lt1 blues
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TECH Apprentice
Joined: May 2010
Posts: 333
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From: Arkansas
lt1 blues 
Car will run fine while in open loop, after it hits closed loop it will surge around from 850rpm's to 1500 but only sometimes, drives fine while accelerating. Seems to idle better with a/c off but if I turn it on it will surge around and sometimes die. Engine is fresh with less than 500 miles on and Did not do this before, or I think. It will also almost everytime die when I clutch it when coming to a stop. New cheap opti, bosch o2 sensors, Iac, and a swapped in a used Icm. I've gotten codes 16 36 41 and 42 severel times, after I cleared them they will stay gone for a while then seem to always come back, I've also gotten codes 46 and 51 2 times but don't seem to be interlinked. I don't think I've got an exhaust leak , I won't rule anything out. The only thing I changed after the build was the compression from stock down to 8.75 now it runs like this. Help I ran Bosch O2s for 2 years with no problems.
My car ran like that for a while but it was the fact that I cut and spliced my old o2s instead of using extensions. I just unplugged my mass air flow sensor so the car would run in open loop for a while until I could figure out the problem.
My car ran like that for a while but it was the fact that I cut and spliced my old o2s instead of using extensions. I just unplugged my mass air flow sensor so the car would run in open loop for a while until I could figure out the problem.
Thread Starter
TECH Apprentice
Joined: May 2010
Posts: 333
Likes: 1
From: Arkansas
Not ruling anything out, I've checked and checked for vacume leaks. And for the bosch's I swapped my old stock ones back in and got the same results, I will but don't really want to be throwing new parts at it twice.
Also what is barometric pressure volts, I'm assuming its my map sensor volts? mine stays around 4.88 to 4.9 volts my scanner has map sensor volts which is around 2v at idle.
And for the future unless it says delphi or ac delco on it its not going on or around this car!
Also what is barometric pressure volts, I'm assuming its my map sensor volts? mine stays around 4.88 to 4.9 volts my scanner has map sensor volts which is around 2v at idle.
And for the future unless it says delphi or ac delco on it its not going on or around this car!
Thread Starter
TECH Apprentice
Joined: May 2010
Posts: 333
Likes: 1
From: Arkansas
I unhooked my maf, it seemed to run better so I thought it was the maf sensor. I came across one for 20 bucks and gave it a try... same result. Why does it not idle bad with it unhooked?
Are you running the pacesetter "O2 Extensions" that you received with the headers?
If so, go ahead and throw them away. Like it was mentioned earlier, crimp connectors and garbage wires are not going to get any sort of quality signal to the ECU after an extended period of time of heat cycling and outdoor elements. Take a look on Summit and find the plug and play 12" or 18" O2 Harness extensions that have the water-proof connectors and the wires are loomed.
Like it was stated earlier, take a look at replacing the Bosch O2s with either AC Delco O2s or NTK O2 sensors. Some people have had luck with them, but as a majority people don't have much success running the Bosch O2s. Do a search in this forum, you'll see that come up quite a bit.
Lastly -- have you taken a look at your spark plug wires? Run you hand along each plug wire to make sure that there aren't any burns, cracks or nicks in them. I had an issue that drove me nuts for months which ended up being the plug wires. The car would run fine when it was cold, but once it warmed up the heat from the headers would interfere with the wires enough to cause it to stumble and miss.
Double check the wire that connects your opti to your ignition coil. It wouldn't hurt to go along all nine wires and put dieletric grease on them to help with connectivity while you're at it.
If so, go ahead and throw them away. Like it was mentioned earlier, crimp connectors and garbage wires are not going to get any sort of quality signal to the ECU after an extended period of time of heat cycling and outdoor elements. Take a look on Summit and find the plug and play 12" or 18" O2 Harness extensions that have the water-proof connectors and the wires are loomed.
Like it was stated earlier, take a look at replacing the Bosch O2s with either AC Delco O2s or NTK O2 sensors. Some people have had luck with them, but as a majority people don't have much success running the Bosch O2s. Do a search in this forum, you'll see that come up quite a bit.
Lastly -- have you taken a look at your spark plug wires? Run you hand along each plug wire to make sure that there aren't any burns, cracks or nicks in them. I had an issue that drove me nuts for months which ended up being the plug wires. The car would run fine when it was cold, but once it warmed up the heat from the headers would interfere with the wires enough to cause it to stumble and miss.
Double check the wire that connects your opti to your ignition coil. It wouldn't hurt to go along all nine wires and put dieletric grease on them to help with connectivity while you're at it.
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Thread Starter
TECH Apprentice
Joined: May 2010
Posts: 333
Likes: 1
From: Arkansas
My wires apear to be ok, I only have about 500 miles on the engine since I had it out, I'll check into the extentions and am either going to get new o2's next or purchase tunercat, which direction should I go along with checking the opti harness which I have tested, but will again. Thanks for the help keep it coming.
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Verdad Gallardo Thread Starter
TECH Apprentice
Joined: May 2010
Posts: 333
Likes: 1
From: Arkansas
I have a queston for the guys that ran bosch 02's and got rid of them. What was your car doing that made you replace them? Symptoms like mine? I also noticed that my car cuts out bad above 5k. It is not a random miss or a single cylinder miss its like a blur or a miss on every other fire. this has me thinking opti, If I replace this one it will be the third trying to solve this issue. I've also traced all wires and found no apparent problems.
my car reall does not miss it seems to run out of fuel or spark and I can't tell which one, my injectors keep firing but my spark does to its as if my pcm is causing it. but hell I have not changed my wires yet, so might as well.
my car reall does not miss it seems to run out of fuel or spark and I can't tell which one, my injectors keep firing but my spark does to its as if my pcm is causing it. but hell I have not changed my wires yet, so might as well.
