until the engine dies again and note if the solenoid rod ever moves from the retracted to extended position. The difference between running and dying is only about a 1/4" of travel of the rod.

Here is a pic of old style and new style fuel solenoids:

2nd, If all appears well with the solenoid "holding" the fuel lever open then you could have a lift pump failing. Engines of this era used a mechanical lift pump to maintain fuel prime/delivery to the injection pump. Unfortunately, this is a bit more complicated to troubleshoot.

3rd, it's possible the injection pump itself is failing. On my '94 8.3C I had to have the injection pump rebuilt. It would die randomly when idling but would always restart right away.

It's most likely the fuel shutoff solenoid as described above and by NHRA225 - I'd certainly start there.

H. Miller · 12-21-2013, 06:22 AM

Quote:

Originally Posted by safehaven

Thanks gentlemen, it is a 300 cummins 6 turbo the model for the coach is vc-26 29 rdrr. It starts and runs for a couple of minutes then just quits no matter if you pump accelerator or not. Then immediately starts again and does the same thing again, and again and again. Thanks

None of the information given is the "engine make & model". I believe there are at least two 300HP Cummins engines.

NHRA225 · 12-21-2013, 06:49 AM

It could be the older 5.9 or the 8.3C, I think they may use the same Solenoid, if that's the issue.
I replaced mine last year- just quit in a rest area- I tie wrapped it open until I got home.

safehaven · 12-21-2013, 09:04 AM

Thanks everyone for your kind help, the unit is in Arkansas and I am in Alberta until Tuesday, I should have copied down the engine serial number but forgot it when I left, it is an inline 6 cummins turbo is all I can give you for now. But regardless you guys have been very helpful. I wanted to get it running well enough to get it into the Tiffin dealer if I could, which is an hour south of where it is parked. Good tip on wiring the cut off solenoid open, I will definitely try that one. Good advice on the fuel filters too. Here is another problem, I don't have an Oshkosh chassis manual for the unit, can anyone give me any leads on where to find one. You guys have been most helpful and very kind. Can't wait to get back south and get me some biscuits and gravy. Thanks again.

safehaven · 12-21-2013, 09:07 AM

Newmar I reread your post and you jogged my memory, in the cummins manual which I don't have here it does say 8.3c so thanks for that, and maybe this will help further. Thanks gentlemen.

lowtiderider · 12-23-2013, 05:44 PM

Check the oil. There is a low oil cutoff that will shut down the engine to prevent damage.

hooverbill · 12-23-2013, 07:53 PM

Whenever I have any type fuel problem, the first thing I do is change the fuel filter(s).

Mekanic · 12-23-2013, 08:09 PM

Quote:

Originally Posted by lowtiderider

Check the oil. There is a low oil cutoff that will shut down the engine to prevent damage.

Quote:

Originally Posted by spike45

Does the start immediately after this? Or do you have to crank for awhile before it fires?

Quote:

Originally Posted by safehaven

Thanks gentlemen, it is a 300 cummins 6 turbo the model for the coach is vc-26 29 rdrr. It starts and runs for a couple of minutes then just quits no matter if you pump accelerator or not. Then immediately starts again and does the same thing again, and again and again. Thanks

since it fires right back up it 99% not likely a fuel supply problem.
I'd look at that fuel shutoff soliniod AND all vehicles i have ever seen that
came with a Cummins have a oil pressure, coolant level and over temp safety shut down. my 94 Ford has it as well.