Ignition Module 1978 Corvette
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Ignition Module 1978 Corvette
Have a 1978 Corvette with low mileage. Every 1-1 1/2 years I have to replace the Ignition Module because the car cranks but will not start(no spark?). First 9 months with a new IM, car starts no problem. After 9 months go by, it takes longer to start and eventually wont start - can always tell when the IM is going bad(takes longer and longer to start). Once I get it started, its starts when warm with no problem. After replacing the IM, car starts no problem.
So my question is - why does this module keep going bad? I have replaced the guts in the distributor, ground wire is good - what gives?
Its not a hard job/repair to do, its not expensive, just don't know why..
Thanks
So my question is - why does this module keep going bad? I have replaced the guts in the distributor, ground wire is good - what gives?
Its not a hard job/repair to do, its not expensive, just don't know why..
Thanks
Last edited by jpkemp; Apr 11, 2021 at 02:18 PM. Reason: correction
Pro
Joined: Sep 2017
Posts: 516
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From: Modesto California
Have a 1978 Corvette with low mileage. Every 1-1 1/2 years I have to replace the Electronic Control Module because the car cranks but will not start(no spark?). First 9 months with a new ECM, car starts no problem. After 9 months go by, it takes longer to start and eventually wont start - can always tell when the ECM is going bad(takes longer and longer to start). Once I get it started, its starts when warm with no problem. After replacing the ECM, car starts no problem.
So my question is - why does this module keep going bad? I have replaced the guts in the distributor, ground wire is good - what gives?
Its not a hard job/repair to do, its not expensive, just don't know why..
Thanks
So my question is - why does this module keep going bad? I have replaced the guts in the distributor, ground wire is good - what gives?
Its not a hard job/repair to do, its not expensive, just don't know why..
Thanks
I assume you're referring to the ignition module inside the HEI? If so I suggest buying a Standard Module (good) or an MSD (better) because they're quality modules and they DO cost more.
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Yes, the ignition control module - I usually buy the AC Delco replacement..Just don't know why they keep going bad,,
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Last edited by jpkemp; Sep 24, 2017 at 11:16 AM.
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Still having issues
As usual, every year the ignition module has to be replaced in order to start the car. Just replaced the IM last Wednesday, car fired right up. Went to start today(Saturday), would not fire up. Battery has a full charge, starter is good, not sure why this car will not start. Could it be a bad IM even though it started fine on first crank on Wednesday?..Any idea why this keeps occurring on a yearly basis or why this car won’t start after replacing IM five days ago. Plug wires are good, cap/ rotor seem to be fine. Any assistance is appreciated.
Last edited by jpkemp; Apr 11, 2021 at 02:11 PM. Reason: correction
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AC Delco original replacement...bought off of Amazon. As stated, these ignition module(s) are usually good for a year. When replaced car starts on 1st crank then progressively starts on 2nd crank about 6 months later.
Last edited by jpkemp; Apr 11, 2021 at 02:12 PM. Reason: correction
Safety Car
Joined: Jan 2004
Posts: 4,549
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From: Glastonbury CT
Your battery charger is most likely spike it .Try plugging charger into receptacle with built in surge! Also any wireing under rotor make sure under side is not grounding to Distrubutor base which is metal Alot of heat will destroy module also so try a different heat sink manufacture under module. Good Luck!
Le Mans Master
Joined: Jun 2019
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From: Indiana
if this one...
sort reviews always from most recent not most helpful...and look at questions and answers..
AC Delco jumped the shark a long time ago on part quality..
reviews full of no markings, doesn’t last...etc...
anything nos USA even standard products would be worth a shot and cheaper...imo
example
https://www.ebay.com/itm/1-NOS-Delco...AAAOSw0sxgOXCm
Last edited by interpon; Apr 11, 2021 at 08:44 AM.
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Your battery charger is most likely spike it .Try plugging charger into receptacle with built in surge! Also any wireing under rotor make sure under side is not grounding to Distrubutor base which is metal Alot of heat will destroy module also so try a different heat sink manufacture under module. Good Luck!
Last edited by jpkemp; Apr 11, 2021 at 02:13 PM. Reason: correction
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Car started no issues for a year, but the last 6 months required multiple cranks to get motor started.
Have not measured the resistance but this has been an ongoing problem for many years....
Module would last for a year and crap out..This is the first time it has only lasted for 5 days...
I will install another module this week with different heat compound...
Last edited by jpkemp; Apr 11, 2021 at 02:13 PM. Reason: correction
