installed my rtek last night filled her up with premix and she is running way better, no cels, it is hesitating/ backfiring now after 6k rpm, im thinking this is because I have no exhaust past the cats, which also look like the factory cats and they may be a bit clogged.

have never been a fan of the s5 oil metering pumps, they aren't reliable. even the FD pumps which are very similar and closer to a huge heat source tend to fail a lot less often.

though it sounds like your ECU was damaged, even though less evident than most, or the harness got cooked somewhere that also isn't readily apparent. premixing is better, though a bit more of a pain. it's also quite possible you just got another bad OMP, it happens a lot more often than i'd like to see.

Yeah I'm glad I was able to find an rtek n351 because they're pretty hard to find and rtek is no longer available. This 6k rpm thing I'm having now makes me feel a bit worried. Hopefully it's just the exhaust but it seems electrical. Do you think tps could be out of whack?

i had a car that had a wall at a similar RPM with an S5 n/a and it wound up being one of the secondary injectors wasn't firing.

The secondaries probably haven't been used in a while considering it's been in limp mode and hasn't been driven. I have to take the intake off to finish the omp delete so I might as well have the injector's cleaned while I'm there. Got a place by me that will do them 15$ a piece

yeah, if the car sat a while and hasn't used them one or both could be having issues.

If the OMP fails, 99% of the time the ECU must be replaced whether damage to board is visible or not. FYI.

that hasn't been my experience, i've actually not even seen a ECU burned out personally but had about 5 of the pumps go bad, replacing the pump fixed them.

It's finally been warm enough to work on this thing and I ended up finding my high rpm hesitation. I started looking at the plugs and wires that the previous owner said he replaced and noticed that all four plugs were leading plugs , it didn't have the correct trailing plugs. Put two bur9eq ngk plugs in place of the bur7eqs that were in the trailing holes and now it pulls strong all the way to redline. So new ecu with omp delete and two sparkplugs later Ive got an 89 gxl that pulls all the way to redline

Just a FYI the plugs shouldnt cause any issues.

I am running right now 4 Leading plugs and no issues what so ever, this is because i am waiting on back-ordered parts because the old trailings were fouled and in my experience i have not had any problems, no hesitations or idle problems.

AND people on here even recommend 4 trailing plugs sometimes so i would assume there shouldnt be any issues.

Edit: its just a hotter plug vs a colder plug thats it, no other difference.

Inspect the old plugs for cracks in ceramic. Heat range will have no effect on everyday engine performance.

Omp
 

I just bought a 1991 in Texas and was driving back to SC when the same problem occurred. I got the OMP codes. The car sat for a year or so before I bought it. Can the pump or lines be clogged because it sat for some time? OR do I just need to replace the pump and lines?

thanks,
Stephen

It's an electrical problem with the motor, not related to oil lines.

So much bullshit in this thread.