My C4 cuts off while driving. Dealer says to replace distributor and ignition module. Has anyone had this problem?

Some details would help.....IE year, engine L98/LT4 ,
there are a lot of differences between the years. Since you say distributor I'd bet you have a 1984-1991.

Next when its cutting off....
....when its HOT
....going around corners
....when AC kicks in
....at Idle
....at high speeds

etc

If you have a 1992-1996 and its when the engine is hot the ICM would be a good guess.
But so would ignition coil...or a plethora of other parts.

How long have you owned a Corvette? Are you mechanically inclined? Do you plan to repair it yourself? Do you own a Factory Service Manual? What part of the country do you live in? These answers can aid in your responses too. Any recent repairs that may relate to your issue?

I'm sorry, It's a 94 with Opti-Spark system.

I replaced the distributor myself six months ago. I live in Fontana, Ca.

It will cut off at high speed, idle, or going around a corners. It happens when the car is warned up. It is an LT/1.

Sounds like the ignition module

Did you vent the opti?

Washing the engine can kill them too.

I had kinda the same thing happeining for a while. I seem to have gotten it under control with some Guru help click here

If it quits when it gets hot and quits like you turned the key off it is the ICM. Starts up again after it cools off does it? ICM.

RonRon,

This could be your lucky day. I live in Torrance.

Ok... questions, that have been asked, but please answer them, it will help us to help you:

Next when its cutting off....
....when its HOT
....going around corners
....when AC kicks in
....at Idle
....at high speeds


I cut that from Aboatguy.

I agree, the ICM really smells like the root of this.

Mileage on the car?

It could also be a bad coil wire. Or a bad coil.

I really doubt it's the opti. They will cause a car to run badly, but rarely do the stop a car from running.

Welcome to the Guru!

I have a 1994 Corvette (not the ZR1) with LT1 engine that's been doing the same thing for about a month now. The engine just cuts out completely periodically. There doesn't seem to be a rhyme or reason.

* Sometimes cuts out within a minute or two of starting it.
* Sometimes runs great for a half hour or more and then the engine cuts out.
* Sometimes cuts out while idling.
* Sometimes cuts out while driving down the road at speed (even at 70 mph on the freeway)

Usually if I put the car in neutral and wait a few seconds and then turn the key back to Start, it will start back up. Other times I have to wait 20 or 30 seconds or longer (sometimes a minute or two) before it will start back up. On those occasions when it won't start back up the engine turns over just fine but it won't start until I let it sit off a while longer.

When it's running it has good power and runs nice and smooth. When the engine cuts out the electrical is all still working fine -- my digital speedometer remains on, all power and accessories still work -- but the engine is dead.

I just replaced the ignition control module and the ignition coil. That did not resolve the problem but now my Service Soon lamp on the center console is lit a lot of the time.

Does anyone have any other ideas about what the problem might be?

Take a paperclip and scan it for codes.

Take a paperclip and scan it for codes?

I don't understand. Am I being dense?

You can take a paperclip and short out two of the pins on the ALDL and get the fault codes. I think I remember it being pins 4 to 12, but surely someone else will chime in shortly. This is the code list:

