1994 3.1 Bad mileage, fouled plugs.

[Mole1333]

I tested that sensor and it showed correct according to the book, it had a nice gradual drop and rise in resistance with a warm pot of water and the cool down. Well the motor I bought he said was good, but mines already in the car and it has 110k and not 150k. And he gave me his 1993 Cutlass with it, since it was still in the car...for $100 with title But hey...I already had it out once, so I can swap that around too. May end up swapping all sensors from his motor. I did read up that there could be a short in my harness causing the injectors to be stuck open all the time. The TCC solenoid was stuck in the car too, so from sitting who knows what else went to hell.

[pmaniac69]

well, step after that is o2 sensor, and after that I would try a new computer



wait a sec, after you replaced all these sensors and tested them......did you do the idle relearn?

[Mole1333]

Thats another issue, I dont have a tech 1 scan tool, but I found online a "way" to get around that. it involved pulling the ECM fuse and then installing starting the car, put in drive quick and idle for 5 mins, then off for 10 secs then repeat. Claimed it worked. But would the idle quality effect my overall MPG by that much? I tested the TPS today, checked good. So thats all the sensors except the knock sensor and O2. After I read the chilton book further on ECMs apparently the 94 has the damn EPROM and not the MEM CAL, so I may be SOL...lol I will call my mechanic and see what he has. My Cutlass is a 93 so do you think the ECM's would interchange and run with the MEM CAL? Just a random thought. Otherwise I am yanking the motor and swapping the tranny into the cutlass. F this sunbird.

[robertisaar]

the GM recommended method is slightly different, but whether idle has been learned or not shouldn't effect economy much if at all.

if your knock sensor is going crazy and causing a lot of advance to be pulled, you most definitely will lose fuel economy and power. O2 can also go bad and tell the ECM that it is constantly running lean if it is or not. since running excessively rich in and of itself will kill an O2, i have to ask: has this been a gradual issue or a one day it went to hell issue?

EDIT: for your updated info: you have a 1227730 ECM, a cutlass supreme in 93 would either have a 16149396(3.1 and 3.4) or a obd1.5 ECM(3100).

they are not difrectly interchangeable due to the difference in the ECM plugs. if you did swap the harness over or something like that, then yes, it would run it correctly.

[Mole1333]

That I cannot tell you, I bought the car with the slight idle issue and I figured it was the IACV, had no idea it was this bad. I replaced the O2, looked original, the hell with testing it. Still have to assemble stuff till I run it. Maybe just grab the knock sensor off the other motor as well. If that doesn't fix it most def has to be harness or ECM. Thanks for all the input.

[Mole1333]

the GM recommended method is slightly different, but whether idle has been learned or not shouldn't effect economy much if at all.

if your knock sensor is going crazy and causing a lot of advance to be pulled, you most definitely will lose fuel economy and power. O2 can also go bad and tell the ECM that it is constantly running lean if it is or not. since running excessively rich in and of itself will kill an O2, i have to ask: has this been a gradual issue or a one day it went to hell issue?

EDIT: for your updated info: you have a 1227730 ECM, a cutlass supreme in 93 would either have a 16149396(3.1 and 3.4) or a obd1.5 ECM(3100).

they are not difrectly interchangeable due to the difference in the ECM plugs. if you did swap the harness over or something like that, then yes, it would run it correctly.

I swapped the 02 and knock sensor from the cutlass. Same issue, pulled the computer to look at it... never looked like it got wet. Didn't check the numbers....all in favor of putting the transmission from the sunbird to the cutlass say I! I!

[robertisaar]

slight issue there: sunbird has a 4t60, culass has a 4t60-e.

[Mole1333]

Touche' and I just sold my remanned 4t60E...damn. I forgot this lil bugger has the 125C and not even the 4t60. I had to do the solenoid in it cause it stalled out. Oh well back to craigslist for parts! Thanks for the help guys.

[IsaacHayes]

Sunbird does not have a 4t anything. It's a 3t40.... Yup those have the famous TCC solenoid that likes to give out.

[robertisaar]

Sunbird does not have a 4t anything. It's a 3t40.... Yup those have the famous TCC solenoid that likes to give out.

i assumed since he was talking about swapping them that he got the option of a 4 speed auto... then i realized that that was never an option with a J... until they went OBD2 anyways...

[Mole1333]

Ya I got a little ahead of myself. I have a 1993 sunbird with a 2.0 5 speed, bad motor, this 94 I can't get to run right for the life of me, and my 93 parts car cutlass with just the 3.1 no tranny. I just want one good one....is that too much to ask?

[60dgrzbelow0]

Is there any chance that on an engine sporting 110 Grand in hard miles...that your Timing Set is involved in making the motor "Do the Huckle-Buck"...? They can get pretty stretched out by then...and contrary to popular belief...not everything on a computer controlled motor can be discovered strictly via ECM/PCM diagnosis...like the worn out cogs and stock, non-true roller chain in the front of the engines...

[Mole1333]

It very well could be. But would it flood out and get 12.8MPG? It runs down the highway just fine at 70. I have no Codes or anything on this car. I do know I am tired of working on it. Looking for a 4T60E now. If anybody else thinks the chain could be shot...which very well we know can't be in great condition, I will change that....not a big deal.

[IsaacHayes]

I replaced my chain at like 180,000 miles, and the motor ran fine before I did it. I doubt that is the problem.

[robertisaar]

if you want to get technical, a worn chain is exactly like retarding the cam... opens the valves later in the combustion cycle. helps build more power in the upper RPM ranges at the cost of fuel efficiency.

but..... i don't think you could EVER retard the cam enough to get the MPG number you're getting.

so, it could be a SMALL factor, but certainly not a main one.