When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I’m working on an 89 IROC 5.7 TPI and it keeps failing AZ emissions tests. After failing the first time, I replaced the gas cap, new fuel, spark plugs, wires, O2 sensor, distributor cap, rotor, fresh oil change and it failed again. The previous owner had a Hypertech chip in there, which I have just swapped back to the OEM one, and I haven’t tested it since reinstalling the original eeprom.
Does the Hypertech mess with emissions output on these cars?
Those chips generally alter open loop fueling - WOT, PE, etc. The closed loop is still going to target the same stoich AFR and dither for the cats using the NB O2 sensor. Should still pass with a chip.
I think the problem is more that due to the chip and thermostat running it cooler the engine can’t burn off the carbons inside and just sends it all right out of the exhaust, hence most likely why it’s failing.
I think the problem is more that due to the chip and thermostat running it cooler the engine can’t burn off the carbons inside and just sends it all right out of the exhaust, hence most likely why it’s failing.
