Now What?

This car is really trying my patience, I owned a corsica with the same motor and virtually no problems, then I buy this. My girlfriend was driving into work last week when the car stalled out, I got there to check it out and it started right up but just when I was going to "put her in her place" the car died . It started to idle funny then all of a sudden just cut right out. I scanned the computer and came up with a code 23, looking it up it turned out to be IAT sensor circuit. So I purchased a new IAT sensor, plugged that in and the same problem. I put new wires, plugs and a starter in it while I had it apart ( the other one was dead ) still the problem, There is evidence of a oil leak towards the firewall side of the car that I have yet to find but I doubt this is my culprit. I got the car home yesterday I managed to keep it running by feathering the pedel. It stalled out once on the way home and no codes were present in the system. I just have no clue I just put a new crankshaft positioning sensor ( pain in the butt ) and MAP sensor in it yesterday but it didnt help, The exaust was smoking really bad as I drove her into the driveway yesterday like my car was on fire the smoke was coming off the catalitic converter, so Im thinking this might be it, any other idea's any help would be a big help! Thanks for the time


Car is a 1992 Chevy Lumina
3.1 V-6

#1. Stop driving it, you are gonna kill it. Smoke. Black, white, blue, brown?

The cat was smoking? Not a good sign. Does the car die while moving, idling, what?

A bad cat will overheat, a really clogged one will overheat AND cause power loss ending in stalling. Sometimes black smoke from the exhaust. Could possibly set off a code about intake pressure if restricted to the point it can't develop good manifold vacuum.

Easiest way to check for restriction, go get a vacuum gauge (about $20) Find a good manifold vacuum supply (like the brake booster line) and plug in the gauge.

Start the car and let it warm up a little. Then bring the RPM's up to 3000 or so and hold steady. If the gauge reading starts off high, and drops steadily, the cat is clogged. If not, we can check some other stuff.

Well I cut the catalitic Converter right out of my Exhaust aqnd its still running pretty rough, I checked for spark on all 6 cylinders and It's good, its not stalling out until you try to give it gas, it cuts out on you, and Idles really rough but once you give it gas it dies. I noticed some oil leaking between the auto transmission pan and oil pan seems to be coming from up high as for the smoke none, it looks like normal exhaust.. No smell really Im stumped, Im getting fuel Im thinking my ignition coil is acting up....Any other ideas, Ill look into the gauge, just need the time Thank You very much for your advise

You Cut the CAT clean off???? On a what year Lumina? If its OBD2 you need that cat for sure. Well, you need it either way for some back pressure, plus you not gonna pass emissions tests. Play it safe, and put a cat back on it. It sounds to me like a leaky injector(s) has sent too much raw fuel into one or more of your cylinders. The raw fuel can ruin the CAT converter, and cause it to overheat. Check out your injectors with an injector balence tester, and a fuel pressure tester. If you need more info, let me know. Good luck.

Well I planned on putting it back on:) Just wanted to make sure the cat wasnt plugged. It still stalled out on me, Im thinking it is the fuel regulator that is dumping raw fuel into the manifold. Also Ive heard that the block used is the same as the distributor version of the car, the reason Im saying this is she has a really bad leak coming from the engine somewhere and I cant find it, its dripping off the oil pan but its comingfrom high up. Someone told me that the seal for the distributor shaft is prone to leaking any ideas were I can find it and how to get it off? Its a 1992 but I also own a 98, I never had a problem with the 3.1 in my Corsica ran like a champ for over 200,000 miles! But this one is testing my patience. Thank you for the help, Im just looking for Ideas

I had a similar problem with my 1990 lumina with a 3.1. It was running bad, stalling, etc. and not logging any fault codes. Turns out it was the engine computer module. I replaced it for 90 bucks and it fixed it. If you do replace it yourself, don't forget to change out the chip inside the module. If you do a core exchange from Autozone, make sure you take out the chip from your old module or it will be lost forever. Replacement chips are $$$$$$$.

