helpful sister, 97 Satrun no injector pulse

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I'm trying to help my brother with his car problem. It started about 2 weeks ago, the car will intermittently die while driving it. When it dies, we have tested and we have spark but no injector pulse. We replaced the ignition module but it still intermittently dies. If you let it sit for 10-20 minutes it will restart. Sometimes it will run only a mile and other times it will go 30 miles before it happens again. We replaced the crank sensor about a year ago for a no start condition but that time we had no spark or fuel. Any suggestions?

posted by  moonfish47

do you have power on one side of the injector plug with key on you should have the ecm is the grounding trigger to activate if you have power then i would guess half the ecm is bad (burnt curcuit)

posted by  osborste

Hi
Thanks for answering! The noid light doesn't flash but we will check what you have suggested tomorrow.
Thanks Again!

posted by  moonfish47

glad to see you know what a noid light is :thumbs:

posted by  osborste

I know what it is just wasn't sure I spelled it right! We'll check for ground, we did a tap test on the ECM and nothing seemed to change.

posted by  moonfish47

the ecm maybe old and overheats opening the curcuit then cools and works again

posted by  osborste

Hey
Just wanted to let you know we tried to check for power and ground to see what we were losing but the damn thing would not die today :banghead: so we'll try again tomorrow. Thanks again for the help. ;)

posted by  moonfish47

i'll watch for it

posted by  osborste

Hey,
We finally got it to die today and would not restart, we checked with the key on and we still had power to the pink wire in all 4 injectors. So......I guess we replace the ECM and see what happens from there. Thanks again for your help.

posted by  moonfish47

before changing the ecm, i'd ohm the injectors. if it fires them in a batch sequence, and one injector has very low or no resistance, that will kill them all and make it die. i've seen that happen intermittently, too

posted by  dodger65

it grounds them seperately

posted by  osborste

I guess I should have put this in my first post but after the ignition module did not help, we did check the ohms in all 4 injectors. We tested them with the motor cold and all 4 were at 12.5 ohms then we ran it till it died and tested them again and hot all 4 tested 12.7 to 12.8 ohms. From my research those readings should be within specs. So then we tried the advise from osborte(thank you very much!) and tested the power to the injectors. So since we have power to the injectors when it won't run, it must be the ECM quad driver has failed and not grounding.

posted by  moonfish47

quote from larry the cable guy

GET'ER DONE :laughing: :laughing:

posted by  osborste

bear with me, here. someone borrowed my wiring diagram "bible" and hasn't given it back yet :banghead:

posted by  dodger65

The injectors have a pink wire(they split off a single pink wire) leading to all 4 of them coming from the fuse box, the wires leading to the computer are all different, Colored with a black band, so that tells me they are all grounded seperately by the ECM (not batch). ALL the wires are intact and have no kinks, bends or cracks in the sheath. We also checked the wires from the crank sensor to the ECM and they also are intact.


I called our local NAPA (Columbus, Ohio) and they have to order the ECM with the VIN number to have it programed, we should have it in about 3 days, it looks fairly simple to change, it's pretty much in the wide open under the dash on the drivers side. The cost was a little shocking $395 plus tax including the programing. We think we can change it so at least we won't have labor charges on top of that.

posted by  moonfish47

did you look for a used one wrecking yard
or www.car-part.com for other wreckers in your area

posted by  osborste

We thought about that but when we found out it had to be programed with the VIN number, we were concerned that we would not get a proper match. We thought we could just change the PROM but we have to have it programed and change the PROM. Thank you, Saturn!!!! :mad:

posted by  moonfish47

that sucks i'm glad i didn't have to do that for my caravan's puter straight re & re

posted by  osborste

just to clarify.... with your noid light hooked up do you get pulse while cranking? how did you test it? jumping to order an ecm is the absolute last resort so keep it simple.

