Alright so I pulled the codes off my 1990 Supra turbo and got codes

25:Air-fuel ratio lean malfunctioning

26:air-fuel ratio rich malfunctioning

51:Air conditioner switch or neutral start switch signal

umm, so where do I start? What can be causing this?

I just recently bought the car and have been getting a check engine light since the trip back home. :(

thanks in advance

hmmm.. check the wiring on the 02 sensor, make sure all looks fine... particularly in the plug

code 51... when you did the diagnostics did you have the a/c on?

if you didn't
then code 51 is also TPS

which if out of adjustment could throw the check engine light i guess.... never experienced tps problems personally

try resetting the ecu (pull main and efi fuse for 30 secs) then plug back in (make sure your ignition isn't on at the time heh) go for another run and see what happens.. obviously don't boot it as we're problem diagnosing ;)

well the o2 sensor took me forever to find, mainly because I thought it was connected to the exhaust pipe <_< I checked the sensor and the plug that the wires connect to and found that one of the wires is broken. Maybe this is the cause? Another question I have is about the egr block-off plate. What are they and do I have to remove it to pass emissions. (Georgia, U.S.A.) The car has a custom dp, a test pipe, and a custom exhaust. If I replace the test pipe with the stock cat should I be able to pass emmisions?

Thanks a bunch suprra_girl

oh, and I didn't have the a/c ... what exactly is the tps? sorry for all the questions

I didn't get a chance to reset the ECU, but something that's been bugging me is that codes 25 & 26 are supposed to be for California cars only. The california cars came with a sub-oxygen sensor and an egr gas temp sensor also (which is why I'm wondering if blocking the egr may have something to do with this). I will try to find a new plug and reset the ecu tomorrow. Thanks again.

BTW, could code 51 be because a jdm engine was installed (don't know if it came off an auto, my car is a 5sp)

disconnecting the battery for a minute or two resets the ECU

tps= throttle position sensor

well... i guess the tps could be out on the jdm engine... i'm not sure exactly how they get out of spec but here's the link to adjusting the tps
http://www.cygnusx1.net/supra/library/TSRM.../fi/FI_101.html

hmm i can't see the egr causing rich/lean problems

make sure your tps is in spec... once it is.. reset ecu then go for a drive round the block.. come back and try again for codes

let us know how you get on