This is the 2003 truck I just put a bank of injectors in a couple weeks ago. It's a construction company support vehicle. The owner rarely drives it; it's usually one of his employees. It did have a no-start a few days after the injectors went in. I went there and hooked up to it and it had essentially 0 ICP with 85% IPR duty cycle. I figured it was a bad or clogged IPR and he trailered over. The next morning it lit right off and ran like a top. I ran it for hours without as much as a little stumble. Shook wiring harnesses, poked and prodded, and nothing made it run poorly at all.

Yesterday, one of his guys told him it was running like dog (excrement). I took the truck and drove it hard and easy, highway and back roads and the thing runs smoother than a sewing machine. One other thing I noticed is that it had an EGR code (I believe it was P0403) that it didn't have before. I cleared it, and it hasn't come back (yet). EGR commanded and actual are nearly identical to each other in the data stream.

I logged data for the whole ride, and the only thing I'm not sure about is the max IPR duty cycle. Idle at operating temperature is about 23% and 640 PSI. It hit about 77% at 3620 PSI under WOT. Is that out of line, or is it about average?

 

Your numbers are not out of line, I actually asked the same question a few weeks ago.
Your IPR and ICP at OT/idle might be on the upper end of acceptable but from what I am told and have read are still ok.
I have an 03 and at WOT my IPR is around 75% with around 3700 to 3800 psi, pretty close to what you are running. EGR is deleted.
If you were running 77% and only 3000 or less then you might be flirting with a leak. Keep in mind these early builds don't have the better HPOP design so you might not see 4000 psi on them.(again, not from my experience but gleaned from other threads and posters)

 

The early HPOP generates more pressure than the 05+, however, it is a more fragile design prone to failure.

Numbers look good.

Josh

 

Almost mirrors what a friend of mine went through with the construction company truck he wrenches for. Have you checked fuel pressure at all?

 

03 running poor randomly is often caused by icp sensors and connectors

 

Is there a better alternative? Hard to believe someone can't make a more robust sensor that more often than not also trashes the pigtail.
On the flip side I'm sure at this point in the game nobody is going to make one either. I do wonder if it's worth relocating the ICP, seems I have read of that being done, wonder it it's worth the hassle.

 

Nope... I am on my 3rd and never have replaced the pig tail.

 

Thanks. I just wasn't sure if the IPR duty cycle should climb quite that high, but if it's normal, I'm fine with it.



Not under load yet, but it pops right up to 60 PSI at key on and the truck doesn't run like it's fuel starved.


I put in a new OEM ICP sensor and pigtail when the injectors were done. ICP voltage and PSI numbers match up.

I told him I want to go for a ride and log data next time it tows a piece of equipment, but I'm starting to wonder if his guys are telling him the truck is running poorly because the front end is shot (there isn't a joint or bearing up there that doesn't have play), and they just don't want to drive it . . .

EDIT: Power balance test, which was all over the map before the four new injectors, is now about as flat as it could possibly be.

 

Just to update this, I've driven the truck home for the past several days and put about 150 miles on it. It runs great. I guess I'll have to log some data next time they tow with it . . .