ECU Problem

Hello all.....I am new to this site so please bear with me if you have answered this question before. I have a 1997 Spyder GS-T with a few mods (intake, downpipe, hi-flow cat, bcs restricter removal, mbc..). My area just initiated the OBD-II emissions. My car did not pass...the reading said that the vehicle was "not ready for testing" (none of the monitors were set). I had recently cleared a check engine light after replacing a coolant temp sensor. My mechanic told me to try to complete the Mitsubishi drive cycles which sould allow the monitors to set. Didn't work! I took it to a local dealership and was told that the cat and rear o2 sensor were bad. I didn't believe them (I got good voltage readings from the o2 sensors). I called another dealership and was told that I was indeed lied to. They told me that they could hook my ECU up to a MUT-II (whatever that is) and set the ECU to "increased sensitivity". They then drove the car to set the monitors and it passed emissions. Finally...down to the question. After driving the car for about 15min I rescanned the ECU and was saw that none of the monitors were set?!?!?! Does anyone know why they would do this? I am told once they are set they should stay set unless you clear them with a scan tool. I was also told that because they are not set that the ECU will stay in open loop (I think) causing a rich fuel mixture all of the time, which will not allow the cat to function properly. The dealership has no idea why it keeps clearing the monitors....HELP. Thanks in advance and sorry for the long post!

Well... the rear o2 wont cause you to run rich.
The front one will.

The front o2 sensor was replaced about 1yr ago...about 11,000 miles. I got good voltage from the scan tool about 0.92V @ WOT. I just need to know why the monitors won't stay set! Thanks!

well, you passed smog, so that is solved. is it driving strange? enough to warrant an inquisition? or are you just wondering why it isn't working as advertised.

I am under the impression that the ECU runs those tests every time its powered up. But unfortunately I dont know more about it.

My concern is that if the computer is running in open loop all the time it will always be running rich. My understanding is this will not allow the cat to function properly and rob me of performance.

Check to see if the STFT and LTFT are changing once the car is warm. If they are, its in closed loop.

just take the cat off and run a test pipe!!! it's a turbo and you need as free flowing an exhaust as possible anyway...

just take the cat off and run a test pipe!!! it's a turbo and you need as free flowing an exhaust as possible anyway...

Just make sure you still have a way of passing emission :)

Finally...down to the question. After driving the car for about 15min I rescanned the ECU and was saw that none of the monitors were set?!?!?! Does anyone know why they would do this? I am told once they are set they should stay set unless you clear them with a scan tool. I was also told that because they are not set that the ECU will stay in open loop (I think) causing a rich fuel mixture all of the time, which will not allow the cat to function properly. The dealership has no idea why it keeps clearing the monitors....HELP.

A coincidence? I have my Eclipse GST in the dealer right now for the same problem; the non-continuous readiness monitors will not stay completed. The dealer did the MUT-II setup and I passed smog ($120 is a lot for a smog certificate). I checked the ECU the next day and found the monitors back to not completed. :mad:

I had 2 out of 5 monitors completed during the first smog test, not enough to pass. The smog tech reset my ECU and told me to drive the car for awhile. Ever since, I have not seen a completed monitor using my scan tool.

Mitsubishi TSB 00-13-005 addresses the readiness monitor issue with 96-99 Eclipse and other Mitsubishis. The monitors are difficult to set without the MUT-II. But they should STAY SET after the ignition is turned off until the ECU is reset or the battery disconnected.

Some Mitsubishis (not Eclipse) will reset the readiness monitors when the ignition is turned off. These models are known to the State Emissions and should get a waiver for these readiness monitor tests.

I know a lot more about this issue but do not have a solution yet. Has anyone resolved this OBD-II smog test problem?