No Hot Start / Random Stalling

dieselpower · Mar 6, 2014

Hey guys I have a 2005 6.0 that is having a no hot start problem. It seems to be somewhat random, although it is usually after it has sat for a couple minutes, although it will sometimes start fine then too. I have tried unplugging the ICP to see if I had a faulty sensor, but it didn't solve the problem. There are no DTC's, and the engine runs fine when started.

Also happening very randomly...stalling. This always happens when I am coming to a stop... below 15mph or so. It seems to happen mostly when given some throttle, and then immediate braking, ie., crossing a road from a stop, then quickly braking on the other side, although this too is not always the case.

Any ideas?

I did monitor ICP today, and WOT netted me 4.75v, and idling was .8-.89v. I tried cranking volts, but my monitor wouldn't let me read then :fustrate: (as stated before I tried unplugging the icp sensor and that didn't help any).

Anyways, any thoughts? Is it two separate problems? Both of them seemed to start around the same time. Oil pressure system problem? Fuel problem? Sensor?

Want to get this fixed ASAP, as the random stalling, coupled with a no start in the wrong situation is super frustrating.

Thanks for the help!

dieselpower · Mar 6, 2014

Gary · Mar 6, 2014

What was your ICP when it didn't start? What is your ICP% at a idle with oil at operating temp?

dieselpower · Mar 6, 2014

I'll try to recheck the ICP at operating temp, although this was pretty close if not at operating temp. Is that number low?

I'll try to check the ICP when cranking next time it doesn't start, although this is random so not sure when that will be.

Snoop · Mar 6, 2014

FWIW, I came across the same situation and it was related to the crank position sensor needing replacement and had to fix the plug wires going in to it. Not really reproducible but you say it happens over bumps, sounds like an electrical problem.

jdeeg4276 · Mar 8, 2014

FICM plugs coming loose?

ICP have the updated plug on it at passenger valve cover?

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dieselpower · Mar 11, 2014

I will have to check the FICM plugs and the ICP...

ICP at idle: 590psi ICP cruising at 60: 1050 psi MAX ICP: 3480psi

Are these readings normal? Is my HPOP for sure ok?

Thanks!

jdeeg4276 · Mar 12, 2014

I believe those number may be on the lower side of normal. High should be around 5k

On and the new Ford oem will be a purple color wires.

What about oem oil filter? Fuel filter?

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dieselpower · Mar 13, 2014

jdeeg4276 said:
I believe those number may be on the lower side of normal. High should be around 5k

On and the new Ford oem will be a purple color wires.

What about oem oil filter? Fuel filter?

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I did change the fuel filter a couple weeks ago, didn't help the problem. I'm leaning toward it being the HPOP itself as sometimes it will not hot start after being shut off for only a minute or two, hardly long enough for a leak in the lines to be a problem. Also the stalling at idle when letting off throttle would point to a weak pump, right?

The randomness is what gets me..

jdeeg4276 · Mar 13, 2014

Have you ran a computer It while driving and saving the info as a video recording.

I found a intermittent cam sensor issue on a 7.3 with video recording and was able to watch when the sensor would drop out worked real well.

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dieselpower · Mar 27, 2014

Well I think it about has to be the HPOP but I'm still not sure and don't want to drop the $ and then find out it's not that. Tonight I was coming home, slowing down for our driveway, and at about 30-35mph I pulled it into Neutral and it stalled immediately. Is this because the HPOP PSI dips when the engine hits idle, and because it may be bad it is killing it? Or is it a trans sensor issue?

Not sure how a trans issue would tie into a no hot start, but maybe I have two separate problems here.

And thanks for the help so far guys..I want to narrow this down as much as possible.

dieselpower · Mar 29, 2014

dieselpower said:
Well I think it about has to be the HPOP but I'm still not sure and don't want to drop the $ and then find out it's not that. Tonight I was coming home, slowing down for our driveway, and at about 30-35mph I pulled it into Neutral and it stalled immediately. Is this because the HPOP PSI dips when the engine hits idle, and because it may be bad it is killing it? Or is it a trans sensor issue?

Not sure how a trans issue would tie into a no hot start, but maybe I have two separate problems here.

And thanks for the help so far guys..I want to narrow this down as much as possible.

bump..any thoughts on this? Could a trans sensor issue cause a no start?

dieselpower · Apr 14, 2014

Now the truck quit while driving, and refuses to start when it's cold as well (a first).

I checked ICP again, and I get about .30mpa, roughly 55psi, after cranking for a couple seconds. I assume my HPOP or injectors are done for? Doesn't there need to be about 500psi to start? Oil level was off the dipstick too, was changed in January. It was only a quart or two low, but does that mean something?

johnp115 · Apr 14, 2014

What is your icp pressure when cranking

dieselpower · Apr 14, 2014

johnp115 said:
What is your icp pressure when cranking

That's when I was reading it. Read .38mpa (doesn't read psi, but a mpa / psi converter says 55psi)

I unplugged the ICP sensor, and it didn't help so doesn't that rule out that it's that?

G Racing · Apr 14, 2014

If the oil level is full and all you are making is 55psi your hpop, stc fitting and or the standpipes are leaking. You can air check the hpo system through the icp sensor location to see where the leak is coming from. You will hear it hissing. You will need to jumper the ipr so that it is closed while testing.

johnp115 · Apr 14, 2014

Id look into the stc fitting being the cause then.

My 6.0 had the same problem. No hot start.
Also my injector o rings were toast. Ill put a link to my thread here and you can read through the headaches i had.

If its only 60 psi when cranking then your stc fitting/standpipes/dummy plugs/ or injector o rings must be that shot to where it'll cut off when idling

johnp115 · Apr 14, 2014

Heres my 2 threads on this.

http://powerstrokearmy.com/forums/showthread.php?t=43441

http://powerstrokearmy.com/forums/showthread.php?t=44214

Lassie · Apr 15, 2014

If 55psi is all you are seeing cranking, I'd bet on STC fitting. Leaks at or beyond oil rails typically will build more pressure than that. Even a completely blown out o-ring will allow about 300ish psi at full IPR%.

Or Pump is done.