No Start When Hot

[HAVOK9INE]

Long story short, my 99 250 with 240,000 miles starts fine when cold, but will not start when oil temp is over 135, and even then it's a long crank. My IPR is fully closed but my ICP will not build adequate pressure, bouncing between 350-400. I know I've got a leak somewhere, but I've pulled the VCs and looked while it was running hot and could not find what I would call a leak coming from the injectors. So my assumption is that I'm leaking inside. On top of that, it occasionally dies when running when the oil temp is over 150 and I shift from drive to reverse, or go from full stop to rolling forward.

I've replaced all injector o-rings, injector cups, the ICP, IPR, CPS, and the ICP and IPR harnesses. HPOP is less than a year old as are the fittings. I am not gaining oil on the stick and my coolant seems to be staying at the same levels (that I can see). I've cleaned the entire valley and top of the engine and have not seen any build up of oil anywhere.

My questions is: is there a way to isolate which injector could be leaking, or do I need to pull all the injectors again? I've posted this issue in another forum and have received great ideas, but does anyone have any other place that I could look or input on something that I may have missed?

I do have FORScan and have several FORScan files that show the issue.

 

[ghohouston]

Have you run a cylinder contribution test?

 

[HAVOK9INE]

Oh man. Completely forgot about that one. I’ll do that once I get home. Thanks.

 

[HAVOK9INE]

Just to confirm, CCT must be performed at EOT of 170+, correct?

 

[HAVOK9INE]

Ran the CCT today with EOT at 170+ and just had a DTC for the AIH.

 

[Petro]

Ran the CCT today with EOT at 170+ and just had a DTC for the AIH.

Not sure what a contribution test would tell you about a hot no start issue do to a high pressure oil issue, nothing useful that I can think of. Was this truck doing this before you replaced the hpop? If no, I would suspect the pump even if it is only a year old. When it refuses to start hot, take a cold bottle of water and dump it on the hpop. Ive personally seen several trucks start right up after doing this, pointing to the pump being the issue.

 

[HAVOK9INE]

I didn’t replace it. The previous owner did, of which I have the service slip that says it was replaced. I’ll give the bottle of water idea a shot. There isn’t a worry about cracking or anything? I’ve never been given this advice.

 

[webb06]

I would remove icp sensor and pressurize the high pressure system. That’ll tell you if you have an injector o ring leaking or not.

Dumping water on the pump will be fine. If anything I’d put my money on ipr valve instead of the pump though.


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[HAVOK9INE]

Dumping water on the pump will be fine. If anything I’d put my money on ipr valve instead of the pump though.

I’ve replaced the IPR recently. Unless you believe I should do it again?

I plan on dead heading the pump this weekend.

 

[dsberman94]

Motorcraft parts?

 

[ghohouston]

Not sure what a contribution test would tell you about a hot no start issue do to a high pressure oil issue, nothing useful that I can think of. Was this truck doing this before you replaced the hpop? If no, I would suspect the pump even if it is only a year old. When it refuses to start hot, take a cold bottle of water and dump it on the hpop. Ive personally seen several trucks start right up after doing this, pointing to the pump being the issue.

You don't think if an injector poppet was leaking, it could cause a contribution test to fail? And cause lower icp with engine warm?

 

[HAVOK9INE]

The IPR is Motorcraft.

 

[Petro]

You don't think if an injector poppet was leaking, it could cause a contribution test to fail? And cause lower icp with engine warm?

I could be wrong, but I seriously doubt it. I have little to no faith in 7.3 contribution test, rarely do they ever tell me jack sh!t. 6.0s on the other hand, are a different story. The computer tech is soo stupid on a 7.3, you're pretty much just p!ssing in the wind.

 

[ghohouston]

What are you running the test with, Ids, forscan, scanner?

 

[ghohouston]

And I do get your point, but I've had quite a bit of success using cct on 7.3's over the years.

 

[Petro]

What are you running the test with, Ids, forscan, scanner?

Snap-On solus edge

 

[HAVOK9INE]

Welp, ran it until EOT was 160+ then tried to do a hot start with no luck. Poured some water on it and wouldn't you know it, friggin thing started right up. Looks like I will be getting a new pump. I'm looking at the terminator for budget reasons, unless there are any other recommendations?

 

[webb06]

Welp, ran it until EOT was 160+ then tried to do a hot start with no luck. Poured some water on it and wouldn't you know it, friggin thing started right up. Looks like I will be getting a new pump. I'm looking at the terminator for budget reasons, unless there are any other recommendations?

I’d try another ipr valve before you replace the pump.


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[KBMKVIII]

Welp, ran it until EOT was 160+ then tried to do a hot start with no luck. Poured some water on it and wouldn't you know it, friggin thing started right up. Looks like I will be getting a new pump. I'm looking at the terminator for budget reasons, unless there are any other recommendations?

The adrenaline from dieselsite

 

[PSD POWER007]

The adrenaline from dieselsite

I second this advice.