The engine idles rough and shakes the truck to about 1300 rpm. 3500 miles on the oil and full, 5k on cps and 8k on fuel filter. No unusual smoke or EGT. No chip or programmer either. Any ideas?

Thanks, Les

 

Bad batch of diesel fuel maybe...

Terry

 

What year model? Is it standard or automatic?

 

Could possibly be the infamous dual mass flywheel.


Steve

 

It's a 99 PSD, no dmfw. I don't think it is the fuel. It started when I had a 1/4 tank and then I refueled at a different station the same day.

 

The first thing on the list in the service manual is to check for aerated oil. Do you have a means to check the HPOP pressure or voltage?

 

No I don't. What voltage are you talking about?

 

take the strainer off and check for debris or any contamination.He probably is talking about ICP voltage or IPR voltage. If you had a good scan tool u may can get the ICP readings from it.

 

Drained fuel bowl and replaced the filter, looked almost new after 8k. Super lopey until I get past 1300 rpm. After 1300 rpm it seems to run strong. Valve cover connections look good

 

Yep, I was talking about the ICP voltage, but I'm thinking now that it won't be neccessary to actually measure the pressure.

First change the oil to rule out an aeration problem.

If that doesn't fix it then try disconnecting the ICP sensor, if the idle smoothes out the ICP signal is at fault, if not, you may have some debris stuck in the IPR.

 

Is the ICP sensor the one on the left head or on the hpop?

 

Do I unplug it with the engine running?

 

Oil changed with no difference. Disconnected the ICP with no change. The only thing that happened was I got the SES light. I see 3 sensors on the hpop, 1 on top, 1 on the upper leftside and 1 on the lower leftside. What are they?

Thanks, Les

 

I'm not sure PS250, but I'll bounce this back to the top of the list for ya.....

 

The upper left is the engine oil temp, the lower left is the electrical connector for the IPR valve, and on top to the right is engine oil pressure.

When you unplugged the ICP (drivers head) with the engine running you made the PCM default to a set oil pressure. Since the idle didn't change the ICP is working.