1997 Powerstroke Lope on startup
 

Hey guys, I've posted this question to a couple of other forums and haven't been able to find anyone with the same problem, and no solution:(

When I first start my truck, it "lopes" or surges and will not stop until I hold the throttle at about 1000+ rpm for a couple of seconds. When you let go of the throttle, the rpms come down to about 500 for a second and then rise back and steadies out at its usual idle speed, 700ish. Once its running, it runs fine.

It is a 1997 with a ZF5 swap. I have changed the IPR, ICP, and CPS. I was told it could be the transmission range sensor from the E4OD, but I've ruled that out with troubleshooting also. Someone suggested I try a tuner, so I did and although I like the way it runs with the tuner :) it didn't fix the starting problem.

It also seems to be worse when the truck is warm, which makes me think its something electrical?

Please help me!

Thanks

Did you use the PCM from the manual truck? If not, that's your problem.

Your PCM is searching for the TRS. There are quite a few threads out there that cover this.

would this happen right away? Because the truck ran for close to a year with the new trans before this started happening.

Yes.

Did you use a factory ZF5 harness or did you splice the old E4OD harness?

I left the harness as is. My reverse lights and cruise control don't work but I decided to live with it until I had more time to clean up the install. Does it sound like this is my problem? I am no master mechanic but love to work on it and am learning a lot.

That is where I would start.

If you shift the TRS into Neutral, does the lope go away when started?

no it didn't go away when i tried that. I might try it again just to be sure because it was a while ago that I did it. But I'm assuming its not that right now.

I have a very similar issue. I just replaced my starter (sluggish, wouldn't hardly start) and now i have issues with it loping, every once in a while, Mainly on a cold start.

Mine does it every time, and it is worse when the engine has been recently run and is hot.

I have a 1996 f250 powerstroke and also did the zf swap and have the same problem lopes when I start no matter if it's warm or cold but steadies out if I hold at around 700rpm and runs fine still have all the automatic wiring and computer

Mine used to do this. When was the last time you guys changed oil? Is the oil level low? The injector run off of high pressure oil, so make sure you have enough oil. That was my issue. I changed oil and it was fine after that.

I don't think it's an oil problem in thinking it's a sensor of some sort was going to get a new IPR sensor and try that I have always run 15 40 synthetic oil

It's because the PCM is looking for the trans range sensor.

If you still have the range sensor you can plug it back in and put it in the N position then tie it up out if the way

I meant more oil level than oil condition.

Well that was an easy fix thanks man I love when you don't have to spend a bunch of money for nothin