Ok, short back story. I had a 90' FC, that ran fine. Body was a bit worked. I aquired an identical 90' FC with a bad engine but a good body. Decided to swap my good engine, into the good car. I completed the swap, started up and ran fine. However, after about 15 minutes of driving, i get the dreaded "27" Engine code. Car goes into limp mode. Clearly this is an oil metering pump issue.

A buddy and I checked everything out as stated in this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-mop-ecu-failure-diagnosis-710938/ as well as anything else we could think of. Looked at how the FSM describes how to check it.

We checked everything. I had the ecu from the current car, and even swapped the old one, with the same result The ecu checks out fine. Nothing looks or tests to be burned out. Checked the harness between the connector to the ecu, and that checks out fine. Checked the OMP itself, and that checks out fine. No signs of any sort of shorts or anything. In theory, it should be working fine. But i'm still getting the light and going into limp mode. The engine, engine harness and ecu are all the ones that previously worked in the old car. I've got premix in it for the time being, but i'd like to get this sorted out.

So i'm wondering if there is anything missing? Is there anything outside of the OMP system that could be causing this? Pretty stumped on it at this point because I feel like i've checked everything. Any help is greatly appreciated.

 

the OMP is probably going over resistance when it is fully warmed up, it is fairly common for them to begin to fail only on hot days with the engine fully warmed up. testing the unit may give passable results.

 

So do you think if I ran this guy to full temp, and then tested it before it had a chance to really cool down, I could get the bad readings?

 

that is what i would do, not alot else you can do aside from swap it with a known good unit.

 

Cool thanks for the insight. I'll get it checked out and report back.

 

What are you trying to do? This is why the ecu retains error codes. If that omp throws a code, don't keep trying to use it. Use the omp from your other car, or swap in an known good omp. Or buy a new omp.

Point is, if the thing is throwing the code, replace it before you burn out the ECU. The ECU won't take out the omp, but a bad omp will take out your ECU.

If you *must* heat it up in the oven to about 200* then test it. Then replace it even if it tastes good. tests!

Good Luck!