2000 Lumina GM 3100 Troubleshooting ideas?

[Breze84]

So I have been fucking around with this SOB for the past couple months and its getting under my skin because I cant figure it out. The car is a 2000 Lumina 3100 with 163K miles on it. One of my wifes nurse friends was going to donate the car and I picked it up back in 2009 with 136K miles on it. Car ran good and she had owned it since like 2002 or something. Anyways, I drove the car just for work for about a year until I got a lower intake mani leak that let coolant into the oil. I pulled the top end apart and did new lower and upper gaskets, Flushed the oil and coolant and car drove great up until around 158K miles which was a few months back. I had a Engine light on so I did a scan and it came up as a TPS "Throttle Position Sensor" and EGR Low Circuit code. Emissions was coming up so I changed the TPS and checked the EGR with a 12V battery and it ended up having a sticky pintle. So I cleaned out the carbon from the TB and EGR port that goes around into the intake neck and I tossed a new EGR on. I tried jolting the BAP fues to clear the codes but they came back So I did a continuity test from the ECU to the EGR plug and it ended up having a break in it. I spliced a new plug on and cleared everything, Drove it for several days, took it for emissions and it passed with flying colors.

Alright so everything is looking good again. A few weeks go by and the car started to get this intermittent misfire stutter only under load. So basically when you leave from a stop it would start to buck and the RPM's would jump around then would plane out until you got more speed then do it again randomly. It was very sporadic and inconsistent. It wouldn't do it unless you were driving for a while though. I took the IAC out and cleaned it up and it didnt do it as bad. I check for any vac leaks and found none. checked the plugs and they were a little ashy but not gummed up. I brought it by a mechanic guy my buddy knows who had a Gucci snap-on scanner and I was getting a misfire in every cylinder when It would happen. I left the car by him for a while and told him everything I did and he dicked around with it for several hrs. I went and picked it up he said he couldnt really find anything but he cleaned out the IAC as well and cleared the codes and said he drove the shit out of it and it never happend again.... ???? Idk.. He said it had a shift code but it was nothing to worry about... So I drove the car for another 2 months up until now and it was running great. Now it is happening again, Not as severe as before but Its doing it again. Im going to change the plugs and wires and throw some injector cleaner through it and see what happens. If that doesnt do it Im scared it may be the TCC "Torque Converter Clutch" maybe idk, That would seem kind of odd because It happens at times even when the Converter would be locked... I checked the dipstick and it seems a bit brown, I may just drop the pan and change the filter and put some new fluid in it "NOT FLUSHING"... What do you W-Body guys think? This is starting to get under my skin... Other then that the car runs great besides a little cold start piston slap which is common. But the car has great heat, Great A/C and drives pretty smooth besides this issue lol...


Also FYI, Its still not doing it all the time. It may happen on 1 drive and not on another so who the fuck knows

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[boostedguy05]

[MENTION=750]RICH17[/MENTION] [MENTION=653]BrianG[/MENTION]

Wasn't arcing ccoil packs a problem in these cars?

 

[RICH17]

Could be a couple of things. I'd check the coils and ICM like Nick said. It could also be a Cat problem. I had that on my Lumina when I bought. Guy thought the trans was going but didn't think a clogged cat would let it shift weird and have no power at times.

Weird thing was that there was never a O2 code or cat code that popped up. And after doing some research that it seemed common.

At 163k I wouldn't be surprised if it was that

 

[RICH17]

oh BTW

 

[Breze84]

[MENTION=750]RICH17[/MENTION] [MENTION=653]BrianG[/MENTION]

Wasn't arcing ccoil packs a problem in these cars?

Could be a couple of things. I'd check the coils and ICM like Nick said. It could also be a Cat problem. I had that on my Lumina when I bought. Guy thought the trans was going but didn't think a clogged cat would let it shift weird and have no power at times.

Weird thing was that there was never a O2 code or cat code that popped up. And after doing some research that it seemed common.

