first off hi all
that said, I have a 1997 F350 power stroke it has 329,000 miles on it and has been a very dependable work trk.
been fighting this prob for 2 months now off and on (it,s been sitting up on the job site for last couple of months)
I start the trk idles great for about 5 mins ,and the check engine light comes on and it starts to run ruff and no power, and it,s not skipping
so started out with a new fuel filter, no improvement, so I bought a new fuel pump, (this 1 is mechanical just put 1 on last fall) no change.
scanner reads no codes (Acutron)
and also it has dual tanks so took fuel lines apart and cleaned them, I thought maybe the fuel switch valve was dirty, so bought a couple of foot long bypass lines and temp bypassed the valve, the back tank is plastic so was able to remove the fuel pickup added a bit of hose to supply line started it and the return flow was full line going back to tank, I wasn,t able to check the fuel pressure through the scanner, put while running I cracked the top of the filter and fuel sprays everywhere, ( I know this sounds dumb, but when broke down on the job and want Togo home at the end of a long day you use what ya have).
so still no improvement a friend of mine has a bigger snap on scanner we plugged that in got 2 codes cpm, and Tps changed was told china parts are crap so went and bought a new cpm at a local ford dealer, both no better, idles for 5-10 mins check engine lite comes on runs like crap
checked out the wiring harness no visible bare wires or breaks
un bolted the connections to the pcm, and the 2 plugs on the firewall, plus the main connection box on the block next to the big fuse box.
all looked good no broken pins no corrosion re greased with elec connection grease and put back together, talked to some peeps and told me the pcm might be bad sent that out and it rebuilt just got it back Wednesday nite put it on Thursday and ran fine for about 15 mins and then the check engine light came back on and it still runs like crap
while it starts to run I'm getting some blue smoke out of the exhaust
but it's never smoked before even with the high miles it has always been a strong motor, I haven't looked at the connections under the valve covers yet but the 4 connections seem good going to them I,m at a loss pls help

 

Sorry ya spent some unguided money on trying to fix this buddy, that can be frustrating.

Let's back up to your original problem before you blow any more money and get the fuel pressure checked first.

If you're not sure how, get an old tire gauge you do not care about any longer, start up the truck and measure the fuel pressure on the schrader valve on the side of the fuel bowl (it's on the drivers side.)
Take note, then when the truck starts to run rough, take a measurement again.

You need a minimum of 40 for the truck to run decent, but it should be in the 60-70 psi range.

Next what you can do to check is just unplugging the ICP sensor on the drivers side bank while the truck is running rough to see what happens.

I'm going to guess your idle will run right, but thats just a guess.

My guess here is that with your ICP sensor code, it is reading that pressure is below or above desired.

With it unplugged, it's going to attempt to run default codes working on other thing and will hopefully try and ramp up the IPR a bit.

My educated guess with what you've described in your post here is that your IPR is bad.

You can order one of those from Riffraffdiesel or terminator engineering.
Do NOT purchase a rebuilt one, they are NOT rebuildable. They are serviceable for cleaning, but usually they do strange things when they wear out like you are describing.

You'll need to make a wrench to get it off with a really deep socket.

There are some how to instructions around someplace.


If you do have a scanner that can read what the sensors are doing.
Look for DC% and watch that while the truck is idling.
Also watch your ICP sensor for your pressures and note what it is while its idling well, and idling poorly.

And of course as always, make sure the oil level is topped off. The injectors are Hydraulically ran, so that is important.

 

thanks will take a look and let ya know

 

Before spending $200 on a new IPR you could just try replaceing the O rings on it first.

 

I,m not going to get back up to the trk again till tomorrow but while looking at it yesterday the plug on the ipr is broke on the male side in the brass housing of the ipr itself so looks like I,m spending 200 bucks it,s the way my luck rolls lol

 

tanks again for the help guys hope I can return the favor some day I've been rebuilding ford trks and turning wrenches, all my life, if I don't have it I can build it this is my first 7.3 I,m a construction foreman and don't have a lot of time this time of yr. to work on my own, hopefully this will fix the prob I'll mark the rest down to preventive maintenance. I do plan on finishing the rebuild of the cab (sheet medal, and paint) would like to find another 7.3 with a standard tranny to install in it it,s a 97 f350 XL dually 4 wheel drive 12 foot stake bed dump I paid 3,500.00 for it 3 yrs. ago and it,s been a great trk
thanks again ,and will keep ya posted

 

Thanks for catching my mistake glenn.

 

hold on now.

The male plug is broke?

IPR wiring is a big fussy thing in our trucks also.

As you can see, trouble shooting with these odd situations can have a lot of things to check. I forget to list them all sometimes because I want to not overload with information.

The IPR actually has a wiring harness that you can remove from the truck.

If you can solder, you can easily fix it.

You might have to remove the fuel bowl to take it out though. It will be easier to inspect with it out.

You can check for damaged wires and bad connectors.

The IPR connector is the same as an injector solenoid connector.

I think you mentioned you replaced some UVCHs? (brain dead still this morning)

You can cut one off a bad UVCH and solder it onto the harness and you fixed it. =)


The O-ring thing would be a good thing to get as well.
I forgot about that, thanks to glenn for reminding me.

 

no it,s broke on the ipr end checked fuel pressure at the Schrader valve yesterday it carries 52 psi when running good and 52 psi when the check engine light comes on.
ordered the ipr and a new pig tail will have it later today hopefully the rain lets up a bit and I can get it on