All Posts (ecorti95)
Re: 1992 Vette Misfiring intermittently |
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Guru Newb
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2009/8/23 12:55 Posts:
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The car does start but won't rev pass 3000 RPM. I believe this is the so call limp or fuel back-up mode.
Posted on: 2021/12/6 22:00
Edited by ecorti95 on 2021/12/6 22:51:58
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Re: 1992 Vette Misfiring intermittently |
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Guru Newb
Joined:
2009/8/23 12:55 Posts:
7
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I performed most of the suggestions indicated by you: check grounds, check connectivity and shorts between ecm and ccm (this was a real pain in the butt). These did not correct the problem, so I sent the ecm to SIA electronics on July 2020. After getting it back and installing it all problems were resolved! The car has run great, until yesterday (12/5/2021) when the problem have reoccurred!
Car stalled at a traffic light, restarted and and was able to drive home. I pulled codes from CCM Diagnostics, jumping Pins A-G in OBD1 connector Module 1: C41, H41 - Loss of ECM Serial Data Link Module 4: displays ERR Module 9: H72 - Loss of Data between CCM and EBTCM ECM Diagnostics, jumping Pins A-B in OBD1 connector. No reaction. Does not pull blinking codes. Something new: the speedometer displayed 0 MPH while driving home. I am probably going to send the ecm back to SIA Electronics, as it has a lifetime warranty for their repair.
Posted on: 2021/12/6 21:23
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1992 Vette Misfiring intermittently |
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Guru Newb
Joined:
2009/8/23 12:55 Posts:
7
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Corvette 1992, 73 K miles, bought it new, the problem is that it started misfiring intermittently a month ago. After driving for a mile or so, briefly misfires and Service Engine Soon, Service ASR, and SYS in speedometer blinks 3 times repeatedly. Also the AC stops cooling. The misfiring gets worse as the engine gets hot. I have been able to get home every time, but seems to be getting progressively worse. I do want to keep this car, it has been fairly reliable. I did have to replace the Opti and water pump at about 40 K miles. The car is stock, except an additional alarm was installed at the dealer when I purchased it.
I pulled codes from CCM Diagnostics, jumping Pins A-G in OBD1 connector Module 1: C41, H41 - Loss of ECM Serial Data Link Module 4: No error codes, or sometimes if the car is hot it displays ERR Module 9: H62 - Tach Pulse malfunction H72 - Loss of Data between CCM and EBTCM ECM Diagnostics, jumping Pins A-B in OBD1 connector. Only display blinking code 12, or no reaction if there was a Module 4 Err when pulling CCM codes I have read lots of posts from this and other forums, but I don't see a consensus about the cause of this problem based in the codes and pattern of misfires. Some recommend replacing the ECM, some replacing the CCM, some indicate it is a wiring issue involving the Serial Data Link wires that are shorting, or grounding. Can anyone provide some additional information that can help me troubleshoot and solve this problem? Thanks in advance!
Posted on: 2020/4/29 19:31
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Re: Corvette 1992 Misfire |
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Guru Newb
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2009/8/23 12:55 Posts:
7
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Thanks to all for the great answers and suggestions. I will post back any info that can be usefull. I did find out the my Vette was the 6th to the last built in 92, so it probably had the "improved" opti.
Posted on: 2009/8/26 3:13
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Re: Corvette 1992 Misfire |
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Guru Newb
Joined:
2009/8/23 12:55 Posts:
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My 92 Vette was built in 07/92, per the sticker in the driver side door.
I am in Kansas City metro area, and am not sure I could do the job myself. I guess I got spoiled with 17 years of trouble free operations. I really appreciate the very knowledgeable comments from the forum. I kind of lost faith in the GM dealer that has serviced this car the last 17 years. I had them do a coolant system flush recently, and when I checked the engine compartment after I got home I noticed that they had not screwed on the upper reservoir cap until the arrows line up with the overflow hoses. The owners manual makes big deal of of this! And, yes they quoted me a very large amount of money to do the job. To be honest, I did not belive them about the opti neededing replacement, but based on the forum and the codes it seems that it is toast.
Posted on: 2009/8/23 22:25
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Re: Corvette 1992 Misfire |
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Guru Newb
Joined:
2009/8/23 12:55 Posts:
7
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Thanks for the answers. The water pump has never been replaced, or the engine washed, I did get caught in the rain once or twice. I will start looking at the connectors and ground cable(s). I love my 92 and hate to see it misfire and stall. Replacing the Opti, is this a job for the dealer?
Posted on: 2009/8/23 16:15
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Corvette 1992 Misfire |
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Guru Newb
Joined:
2009/8/23 12:55 Posts:
7
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Corvette 1992, 48 K miles, bought it new, the problem is that it started misfiring intermittently 1 year ago, and stalls occasionally, it seems to run well for the first 15 minutes, but it gets worse after engine warms up. I pulled codes:
Module 1: C41, H41, H74 Module 4: H36, H16 Module 9: H62, H72 It will run well for a time, but then it will start misfiring and stalling again. It has always re-started without problems after stalling. Can anyone tell me if this is the optispark gone bad?
Posted on: 2009/8/23 13:04
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