Intermitent no start

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Jun 8, 2011 | 12:43 PM

jsmahan

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Intermitent no start

Back to pick your brains. Got a 99 350 with 175000 on it. Been having intermitent no starts. Seems to happen when temps get up and its been run a little. Found oil in ICP, replaced. Changed O-rings and cleaned IPR. Changed oil. No improvement. If anything, its worse. Now idles rough.

When cool, ICP pressure is 600 easy and starts right up with rough idle. After performing test with AE, about 5-8 minutes, no start. ICP 260-300 with 50-65% DC. Have not pulled VC's off yet but plan to in the morning. I have a spare IPR I also plan to try as this one just "feels" rough when shaking.

Any additional ideas are appreciated.

Jun 8, 2011 | 07:15 PM

F350-6

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From: Texas

Sounds like an IPR issue. Let us know how the spare does. I'd try that before I pulled the valve covers.

Jun 9, 2011 | 11:40 AM

jsmahan

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Replaced IPR and all ailments seem to be cured. Starts up and runs great.

Jun 9, 2011 | 12:31 PM

clintbonnie

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From: Ardenvoir, Washington

Good news.. thx for reporting back..

Jun 9, 2011 | 06:56 PM

YellerMax

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Glad to hear. I am in EXACTLY the same boat. Same no-start symptoms. ICP had oil, replaced it. Still have the problem. I'll see what I can figure out tomorrow, but this gives me some hope. Unfortunately I don't have the benefit of equipment to run the duty cycle % where I am, but we'll see what happens.

I did notice that when my truck doesn't start, it turn over VERY fast. Knowing what I do about Dalton's law of partial pressures, that suggests to me that there is no fuel being injected--either none being supplied to the injectors, or no pressure applied to injectors via the HPOS (i.e. bad IPR?)

Jun 9, 2011 | 07:32 PM

F350-6

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From: Texas

Quote:

Originally Posted by YellerMax

Knowing what I do about Dalton's law of partial pressures, that suggests to me that there is no fuel being injected--either none being supplied to the injectors, or no pressure applied to injectors via the HPOS (i.e. bad IPR?)

You're on the right track, but leaving out the electrical side of the equation. Oil and fuel can be present in sufficient pressure, but you get the same results if the IDM does not command the injectors to fire. So now you have 3 angles to look at.

No smoke while cranking is another sign the injectors are not firing. Hints on the electrical side might be dash lights not functioning normally, and if you have a chip, remove it for diagnostic purposes. Also, don't forget to keep the batteries on a charger while figuring this out so you don't get a low voltage no start.

Semper Fi.

Jun 11, 2011 | 02:55 PM

YellerMax

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No smoke while starting. I will try pulling the DP Tuner to eliminate that variable, but the problem is so intermittent it is hard to replicate. Basically, it only happens at EXTREMELY inconvenient times, not when I am purposely trying to replicate it.

Any way to visually inspect the IPR to see if it is any good?

Thanks
Max

Semper Fi back at you