91 240 (ka24de) not running right HELP

[duey]

Yesterday coming home from work i was hauling *** on some local twisties. Then i get to a set of lights all of a sudden my car is spuddering like high hell, idle is rough also. I've already checked for spark, fuel, and loose vacuum lines. Now i'm not sure what it is.., only thing i can think of is that the timing is completely off. When i first start it up it seems to almost stall (drops to almost 400rpms). The car is dead on the road near my work and i'll be towing it back to my workplace sometime today (work has a lift so i can work on it there).

Anyone have any idea's on what the problem is and how to fix it?

thanks for any help/suggestions/idea's

-duey

[NISTECH]

check coolant temp connector for corrosion and airflow meter circuit voltages. one will be 12 volts one will be 0v but has to be at or below .02v that would be your ground if out add another ground to the exiting ground run it to the intake manifold not the battery. the third wire should be between 1.3 and 1.5 volts at idlecheck these and post back results

[duey]

thanks again NISTECH,

but one question..., where would the coolant temp connector be located?

One other strange thing happened today, i didn't get chance til today to tow the car, so when i tried to start her up she ran perfectly normal, but i didn't take my a chance so i towed it anyways. I didn't get a chance to check the airflow meter yet but i let the car run in the garage for about 15mins, then thinking that the car is fine, i pull out into traffic then it starts spuddering all over again, so it seems like it's only doing this when its warm. I won't have a chance to do a full breakdown til late tomorrow but anymore help suggestions would be appreciated.

thanks again,duey

[NISTECH]

coolant temp sensor is a red or yellow 2 wire connector near your water inlet on the fron of your intake manifold.

[duey]

coolant temp sensor - clean and free of dirt/debreemaf sensor -white wire = 1.4vblack wire = .05vblack w/yellow = 14v

restarted the car this morning (after being left out in the cold) and it still had the problem so my theory that it only does this when warm is out the door.

[duey]

update again:

since everything you suggested doesn't seem to be the exact problem, i went ahead and checked the sparkplugs and the fouled to hell (tons of carbon buildup). So i changed them and also got a new fuel filter just in case (all oem stuff, would've changed cap/rotor but they seemed ok). That didn't help remedy the problem still. So i'm going to check to see if my sparkplug wires are defective in anyway.

Now when i'm sitting in the car, it'll sputter only once in awhile, and the other times it'll be fine. BTW : No check engine light is coming on either (the light does work with key in the ON position).

[NISTECH]

if the plugs were fouled as you said they were you have a rich condition. 3 things pretty much control that. Airflow meter, Coolant temp sensor, and O2. Your air flow ground is too high should be no more then .02v take a wire long enough to run from your airflow meter to your intake manifold put an eyelet on the side going to the manifold and attach it where the other grounds are. on the end at the air flow meter strip some insulation from the existing wire and soldier the wire to it then seal it up.

then recheck your idle quality. I dont suspect this will completly resolve it but it is a known incedent that needs to be addressed before you persue any further diagnostics.

[duey]

ok i'm retarded cuz i think it's the coolant temp sensor. I confused the plug with another sensor.

Now the main problem, i'm looking at the FSM for my car and according to it, the coolant temp sensor is right off the harness where the fuel injector harness is.., but no damn sensor/frayed wires/ or signs of anything missing. I'll be tearing apart the complete harness today and look for those wires.

[duey]

ok another update:

this is VERY strange and makes no sense to me what so ever. First off i forgot to mention that this isn't the oringal motor, found out from the previous owner that the motor was swapped cuz he blew the original motor, exactly what year motor it was replaced with is another question.

I did a complete teardown of the engine harness looking for the wires for the coolant temp sensor, and that was no where to be found, so i gave up on that. But i think i found the problem, the MAF, when i wiggle it it'll run like normal but after a bit it'll go back to it's spuddering self, BUT here's another weird development..., when i comepletely unplug the MAF the check engine light DOES NOT light up. I know the light works... so i'm going to have to investigate that problem further later. Tomorrow i'll be installing a new MAF so that'll hopefully remedy the studdering problem.

NISTECH, any idea why my CEL wouldn't come on with the MAF disconnected?

btw: i did run that separate wire for the ground on the MAF and it is now reading .01-.02, thanks for that...u think because it was getting the incorrect reading it would cause my MAF sensor to be junk?

[NISTECH]

no not nessesarily. if by wiggling the air flow harness it affects idle quality you have found your problem. you need to find the poor conection there and fix it. this will likely solve your problem.

what your looking for on the coolant temp sensor is corrosion in the plug(green crusty s***).

[Nitrus0nous]

I had this same problem. With the MAF harness anyway. Wiggling it would clear up my idle proibs, but they would go back after awhile. I'm planning on buying a new MAFS, hoping it will clear up some probs, but if the wiring is definately the prob, how hard of a fix is it?

[duey]

UPDATE:

replaced the MAFS and everything is back to normal. Thanks for your time/help NISTECH.

[NISTECH]

no prob. if your car acts up again though you should take a close look at the harness leading up to the maf.