238/80 injector issue

[psdguy95]

I just recently installed a set of 238/80s in my truck and I'm having a problem where the engine will romp really bad on startup and will randomly run rough at idle. Almost sound like a miss at idle when it's doing it but as soon as you give it throttle and take off it goes away. The trucks runs great when your driving it's just an idle and start up issue. Doesn't matter what temp it is. I have custom tunes from php and Dyno proven and all the tunes do it. I didn't have this issue with the stock injectors and canned tines from php. I ran a buzz test with my scan gauge and I can hear all 8 injectors buzzing. I ran a cylinder contribution test with it and I got a code for #8 injector. I am running the gray cps and all the injectors were just flow tested and came back good. It also have new valve cover gaskets and harnesses. Is this I tuning issue still or am I looking at another problem?

 

[Bluke]

Un plug the icp and see what happens.

 

[psdguy95]

Unplugged it at idle and it started to run like it had a miss

 

[superpsd]

I would watch ICP or catalog ICP when it was starting up to see what the ICP does when it's lopeing.

 

[psdguy95]

If I remember right when I start it my ipr percentage and icp jump all over the place then smooth out when it starts running correctly

 

[mandkole]

:whs: Sounds like HP oil control--IPR sticking, magnet failing, wiring, etc.

Also, you have the tuning redone for single shots? The truck will run with split tuning, but its a little rough.

 

[psdguy95]

Do they even make split shot 238/80s? I'm assuming they wrote the tunes as single shots. I didn't say they were or not. I questioned the ipr myself but the odd thing is I can put the stock injectors in and put my canned tunes back in and the truck runs just fine

 

[Justin@DP-Tuner]

If ICP is jumping around, I would suspect the IPR. However, it could also be the oil you are using. What brand and weight? Also, how many miles do you have on the oil? The reason I ask is because I have ran a couple different oils that make the truck run bad until the oil gets some mileage on it and thins out. All I run is 15w40, but different brands of oil run differently in my truck.

I could also be related to the single shot/hybrid design or the tuning, but since you see ICP jumping around, I would look into IPR first.

 

[psdguy95]

I am using amsoil 5w40. I have 500 miles on the oil since it was changed. I had my tuner tweak the tunes and its cured the loping on start up. But I'm still fighting the random rough idle.

 

[Justin@DP-Tuner]

I am using amsoil 5w40. I have 500 miles on the oil since it was changed. I had my tuner tweak the tunes and its cured the loping on start up. But I'm still fighting the random rough idle.

Okay. Random usually means it is not tune related. Normally something mechanical or more commonly, electrical. I would suspect the IPR at this point.

 

[psdguy95]

Okay. Random usually means it is not tune related. Normally something mechanical or more commonly, electrical. I would suspect the IPR at this point.

My ipr duty cycle when it's running smooth or not is about 10.9% ish. Icp fluctuates too fast for me to read it but I thinks it's between 450 and 550psi at idle.

 

[psdguy95]

I shouldn't say it's a random rough idle. It feels more like a random miss fire. The whole engine and truck shakes when it does it. But it smooths out as soon as I start giving it throttle. If I run a buzz test all 8 injectors buzz. My fuel pressure is good too. I don't have s scan tool but I would really like to run a cutout test when it's doing it so I can narrow it down better

 

[BS Hauler]

Maybe have them raise the idle by 50 rpms in the tunes.

 

[Justin@DP-Tuner]

My ipr duty cycle when it's running smooth or not is about 10.9% ish. Icp fluctuates too fast for me to read it but I thinks it's between 450 and 550psi at idle.

The duty cycle does not indicate a physical location of the valve/needle in the IPR. It is the commanded location. If you are having issues with the valve/needle in the IPR sticking, it will not matter what the duty cycle says to do, the needle is stuck.

When I had a bad IPR, it was fairly random on my truck too. Normally at idle. It would feel as if the injectors dropped out for a millisecond and then picked back up. This actually happened with a brand new Motorcraft IPR I had just installed a few thousand miles before the issue started.

 

[psdguy95]

The duty cycle does not indicate a physical location of the valve/needle in the IPR. It is the commanded location. If you are having issues with the valve/needle in the IPR sticking, it will not matter what the duty cycle says to do, the needle is stuck.

When I had a bad IPR, it was fairly random on my truck too. Normally at idle. It would feel as if the injectors dropped out for a millisecond and then picked back up. This actually happened with a brand new Motorcraft IPR I had just installed a few thousand miles before the issue started.

True. I didn't think about it like that. Thanks for clearing that up. I will get an ipr ordered and throw it in when I get back from my trip to Tennessee next week. Another thing I noticed is that my icp sensor reads 14psi koeo after sitting all night. Is this normal? I'm so used to working on the new international junk so I'm not too familiar with what readings are normal with 7.3s

 

[Justin@DP-Tuner]

True. I didn't think about it like that. Thanks for clearing that up. I will get an ipr ordered and throw it in when I get back from my trip to Tennessee next week. Another thing I noticed is that my icp sensor reads 14psi koeo after sitting all night. Is this normal? I'm so used to working on the new international junk so I'm not too familiar with what readings are normal with 7.3s

That sounds like it is reading absolute pressure for some reason. Mine does not do that. With KOEO, mine shows 0 psi.