At 163k I wouldn't be surprised if it was that

Yea I thought maybe the coils or ICM as well, Just havent checked them yet. You would think I would get a Cell on the dash but Im not getting anything. I should drop the exhaust and take a peak inside as well I guess... So annoying

 

[RICH17]

I hear ya. I bought my old Lumina with 87k and it had the bad cat. But I am certain it was a mall security car or something like that cause the cat should've lasted longer.

 

[Wrencher]

I'd look @ coils first.
Also seen crank sensor harnesses not retained to the heater tube like OEM & getting cooked by the exhaust.

 

[Breze84]

I'd look @ coils first.
Also seen crank sensor harnesses not retained to the heater tube like OEM & getting cooked by the exhaust.

Yea Im going to check the coils ect first... I highly doubt its the 24X Crank Sensor or Harness... The car would run like shit 24/7 if that were the case... But then again you never know and it doesnt hurt to look right :smile:

 

[RICH17]

How rusty is the car?

 

[RICH17]

 

[Wrencher]

I've seen so many of those harnesses fried over the years, the symptoms varied wildly.
From intermittent misfires, cut out stall to correlation or CMP CKP codes.

 

[Breze84]

How rusty is the car?

Not to bad, It has the infamous rust by the gas door and a dent on the fender because I wacked it with a tool I made to pick up the rocker and pull the pushrods out when doing the mani gaskets. I dropped the lobe on the car found a couple rockers I was able to lift and was doing the ones to the front of the car pulling back towards me. I had my younger brother pulling the pushrods As I did this and he was dicking around trying to pull one when it slipped and hit me in the forehead. I got pissed and wacked the fender with the tool lol... By brother got real quiet and was like WTF man take it easy hahaha...

I've seen so many of those harnesses fried over the years, the symptoms varied wildly.
From intermittent misfires, cut out stall to correlation or CMP CKP codes.

I hear you... Its worth a look...

 

[Breze84]

I just went out for a smoke and took a look, And I assume from what I can see the Crank sensor harness runs along the front of the motor below the exhaust manifold. Doesnt look like its been affected from heat or burned. The split wire loom around it still looks intact so I think it may be ok there... Seems the best bet and probable solution would be the coil packs and or the ICM... Whats the best way to go about testing these. I was thinking pulling the 2 plugs from each coil pack "1 PACK AT A TIME" and taking some rubber hose and bridging the gap between the coil pack and plug so it doesnt arc and I get zapped. And testing them from a idle with a 12v tester piercing the rubber hose... That would probably work you think? Also what do you guys suggest for reaching the back plugs? I was thinking cutting loose the 2 front fork mounts that go to the core support and hooking a come along to the the steel eyelet bracket to the right of the front valve cover and dogging it off to something and winching the motor forward? I shouldnt have a problem with any mounts below should I?

 

[RICH17]

I usually just pull the ICM braket to get to the rear plugs but you can pull the dog bones as well.

When the ICM braket is off I would check and see of the coils are sitting on there good or if they're corroded. Maybe even pull them off and check for any problems with the ICM itself. And throw it all back together with some dielectic grease.

 

[Breze84]

I usually just pull the ICM braket to get to the rear plugs but you can pull the dog bones as well.

When the ICM braket is off I would check and see of the coils are sitting on there good or if they're corroded. Maybe even pull them off and check for any problems with the ICM itself. And throw it all back together with some dielectic grease.

Sounds good, I will give it a shot tomorrow and see what happens... Fingers crossed because I dont want this to be a trans issue which im reluctant to write off.. I dont have any shift problems so fingers crossed again hahaha... It makes me wonder because I never had this issue until I changed my TPS and that corresponds the operation signal with the TCC correct? Maybe the TPS I purchased from Advance Auto could be faulty. That would be wishful thinking though... Im pretty sure the Torque converter clutch gets its operation signal from the Throttle position sensor... A faulty TCC will cause this exact same problem along with every other fucking idea tossed around in here... I should just set the car on fire and sleep like a baby

 

[Breze84]

Update with new issue lol, Never fucking ending with this heap...

