Well went to smog my Renix today and she failed with flying colors lol. Ive replaced: head gasket, VC gasket, RMS, oil pan gasket, cap, rotor, plugs, wires, oil pressure sensor, catalytic converter and thermostat.
The measurements were: HC: 15mph-203 (max-123) 25mph-213 (max-103) CO: 15mph-2.83 (max-0.73) 25mph-3.33 (max-0.93)
NO (ppm) was good.
It was a pre-test so it didnt send the results to the state, and im glad because she was labeled a gross polluter!!
Seems like im running way super rich, but i dont have a check engine light and the car idles great. But then again i just realized that when i cycle the jeep on, the check engine light doesnt even cycle on so its prolly burnt out. Somebody help me out id like to actually fix the issue. But if not ill be visiting the special smog man hahaha. Im thinking maybe the O2 sensor is out and i just dont know, cars runs and drives great, no stumbles, misfires or hiccups.
RENIX is pre-OBD, so no CEL/MIL and no DTCs. The light isn't burned out - it's just not there in the first place (the window for it is a holdover from the GM V6-173, which used GM OBD-I controls.)
Did they check NOx? What were your CO2 and O2 levels? In cases like this,
all numbers are instructive, pass or fail (my usual advice is to take a picture or scan of the actual report and attach it to the post.)
Elevated HC and CO mean either you're running rich (probably a HEGO failed/failing. Replace with Bosch or ACDelco - I've had good results with both, but Bosch is probably a bit more common.
DO NOT use a "universal" type sensor - it
will not work!) or your fuel is in trim but is not being burned all the way (typically caused by an incipient ignition failure - check the secondary wiring, the cap, the rotor, the plugs, and the coil. Make sure the plugs are gapped properly. The coil may be tested with an ohmmeter - I don't recall the specs, but they can be looked up by someone here if you can't find them in a search. Test
both sides of the coil - a failed/failing winding leads to depressed spark energy, which leads to reduced combustion efficiency.)
When was the last time the HEGO was changed? Spec life on the thing is 60Kmiles or so for OBD-II. OBD-I gets away with pushing out around 80-90Kmiles, usually, and I did finally replace a RENIX (factory original!) after the signal started to degrade - at about 190Kmiles! As control systems get newer, they're less tolerant of "fuzzy" signals (part of why I don't like them...)
However, it won't go amiss to check your secondary ignition circuit - which can be done in something inside of an hour using your eyeballs and an ohmmeter. Easy and cheap - and if the problem is there, replacing the HEGO won't fix it anyhow.
Figure about $70-80 for a replacement HEGO sensor. If you don't have a HEGO socket, you can usually pick one up at the local (you can remove the old one with a wrench, but properly torquing the new one is not advised - it has a torque spec, and exceeding it will cause you loads of trouble later! The manual spec is for "clean, dry" fit - but the replacement HEGO usually comes with a small packet of never-seez. Don't get any on the sensor tip, but put it on the threads and torque to half of book value. You should be able to find the spec on my site, in the Tech section - link in sig.)
Ed - just saw where you'd changed cap/rotor and wires, but did you
check them before you put them in? I've run across cases where someone had returned a (used) cap for a refund (which is why I always check parts - particularly electrical parts! - before I pay for them! A good counterman will understand...) and I've had a couple of spark plug wires that failed test right out of the box (which is why I take a DMM in when I'm buying anything electrical anyhow. I'm paranoid - but anything electrical is a "You install it and it's
yours" part...)
