No start when warmed up, but great when cold?
#1
No start when warmed up, but great when cold?
Ok, try this one out for size. 2001 2500 4x4. Relatively new set of fuel pumps. Always kept good filters in place. Starts on first spin when cold and runs like brand new all through warm up. When warmed up, especially in warmer months, and only after sitting off for about 20 min it turns over but won't light off. Oddly enough though, I can just leave it alone until nearly dead cold and she'll fire right up. Or, I can pop the hood and bleed a few injectors when while hot and she'll fire up and smooth out in seconds and run like new again. Bleeding injectors should indicate either air or lack of fuel in the rack. But if air-bound and/or loss of fuel in rack, why would it crank immediately when cold again? My thought is that perhaps the heated air in the intake manifold expands while the engine's shut off and forces fuel away from the injectors causing a vacuum/pressure lock. And as the air cools and 'shrinks' per say, it sucks the fuel back into position to feed the injectors. Anyone have this problem, or can add an opinion and solution? Ragin' Cajun
#3
Actually had the VP44 replaced not too long ago considering the mileage since replacement. A parts supplier called Glacier out of Canada I believe. Gave a great price for new pump compared to all others. Also went with electric lift pump at the time. The symptoms were somewhat different for requiring new VP44, but that's not to say there are several variables regarding the pump failure. And I'm hoping there may be a sensor, regulator component, or other 'minor' issue to be resolved before the inevitable. I recall another guy mentioning something about a valve of the sort somewhere in the fuel rail to control intake and return fuel. Maybe the 10" long 3/4 box end wrench I'm now using as a key chain will fit the part and I can kill two ducks....the fuel issue, and keep my britches from drooping on my belt loop!!!
#6
Registered User
Hearing your issue, I'm sure everything is fine. But I need to know what fuel pump you have on there since you mentioned replacing the fuel pump. And also, whats your idle, running, and WOT fuel pressures. Depending on what you say, I may have an easy fix.
#7
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Join Date: Nov 2003
Location: Chattanooga, TN
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This sounds similar to my issue years ago with my 2001. A hot start issue... crank and crank and finally light up after 30 seconds of cranking - if I remember. I never tried the bleeding of the fuel lines so not sure if that would have worked for me like it does for you.
But here is what I did that solved it...
I swapped the "fuel system relay" in the underhood box for the "fog light relay". Both in the lower left area of the box. Never had the problem again. My guess is it had something to do with a relay getting hot during those hot months and not operating normally. Did this swap about 6 years ago.
Just thought I'd throw that possibility out there. And also, I'm still on the original VP44 today so it was not related.
But here is what I did that solved it...
I swapped the "fuel system relay" in the underhood box for the "fog light relay". Both in the lower left area of the box. Never had the problem again. My guess is it had something to do with a relay getting hot during those hot months and not operating normally. Did this swap about 6 years ago.
Just thought I'd throw that possibility out there. And also, I'm still on the original VP44 today so it was not related.
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#9
Cummins Guru
Try cooling the injection pump with water from garden hose. If it starts right up after cooling injection pump down then replace injection pump.
#10
Registered User
#11
I have had the exact same problem,long or no hot start with 2001 4x4,i to changed relays and it was ok for awhile.Then i discovered the material liner stuck to the bottom of the hood was holding the heat in,i removed it and that also helped.The dropping liner was holding the heat in and screwing with both the relay and the injector pump getting excessively hot.Unfortunately it may be to late the damage already done,i have heard from a very reliable source if your vp44 will not start while hot but just fine cold,if you run cold water over the hot injector pump and she starts right up,start saving your money she,s on the way out
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