Hard Start, Low IPC durin crank, Loss of power

[W1ldBi11]

I'd like to start off by saying that there is a wealth of knowledge on these forums and thanks to those who are more knowledgable than I for getting me this far.

I have an early 99 F-250 with 202K on it.

I've had a problem with my truck since early December. The symptoms were harder than usual starting and loss of power (feels like about 80% of normal). I ended up taking the truck to a diesel repair shop where they ran a cylinder contribution test and found that #8 was weak. They recommended a full injector replacement given the mileage, but wanted about 4K to do so. They didn't want to use reman injectors either.

Looking for an acceptable alternative I asked a friend that has a few 7.3s his opinion and he recommended that we replace the injectors with remans from BDP. We sent the injectors off, they were tested and found to be in pretty rough shape. They rebuilt them and sent them back.

My friend installed the injectors but the truck ran even worse than before and would only start on ether (I've never had to use ether before even in 15 deg cold). It was so weak that you could barely move it around in the parking lot.

I borrowed AE from a friend and found that bank 2 was not talking to the engine. With help from your forums and alldatapro I tested the voltage input from the IDM to each bank of injectors.

I pulled the valve covers and found the UVC unplugged and two of the injectors disconnected. I hooked everything back up and started the engine to notice that engine would now rev like it used to, or pretty close anyway.

I put it all back together but it is still running rough like it was before any of the injector replacement, but now it has to be started on ether. I tried unplugging the IPC sensor and it still wouldn't start. btw, codes were cleared at several points whenever I changed anything.

Using AE I found the following:
Cold idle ICP is 724 PSI with a duty cycle of 14.45.
Cranking ICP ~150 PSI (very low), ICP volts ~.42, RPM was 130, duty cycle increased from 14.84 to 64.48 as I floored the accelerator.
Floored Accel ICP was over 2000 PSI at first then tapered, Duty cycle was 30.86, ICP volts 2.77, RPM 3186 (reved up to a peak of 3484.1).

I realize that a cranking psi of 150 is way to low to start so I should focus on that. Removing the IPC sensor doesn't help. Would the next step be to remove the IPR and clean it, then replace if no change? Are my running injection pressure values OK?

I hate to throw more parts at this thing since replacing the injectors didn't fix my problem.

BTW, I filled the truck up with truck stop diesel and added some Diesel Klean.

Any help is much appreciated as money is tight and I need my truck!

[dray8165]

Since unplugging your ICP didn't make a difference, and you presumably changed your injector o-rings, the only thing left is the IPR and the HPOP. Read through this manual:

http://www.forddoctorsdts.com/public...3HPOPGuide.pdf

I think replacing the IPR would be the next logical step. Unless you just happen to pull it and find the o-ring torn.

[W1ldBi11]

Hi Dray, Thanks for the response!
The injector O-Rings all appeared to be brand new when they came back from BDP so I should be good there.

I like that document - very good information!

With the HPOP pressure output from the truck at full throttle being above 2000, would it suggest that I still have a good HPOP?

[dray8165]

I think so. It sounds like a weak IPR to me. Your top end oil is fresh since you essentially drained it with the injector change. The HPOP is capable of making good pressure. I don't see anything else it could be.

[forddieseldoctor]

So let me get this straight... You didn't have any icp issues before the injectors were replaced. If so I would start by looking at what was fixed when the issue presented itself. check your fuel in the filter, make sure it doesn't have oil in the fuel. Then remove the valve cover and watch for oil leak by the injectors that were removed while cranking. This would indicate leaking injector o-rings.

[dray8165]

Originally Posted by forddieseldoctor

So let me get this straight... You didn't have any icp issues before the injectors were replaced. If so I would start by looking at what was fixed when the issue presented itself. check your fuel in the filter, make sure it doesn't have oil in the fuel. Then remove the valve cover and watch for oil leak by the injectors that were removed while cranking. This would indicate leaking injector o-rings.

That's not quite what he said. He says it was hard to start and ran rough before the injectors - that the shop told him to replace the injectors, that it ran worse after the injectors and he found that it was due to the valve cover harness, and having corrected that now he is back to it still being hard to start and running rough.

Basically, the injector work made no difference - so, FordDieselDoctor, if you took out all the injector saga, and had a hard to start truck that was showing low pressure on cranking, and you had ruled out the ICP and knew that you had good o-rings (they are new - assuming they didn't tear them up on the install) what would your diagnosis be? I know you are a master mechanic and we all respect your opinion.

[forddieseldoctor]

Ok I missed the hard start listed in the initial description. First check to make sure that your oil resivor is full before you attempt to start. Then I would remove the ipr and inspect for damaged o-rings. You may have a bad ipr. otherwise the next thing I would do is isolate the cylinder heads one at a time and see if it build pressure in a normal amount of time. If both heads get blocked off and still no good then you need to replace the ipr and see if it's any good, otherwise you need a pump. However if my memory serves me right the block off tools are a special tool from ford.

[W1ldBi11]

Unfortunately I had no way of checking the IPC level before I replaced the injectors. Pre-Injector replacement, it was harder to start than usual, but would eventually start if I gave it some peddle. Granted, it is freakin' C-O-L-D here, around 20* and it was about 40 degrees when I first started to have issues back in December. That could explain the difference in cold "startability." However, it won't even start back up after it's been running for an hour (with the exception of one time that it did start after about 30 seconds of cranking with the peddle to the floor.)

[forddieseldoctor]

yeah it definitely sounds like you have a high pressure oil issue. Sorry about the multiple posts before. My browser froze and I clicked post reply a couple of times and then walked away.

[W1ldBi11]

Thanks for the information! I'm hoping to get some time to dig into this issue this weekend and will provide some feedback. I do have one question though, does the IPR regulate fuel (diesel) pressure or engine oil pressure that runs the injectors?
Hopefully it is the IPR and I won't have to pull the injectors!!