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Old 07-15-2012   #1
90 L98 TransAm
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Ignition Module Failure Mode?

Does (or can) the ignition module under the distributor cap literally burn up and give off smoke and fumes when it fails?

Same question on the ignition coil.

And does the factory rotor simply press in and lift out of place with no fasteners retaining it?

thanks
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar

Last edited by 90 L98 TransAm; 07-15-2012 at 09:41 PM.
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Old 07-16-2012   #2
djmarch
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Re: Ignition Module Failure Mode?

I know ignition modules can go out like a flash, as it happened to me driving down a highway and my car just died...But I've never heard of one going up in smoke. The rotor just pulls off. No fasteners.The distrubitor shaft is keyed for the notch on the rotor and sometimes they are difficult to pull off, but they do.
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Old 07-16-2012   #3
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by djmarch View Post
I know ignition modules can go out like a flash, as it happened to me driving down a highway and my car just died...But I've never heard of one going up in smoke. The rotor just pulls off. No fasteners.The distrubitor shaft is keyed for the notch on the rotor and sometimes they are difficult to pull off, but they do.
thanks for the info DJ.

i checked the coil with an ohmmeter per the GM Service Manual and it is good. got the module out and will have it checked though after looking at it i'm pretty sure it's also good (at least it didn't burn up).

found this on rotor removal:

http://www.thirdgen.org/techboard/el...r-removal.html

figured i'd replace the 18-yr old cap and rotor while i have easy access to them.

i've got smoke/fumes coming up at the firewall near the distributor. hope i don't have to replace or rebuild the old slushbox again or maybe it's time to get a real transmission!
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-16-2012   #4
YumikoGTA
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Re: Ignition Module Failure Mode?

Yes the rotor just is suppoed to lift off without fasteners, however over long periods of time, it can become stuck onto the distrubutor.

In reference to the ignition module, there is high voltage that goes into it I think and I guess if there was a serious malfunction, that could cause it to smoke. But I would also say that if it in fact had such a serious malfunction, it would probably completely ruin it and it would not work anymore. They still have them at GM and I would suggest buying a replacement one from there instead of the chain auto parts stores. The GM ones are better and last longer. Good luck.

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Old 07-21-2012   #5
MunsonGTA
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by 90 L98 TransAm View Post
Does (or can) the ignition module under the distributor cap literally burn up and give off smoke and fumes when it fails?

Same question on the ignition coil.

And does the factory rotor simply press in and lift out of place with no fasteners retaining it?

thanks
i have went through 3 ignition modules, none of them have ever smoked. Did you see smoke coming from under the hood?
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 07-21-2012   #6
90 L98 TransAm
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Re: Ignition Module Failure Mode?

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Originally Posted by MunsonGTA View Post
i have went through 3 ignition modules, none of them have ever smoked. Did you see smoke coming from under the hood?

yes i've got light some smoke coming up between the rear of the engine and the firewall after the car is hot. could not pinpoint the source but it was in the general vicinity of the distributor which led me to poke around there in the first place.

i ended up having to dremel the 18-yr old rotor to get it off and in the process damaged the reluctor (which was pretty rusty)





so now i get to replace the entire distributor unless i can find just the shaft with a good reluctor. the module tested good at NAPA which i suspected it would after removing it and seeing what condition it was in. is it possible that the smoke could be due to a leaking distributor seal?



i suppose it's either tranny fluid or engine oil burning off from somewhere but i crawled under the car twice and there is nothing obvious. i took off the plastic shield between the oil and tranny pans and found a small amount of fluid there but not much.

i'll probably take the car to a tranny shop (after i get it running again) and have them take a look.

now - does anyone have recommendations on an aftermarket slushbox that could easily handle 400 HP?

thanks
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-21-2012   #7
MunsonGTA
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Re: Ignition Module Failure Mode?

You can buy the shaft seperate, however they are pretty expensive. Try rockauto.com for the shaft. As far as the smoke you see, it's most likely either oil coming from the distributor gasket, the rear intake gasket, or a valve cover gasket. Have you had the valve covers off recently? It's possible that it's coming from the underside of the vehicle, burning off on the exhaust and the smoke is just coming up where it is.
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 07-21-2012   #8
90 L98 TransAm
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by MunsonGTA View Post
You can buy the shaft seperate, however they are pretty expensive. Try rockauto.com for the shaft. As far as the smoke you see, it's most likely either oil coming from the distributor gasket, the rear intake gasket, or a valve cover gasket. Have you had the valve covers off recently? It's possible that it's coming from the underside of the vehicle, burning off on the exhaust and the smoke is just coming up where it is.
i bought the cap and rotor from RockAuto but didn't see just the shafts there (or anywhere else). i'll probably buy a used distributor and put my components on it.

would be great if the smoke is from a leaking distributor seal. i guess replacing the distributor will eliminate that possibility.

the intake and valve covers have never been off. car has 62,000 miles on it.

yes, it's very hard to see the exact source of the smoke. maybe once it's up on a lift it will be obvious.

