My 1990 GXL has just been rebuilt and is throwing codes 17(feedback system) and 27(MOP). Before I start tearing things apart I was wondering if you guys might have a slight idea about what could have triggered these codes. I was told the car has bigger than normal injectors, I think 550s but i dont see that causing these codes. The metering pumps oil lines have oil in them so im assuming it still works. Other than that the car runs great, im just paranoid and want to diagnose this before something bad happens.

 

Don't you mean ECU (Emissions Control Unit or Engine Control unit) rather than CPU which is the body computer and has no trouble code reporting

 

No idea what the feedback system is, but the MOP means that either the OMP (MOP) is disconnected or not working. Either way I wouldn't drive the car much until you get it figured out, or just premix for a little while.

 

I get those mixed up, I guess I thought they were the same thing. But yes its the ECU and code 27(OMP) went away but 17 is still there. I got some info from a Haynes that sayes 17 is Feedback System and that doesnt mean anything to me. Im thinkin about changing the O2 Sensor, that is about the only thing I can think of.

 

I had a Code 17 before on my 90 Vert. Mine turned out to be the 02 sensor, but not any 02 sensor. I had put a new Bosch sensor on but it still had the code 17. I replaced it with NGK #24036 sensor w/connector and it got rid of the code. I got the sensor at Sparkplugs.com for like $45. Not sure if this is your problem since you replaced the injectors, but it worked for me.

 

Thanks for the reply, I was kinda hoping it would be the O2 Sensor, and im glad you mentioned that the Bosh sensor didn't work because I work at Advance Auto and that is all we keep in stock. Looks like I'll be ordering the NGK sensor instead.