Injuneer

If its the passenger side O2 sensor harness bundle, its a ground wire that attaches to the block. See Shoebox's harness photo:

http://shbox.com/1/harness.htm

pro94lt

Thanks Injuneer that's it, I got the harness out and looked it over, nothing caught my eye so I'll move onto the pcm and coolant temp sensor, Also I changed my compression with a recent engine rebuild from 10.4 to 8.75 with a much heavier forged piston, I'm starting to wonder if the compression and heavy pistons are causing problems. It was running alot better than it is now before I pulled the engine. Also while my pistons were on backorder for over 7 months, my pcm was unpluged laying on the work bench.

pro94lt

OK is it safe to weld with everything still hooked up? Just hit me that I did it.

pro94lt

Come on anybody welded on their car?

ACE1252

My Dad has welded on my exhaust system with the battery hooked up. I have had no issues, but the electronics were on the other end of the car(for the most part).

What did you weld? Where on the car? Where was your ground cable, for the welder, located during the welding?

Injuneer

When I've had work done on the exhaust system, they pulled the battery cables. I'd also pull the O2 sensors if I was welding the exhaust.

pro94lt

I welded on the exhaust right under the transmission tailshaft, The alignment shop drug my exhaust loose when they drove it on the rack. I did'nt realize it untill it came loose while running about 60. They didn't bother to tell me.

From what you have seen over the years have you seen a bad running car only in close loop do to anything other than bad o2's or an exhaust leak? From what I've read from searching and talking to others that seems to be what it always is.

T WS6 A

If you unplug your o2 sensors from the harness will the car run in open loop? My car has had the same problem after the header install a few years ago and I never got it running perfect again. The car would always search for idle in closed loop so I just turned the tb screw out a little more and it holds idle now but still has a slight miss. Im wondering if I unplug the o2 sensors, the car might run smoother untill I can get them tuned out and run in open loop all the time. Sorry for hijacking the thread

pro94lt

Runs great but a bit richer in open loop with the sensors unhooked, I'm gonna take the belt off the blower and see if it runs ok that might tell me It needs a better tune for the blower.

pro94lt

I unhooked the supercharger belt, it ran really bad for the first couple of seconds searching around, after it learned itself the problem did not seem to exist. throtle responce was great even in closed loop, it did not die when i turned the air on, and it idled fine. Seems to be ok with the belt off. This tells me I need a better tune, any thoughts?????????????????????

pro94lt

got codes 16, 42, 41, 36, 51 deleted them and code 36 came back and stayed I kept deleting it and it stayed for about 5 min. now is gone. Bad opti?

pro94lt

I've spent alot of my time in the last couple days driving my car I also got another new 02 sensor (warranty) borrowed an iac, icm and coolant temp sensor, the one in the water pump. I've gotten no codes however it seems that my problem is getting better or either the o2 sensor helped. the others did nothing. Is their anyghing you guys can think of I need to check? It now will idle without the a/c on and sometimes will with it on but when the compressor engages it usually surges around and idles down then up and dies. while driving if I clutch it while coming to a stop it will sometimes die once rolling around 5mph never if I clutch it if going fast.

johnnyb

Its been a couple weeks so hopefully you figured this out, but i'll offer a few suggestions. When my opti went bad, I had some of the codes you did including 16, 36, 41, 51, and 42. You say it is a problem with open/closed loop, but are you 100% sure? Are you positive its not just a temperature issue? Some people (myself included) have had trouble with the icm overheating... possibly try the icm cooling mod found on shoebox's site. I've also read time and time again, if it sounds like the opti, its probably the.... opt i

Something kind of random though, ...does your speedometer work correctly? I recently had some troubles with my tune because my vss was messed up and the pcm was not switching out of the idle fuel cells because it always saw 0mph, which became a problem when it tried to run closed loop.

I dont know anything about autoxray i've always used freescan and datamaster, but i suggest posting a log from datamaster (free trial) to see if someone else can see something you're not seeing.

Good luck!

pro94lt

I need more than luck! I need a lt1 witch doctor, no its not fixed. I am still trying to decide whether to buy 2 new delphi o2 sensors or get the cable and logging software. Since the last time I posted I unhooked my maf and it ran much better,and in act of extreme joy I purchased a maf thinking my car would be fixed. installed and the same issues. I cannot rule out its a heat issue, I can rule out that it does not act up in open loop and I am thinking it's my bosch 02's since it runs fine cold in open loop, a few seconds after it hits closed loop it will stumble, and once it has been driven for another 10 or 15 min it is not nearly as bad. I Really don't understand why my plugs still look brand new it was running so rich it would burn your eyes if I left it running in my shop for a while. o and my icm is mounted on my procharger bracket off the head, it's not spaced away with the washers. I've traced every wire, plug tested everything twice. One thing I have not done is have someone look at my logs. And it does work and my cells shift from 16 at idle to 18 and 10 maybee more but those are what I remember. I'll space the icm away from the bracket. As soon as I can I'll post some logs. Thanks

pro94lt

I broke down and purchased a new delphi opti since my BRAND NEW EBAY opti had a mind of it's own, purchased tunercat and messed around with the tune (knock on wood). I raised the iac counts in anticipation of the ac and some other basic things related to speed and idle. Thank you to everyone that helped me out. It took around a year from when I blew a head gasket to now to get it all back and running right. Thanks again