1994-1996

DTC #11: Malfunction Indicator Lamp Circuit.
DTC #13: Bank #1 Heated Oxygen Sensor #1 Circuit:
DTC #14: Engine Coolant Temperature Sensor Circuit Voltage Low.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High.
DTC #16: Distributor Ignition System Low Pulse.
DTC #18: Injector Circuit.
DTC #21: Throttle Position Sensor Circuit Voltage High.
DTC #22: Throttle Position Sensor Circuit Voltage Low.
DTC #23: Intake Temperature Sensor Circuit Voltage High.
DTC #24: Vehicle Speed Sensor Circuit.
DTC #25: Intake Air Temperature Sensor Circuit Voltage Low.
DTC #26: Evaporative Emission Canister Purge Solenoid Valve Circuit.
DTC #27: EGR Vacuum Control Signal Solenoid Valve Circuit.
DTC #28: Transmission Range Pressure Switch Assembly Fault.
DTC #29: Secondary Air Injection Pump Circuit.
DTC #32: Exhaust Gas Recalculation.
DTC #33: Manifold Absolute Pressure Sensor Circuit High.
DTC #34: Manifold Absolute Pressure Sensor Circuit Low.
DTC #36: Distributor Ignition System High Pulse.
DTC #37: Brake Switch Stuck On.
DTC #38: Brake Switch Stuck Off.
DTC #41: Ignition Control Circuit Open.
DTC #42: Ignition Control Circuit Shorted.
DTC #43: Knock Sensor Circuit.
DTC #44: Bank 1 LF Heated Oxygen Sensor #1 Circuit Lean.
DTC #45: Bank 1 LF Heated Oxygen Sensor #1 Circuit Rich.
DTC #47: Knock Sensor Circuit Or Module Missing.
DTC #48: Mass Air Flow Sensor Circuit.
DTC #50: System Voltage Low.
DTC #51: EEPROM Programming Error.
DTC #52: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #53: System Voltage Low.
DTC #55: Fuel Lean Monitor.
DTC #58: Transmission Fluid Temperature Sensor Circuit Low.
DTC #59: Transmission Fluid Temperature Sensor Circuit High.
DTC #62: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #63: Bank 2 RF Heated Oxygen Sensor #1 Circuit Open.
DTC #64: Bank 2 RF Heated Oxygen Sensor #1 Circuit Lean.
DTC #65: Bank 2 RF Heated Oxygen Sensor #1 Circuit Rich.
DTC #66: A/C Refrigerant Pressure Sensor Circuit Open.
DTC #67: A/C Pressure Sensor Circuit Sensor or A/C Clutch.
DTC #68: A/C Relay Circuit.
DTC #69: A /C Clutch Circuit.
DTC #70: A/C Clutch Relay Driver Circuit.
DTC #72: Vehicle Speed Sensor Loss.
DTC #73: Pressure Control Solenoid Circuit Current Error.
DTC #74: Traction Control System Circuit Low.
DTC #75: Transmission System Voltage Low
DTC #77: Primary Cooling Fan Relay Control Circuit.
DTC #78: Secondary Cooling Fan Relay Control Circuit.
DTC #79: Transmission Fluid Overtemp.
DTC #80: Transmission Component Slipping.
DTC #81: Transmission 2-3 Shift Solenoid Circuit.
DTC #82: Transmission 1-2 Shift Solenoid Circuit.
DTC #83: Torque Converter Solenoid Voltage High.
DTC #84: 3-2 Control Solenoid Circuit.(Auto Only).
DTC #84: 2nd And 3rd Gear Blockout Relay Control Circuit.
DTC #85: Transmission TCC Stock On.
DTC #90: Transmission TCC Solenoid Circuit.
DTC #91: One To Four Upshift Lamp(Manual Only).
DTC #97: VSS Output Circuit.
DTC #98: Tachometer Output Signal Voltage Wrong.

Measure the resistance of the fuel injectors. If the measurements come out OK I would measure fuel pressure next.

This does sound more like a fuel loss than an ignition loss... but the codes must be checked.

on the dash board, on the carpeted cover by your right knee, is a black plastic thing. It might have a cover on it. This is the ALDL. This is what you jump pins with the paperclip with.

I will post a more detailed instruction shortly.

Gee... I wish I was closer, I am down in San Pedro.

I really appreciate all the information Elite Guru, Senior Guru and God-Like Deity.

God-Like Deity, I look forward to your more detailed instructions to follow.

I am 'bogus'... I kinda run this zoo.

Welcome aboard!

Ah yes, I see my error. I was looking in the wrong spot in the left panel for the name of the poster. Sorry about that 1Fast04Vert, Woodstock and bogus.

Thanks for the welcome, bogus. Looking forward to your more detailed instructions.

It says 1990-1993, but 1994 should be really, REALLY, close.

You will need to refer to a different list of errors, because 1994 does have Sequential Injection, vs bank-to-bank that my 92 has.

Attach file:

---

CCM Code Pull.pdf Size: 336.94 KB; Hits: 338

Quote:

Bogus - That will NOT work for 94-96 years. 94-95 are OBD1, but have the OBD2 ALDL. For the OBD2 ALDL in the 94-95s from top left count over 4 pins, ie the #4 pin, then the number 12 pin is directly below it. Here is the complete deal:

--------------------------------------------------------------------------------

Paper clip from pin 12 to ground (4 or 5 are both ground)

On a 94-96 you can check the codes with a paper clip as follows:

You short pin "12" to pin "4" and turn the ignition switch to "On" without starting the engine.

The speedometer will display any codes using the same protocol as the 1990-1993 model but there are some changes in the designation for the modules plus additional modules are added:

Module "1" is still the CCM module.

Module "4" is now called the PCM module (Powertrain Control Module) because automatic transmission computer control was added to Engine Control Module in 1994.

Module 7 (on the 1996 model only) is the RTD module. (This is the Real Time Dampening module which replaced the Selective Ride Control module in 1996).

