Vert has a CEl for OMP and just want to delete the omp and premix now. What would be the easiest and most cost effective solution to do this?

 

Finding a used RTEK ECU would be the most cost effective...but they're ancient.

Getting rid of RTEK was one of the best decisions I ever made, but that was a different time and it still is the most cost effective solution.

 

Some have removed the pump and put it on the side but left it connected.

 

With your S5 being over 30 years old, more often than not a CEL code issue related to the OMP is due to failing wiring. Corrosion & heat cycles really beat the crap out of these, and any intermittent open circuit or short will cause all kinds of electrical gremlins. Find a new (or like new) ECU/emissions harness and replace the old one if you can, or for the cheaper fix, get new OMP connectors & pins, some Tezel wire and proper sized butt crimps & heat shrink and rebuild the OMP part of the harness.

As for sources for new connectors, the 6 pin OMP connector is the same one as is used on the TPS, and you can get one of those here: https://lms-efi-llc.myshopify.com/co...-tps-connector

Not sure where you would find the 3 pin OMP connector, but since there's a pretty long pigtail of wire coming off the OMP, you can get a mating Deutch 3-pin receptacle/plug pair to deal with that.

 

On my 90’ GTU the previous owner removed the OMP and mounted it to the passenger shock tower.

Blocked off the injection ports on the rotor housings

Installed a block off plate on the front cover and began premixing.

The OMP is still plugged in

-M

 

^But simply moving the OMP while keeping it wired in doesn't solve the OP's root problem. He says he's getting CEL codes for the OMP, which since it's an S5 also means that the ECU is running the car in limp home mode. Need to fix the electrical issue that's causing the CEL, which is most likely bad wiring.

 

The most cost effective way to fix the issue at hand is to find a known good ECU and OMP and install them.

 

Not if the wiring is the cause of the problem. 9 out of 10 times I've had to troubleshoot OMP related CEL code/limp home problems, the issue was the wiring not the parts. And finding good, used S5 ECUs and OMPs is getting a lot harder and more expensive as the supply drys out.

 

Correct, the OMP needs to working if one were to pace it on the side of the engine, but I guess if you go through all that trouble, just might as well fix or install another unit in the original position.
When mine went out a few months ago, it was the pump. Everything checked out OK, so just installed a used unit and it was good to go.

 

I have had two failures which burnt the ECU as well. Usually the motor starts to pull excessive amperage from being worn and burns up wiring and takes out the ECU.