IPR changed. Truck started after a few seconds of fast cranking which sped up until it finally idled. Everything looked normal on the scope. Injector pressure and duty cycle were normal. Truck idled smoothly but still had the stumble as I ramped up the RPM to 2000. After a few minutes, it seemed to lose the stumble and ran smoothly. I did some fast throttle bursts up to 2000RPM then let off to see if it would idle. No issues while it was still cool. After it warmed to around 125F oil temp, I gave it some throttle and let it return to idle. Died. Cranked and had the same exact results prior to changing the IPR. ICP was 240ish and duty cycle climbed to 99%. No start. Unplugged the ICP sensor pigtail and tried again. This time, ICP hit 2169 with a duty cycle of 31% but still no start. What in the world is going on here? Buzzed all injectors again with good results. I'm at a loss here.

 

Sorry to read the results, my gut feeling was not right this time.

 

Unless someone here has any other ideas, I'll be pulling valve covers on Monday. Makes no sense to me how it can build 2000psi in the oil rail and not start. I'll bet money that it will start again when cold.

 

Any chance your oil is contaminated with debris or coolant? Making the IPR fail again?

 

I don't know enough about the IDM to say, but I think I remember reading about a bad IDM causing no start when hot...?

 

Changes the oil and filter so I can't see how it could be oil related.

 

I live between Dallas and Hillsboro. Your truck hasn't seen any heat that mine hasn't seen, with less than half the miles on it.

Good idea.

 

I'm curious about your driving. Long haul highway miles or lots of city driving? I know several co-workers who drive Powerstrokes and can't recall any that have gotten that many miles without cup and injector work. Whatever you are doing, must be working pretty dang well.

 

Both city and highway. I've heard 250k or so was the limit on the injectors also. I think that's mostly a holdover from years and years ago. All except one of the properly maintained super duty's I've been around have had their injectors and cups last longer than 250k. The one that we changed the injectors and found a cup leak along the way was bought used so we don't know what happened before.

 

That's what I thought was going to be your results. You have a o-ring or injector issue. I know you installed different injectors but I still wouldn't rule them out. Before you pull both valve covers do the shop air test we have been trying to get you to do that will tell you what side your issue is on. You may need to get things warm before pressuring up with air.

 

when did you see 2000 psi and have a no start? When the ICP was unplugged? Your PCM defaults to that number when the sensor is unplugged. You actually only had the 250PSI and that is why it wouldn't run.

 

Yes, I unplugged the ICP pigtail just for grins then cranked. I thought there might be a sensor located in the system that actually read the pressure but I see what you're saying. I'm worn out with this truck. Sadly, I'm doing all of this just to sell it. Nobody would want it in the state that it was in puking diesel into the coolant. Might have been better off to just sell as is. I just hate seeing a good truck go to waste. Hell, I may keep it at this point if I ever get the issue solved. It's a utility body crew cab and sure comes in handy. Thanks for the advice. Come Monday, it's time to open it up.

 

Yeah the sensor you unplugged is what reads the actual pressure in the rails and reports to the PCM which then commands the IPR to open or close more. If the ICP sensor goes bad you can make it home by unplugging the ICP sensor.

 

Is there any way that I can monitor each cylinder via AE scan tool to see which one is not opening? I can't help but feel that it's one injector that's goobered up. I'd try the air test but I don't hear very well anymore and might not catch it.

 

Finally found a shop guide to diagnose a no start or hard start condition. It's long but pretty comprehensive. Does require special plugs to block off one side of the engine at a time.

Here's a link to the PDF:

http://www.shopinjectors.com/diesel/...nosis-info.pdf