thanks
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-21-2012   #9
MunsonGTA
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GTA Year: 1987
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by 90 L98 TransAm View Post
i bought the cap and rotor from RockAuto but didn't see just the shafts there (or anywhere else). i'll probably buy a used distributor and put my components on it.

would be great if the smoke is from a leaking distributor seal. i guess replacing the distributor will eliminate that possibility.

the intake and valve covers have never been off. car has 62,000 miles on it.

yes, it's very hard to see the exact source of the smoke. maybe once it's up on a lift it will be obvious.

thanks
I went and checked rockauto again and couldn't find a shaft for a 90 year model. However there is one for the 87 year model I have. I don't see why there would be any difference in the two. I'm actually running a distributor from a 91 camaro at this very moment in my 87 GTA.

STANDARD MOTOR PRODUCTS Part # DG43 {#10467353, 10496786} Distributor Shaft Assembly Includes Rotor;Material: Steel Shaft; Contents: Distributor Gear

$78.99
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 07-21-2012   #10
90 L98 TransAm
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Re: Ignition Module Failure Mode?

thanks Munson. a new/reman shaft would probably be a better option than a used distributor with an unknown history.

when i asked RockAuto a question about our distributors their response was "i can't tell you because i'm not a mechanic". well, at least they were honest!

does anyone know if the distributors from '87 to '90 GTAs/TAs are all interchangable and does it matter if they are 5.0 or 5.7L?
__________________
Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-22-2012   #11
YumikoGTA
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Re: Ignition Module Failure Mode?

The rotor is plastic, how could you damage the metal distributor by removing the plastic rotor? I know you must have damaged it with the tool that you used, but I would have thought you could have been more careful and be able to remove the plastic rotor without damaging the other part. Take your time next time and that might help. As this same thing happened to my own GTA, I was careful and took my time and was able to remove the plastic rotor without damaging anything else except for just the rotor itself.

As for the smoke, yes it could be a few different things but probably oil being burned somewhere on the back of the engine near the transmissions.

Maybe you should get the electronic ignition module from GM. Just my suggestion as they are still available from there and I read other members on this forum in the past years saying that the ones they bought that were from the chain auto parts stores would not last long and fail in not too long of time. Good luck.

Yumiko
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Last edited by YumikoGTA; 07-22-2012 at 12:59 AM.
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Old 07-22-2012   #12
90 L98 TransAm
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Re: Ignition Module Failure Mode?

"YumikoGTA;434324]The rotor is plastic, how could you damage the metal distributor by removing the plastic rotor? I know you must have damaged it with the tool that you used, but I would have thought you could have been more careful and be able to remove the plastic rotor without damaging the other part. Take your time next time and that might help. As this same thing happened to my own GTA, I was careful and took my time and was able to remove the plastic rotor without damaging anything else except for just the rotor itself."

believe me i anticipated the rotor just pulling up and off without much difficulty. yes the rotor is plastic but it has metal inserts which corrode and bond to the distributor shaft. how long had your rotor been on when you removed it? 18 years? and did you remove it or did your mechanic? and was the distributor installed in your car when you removed the rotor?


"As for the smoke, yes it could be a few different things but probably oil being burned somewhere on the back of the engine near the transmissions."

yes that's what i concluded and stated previously.


"Maybe you should get the electronic ignition module from GM. Just my suggestion as they are still available from there and I read other members on this forum in the past years saying that the ones they bought that were from the chain auto parts stores would not last long and fail in not too long of time."

i don't need another ignition module. as i stated previously the factory original one i have tested good at NAPA.
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-22-2012   #13
YumikoGTA
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Re: Ignition Module Failure Mode?

I think it was in my car about five years before I removed it. It was stuck on there and so I just used some pliers and squeezed it around the part that is slipping onto the rotor. When I did this, it cracked the plastic and this was how it then was able to be removed. As for the metal inside, that is only on the one side and it is just a flat small piece of metal which if the plastic is broke or bent out of shape, it does not have any way of connecting to the distributor.

What I think you may have done is when you cut off the rotor on your GTA, you also cut into the metal shaft of the distributor or something like that, yes? Or did you hit it with a hammer or something and cause the other damage to occur? When you put the new one on, maybe try to put something in there so it does not stick the next time that you have to remove it.

Yumiko
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Last edited by YumikoGTA; 07-22-2012 at 03:48 PM.
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Old 07-22-2012   #14
90 L98 TransAm
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by YumikoGTA View Post
I think it was in my car about five years before I removed it. It was stuck on there and so I just used some pliers and squeezed it around the part that is slipping onto the rotor. When I did this, it cracked the plastic and this was how it then was able to be removed. As for the metal inside, that is only on the one side and it is just a flat small piece of metal which if the plastic is broke or bent out of shape, it does not have any way of connecting to the distributor.

What I think you may have done is when you cut off the rotor on your GTA, you also cut into the metal shaft of the distributor or something like that, yes? Or did you hit it with a hammer or something and cause the other damage to occur? When you put the new one on, maybe try to put something in there so it does not stick the next time that you have to remove it.

