Oct 26th, 09, 04:34 PM
I have been running my 69 with 96 lt1 all sunner, almost 2500 miles, but i keep getting o2 sensor faults. Changed o2 sensor ran good for about 200 miles, but then came back, Pulled sensor it has a lot of black carbon on it,
Changed plugs twice, Running mid lenght headers sensors in collectors.
can anyone tell me what to try to solve this problem.:confused:
Oct 28th, 09, 05:53 AM
I had an issue when i put long tube headers on my 97 trans am. I put in some bosch ones and same thing good for a while then went to crap. I ended up putting in the AC Delco ones and havnt had a problem since. Can't guarantee that is what it is though.
Oct 28th, 09, 02:40 PM
Bosch sensors will not work period with many American vehicles. Not necessarily true for newer ones. They are manufactured to European standards but still shouldn't cause your problem. Just shying you away from bosch. Delco is what you want.
The problem is most likely due to the heater circuit is failing on the O2's. The bad thing about the LT1 is it has no check in the computer for heater circuit resistance. Doesn't happen till 04.
What you want to do is turn your key on to run position... DO NOT START.
Get a DMM unplug your O2 sensor and check to see if any current is coming from PIN D (brown on engine side and pink on connector side)
Problem is when doing harnesses, if you did an emissions delete, and are no longer powering those circuits it usually includes the heater o2 circuit. If you are not getting current there you will want to check fuses if the harness is not done for it you will need to run wires from an ignition source with a 10-15 amp fuse.
EDIT::: I thought this sounded familiar... Do yourself a quick favor and just wire in your own 02 heater circuit power wires and ground PIN C the black wire directly to the transmission. 100% eliminate the possibility of anything messing with the heating circuit current. VERY important with headers where heat at the 02 sensor is significantly reduced. If you have your harness set up most with multiple sensors off one circuit depending on draw it will lower current at the O2's because its most likely in parallel where voltage will be constant.
Oct 30th, 09, 12:25 AM
Two things come to mind:
1. Do the bungs in the headers position the sensors so that the tips are at a downward angle? Crud and moisture can accumulate in them and take them out if not.
2. A '96 LT1 if using the original code uses sensors after the cat to provide feedback for catalyst efficiency. Not having sims if they are removed can cause codes and other issues. Michael is no doubt a lot more well versed in what the exact issues are than I am.
A friend of mine had a problem with a Mustang without the cats and with the secondary sensors still installed that only reared its head at 40 mph. Forgive me because I can't remember his exact wording but based on his data logging, without the sims the computer kept dumping fuel in at and only at 40 mph for some reason. He just eliminated the secondary sensors in the program though. During all that time of having the problem, he only got a code once.
Oct 31st, 09, 11:43 AM
The rear 02's shouldn't cause problems. Its just O2 efficiency. If you don't want to throw codes they can be disabled but it won't affect performance. I am running no rear o2's in my 96 truck just sets a code.
Nov 2nd, 09, 05:35 PM
Sorry for the long delay in the reply guys, The wiring harness is from Street Performance it has had the emisions deleted, Only set up for one set of o2 sensors, The ones I've been using have been Bosch, Sensors are positioned with tips facing down, They are 4 wire senors. Don't have cats, but computor is suppost to be set up to run without cats. Radcannon can i still do the check you explained above.