one2burn

My 1991 3.1 v6 starts cold runs smooth - fuel filter changed air filter new - but once hot as soon as you tap the gas pedal it bogs and wants to die, let off and it holds an idle fine. You can play with it and get it to rev up but cannot even start letting out the clutch to put under a load without it trying to die again. Im thinking throttle position sensor parts store man says maybe ing. module. This car was in the junk yard for a while I had to experince the vat issues got threw that started there and drove home 2-3 miles max and progressively got worse ( cat. had been taken off behind o2 sensor to bolt on flange - new one on now no change) The cooling fan is also comming on to soon thats whats stopping me from going further thinking chip problem possibly. I put more fuel in and water remover in case of it being the problem it still might be the problem and or fuel pump pressure / volume issues. Looking for anyone who's had the same for info whats your guess, thanks George. Ps. No Codes lost when changed battery but check eng. light did come on on the way home but has not been on since. will check for codes and get back with results, I read other threads possible o2 sensor bad causing boging due to rich cond. what do you think? Thanks again, George.

OldCelica

Start by checking codes. This can save you a LOT of time and headache.

One thing that you can check is if the computer is advancing the timing. Be sure that your trigger wire (Brn/Blk single connector wire on passenger side under the hood) is connected. Hook up your timing light and rev the engine. You should see the timing advance. While you're there be sure that you check the timing. Disconnect the wire mentioned before. Have someone put the car in drive with the brake on. Set timing to 10 degrees. Tighten distributor and then verify the timing. then hook your wire back up.

If your computer doesn't throw any codes see if you can get a hold of one that actively reads what the computer is doing. If it runs okay in open loop, but not in closed loop that can narrow down possible problems.

jnm9192

i have a 91 with 3.1, i'm having the same problems, the previous owner has "checked" all the relays and what nots. don't know for sure. they told me this one would run fine for a trip around the block and then go to running bad, they say it's backfiring to. i'm thinking timing or a control mod. is going bad or even maybe a fuel pressure problem. i say that because i have fuel in my oil. unlike your car i have no codes.....yet. any help or anserws you find with your car i sure would like to hear what you find. if i find any i will pass on.thanks jnm9192
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do you think that maybe the pickup coi in the dist. is getting hot and breaking down or even the main coil.....control mod?

one2burn

I checked my codes again today and none, checked fuel pressure and 45psi when key turned on 38psi started and running tried to accelerate went up to 42psi but died from the instant bog problem when I restarted cooling fan came on and I dont think it should have not hot enough yet so I think possible TPS sensor or back to the chip or ing. module giving bad info to computer even though it starts and runs.

OldCelica

You can check your TPS with an ohm meter. There are three wires (usually black, blue, and grey). Disconnect connector. Test the resistance between the pins that the black and grey wire connected to. You should get 5.77 ohms. Then test the resistance between the pins for the blue and black wire. This should read the same as the other reading or slightly more resistance. If there is less resistance then the TPS is sending a signal to the computer that the throttle is open a certain amount. I can't remember what WOT reads. I think somewhere around 1.45 ohms, but I could be wrong.

Or, you could just plug a scanner that reads the live data and look at exactly what the computer is getting for a signal.

one2burn

I have a 91rs 3.1 v6 that would start, run, no codes, as soon as you crack the throttle it would die. Things I checked before replacing ECM, Fuel Psi., timing, coolant temp. sensor., Tps, Iac Solonoid, Things I just replaced for GP because I got this Car from a junk yard, Ing. Module, Dist. rotor and cap cleaned rust off contact points under rotor, Plugs and wires, fuel filter, drained and filled tank 5 gall. prem., found a lot of play in the chain and changed it both gears and damper, fuel psi would not drop after starting changed fuel psi. regulator fine now and found one bad injector mine all read 11 to 12 ohms. but one, book says anything below 8 is bad. New Cat and clear pipes/muffs. Even got a code 13 once and changed O2 sensor and found knock sensor wire disconnected and hooked it up. So now after all that no change but as I read in the book I found a line that said that in the event of a ecm failure the cooling fan goes on to save from over heating. Bingo as soon as the car came down off of high Idle from cold start the fan kicked on. so that left me to thinking is it the ECM or Chip. I guess you have to think about the two like this when your dealing with them, Chips are the brains and the ECM is the body and the body is what more often gives out first, so I'm so glad this one did'nt have DE DE DE also.

mark_e21

I had the same prob. with a cavalier, at first it started off runing good then one day i was going down the road and all of asudden it started bogging out on me mostly after about 2.5 grand, as i was going down the road i would turn the car off then turn it back on and it would be ok for a while, but the more i did that the progessivly worse it got, so bad that like u said under any load it wanted to stall I tryed every thing from new injectors to new sensors nothing helped i did a fuel pressure check and it was fine according to the book until you would try to accelerate then it would drop off dramaticly so i changed the pump and that fixed the problem(about $700 later) save yourself some cash...... check the pump first