Runs rough when warm....

[Big_Red_Stroker]

ok any ideas? my truck runs smooth when its cold but once you drive it a few miles it starts to get rough and the RPM jumps around. like its turning on and off. and i have replaced the ICP and no change. and when its warm and parked running its choppy shut her down and let her cool off and she runs good. its just when its worm it runs like crap. I was thinking a TPS but would that have anything to do with it at idle? And only when she’s warm….. and my scan gauge says P1111 (good to go) so im lost! any ideas guys

[kanuck15]

bad ipr o ring letting high pressure oil seep past?

[Big_Red_Stroker]

Originally Posted by kanuck15

bad ipr o ring letting high pressure oil seep past?

could be, i have a new set and should swap them out. its a new IPR from ford though. and it looked good when i but in the twins

[kanuck15]

who knows, I know warm oil works through stuff better than cold oil

[Spanky88]

yea a bad ipr would have been my first guess but im at a loss

[Big_Red_Stroker]

i might put them new O rings i have in and see if it fixes it

[chvyrkr]

Put a mechanical gauge on the oil rail in either head and see what it looks like. If it's bouncy, then your dual pumps are aerating the oil, or the IPR is gettin really sticky.

And I fixed the thread title lol.

[Big_Red_Stroker]

Originally Posted by chvyrkr81

Put a mechanical gauge on the oil rail in either head and see what it looks like. If it's bouncy, then your dual pumps are aerating the oil, or the IPR is gettin really sticky.

And I fixed the thread title lol.

i was hoppin you would show up bud and thanks for fixin the title so you dont think its the O rings? and the IPR is brand new from ford.

[chvyrkr]

Brand new don't mean it's good.

You'd be shocked if I shared stories of the hundreds of thousands of dollars of aircraft parts we get that're DoA.

However, that's unlikely.

I doubt the injector o-rings are bad haven't been in the truck long have they? Might try new o-rings on the IPR, and/or a spare IPR if you have one available.

Twin pumps on a single IPR, like the termies, are famous for aeration. One of the symptoms of that is a choppy/rough idle. But, the mech gauge will tell the tale there.

The ICP sensor doesn't see the difference between oil pressure and air pressure. It just see's pressure in that oil rail. Where as a mech gauge will flutter/bounce as air pockets pass under it.

Any hot start issues? What's the story on the injectors? New when installed?

How about the pumps used in the twins? New or used?

[95dieselsmoke]

IIRC he was having horrible hot start problems until he put in the duals with the new IPR and that solved his hot start issues. Still sounds like the current problem is IPR related to me.