Random Stalling

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Oct 1, 2008 | 08:33 PM

shabangles

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Random Stalling

I started having problems last week with my truck randomly stalling. It is a 2000 7.3 with a 6 speed and DP tuner. The first time it gave me problems, I started the truck and as I was putting a few things in the back seat it just slowly died. I restarted the truck and watched the tach and after a few seconds of running the RPM's slowly started to drop. The truck seemed to run smooth, but just would not stay running much below 500 RPM. It would also not respond to the throttle as it was loosing RPM's. On the third try I set my tuner to stock and it started and ran fine. I switched it back to 80e after some driving and everything seemed ok. Since then I changed the fuel filter and checked the oil (500 miles on rotella syn). The truck never stalled again untill tonight driving home. I was going up a hill and the engine just stopped firing and the tach began to drop. After downshifting the truck restarted like nothing happened. From what I have read this sounds like a CPS problem, but the tach continues to work and I do not get any erratic readings at all. My only other thought is that the chip could have come loose. Any ideas?
Thanks

Oct 1, 2008 | 09:14 PM

Pocket

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From: Parker, CO

With it slowly dying like that, it doesn't sound like a CPS issue or a problem with a loose chip. If it was one of those, normally the truck would just stall instantly.

Since yours is slowly dropping RPM's, I would think you have a fueling issue first. Could be the fuel pump is dying, and as you lose fuel pressure, the engine has a hard time running. That would be my first guess, since you don't mention anything about the check engine light coming on. Fuel pressure is the one thing the PCM can't see, so if the pressure is dropping, you wouldn't set a check engine light.

Anyway, that's my guess.

Oct 1, 2008 | 09:40 PM

shabangles

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I just checked the computer for codes and none came up. The check engine light never came on or anything. It does not feel like the truck runs rough or anything before it dies. Today I just noticed that it got quiet and started to loose speed. Would a fuel problem cause it to just cut out also?

Oct 3, 2008 | 01:53 PM

Clint40

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From: Mid Michigan

possible UVC ( under valve cover ) harness when connected you wouldnt see codes but when loosened it would act like your saying. Just an idea.

Oct 3, 2008 | 06:06 PM

camodown

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From: West Tx

Did you clean the contacts on the pcm for the chip really well? Only thing i can think of is the contacts are dirty or something. Maybe your fuel pump is slowly dying.

Oct 3, 2008 | 06:08 PM

camodown

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From: West Tx

A plugged pickup would cause it to get real quiet. Ask me how I know haha. I was filling up one time and the truck went as quiet as a 6.4 almost, then when i went to drive off it was really sluggish and came back. Then a second time I ran the tank down and the pickup clogged. Filled the tank all the way back up, and still had trouble. Had to remove the fuel line and reverse pump it to get the screen clear.

Oct 3, 2008 | 07:23 PM

shabangles

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I cleaned the chip contacts as per the instructions when I installed it. I pulled the chip out yesterday to check that it was seated properly and reinstalled it and everything seemed fine. I also replaced the cps with the spare I had and have not had any issues yet. I will try to get a fuel pressure reading on it this week to check on the fuel pump. Thank You for the ideas.