91 Sunbird keeps killing ignition modules

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Toolman_Tom

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Hi all! I just joined. My daughter has a 91 Sunbird convertible 3.1L V6. It's been running bad and the check engine light came on. Code 42. That's for the ignition module right? Well, this would make the 4th one in about 3 years!!! I know the location of the ignition module isn't the best for electronics under the exhaust manifold. Could something besides heat be the cause of all these bad ignition modules? I have looked over the wires and connections before and I didn't see anything. Is there anyway to relocate the ignition model to somewhere else under the hood. Each time I have replaced it, I have used the white grease under it. Thanks for any help!

Tom
 
If you have a P0042 code that has to do with the heater control circuit of the O2 sensor ( bank 1 sensor 3). Have you ever replaced any of the O2 sensors?
 
OBD1

Code 42
4 flashes, pause, 2 flashes
The Electronic Spark Timing (EST) signal did not change when the ECM applied bypass voltage to the ignition module. Check for faulty connections, or a faulty ignition module.

Doug in P.R.:cool:
 
CODE 42
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module and the ECM grounds the EST line. It expects to see no activity on this line at this time. When the ECM enters EST mode, it applies +5 volts to the BYPASS line and expects to see voltage variations on the EST line.
Reasons for the ECM to set Code 42:
? System in BYPASS mode (i.e. EST line supposedly grounded) but activity sensed on EST line
? System in EST mode (i.e. BYPASS line driven with +5 volts) but no activity seen on the EST line

Possible causes include:
1. BYPASS line is open or grounded
2. EST line is open or grounded
3. Poor connections between ignition module and ECM
4. Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise
5. Faulty or incorrect ignition module
6. Faulty ECM

Doug in P.R.:cool:
______________________________
 
http://wiki.answers.com/Q/GM_Scanner_found_code_42_EST_How_do_you_fix_it


http://straighttalkautomotive.com/OBD1/GM_OBD1.html

CODE 42

Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.

During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.

An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.

The conditions for setting this code are:

System in BYPASS mode but the ignition module is still controlling timing

- or -
Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.



Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM



Doug in P.R.:cool:
 
Being a 91 and/or a convertible , I would check all your wiring connections to the computor and module.

These cars allready had problems with the fuel pump wiring corroding on the floorboards and not letting the pump run, so I would check your wiring first.

Check all your grounds also, as they have to be clean. ( I had a S10 that gave me the fits cause of this)

All the grounds are usually all together bolted to an engine bolt / head stud.

Doug in P.R.:cool:
 
3.1 V6 problems.................#6

6. Intermittent Electronic Control Faults. GM tech bulletin 09-06-03-004D says various fault codes and intermittent driveability problems and other faults may be caused by corrosion and fretting in various control module wiring harness connectors.
Vibration and corrosion can take a toll on the wiring in any vehicle after many years of driving. What happens is that the little pins inside the connectors may lose electrical contact either intermittently or permanently as a result of vibration, rubbing and/or corrosion.
This obviously upsets the operation of whatever module the wiring is connected to. The fix, says GM, is to unplug the wiring harness connectors, inspect and clean the pins and terminals as needed, then reassemble using a small amount of dielectric grease (don’t overdo the grease or it may hydrolock the pin cavities and prevent the pins from making good electrical contact).
If the problem goes away, the fault has been fixed (at least temporarily). If the problem is still there, it may be an intermittent wiring fault or an internal control module problem.

Doug in P.R.:cool:
 
Ok. That helps a lot, Doug. Since the ignition control module on this one is down on the engine and it gets wet from the road, I could have some corroded connections. Man, I hate electrical stuff. I just changed the plugs and wires about a week ago. I was hoping that would have cured the hesitation. It helped for a couple of days. LOL

Tom
 
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Remember too that in all these years some douchebag could have hotwired it and that wiring could be on all the time.
 
Nice Im in the clear mines too old to have half of that shit lmfao. No airbag, ABS, ESC (to my knowledge), etc. But I feel pretty safe in it cause I know if it hits another car pretty sure it will cut through all the fiberglass, plastic, Styrofoam bumpers. I'm really only screwed if I hit a Mack truck or a 50's model Buick or something of that nature lol.
 
It's funny if you look at the evolution of automobiles that the 80's cars really sucked and they tried to fix it in the 90's but it all went to @%#$!
 
TrojanMan said:
It's funny if you look at the evolution of automobiles that the 80's cars really sucked and they tried to fix it in the 90's but it all went to @%#$!
Click to expand...

Sorry to bust your bubble "TM" ,Ask any Mechanic, 90's cars were the best and longest lasting cars ever made. Most domestics even go to 300k miles.


Doug in P.R.:cool:
______________________________
 
Yeah I have to say the 80's sucked hard for cars. but I am with doug on the 90's cars. Even now it is quite common to see cars from mid to late 90's that still look pretty good. hell I put 30,000 miles on a 90's S10 4 banger in a matter of 8 months and come winter it started and drove like a brand new car.......I really miss my S10.

As far as 2000's go I still deem it too early to tell how they will hold up over time. But to me there will never be anything like the old packards with the straight 8's in em from around the 30's and 40's. Cars then were meant to last. I even seen an old man clean a rats nest out of the pan of a straight 8 engine from 46 I think and he got it to crank and run. Nothing will ever match that quality. I do not believe when 80's and 90's cars get to be 80 years old that they will fire and run with a simple cleaning like that engine did.
 
Naw, you guys got me wrong. 90s cars are good but after that it gets crappy. I mean, 80s cars barely ran on the new gas. 90s cars were zippy and strong. Anybody ever drive one of those Turbo 2.3 T-Birds?? Holy [Bleep]! My 90 Ranger was a great pickup too. No leg room but a great pickup till the transmission froze. I could probably get another hundred thou on that engine now. Emmisions control systems were add-ons in the eighties but in the nineties, the sensors were better and they actually aid in the operation of the engine instead of just restricting it.
 
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