Intermittent crank, but no start.

[oachs83]

either way you are running lean with ghost white plugs and need to address this issue.

 

[cbxer55]

Well, for awhile I have had the CEL come on occassionally. Sometimes its on for a few weeks, then off for a few weeks. When it is on I get an EGR code. I pulled the EGR valve and it is good. Since I have the old metal DPFE, I went and bought one of the new-fangled plastic units from Auto Zone and installed it today. Since then the truck has started every time I have tried.

This leads me to believe the EGR may have been stuck in the open position, possibly causing the lean condition that resulted in white plugs. Don't know that for sure, but it makes sense. The truck starts instantly when cold, as the mixture is enrichened. But when warm it refused to start, since the ECT would not signal for more fuel. And a lean mixture, with no cold enrichening, would make it difficult to start.

The new DPFE seems to have done the trick, for now. Time will tell.

 

[oachs83]

Wish you would have said something about that before. Next time tell us about every little code, hiccup, anything that the truck is doing and it saves a lot of guessing. Let me guess a P0406 code? I just went through this on one my trucks at work ( I am a mechanic for a construction company) it was a 1999 V10. The idle would surge up and down at cold start, sometimes would take two or three tries but once it got warm it ran fine. I took the EGR out and the spring was broke so the valve was just floating around at it's own will. Changed it out and acted like a completley different truck. If your valve was stuck wide open it would cause a huge vacuum leak and would run like crap at low RPM and cold startups. It sounds like you may have found your problem good luck.

 

[cbxer55]

Well, here is the latest. After replacing the DPFE the hard starting still exists when warm. I have narrowed it down to a lack of fuel, although I cannot figure out why. A noid light shows the injectors getting power, the pressure is in the middle of the required 56 to 72 psi, engine off or running.

I have found that if I remove the plug from my air intake for the crankcase vent, and squirt some fuel into the tube, then it will start up everytime, first turn of the key. So as to what is not doing its thing, I have not the faintest idea.

No CEL and no codes showing. Guess I'll be scratching my head on this for awhile.

 

[oachs83]

If you prime the system by turning key back and forth does it start easier? How about your EGR itself is the valve properly working?

 

[cbxer55]

EGR valve is fine, I removed it and checked it with a big 5 ounce syringe, works like it is supposed to. I cleaned it while it was off. Anyhow, if there was anything like that wrong, the CEL would be on. I got no light and no codes.

Priming the system does not help at all, I have tried that. Anyhow, as I stated above, I get 62 psi fuel pressure when I turn the key on, engine off. And it stays that way for near half an hour, so no pressure drain off.

 

[cbxer55]

Well, I finally appear to have this problem under control. I replaced the Engine Coolant Temperature Sensor, which did nothing. I then replaced the Idle Air Control motor, and the problem has gone away.

I do not know how the IAC could cause intermittent problems, as my truck has had this problem on-and-off for two years now.

Hopefully this is a permanent fix, and not temporary. But at least for now, it starts hot or cold.