I have an 01 f350 7.3L. For the last month or so it will turn over great but won't start on the first try. Usually on the 2nd or 3rd try it will start. This doesn't happen every time only occasionally. Last week it would not start over a period of several hours. I had it towed to the garage and they were going to look at it the next day. Well by the next day it fired right up and ran like a top every time they tried it. There were no codes on the computer. It ran for about a week and started first try everytime. Last night when I picked up the kids it took three tries to start it and now this morning it won't start at all. The guy at the garage had a guess that it might be the IPR valve but he didn't want to work on it until he knew for sure. I don't want to have it towed again just to have it start when they try and work on it. What would you do? Should I replace the IPR valve and see what happens? Is there a way I can test it at home? any suggestions would be appreciated.

 

Hi nmaine, welcome to FTE! I'm sending this one down to the 7.3L forum, the folks down there will be better able to help you with this one.

 

Welcome to FTE. Start by checking the oil level in the HPOP reservoir after it's been sitting a while. Low oil level (should be within an inch of the top) will cause starting issues like you're describing.

An IPR can too, but any decent diesel mechanic I would think should have a scan tool capable of reading IPR duty cycle to watch what's going on during the no start.

There are also scanners available where you can watch this data yourself. If the tow bills are starting to rack up, this may be a worthwhile option.

In the mean time, it doesn't cost anything to check the oil level in the HPOP reservoir before you try and start the truck and watch to see if there's a difference in the level when you have a start or no start situation.

Oil is the same motor oil you put in the engine and it constantly cycles through the reservoir. When it drains down is when the issues can start.
Check the oil level here. Just replace the plug before you crank the truck.

 

I ended up having the truck towed again after it wouldn't start. When the truck got to the garage it started right up He left it running for a bit and tried it again and it started. After a few more tries it finally decided not to start on him.. That was at the end of the day yesterday, the computer was showing no oil pressure and no rpms. I'm not sure what the cause of this could be or what he is going to look at now

 

Sounds like the oil could be draining back from the HPOP, or maybe the cam sensor is crapping out. do you know the color of the cam sensor, is it black or grey?

 

No rpm's means a bad CPS (if the scanner is the kind that can actually read data from a PSD). No oil pressure? Do you mean on the low side or high side?

Has to be the high side he's talking about, but both the rpm's and oil pressure shouldn't be intermittently, randomly failing at the same time, so it sounds like either a scanner or possibly a PCM issue.

If you want to throw money at it, the CPS is the cheapest piece of the puzzle. Keep the old one in a ziplock back in the glovebox as a spare in case you have a CPS failure in the future.

 

It's not building pressure on the high side. They are supposed to be putting an ICP valve in this morning. According to him that SHOULD work if for some reason it doesn't CPS is the next step as far as I'm concerned

 

This could very well be a bad Injector Pressure Regulator (IPR).

 

The ICP is a sensor. The IPR is a valve. While the IPR can explain the lack of oil pressure, it doesn't explain the lack of RPM's. The IPR is also about 10 times more expensive than the CPS, which is why I suggested starting with the cheap part first if you're just throwing parts at it.

If they have a good scanner, what was the duty cycle of the IPR?