Module 9 is the ABS/ASR module number from 1994 through 1996.
Finally, Module "A", the DERM (Dynamic Energy Control Module --- (the air bag control module) will be requested to show any codes.

Just like the 1990-1993 display, you read the codes on the speedometer (big) and read the module number on the trip odometer (small).

A series of dashed lines for instance “ - - -“ indicates no more stored codes for that module.

A code showing as “C12” for the CCM module (module #1) means no codes are stored. So C12 is a good thing to see.

Again, you can cause the codes to repeat by turning the ignition off for five seconds and then back on.

Turn the ignition off and remove the short to restore normal operation.

To clear the codes,

1. With ignition "off" ground terminal #12 of the DLC (use bent paper clip to connect pin 4 to pin 12)

2. Turn ignition "on".

3. Press trip/odo button on the DIC until 1.7 appears in the trip
monitor area of the instrument cluster.

4. Press eng/met button on the DIC & hold until "---" appears in the
speedometer area of the cluster, this will clear CCM DTC'S.


To clear PCM/ECM codes do the following:


1. Press the trip reset button on the DIC until the desired system is displayed. In this case it will be 4.0.

2. Press trip/odo button on the DIC until the desired diagnostic mode(4.7) is displayed on the trip monitor area of the cluster.

3. Press & hold the eng/met button on the DIC until "---" is
displayed in the speedometer area of the cluster, this will clear PCM codes.


To clear ABS/ASR codes do the following:

Same as above but you’re looking for “9.7” on the trip odo

And here are the codes

1994-1995: Diagnostic Trouble Codes
DTC #11: Malfunction Indicator Lamp Circuit.
DTC #13: Bank #1 Heated Oxygen Sensor #1 Circuit:
DTC #14: Engine Coolant Temperature Sensor Circuit Voltage Low.
DTC #15: Engine Coolant Temperature Sensor Circuit Voltage High.
DTC #16: Distributor Ignition System Low Pulse.
DTC #18: Injector Circuit.
DTC #21: Throttle Position Sensor Circuit Voltage High.
DTC #22: Throttle Position Sensor Circuit Voltage Low.
DTC #23: Intake Temperature Sensor Circuit Voltage High.
DTC #24: Vehicle Speed Sensor Circuit.
DTC #25: Intake Air Temperature Sensor Circuit Voltage Low.
DTC #26: Evaporative Emission Canister Purge Solenoid Valve Circuit.
DTC #27: EGR Vacuum Control Signal Solenoid Valve Circuit.
DTC #28: Transmission Range Pressure Switch Assembly Fault.
DTC #29: Secondary Air Injection Pump Circuit.
DTC #32: Exhaust Gas Recalculation.
DTC #33: Manifold Absolute Pressure Sensor Circuit High.
DTC #34: Manifold Absolute Pressure Sensor Circuit Low.
DTC #36: Distributor Ignition System High Pulse.
DTC #37: Brake Switch Stuck On.
DTC #38: Brake Switch Stuck Off.
DTC #41: Ignition Control Circuit Open.
DTC #42: Ignition Control Circuit Shorted.
DTC #43: Knock Sensor Circuit.
DTC #44: Bank 1 LF Heated Oxygen Sensor #1 Circuit Lean.
DTC #45: Bank 1 LF Heated Oxygen Sensor #1 Circuit Rich.
DTC #47: Knock Sensor Circuit Or Module Missing.
DTC #48: Mass Air Flow Sensor Circuit.
DTC #50: System Voltage Low.
DTC #51: EPROM Programming Error.
DTC #52: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #53: System Voltage Low.
DTC #55: Fuel Lean Monitor.
DTC #58: Transmission Fluid Temperature Sensor Circuit Low.
DTC #59: Transmission Fluid Temperature Sensor Circuit High.
DTC #62: Engine Oil Temperature Sensor Circuit Voltage Low.
DTC #63: Bank 2 RF Heated Oxygen Sensor #1 Circuit Open.
DTC #64: Bank 2 RF Heated Oxygen Sensor #1 Circuit Lean.
DTC #65: Bank 2 RF Heated Oxygen Sensor #1 Circuit Rich.
DTC #66: A/C Refrigerant Pressure Sensor Circuit Open.
DTC #67: A/C Pressure Sensor Circuit Sensor or A/C Clutch.
DTC #68: A/C Relay Circuit.
DTC #69: A /C Clutch Circuit.
DTC #70: A/C Clutch Relay Driver Circuit.
DTC #72: Vehicle Speed Sensor Loss.
DTC #73: Pressure Control Solenoid Circuit Current Error.
DTC #74: Traction Control System Circuit Low.
DTC #75: Transmission System Voltage Low
DTC #77: Primary Cooling Fan Relay Control Circuit.
DTC #78: Secondary Cooling Fan Relay Control Circuit.
DTC #79: Transmission Fluid Overtemp.
DTC #80: Transmission Component Slipping.
DTC #81: Transmission 2-3 Shift Solenoid Circuit.
DTC #82: Transmission 1-2 Shift Solenoid Circuit.
DTC #83: Torque Converter Solenoid Voltage High.
DTC #84: 3-2 Control Solenoid Circuit.(Auto Only).
DTC #84: 2nd And 3rd Gear Blockout Relay Control Circuit.
DTC #85: Transmission TCC Stock On.
DTC #90: Transmission TCC Solenoid Circuit.
DTC #91: One To Four Upshift Lamp(Manual Only).
DTC #97: VSS Output Circuit.
DTC #98: Tachometer Output Signal Voltage Wrong.