Yumiko
Yumiko - i tapped the top of the rotor with a hammer and block of wood trying to free it up and tried the other things described in the third gen thread i posted a link to.

the mistake i made was trying to pry it up from the bottom when the tapping and twisting failed. that is what damaged the small metel reluctor components you see in my photos. in hindsight (and knowing what i know now) if i had this problem again i would simply dremel the side of the rotor body until i could split it wide open and take it off.

this rotor was install by a pro mechanic at a Pontiac dealer 18 years ago back when about all i did on my cars was oil changes, tire rotations, etc.. and i strongly suspect they didn't use any anti seize or grease!

thanks for your help.
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-22-2012   #15
MunsonGTA
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Re: Ignition Module Failure Mode?

i really don't see any damage from the pictures you have posted. What exactly did you damage? if you are talking about the copper piece on the outside, that is easily replaced and very cheap.
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 07-22-2012   #16
90 L98 TransAm
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Re: Ignition Module Failure Mode?

Quote:
Originally Posted by MunsonGTA View Post
i really don't see any damage from the pictures you have posted. What exactly did you damage? if you are talking about the copper piece on the outside, that is easily replaced and very cheap.
the small, movable, riveted pieces next to the shaft (that spin inside the inner diameter of the 4 post-pole-piece) are what got damaged. i was surprised to see how rusty/crumbly they were. is this typical?

supposedly you can replace just the damaged reluctor but i read you need a "bearing heater" to expand it and get it on the shaft. and i'm not sure if the reluctor would have to be installed in any particular orientation.

if anyone has just a distributor shaft with a good reluctor on it let me know. or maybe a good used distributor. might even make more sense to replace the entire distributor and sell the components i don't need. not sure which way i want to go yet.

and i looked at that shaft you mentioned (STANDARD MOTOR PRODUCTS Part # DG43). the fitment tables say it will work on a '90 Camaro with the 5.7L so i'm pretty sure it would work on a 5.7L TA or GTA.
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Vortech V-3 SC, ~7 psi max boost
0 - 60 in 5.40 Seconds
1/4 mile in 13.9 seconds @ 103 mph @ 5,000' elevation, 309 HP (per Escort GT-2 meter)
Shift kit, 9 clutch 3/4, Corvette servo
Magnaflow 16829 catback exhaust
TDS fr. sway bar bushings and end links. Wonderbar
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Old 07-23-2012   #17
MunsonGTA
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Re: Ignition Module Failure Mode?

Just throw in a new shaft then and be done with it. The shaft was the only thing I didn't replace on mine when I rebuilt it, mainly because of the cost. As far as rust on it, it's very typical. Every distributor from a 3rd gen i've ever seen has rust on that piece. Mine still has alot of rust and it works fine. If you are going to put in a new shaft, I would recommend a new gear, pole piece, and pickup while you are in there. They are all relatively cheap.
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 10-05-2012   #18
90 L98 TransAm
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Re: Ignition Module Failure Mode?

well, i ended up buying a used distributor (and coil) off the third-gen classifieds. swapped my ignition module and the new rotor and cap onto it and re-installed the distributor.

the car would start and run but would die when i took my foot off the gas so i had to get help setting the timing to factory spec. found a young mechanic but he seemed to know what he was doing. said he was a Mopar guy but had owned several F-bodies.

she's running good again. been checking under the hood after every drive and so far no more smoke!
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Old 10-05-2012   #19
MunsonGTA
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Re: Ignition Module Failure Mode?

good news
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87 GTA: Forged 408 LSX short block, TEA stage 2 cnc ported 243 heads, BTR Stage 3 stroker cam, Fast 102 intake, NW 102 TB, Longtube headers, custom 411 ECM, custom harness, custom tuned, Performabuilt stage 2 4l60E with PTC 2800 stall, 9 bolt rear with 3.70 gears and TAP girdle.

11.16 at 123 mph.
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Old 1 Week Ago   #20
90 L98 TransAm
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Re: Ignition Module Failure Mode?

Back from the dead six years (and 1,500 miles) later:

Did a high speed run last Fall. The car was running fine. Parked it in the garage for the winter. Tried to start it several weeks later to charge the battery, run through the gears, run the AC etc.. but it would not start. Began troubleshooting and eventually traced the problem to the pickup in the distributor.

Here's what the top of my distributor looked like this time:








Rust never sleeps! At least my rotor wasn't stuck on the shaft like before.


Unfortunately you have to remove the distributor to replace the pickup.

Ended up buying a good distributor wrench and a timing light. Used a white paint pen on the timing marks on the damper and followed the instructions on the sticker on the underside of my hood to set the timing on my rebuilt factory original distributor:






Got the distributor with dead pickup rebuilt and ready for next time:



I've never heard of a Mobiletron Ignition Module which is what the rebuilder used. I'll probably swap my spare AC Delco module on if I ever need to install this distributor.
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