A
AEkrot
Guest
I have a 1996 LT1 Corvette (4L60E automatic, OBD-II). It has ported heads a Crane C.A.R.B. legal cam, 30# injectors, recalibrated MAF, stock exhaust, 3.73's. I had it dyno tuned and the tuner was able to reprogram the factory ODB-II computer- the car runs great and I don't want to mess with it.
Problem is, Texas recently implemented a new state inspection. My car has no EGR valve installed (just like the LT-4) but does have new CATS, all 4 O2's and passed the previous CO, HC tailpipe tests with 0's (very clean) but the new program doesn't care about tailpipe emissions for 1996 and newer vehicles. They trust the OBD-II computer to tell them if the car is running right or not.
Problem is, the cam is just a little too rough with an automatic transmission in gear for the stock program so the tuner had to turn off some of the OBD-II diagnostics because ECU program would misdiagnose the rough cam idle as a misfire. The EGR test is also disabled but I could live with putting the EGR back on the car (it just dumps so much soot in the intake) and I know that this would clean up the NOx during cruise thus improving the Houston skyline a tiny bit. I think the tuner also disabled the O2 sensor diagnostics since the idle was richened up some - the O2's notice the richer mixture but a tail pipe sniffer would not as long as the CATS are installed and working.
Turning off the OBD-II MIL indicator on any tests causes the state's inspection program to report a "not ready" test tatus, similar to what you would get on an ECU that had power removed and had not performed all the required diagnostic tests yet.
I am looking for suggestions and help on what to do next.
Here are the current options I have come up with so far:
1) find some idiot and buy an illegal sticker - not my preference but probably the cheapest and most expedient - I really don't want to do this.
2) Send my ECU back to the Tuner, get a "stock" like program and hope it will pass - get a sticker - send the ECU back to the tuner to restore my previous program - repeat every year - very expensive, both in down time and fee's
3) Buy a used ECU from a salvage yard - get it programmed with a stock program (I have access to a GM tech-II and can do this) - again, hope it will pass, get a sticker, swap back in my original ECU, repeat every year - cheaper than #2 above in the long term IF it works.
4) figure out what chip is the "flash" chip in the ECU. Buy another one of these chips. Remove the current chip. Install a socket. Program the new chip with a factory program. repeat as above. Cheaper providing I can find the rom and socket which are less common than the older 74xxx DIP style parts.
Returning the car to stock is not an option.
Any other ideas?
Alex
Problem is, Texas recently implemented a new state inspection. My car has no EGR valve installed (just like the LT-4) but does have new CATS, all 4 O2's and passed the previous CO, HC tailpipe tests with 0's (very clean) but the new program doesn't care about tailpipe emissions for 1996 and newer vehicles. They trust the OBD-II computer to tell them if the car is running right or not.
Problem is, the cam is just a little too rough with an automatic transmission in gear for the stock program so the tuner had to turn off some of the OBD-II diagnostics because ECU program would misdiagnose the rough cam idle as a misfire. The EGR test is also disabled but I could live with putting the EGR back on the car (it just dumps so much soot in the intake) and I know that this would clean up the NOx during cruise thus improving the Houston skyline a tiny bit. I think the tuner also disabled the O2 sensor diagnostics since the idle was richened up some - the O2's notice the richer mixture but a tail pipe sniffer would not as long as the CATS are installed and working.
Turning off the OBD-II MIL indicator on any tests causes the state's inspection program to report a "not ready" test tatus, similar to what you would get on an ECU that had power removed and had not performed all the required diagnostic tests yet.
I am looking for suggestions and help on what to do next.
Here are the current options I have come up with so far:
1) find some idiot and buy an illegal sticker - not my preference but probably the cheapest and most expedient - I really don't want to do this.
2) Send my ECU back to the Tuner, get a "stock" like program and hope it will pass - get a sticker - send the ECU back to the tuner to restore my previous program - repeat every year - very expensive, both in down time and fee's
3) Buy a used ECU from a salvage yard - get it programmed with a stock program (I have access to a GM tech-II and can do this) - again, hope it will pass, get a sticker, swap back in my original ECU, repeat every year - cheaper than #2 above in the long term IF it works.
4) figure out what chip is the "flash" chip in the ECU. Buy another one of these chips. Remove the current chip. Install a socket. Program the new chip with a factory program. repeat as above. Cheaper providing I can find the rom and socket which are less common than the older 74xxx DIP style parts.
Returning the car to stock is not an option.
Any other ideas?
Alex