To run a diagnostic on the PKE system, connect pins 4 and 8 on the ALDL (see pic below to see pin label order)


And the PKE diagnostic system works as follows:
With pins 4 and 8 connected, the PKE light in the Driver Info Centre will flash the codes.

Here is the list of DTCs and what they mean:

DTC #12: Receiver Memory Bad
DTC #13: Transmitter Not in Range
DTC #14: Non-Valid Transmitter Received
DTC #15: Valid Transmitter Received
DTC #16: Passenger Door Button Depressed
DTC #17: Hatch Button Depressed

Wow! Lots of information in that PDF. Thanks, bogus.

1Fast04Vert, are the codes you posted above for the 1994 Corvette?

1Fast04Vert, you apparently posted about the same time I posted. Thanks for the great information! Sorry for the posts that must have pretty much passed in cyberspace.

I thought that 1994 still had the old ODBI connector?

This is the OBD1 16 pin connector in 94-95 Corvettes, which is the same connector used when GM went to OBD2 in 1996. The 94 F-bodies Bogus is thinking about have the OBD1 ALDL, but that isn't relevent here.

that must be it... too many details to keep in one poor brain...

How do you know it's the optispark? What specific troubleshooting has been done? There are other things that could mimic opti symptoms, like a loose coil wire.

Quote:

Yea, quite a few accounts like this where someone bought an ebay opti just to save a few bucks (or make a few bucks).

Personnally for the price on a GM unit, I'd put on a MSD Opti.

From my experience, when the opti fails, it WILL throw a code.

H16 or H36 (1996 has a different number).

If it dies and has that code in it, bingo.

However... they can run pretty bad on a bad opti, ask how I know...

As for failure? Crap electronics... they may have stopped using the good Mitsubishi sensor. I swear, I will rebuild my opti before replacing it.

The Optical sensor is good for 2 forevers, and most of the time, the code is actually cause by bearing failure, allowing the tone disc to wobble about.

I agree re: MSD unit. they had some teething issues, but after that, they got them down pretty good.

Quote:

Neil, I understand your feelings about the warranty and they are justified somewhat.

Here's a post from 2010 on my MSD and what it looked like after 10,000 miles.

It probably still looks like this inside today. I'll never install another GM, not that the GM is a bad unit, it's just that the MSD is built better especially the O-ring seal vs the GM paper gasket.

http://www.corvetteguruforum.com/modu ... id=133157#forumpost133157

Good luck either way.

I still want to know how the dealer diagnosed it specifically. And when that isn't the problem, are they going to refund your money....doubt it.

And $1400 to swap an opti seems steep to me.

$185 an HOUR!!!!!

I am in the wrong business...

I know where it is... and I can swap one in about 4 hours... but that's $800!!!!!!!!!!

My "!" key just fell apart. I am at a total loss for words.

You need to buy tools...

Can you post what all they replace/repaired? Scan a copy of the invoice? I am really curious.

In general, Hendricks operations are pretty legit, but even the best make mistakes. I have never heard of overall bad business practices...

Quote:

That's engine swap labor costs!


Mike

Here's an update for all of you kind gurus who have read and/or replied on this post.

It has been just over 2 months since my last post. I just got a call from Hedrick's Chevrolet a few minutes ago saying my car is ready to pick up. They're saying it's really fixed now. I won't be quite ready to make that statement until I've driven the car for a few week.

Here's a recap of what has happened since my last post on February 22, 2013.