You can see above the issue I was having, Havent really fucked with the car that much but I did check the ICM, Coilpacks ect and tossed in some new plugs and wires and was still having the random misfire under load issue. Had a mechanic guy I know look at it who can see live data with his scanner. He said everything looked good besides the Misfire. He seen a TPS code so he changed it for me, I just put one in but whatever, maybe I threw a code again because I was fucking with it before I took it to him... According to him he was leaning towards a faulty PCM which I was skeptical about.

So to the update:
I drove the car for a couple weeks after this and noticed that when I would get the misfire my Lights would dim and my Volt light would come on. I just put a new interstate battery in a few months back so I decided to check the Alternator. The car was pulling 13.8-14.0V in Park and when I would turn on Accessories and put it in Drive it would drop to low 11's high 10V. So I assumed that the Alternator had some bad diodes and was dropping the voltage low enough to the point that either my ignition system or fuel system was cutting in and out. I tossed a new Alt and Belt on and the car drove flawless, No more misfire nothing. Im thinking fuck yea this is great. Drove the car for a couple days with no issues.

So now yesterday I started the car up to take a ride somewhere and I noticed my Idle was high around 1500 and wasnt coming down. I put the car in drive and it would drop to 1100. Still a little high! I gave the car a quick rev and it seemed to drop back to normal which is around 800 or so. Did my thing, went home and shut the car off. Came out a little later started the car up and it died instantly on 3 attempts. I then started it with the aid of a little gas and it didnt die, BUT the RPM's were chugging around 500 and my A/C clutch seemed to keep engaging and disengaging loudly until I reved the car up. My check engine light came on and I had a P0506 code "Idle Air Control System RPM Lower Than Expected". So I check for Vac leaks and I had one little one up by the EVAP tube where it goes from the PCV valve in the front valve cover to the Intake neck right after the TB. I fixed that lamely enough to where I wasnt getting a leak anymore and pulled the IAC out and cleaned it up and pulled the PCM/BAT fuse to clear the cell. The car was still having the issue so I tried doing a idle relearn which was bringing the RPM up to 1500 back down to around 750 or so until it idled on its own for a min, Put it in drive and let it idle for a min, Put the A/C on and let it idle for a min and it seemed to be good until I shut the car off and started back up again. Same issue as before! So I put a new IAC in and did the same thing again and its not fixing the issue, The MIL came back... What do you think is going on? I have no vac leaks at all Im going to clean the TB and MAF tomorrow, Just kind of odd that this wasnt a issue before and now this is going on, If its not one thing its another... Also, When I get the car idling normal, I can give it a rev up to about 3500 and let off quickly and the RPM's will drop enough to stall the motor...

FYI: On a good note the car doesnt misfire anymore lol

 

[Runtz52]

Random shot in the dark here, I had a very similar issue with my 1990 lumina 3.1L, car would misfire and die at highway speeds and I'd lose all electrical though. What I did was removed all the relays and fuses from the relay box by the washer tank (I could hear a relay clicking in there when it would die and I would try to restart it) and put dielectric grease on all of them and and put everything back in and I never had any other electrical issues. Something cheap and easy to try

 

[Breze84]

Random shot in the dark here, I had a very similar issue with my 1990 lumina 3.1L, car would misfire and die at highway speeds and I'd lose all electrical though. What I did was removed all the relays and fuses from the relay box by the washer tank (I could hear a reltime clicking in there when it would die and I would try to restart it) and put dielectric grease on all of them and and put everything back in and I never had any other electrical issues. Something cheap and easy to try

What I think happened is when I put the new alternator in, the pcm reset and lost the learned idle trim from over the years. The computer slowly compensates idle when carbon builds up on the tb. Now that it reset back to the oem pre programmed settings I think the tb blade is having a hard time figuring out a sweet spot. I may just drive it and let it relearn real time idle...