Thank you for the advise. That is my next step if it dosnt stay running, I got the fuel regulator in so once I get the plenium back on Ill let you know. Thank you once again, Do you think a bad egr valve would cause the problem?

Typical EGR symptoms would be stalling after dropping the throttle, (like coming off the highway, or coasting down a hill), and lean misfire at idle, if it would idle.

Well I got the whole car put together and I still have the idle down problem. I unplugged the TPS sensor when the car was running and the idle smoothed right out, So I replaced the sensor only to have the computer throw a code 22 low TPS voltage the sensor is new, any ideas? I pulled off the fuel filter and it was plugged really bad so I replaced with a new one. I verified the fuel pump is working ( turned the car on with the filter off :) ) I have fuel at the rail, spark on all the cylinders... Im at a loss, what about the iat sensor? Would that cause a no start bad Idle condition? Also I replaced the crankshaft sensor, but do the 92 3.1 MP engines have a camshaft sensor? I cant seem to find one. Thanks again for the help

Think the code 22 is just from you unplugging it while running. You have to verify fuel pressure with a guage at the service port on the rail. You could have low pressure, or too much, if the pressure regulator is bad.

I don't think they have a cam sensor. Did you clean the throttle plate and IAC bore yet (I don't remember)?

A bad coolant temp sensor for the ECM will make them idle rough and rich also.

A bad coolant temp sensor for the ECM will make them idle rough and rich also.[/QUOTE]


Well I dropped the tank and am replacing the filter as we speak, I didnt clean the plate as it wasnt very dirty at all, The engine has always ran great, not even a rough idle which is very common with the motor. I replaced the Fuel regulator already and re assembled the components. When I started it up it still would crank unless you primed the fuel pump ( leaving on ACC for a few seconds ) and when it did start sounded good for a littel bit then as time goes on it will sometimes idle funny ( not all the time ) and when you try to give it gas the motor almost stalls out on you then it will catch then sputter.. It is really trying my patience, Ive replaced the starter, IAC solenoid TPS sensor Fuel pressure regulator, Map sensor the C.P.S Spark plugs/wires, I have checked all cylinders for spark ( which i have on all 6 cylinders )

I replaced the fuel pump, which led me to the fuel pump, as the filter ( in line ) was totally clogged ( i could not blow through it ) and the gas that ran out was very black and dirty. After I cut the straps and dropped the tank, I removed the pump and it looks good ( I will be buying a new one though just to be safe ) I was getting fuel to the Shrader valve after I replaced the filter, So I dont believe it is a clogged line,

Thanks for the time just thought Id vent, Any Ideas on were the coolant Temp sensor is? Any help would be greatly appreciated, for the first time Im really stumped Chevys dont act like this;)

The oil "O" ring for the distrubtor (plug) part No. at a GM dealer is:
#10477565 this is for a original O ring.
and if you remove the throttle plate to gain access and need a new throttle plate gasket, it is : # 10209678
just fixed mine, cost for the 2 parts was 5.00

Maybe Im a little slow but why would I need to change an o ring for the distributor shaft? It isnt leaking, that I know of...

What did you guys figure out about the stalling/power loss. My '97's got it bad! I can make it to work in the morning and home in the afternoon, but anything after it gets warmed up (20 miles or so) and it's sputterin' and stalling to the point where I have to pull over every block or so, shut off the engine, wait a few minutes, start it up and go the next block, etc. Then it gets hot and it's harder to start it...and it's a heck of a lot of fun with three kids and a slobbering Rott in the car! I've got a guy coming to look at it tonight, but I'd really rather not go thru replacing everything on the car if possible. I love my Lumina, but I can't trust it anymore. Any help would be greatly appreciated.

Mine turned out to be the fuek pump, it wsnt totally bad just had an internal leak so it wasnt pumpimng enough