jimmycivic

to start off with this is not a problem for a honda its with a 1989 oldsmobile cutlass ceria with a 2.8 motor multi fuel injection and the problem is it just keeps stalling at low rpm at high rpm right before the fan kicks on when i shift into any gear p r n d 2 3 . what i have done so far,checked for air leak.nothing,complete tune up plugs,wires,cap,rotor,filter,antifreze flush,new oil,went to a higher octane gas.nothing,crank sensor ,nope,fuel filter,sending unit with new pump.nope,coil packs,icm,ecm,nope.and its a obd1 system and the only code is just the basic gm code which is code 12 then nothing else after it, and im compltly lost if any one knows what i should do next or if you know what the issue is please help, the car is in good shape with only 120k on it.and i dont like getting ride of things without figuring it out. sincerly,jimmycivic

ezone

Jeez, been a solid 10 plus years now since I was making good money fixing cars like that.

You don't have access to a real scanner that can be of any help on a car like that?


Ok....
Run the engine.......Get to the ECM and smack it. Maybe even pull it out and smack it with the palm of your hand.

Replace it if anything unusual happens when you tap on it.
Watch the dash too, it probably runs the speedo needle and it might go haywire.

You might replace it several times (remans tend to suck) before you get one with no issues. I know I have, and I used to use a Sharpie to write the problems right on the metal housing (false code 43!) so I knew if they sent me one I already tried. I also figured this helped the rebuilders when it finally got back to them.



Does it cut out when you mash the gas pedal? (ohm test all 6 injectors)
Is there ANY pattern you can establish here?




Wiggle wire harnesses, see if it stumbles that way?
Doesn't really make me think of an idle learn problem if it is random and intermittent...

jimmycivic

its obd1 so i'm using a paper clip, i can sit there for 30 minutes and it will still read code 12, and the check engine light dosn't come on any way i tried tapping on the ecm while the car was idling dosn't do anything wiggled the wires nothing i did this while the car was cold it runs fine when cold then when it warms up it acts as if it is doing a idle relearn then returns to normal then she stalls no matter what i touch even if i so much as rock the car but again this only occurs when shes fully warmed up right before the fan kicks on thats why im completely lost.And ive also tried tapping on the icm and egr valve but no change.

ezone

Code 12 only means the ECM isn't seeing an ignition signal, and it will never see one as long as the engine is not running. Normal.




Only when warmed up....

Can you ohm test all 6 injectors? With the engine still hot?

Hint: I don't pull the manifold yet.
Use a wiring diagram, see if they are batch fired (pretty sure they are). First try the upper manifold harness connector that contains all the injector wires. Measure ohms.


OR Go to the inj fuse and ECM control wires for each batch, measure there.

Use Ohms law and math to see if you need to actually pull the plenum off and check individual injectors. Cold spec is usually 12.7 ohms, + a little for heat, divided by 3 injectors = 4 point something ohms per batch of 3. If any lower than that, you have shorted windings.

That's my only thought right now, without being able to see it for myself.