1. Hedrick's did further testing and decided it was not the Opti-spark that was the problem after all. They found a fault on the 5 volt side of the PCM. This was the very same PCM that had shipped off to Florida to be rebuilt by whatever company they are using to provide that service. The mechanic put a detailed note in with the PCM about what they found with their testing and shipped it back to them.

2. About six weeks later they got the PCM back, installed it, programmed it, then started the car to test it and found it was still dying continually just like it had been doing. The mechanic retested everything and said the PCM was still faulty. They looked around for about a week to see if they could locate a used PCM at a price they were willing to pay so they could install the used one to find out if the car continued to die even with the used one or if it ran properly with a different PCM. Their objective was to be able to "prove" to the place that had rebuilt my PCM (twice already) that they were not fixing whatever was wrong with it. Unfortunately they were not able to find a used PCM at a price they were willing to pay so they packaged my PCM up and shipped it back to the place to be rebuilt for a third time with another note about what the mechanic found during testing.

3. This morning (April 22) they got my PCM back after the third rebuild. They installed it, programmed it, started the car and drove it a bit and they say the problem seems to finally be resolved.

I'm going to pick the car up late this afternoon and drive it home and see what happens. If it doesn't die on me on the way home, I'll drive it for a few weeks to make sure I don't have any further problems with it dying. If I can successfully drive it for two or three weeks without it dying, I'll finally feel fairly confident that the problem has been resolved.

I'll update this thread again -- hopefully in two or three weeks with the news that my 'Vette is still running great!

Thanks again, everyone, for the comments, feedback and recommendations about this.

Geez.....you Sir are a patient man....I hope that it runs well for a long long time.....

Wow, thanks for the update. So they did not replace the opti after all, huh?

Hopefully the pcm fixes the problem!

Matthew

Alas, it was not to be. At least not yet.

The dealership called me today and said the mechanic had taken the 'Vette out for one more test drive this morning to make sure it was still running well since I was supposed to pick it up this afternoon. The engine died on him while he was driving it. Then he wasn't able to get it started. After trying for about 10 minutes he finally got it started and got it back to the shop where it died again.

They're still having the exact same problem. It runs and then it dies.

The mechanic seems to think it's still the PCM causing the problem, even though it's been rebuilt three times now. They're going to do some additional testing to try to nail it down to definitely being the PCM or maybe being something else after all. If they decide it's definitely the PCM, they're going to send it back a FOURTH time to be rebuilt.

Ugh!

I wonder if I'll ever get to drive my car again?

Do you know anyone with a 94 (I think 95 might work) pcm you can swap with to test that theory?

I would be looking for a repair shop that can find their asses with both hands to work on your car....WTF! Send it back for the 4th time????? I'd be in there ripping someone a new one and then having my car picked up and taken to someone who can get the damn thing fixed......but that's just me..... I also would not pay these guys anything....

Wow, I find this post very intriguing! I'm having the same exact problem! I haven't done much other than a 15 dollar fuel filter. But the problem persists. I can attest to the opti comment above that the car will run, even with an almost completely failing opti. It will run like a turd, but it WILL run. (Found that out in my father's identical vette to mine). I replaced his with an MSD and couldn't be happier with it! My opti was replaced shortly before I bought my car as well and I'm having the same problem. I'll see what you come up with and maybe it will give me a decent place to start. Thanks!

After further testing for several days the mechanic at Hedricks Chevrolet was repeatedly getting codes from the Opti-Spark system so they replaced it with a new GM Opti-Spark. They kept the car for two more days and tested it repeatedly and were not able to get it to die any more so Thursday night after work I picked it up.

They graciously gave me about a $200 break on the price of the Opti-Spark distributor -- $650 instead of $850 -- because of the amount of time they had the car. Total additional repair price for the Opti-Spark, about $1,120 instead of $1,430.

Friday was a work day so I really couldn't test the car that day though it ran great all the way home from the dealership Thursday night.

I drove the car most of the day Saturday. I had one problem with it that may or may not be related to everything that's been going on. My wife and I went into a store for about a half hour and when we came out and I started up the Corvette, it ran for a couple of seconds and then started idling really rough and died. I started it right back up and it idled very rough for a few seconds and died again. I started it again and it was idling rough so I gave it some throttle and it smoothed out but when I let it return to an idle it got rough again and acted like it was going to die so I gave it some throttle again for a few seconds and it eventually smoothed out again. I let it return to an idle and put it in gear and drove it. It drove fine all the rest of the day.

The jury is still out on this. I wish I could say I had high confidence in the car again but I do not, at least not at this point.

I'm going to drive it quite a bit again today (Sunday) and see if any problems surface or re-surface.