I was wondering if anyone here on Honda-Tech knows where I can get a copy of Emission TSB for 1991 Honda Civic that explains why car might fail. Don't want to pay alldata price for one TSB. Also what chemicals to add to tank for it to pass test. Any info would be great.

Thanks

 

Best no-cost option is ebscohost.com, typically available via your public library. Many libraries will give you a password so you can access ebscohost at home. There is one TSB in particular that might help; it emphasizes how the car is warmed up and must be kept idling and not shut off during testing yada. My 91 was failing emissions recently. I did an enormous amount of troubleshooting per various TSBs and the shop manual. In the end I think a new oxygen sensor might have fixed it. Hard to say. I sold the car to a person in a non-emissions county (disclosing the emissions problem; try to do the right thing and all). The problem with the 88-91 drivability CEL yada system is that a degraded O2 sensor may allow the car to run fine with even pretty good MPG, and no CEL, but your Civic will still fail emissions, because the sensor is sluggish. Fortunately a new OEM-make sensor (Denso) runs only around $30.

The only chemical I would add to the tank is Chevron Techron to clean the fuel injectors. A good throttle body cleaning using TB spray is not a bad idea, either.

Good luck. I think the threads here that most frequently end up unconcluded are the ones concerning failed emissions on older cars.

 

Thanks honda.lioness for replying to my post. Like you said I will check out the library for the ebscohost.com web site.
Thanks A million, Mar