Alright guys, here it goes. I'll try to make it short.

00 f550 7.3 with 6 speed

Truck one day last week lost power. Barely ran, and stalled. Couldn't get it restarted. Replaced fuel filter. Truck barely ran but ran. Still no power. Thought it was the pump. Replaced pump, nothing wrong with old one. Cleaned fuel bowl. Cleaned fuel return regulator. Truck ran and had some power. Still wouldn't built good pressure. Replaced fuel return regulator. Truck built 65 psi. Didn't hold that pressure at first, but now does. Air must needed worked out. But, still have a slight miss/rough idle. The roughness goes away as the idle is brough just over 1000rpm. But when shifting it will act up a little more, and then builds up and goes away it feels like. Don't know if this could be injector, sensor, flex plate. Need ideas....Heres what I did

-Dissconnected icp, no change.
-Took off valve covers and ran truck, no obvious injector problems. Tried cutting them out with just unplugging but could not find one that was more prone to miss and less of roughness.
-Ran truck more to see if there was more air in system.

Any other ideas? I'm kind of out of ideas. We might take it to a dealer to get them to run a cutout test. I think i've heard that the flex plates can crack on these? Any way to tell besides pull the trans? Anything and everything you can give me is appreciated.

 

Have you done the intank mods to do away with the socks that get stopped up and RESTRICT the fuel?
How old is the CPS?
Was the UVCH plugged in good on both sides of the valve covers?

Welcome to guzzle's In-tank Hutch Mod Web Page

 

Remind, or refresh because i forgot. This is a work truck, with utilty body. F550.

-But no, no intank mods done yet.
-I switched the cps with a new black one from IH and ran just the same as the one that was in their, so switched it back.
-Yes, the UVCH was good. I did the .50 cent mod about a year ago to it.

 

O.K..I will bump you here so others will see this.We will get this figurred out.Sounds like you are plenty mechanically inclined.Hold off on the stealership until somemore folks see this.

 

10 4. Yea, this situation just gots be puzzled a little. Well heres to bump it again to find someone who might have had this same problem.

Also to add, because i forgot again. Oil was overfilled by approx. 3qts. I suspected fuel might have diluted it so i drained and refilled with fresh. I sent the oil sample off to get analyzed also. This is my service truck for work, so they will pay for it

 

If you had low fuel pressure before and the pump and FPR were good, the metal tanks in the trucks like yours have been known to have the coating liner come off inside the tank which can cause all sorts of fuel restrictions.

Also starving an injector of fuel and introducing too much air might cause an issue with the injector. I'm guessing when you removed the valve cover you were watching the oil discharge from each injector in addition to just unplugging them? Was discharge the same on all injectors?

Do you have gauges on the truck? Running a tune with a 4.88 rear end would make it a lot more easy to overheat than most of our trucks. How rough is the idle and is there any pressure out the oil fill tube?

 

TPS/APS ?

I have a miss and sometimes an idle issue.. Never had any codes. I tested out the TPS/APS with my volt meter and it was all over the place.. However didn't have any codes.. Not until a couple days ago.. Now I have a TPS code.. So hopefully the one I ordered will fix everything..

 

Yea, i have heard the coating coming off from the inside. Our newer trucks, the 03's had that problem. The 00 does not have that coating. Another truck of ours same year and model and everything was rusting at the top of the tank on the inside, but there was no coating.

Yes, i did watch the discharge. They all look approx the same. With no way to measure it was hard to tell. But from what it looked like, they all were close.

No gauges on the truck. no tunes on the truck. Bone stock. Work wouldn't let me do anything to it. The truck shakes pretty good, almost doesn't feel like a miss, but just rough. Like something is way out of balance. Or if one or two injectors are firing, just not the precise metered amount needed. Once the rpm is raised to 1000, the truck smooths and doesn't shake as much. I at first thought ya know, cps, a timing issue, but no luck was found there.




I'll have to check that out tomorrow. Its a start, Thanks fellas

 

Chris, what's the oil out the fill tube mean? I know of this rough idle issue, mine is starting to do the same.

 

Not oil,pressure,he is trying to see how much blow by it has.If you take the oil cap off and sit it upside down on the fill tube it should sit there or rattle off....not blow off.

 

Well, no fuel in the oil. So theres one to cross off the list. No pressure out of the oil fill tube.

I pulled everthing off it today to fix some oil leaks. Pulled turbo, found lots of oily soot inside the compressor housing going into the spyder. I guess this is normal. Cleaned up the pedistal and deleted the ebpv. Put it all back togethere. Truck had pretty obvious boost leak at lower orange boot to head. Buttoned up. Ran truck. Still ran rough but has power. Took for a ride. Brought back in, started getting pissed at the rough idle and ****. Standing around the truck and boom....The da*n thing starts to idle smooth. Just like out of nowhere it stopped running rough. Man was i excited, the air is finally out? Well drive it more, have other people drive it. Lots of power. Bring truck back in, and guess what, back to rough idle again.

We have no access to a scan tool to see the icp duty and ipr. I think i'm just going to replace them before i go replacing injectors. Any other ideas???