posted by  BanffAutoSpa_ap

Nope had no pulse (no flashing of the noid light) while cranking, we have checked it several times, we have power to the pink wire when the car is dead but no injector pulse (noid light does not flash), we have checked all the wires for bends, breaks or cracks and all are OK from the crank sensor to the ECM and from the fuse box to the injectors(pink wire) and from each injector to the ECM, we have the proper ohms when cold and hot and when dead. After we determined the crank sensor was still good (we have spark, no injector pulse), we tried an ignition module and still the car would intermittently die. So.........with having power in the pink wire when the car is dead, from my research and with the help of "osborste", we have come to the conclusion that it must be the ECM quad driver has failed.

posted by  moonfish47

Well, here goes!! We got the new ECM today and did all the proper things to install it from the instructions that came with it. Then the car dies more often than it did before (about 2 minutes after installation) then about every 2 minutes after that and we have a flashing service light with a little wrench beside of it, I called NAPA back and he said he forgot to give me one other paper that Cardone had sent, we need to do a Crankshaft Position Variation relearn procedure now. I don't know if that will help or not because we still (after installing the new ECM) have NO injector pulse and still have power in the pink wire. :banghead:

posted by  moonfish47

checked at autozone.com this is what i got for replaced ecm's

The PCM module contains a built-in learning ability that allows it to maximize driveability by correcting for minor variations in the fuel system. Any time the PCM is replaced or the power is removed from the PCM, the module must go through a relearning process. Maximum performance may not return until after this is accomplished. To enable the PCM to relearn the fuel system:

Start the vehicle and warm it to normal operating temperature.

Drive the vehicle at part throttle, with moderate acceleration and idle conditions, until normal performance returns.

Park the vehicle and engage the parking brake.

For automatic transaxles, shift into D. For manual transaxles, shift into N.

Allow the engine to idle at normal operating temperature for about 2 minutes, until the engine stabilizes.

hope it help's

posted by  osborste

Thanks for the info, NAPA also gave me an instruction sheet on how to relearn the Crankshaft position Variation last night, we are going to try it tonight if we can keep the car running long enough. I don't think this relearn will make the symptoms it's still having go away, will it? I mean it still dies and we still have power to the injectors when it dies. So the ECM does the grounding and it is still not grounding even with the new ECM. From what I understand the crank sensor sends a signal to the ECM to fire the injector, so if the crank sensor is good (we still have spark and fuel), is there any other sensor that tells the ECM to ground?

posted by  moonfish47

looking at the wiring diagram it show the crank sensor goes to the ecm the ignition module to ecm and the injectors are grounded by the ecm all the other 's are input/output sensor's for fuel and emmission's
have you checked the wire's from the crank sensor to the ecm (ohm's)
maybe the sensor's good but the wiring or connector is bad

posted by  osborste

We tried to do the relearn procedure last night but it kept dying and we weren't able to complete it, we put the old ECM back in and it ran for 2 hours and never did die. We will test the ohm's in the wire from the crank sensor to the ECM next. I'll research to see what the ohm's should read. I would think if the wiring or connector is bad we would not have spark.

posted by  moonfish47

can you keep it running while holding the throttle keeping the idle up around 2000 rpm this would help the computer relearn if its similer to other gm's with the relearn on there iac valve's
if this doesn't work trying to keep it idling i think its a bad ecm or bad programing
the old ecm would still have the learning remembered in its program so i think thats why you aren't haveing problems with the old ecm
the wiring may have resistance in it. but i don't think so to much anymore as the old ecm still picked up the signal and so does the new ecm just need's to keep running to learn it

posted by  osborste

Well, we gave up and towed the car to the local Saturn dealer, they diagnosed it with a bad crank sensor. I don't know their reasoning on that yet. I will talk to my brother tonight and post why they think it's the crank sensor. Thanks so much!!!!for your help. :wink2:

posted by  moonfish47

did you do an ohm's test on the crank sensor? (700-900 ohm's was the spec i found) i know you said you checked the wire's to the sensor and still had fuel and spark

posted by  osborste

I am totally mystified as to how the crank sensor being replaced fixed this car, i know what the crank sensor is and how it works so it makes NO sense to me that that was the problem, we had spark, when the car died it would run when we gave it a shot of ether until the ether fumes were gone then it would die again. So I'm dumb founded, but the car has ran without dying for 2 days now. We didn't do an ohm's test on the sensor because with having spark we were certain that wasn't the problem.

posted by  moonfish47

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