hey all i know everyone and their brother has asked these question but here they are. First i guess i should tell you about my ride its a 1990 gtu w 140k miles on it.

1. should i premix ?

2. if i do will it clog the cat?

3. what brand of oil should i use if i do premix?

4. does anyone have pics of the process of removing/blocking off the omp?

 

There's bound to be some difference of opinion on this topic, but I would say that IF the car is a daily driver AND IF the current oil-metering system is intact and functioning properly, THEN I would not choose to run premix.



If you do choose to run premix, use only TCW-3 certified 2-cycle oil, and use the correct dilution (something like 100:1, I think?). If you use too much, it will likely cause problems with your cat.

 

1. no, the stock ecu wont let you take the metering pump out. if you're running it really hard, then adding a couple oz of premix to the tank is ok

2. the stock setup injects oil, if you keep the premixing close to stock, the cat will be fine. if you put so much in there that it smokes like crazy, then the cat might no like it

3. anything TCW3

 

so if you remove the OMP from a S5 what happens..??? why wont the ecu let you remove the OMP..???? does the ecu cut spark or fuel or somthing if you remove the omp..??



Because I have swaped a S5 Turbo II into my FB and I used a GSL-SE front cover for the swap, and the S5 OMP will not bolt up to the GSL-SE front cover..????



So if it is true that you can not remove the Oil metering pump from a FCS3 with out having problems with the ECU. How can you swap a Turbo II into a FB and still have it work with the stock ECU????? Cuz the OMP from a S4 nor a S5 will not bolt up to a 12A front cover or a GSL-SE 13B front cover..??????

 

I can't replace the banjo bolt with a normal one? with the omp still in will it still throw a code and go into limp mode?

 

The series 5 engine (1989-1992) uses an electric metering oil pump, not a mechanical on as found on earlier models. When the pump is unplugged the ECU will not allow the engine to run to prevent damage. Some people have gotten aroud this by plugging the electric pump in and leaving it hanging by the engine to fool the ECU. I suppose this could also be accomplished with a resistor, though that's merely a speculation.



Why are you not using the s5 front cover? Doing that would solve your problem, I would think.

 

as far as a mixture i run 16 oz of premix to 16.5 gal i have a gs with 215,000Mi on the stock block. I never have a problem but then again i also dont have a cat... or any emissions for that matter i also still have the omp still hooked to the carb, i guess i am a little paranoid after i lost a block at 125,000Mi before i knew anything.