I have a 89 Automatic Camaro, TPI, 305. Two weeks after buying it, the tranny started slipping. After that was fixed, my roommate and I did a throttle body coolant bypass. The car started running horribly, so we reversed in, but within a two week span, my distributor cap/rotor were burnt, I had to get a new MAF sensor ($500!!!) and a now a new Idle Air Control sensor.

I also seem to be running rich, and he can't figure out why as he says the mixture is controlled by the computer, and we've run a scanner on it and we have no codes for anything i.e. oxygen sensor.

The only other modification we've done is putting in K/N air filters, and putting an aftermarket fan switch on it which has the fans come on at about 170 degrees (add on to existing fan switch). Is there anything with the car running too cool maybe which is causing this or this Hayden fan switch screwing around with computer settings maybe? Please help!!!1

 

...also....runs super rich while idling, to the point where it's so rough it shuts down. Timing is fine, fuel injectors are fine.....any advice?

 

Welcome to thirdegn.org

If you're obviously running rich, yet the O2 sensor is switching normally as viewed by your scan tool, then I'd suspect the O2 sensor needs replacing.

You have to keep in mind that codes set when a sensor output is detected to be OOS, not necessarily indicating a sensor is bad.

 

Just another point, regarding your second statement, is that your 170°F fan control probably isn't doing anything unless you have changed the factory 195°F thermostat. If no coolant is flowing to the radiator, there will be no heat for the fan to extract at 170°F.

If the thermostat was changed to a lower opening temperature, you must also alter the factory EPROM in the ECM to operate with the cooler engine temperatures. Factory parameters require that the coolant reach at least 176°F for full closed-loop operation and mixture control. You can generally get away with a 180°F thermostat without altering the EPROM, and that 15°F can make a significant difference in operation in hot weather. Again, setting the fan control below the thermostat opening temperaturte is useless.

As for the rich condition, I'd suggest following Mike's advice and checking into the O² sensor if you haven't already replaced it within the last 30,000 miles. A weak signal from that, coupled with potential enrichment form a lower than expected CTS can really make for a rich condition.

 

Hi Vader, thanks for your tips. Now how do I alter the EPROM in the computer?

 

At a minimum, you'll need one piece of hardware that can read/write PROMs. Pocket Programmer II seems to be a popular unit, and they can be purchased for about $150.00 or so.

You'll also need some software that can interpret the retrieved data, edit it, and write a binary file that the PROM writer can use to write teh blank EPORM.

The software can be purchased, or there are some pretty good freeware programs available.

You can find a lot of information on the "how to" on the DIY PROM Board.