Engine/Transmission (1994 - 1998) Cold Running Issue

[TAchterberg]

My brother's '94 has the following issue ... .



Starts fine in the cold (Batteries load-test good, grid heater functioning properly, block heater working), but will only run for 2-3 seconds and then it dies. Will re-start just fine and do the same thing repeatedly. However, if enough throttle is given to keep it running, and done for about 10 seconds or so, it will then idle on it's own without any foot feed.



Any ideas on what to check/replace/adjust?

 

[NIsaacs]

I would adjust the idle up some, with cold weather it takes more power to turn everything.



Nick

 

[GAmes]

It could be any number of things. Low fuel pressure caused by a clogged filter, weak overflow valve or a weak lift pump. It could be air entering the lines thru small cracks in old rubber hoses. The overflow valve is also a check valve that keeps the fuel from being siphoned from the IP when the engine is shut down. Here is an article that gives all the info;

http://www.cumminsforum.com/forum/94-98-engine/58777-joe-gs-fuel-system-writeup.html

 

[Missouri Mule]

Idle seems to be to low!



Low idle speed

Automatic trans, 750-800 rpm with trans in drive and a/c on.

Manual trans, 780 rpm trans in neutral and a/c on.

Engine at operating temp.

Low idle screw is located at rear of p7100/ governor housing, thottle linkage contacts the lever stop.

 

[Big Red 94Ram]

When the truck is cold, it idles around 400-500. then when it warms up, its at where it should be. around 800. Fuel filter is new, atleast the one by the injection pump.
(I'm the other TAchterberg, my brother started this thread for me. )

 

[BDaugherty]

One of my customer's trucks had a similar issue. I replaced all the rubber fuel lines and the pre-filter located in the fuel heater bowl. You will also need new gaskets and if you have low fuel psi, this is the time to install the new lift pump. His problem was getting air in the lines. Once the fuel was not bleeding back, it was night and day difference starting it. Especially after sitting for a day or two.
http://www.genosgarage.com/FLEETGUA...HEATER_PRE-FILTER-94-98/productinfo/3845400S/
http://www.genosgarage.com/CUMMINS-FUEL-PRE-HEATER-LIFT-PUMP-GASKET-94-98-12V/productinfo/3939258/
http://www.genosgarage.com/REPLACEMENT-FUEL-TRANSFER-PUMP-94-98/productinfo/PUMP_4988747_KIT/

 

[GAmes]

When the truck is cold, it idles around 400-500. then when it warms up, its at where it should be. around 800.

That is normal when the outside air is very cold. Did you check the other componants? Prefilter, OFV, lift pump. Have you checked fuel pressure?

 

[Cosmo]

Normal to idle at 400-500?? It was ~27 degrees this morning and my truck idled ok after about two seconds. Yesterday, when I forgot to plug the block heater in, it took a good 10-15 seconds of cranking to get it to actually fire, but when it did it only took a few seconds - of blowing lots of smoke- before the idle settled in at ~800ish. Even with the exhaust brake on it still idles in the 650 range.

 

[GAmes]

It is normal for mine, and it makes sense. The block is cold so the fuel doesn't burn completely and the oil is thick which slows the engine until the oil warms up. 24 valve computers will compensate for the cold, no such animal on ours.

 

[yenga80]

mine will also idle around 500 when first started in this cold weather then after a bit it will pick up rpm's.

 

[hsmith]

Just happened to me. Returned from a great reminescent trip to Big Bend area. Trouble free 'til I got home then truck would start and die repeatedly. Well, I am not one to procrastinate, always do pm, times before necessary. Not this time. Fuel hoses were brittle and porous. Must have been longer than I thought since replacing them. Used good hoses also. Waiting on a hose from the dealer now for the lift pump. Changing them all.



Oh, and now the radiator has a split tank, only 17 years old. Things just don't last anymore. Good thing is all this waited 'til I got home.