96 Lumina - Noone knows how to fix (dealers/mechanics)

[jsnake4416]

I have a 96 Chevy Lumina 3.1L that has problems with stalling when coming to stops and power loss. It doesnt occur all the time but can happen repeatedly. The car starts right back up immediatly. I have replaced too many sensor to write them in and have taken it into the dealer to be hooked to the computer. They said that the engine was -23 degrees. However, i have tried to replace the knock sensor already and when i do anything to it the cars electrical will shut off completely. I then need to get the knock sensor back to the orginial position to get the car to start. If it is unplugged it again wont start. (new sensor doesnt work at all)

If you can help i would greatly appreciate it as i need the car to run as long as possible. Any questions i can awnser but remember any sensor/normal fixes have been attempted.

PS. stalling is not from catylic converter & fuel pump....

PSS. When i say the car wont start, all the electrical dies in the car like something has shorted out. But once i move the sensor around a few times the car will start and run (key needs to also be removed from the ignition to start). If the car dies at a stop (when stalling), i can restart the car with no problems and may take 0.5sec to start.

[The_Mechanic_33]

"-23 degrees" Is this temperture or timing?
Knock sensor has no position maby your refering to another sensor?
Try to be a little more specific.

[jsnake4416]

Timing is off -23 degrees, the car is adjusting to something. the knock sensor problem might be the cause or not, but thats why no one can figure it out. the sensor shouldnt need to be in a specific spot but for some reason the car will only accept it in a specific position.

[The_Mechanic_33]

so you wiggle the knock wire or use a wrench to tighten sensor?

I would tug on the fuseible links @ the starter and see if they break. sounds like you should check the wiring in that area.

[jsnake4416]

The wire to the sensor is ok, the sensor can't be tightened by a wrench. Its a snug fit by hand and will only sit in one position and the car wont start if the sensor is unplugged (car should start with sensor unplugged though).

When i say the car wont start, all the electrical dies in the car like something has shorted out. But once i move the sensor around a few times the car will start and run (key needs to also be removed from the ignition to start). If the car dies at a stop (when stalling), i can restart the car with no problems and may take 0.5sec to start.

[The_Mechanic_33]

yes it should,and i guess i'm focusing on the power loss issue.There should be a large hex like shape(part of sensor) to tighten the sensor

[jsnake4416]

Sorry, i didnt mean that the sensor cant be tightened by a wrench, but the fact that if i do tighten it by wrench the car wont start remains. (My fault on not understanding your ?).

i think that the sensor issue might play a part in most of the problems, but the timing issue also should make starting the car extremely hard. However the car starts with no problems & quickly.

[The_Mechanic_33]

Check wiring by starter,fusible links,etc.
Wish I could be more help.
Please make sure to post fix when you find it.

[16th hippy]

i could be totally off here, but bear with me, it's late and there's all sorts of ideas runnnig through my head. typical knock sensor is peizo electric, vibration(knock) produces voltage in it. runs up wire to PCM and so on. sensor grounds in block. somehow sensor is POSSIBLY acting as ground for other things. if sensor is not in right position, car won't start and when you try after turning key all goes dead. seems as if maybe there is a major ground problem keeping the car from turning over. check ALL grounds, espically negative battery cable. check the positive too for acid or other corrosion. the tipoff here is that the car is retarding timing 23deg, quite a bit IMO. that would mean that the knock sensor is either picking up one heck of a knock, and i doubt this as you mentioned no such extreme knock, or something is backfeeding through the sensor making the pcm think the engine has a big spark knock and is retarding timing. this could also explain why car won't start with sensor unplugged, even though it should. like i said, is off the wall, but it hit me like a ton of bricks at 4am, so here it is. best of luck, and please post back the fix.

[j cAT]

unless you have a volt/ohmmeter and are familiar with finding electrical problems you must find a repair shop that will locate the bad wiring. i to believe that the knock sensor is acting as a ground circuit. possible computer[pcm] or wiring/connector pcm.dealers are not the best place to have this repaired. your vehicle is too old for them to be knowledgable in these types of problems. call around and get a mechanic that is electronic tech should find it quickly...........check pcm ground especially if vehicle has excessive rust good luck!

[jsnake4416]

If the sensor is acting as a ground like you are saying...then why doesnt a new sensor work when its put into the car at all (tried to start it in tons of different locations too)?? and what determines that the senor has to be in a specific spot if its a ground?? If i move the sensor even the slightest bit the car wont work....and i would think that if its acting like a ground, then as long as its in the engine block it would be grounded??

Im just not sure how its possible for it to act as a ground i guess....

[16th hippy]

old sensor was probably good. as far as if it is in a different position, i couldn't answer that. that is the real stumper. but in any case, this sounds like a major ground problem.

[AdymeBlack]

What about the main wire harness? If there is a fault in there then all sorts of crazy stuff can happen.

Also, has the starter been replaced lately? I had a problem similar to this with my lumina, not quite this severe, but my car would randomly die like something had shorted out. Oddly enough it was a bad ground wire on the starter, got that fixed and it runs just fine.

Just thought i would drop a couple ideas.

[nascartony05]

I had a 93 that had this exact problem. What it ended up being was the torque converter lock out switch in the tranny. I just pulled the plug on the front side of the tranny(about 6 wires if memory serves me right) and I never had another problem. I drove mine for another 30,000 miles that way before selling it. It does loose a little fuel mileage though.

[j cAT]

Originally Posted by nascartony05

I had a 93 that had this exact problem. What it ended up being was the torque converter lock out switch in the tranny. I just pulled the plug on the front side of the tranny(about 6 wires if memory serves me right) and I never had another problem. I drove mine for another 30,000 miles that way before selling it. It does loose a little fuel mileage though.

this guy has / had a knock sensor that if he moved the wires to it the engine would not run . repair shops said timing retarded. your problem of torque converter lock up at all gears is not what was occuring to him since it would die in and out of drive. to remove lock up in the lumina you had it would have been better to disconnect the brake switch wires that control the torque converter.