TI ignition problem
Thread Starter
Cruising
Joined: Jun 2013
Posts: 10
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TI ignition problem
I have a 1967 427/435. It is numbers matching. I am having problems with the transistor ignition system. I have replaced the oem transistor module (after it died) with a new updated module that fits the existing housing. This is actually the second replacement due to the same problem when I installed the first module. After installation the car starts and runs great. It will sit and idle as low as 800 RPM with no problem. Runs great on the road for about 10 miles. After that, it is difficult to keep it running even at 2000 RPM. It acts like it is not firing properly. If I pull over and let it try to idle, it sounds like it is hitting on two cylinders.
Once the engine cools over night, it will start up and run great again until the engine is up to temperature. After that the engine starts missing again. Does anyone have any suggestions on where the problem lies?
I don't mind replacing parts that need replacing but I don't want to replace existing original parts that are good. I want to keep the car as original as possible. It has less than 43,000 original miles. I bought the car in 1973.
Finding a mechanic nearby that knows anything about the original TI systems has not been possible in the Athens, GA area.
Once the engine cools over night, it will start up and run great again until the engine is up to temperature. After that the engine starts missing again. Does anyone have any suggestions on where the problem lies?
I don't mind replacing parts that need replacing but I don't want to replace existing original parts that are good. I want to keep the car as original as possible. It has less than 43,000 original miles. I bought the car in 1973.
Finding a mechanic nearby that knows anything about the original TI systems has not been possible in the Athens, GA area.
Thread Starter
Cruising
Joined: Jun 2013
Posts: 10
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Thanks for the quick reply. The coil has been my first thought. I have also heard that there is a resistor wire in the amplifier wiring harness that could be a problem. Of course that suggestion on the wire came from a company that makes replacement wiring harnesses. Not saying they are wrong but can see why it would be their first thought.
Thanks again.
Thanks again.
Race Director
Joined: Jan 2003
Posts: 17,695
Likes: 3,683
From: Central Arkansas
Sounds like classic coil problem. There is a resistor wire built into the harness but I don't know what the Ohm values for it are. You might try Electric Limited for tech support and maybe they can tell you what readings you should get across both ends of the wire. But it seems like most resistor units - whether coil or wire type - either work or they don't work. So coil would be my first try.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
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The resistor wire acts like the ballest resistor in a non TI car. Or any other gm car. I want to say its 4 ohm but not sure. It should be in the service manual Or call Dave Fiedler of TI speciallys
Drifting
Joined: Sep 1999
Posts: 1,417
Likes: 161
From: Des Moines, Iowa, USA Iowa
Try here http://tispecialty.com/articles.htm
Your description sounds like a failing coil IMHO
Good luck with the repairs!
-Don
Your description sounds like a failing coil IMHO
Good luck with the repairs!
-Don
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Thread Starter
Cruising
Joined: Jun 2013
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Thanks. I thought it was probably the coil, but I wanted to get some additional thoughts on the issue.
I now have a new coil on order. We will see if that eliminates the problem. The new coil should arrive Monday.
Thanks for the help.
I now have a new coil on order. We will see if that eliminates the problem. The new coil should arrive Monday.
Thanks for the help.
Thread Starter
Cruising
Joined: Jun 2013
Posts: 10
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Here is where am am with the TI problem.
I have a new amplifier module installed.
I have purchased and installed a new GM restoration coil of the correct type.
I have verified that the amplifier ground is good.
I have visually looked over the amplifier wiring harness and everything looks very good. No frayed wires.
After installing the new coil, I started the engine and it idled great at 800 RPM for about 20 minutes. No problem at all. Let the car sit for about 2 hours and started it again. Waited another 2 hours and started it again with no problem what so ever. Let it sit overnight. Came out the next morning and it would not start. The engine would try to start but for about 3 seconds it acted like it was hitting on two cylinders again. I have been unable to start it since.
Any ideas? Makes no sense to me that it start and run fine one day but not start the next after just sitting there over night.
I have a new amplifier module installed.
I have purchased and installed a new GM restoration coil of the correct type.
I have verified that the amplifier ground is good.
I have visually looked over the amplifier wiring harness and everything looks very good. No frayed wires.
After installing the new coil, I started the engine and it idled great at 800 RPM for about 20 minutes. No problem at all. Let the car sit for about 2 hours and started it again. Waited another 2 hours and started it again with no problem what so ever. Let it sit overnight. Came out the next morning and it would not start. The engine would try to start but for about 3 seconds it acted like it was hitting on two cylinders again. I have been unable to start it since.
Any ideas? Makes no sense to me that it start and run fine one day but not start the next after just sitting there over night.
Safety Car
Joined: Dec 2009
Posts: 4,171
Likes: 335
From: Homewood Alabama
I know you said you verified your ground, but i would at least run an extra temporary straight to the ground post on the alternator. I had a very similar issue with a TI system two years ago and running that extra ground solved all problems.
Drifting
Joined: Jul 2005
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From: Putnam Valley, New York. Amateur Radio Operator K2NS
T I Problem
The only thing left in the system is the pickup coil in the distributor. GM discontinued them years ago, but I'm sure somebody has one at a ridiculously high price somewhere. Good luck.
RON
Race Director
Joined: Jan 2003
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From: Central Arkansas
Do you have the shielding lid installed? Slight chance it could be the coil wire arcing to the shield lid.
Also, if you haven't already, double check the distributor lead plug to the wiring harness. Once I didn't get that plug hooked back up solidly and after a few miles of driving it started missing and laying down on me. One of the leads had actually started to back out of the plug housing and wasn't engaged solidly.
Both are long shots but sometimes things just happen.
Also, if you haven't already, double check the distributor lead plug to the wiring harness. Once I didn't get that plug hooked back up solidly and after a few miles of driving it started missing and laying down on me. One of the leads had actually started to back out of the plug housing and wasn't engaged solidly.
Both are long shots but sometimes things just happen.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
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Thread Starter
Cruising
Joined: Jun 2013
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Thanks for all of the suggestions.
I ran a ground to the alternator ground post.
Still did not want to start. Battery was also getting low so I put it on a charger.
I checked the connections to the distributor and they appear to be okay.
I did remove the shield lid. It did not look like that the coil post would be to close however I could not remember if it was on or removed when I had the car running yesterday.
I really hope that I do not have to replace the distributor coil.
After charging the battery for a while I tried to start it again. Took several tries but it did start and continue to run. :-) That is a start. Will try it again tomorrow to see if it will start again.
I will let you know what happens. Thanks again for the suggestions.
I ran a ground to the alternator ground post.
Still did not want to start. Battery was also getting low so I put it on a charger.
I checked the connections to the distributor and they appear to be okay.
I did remove the shield lid. It did not look like that the coil post would be to close however I could not remember if it was on or removed when I had the car running yesterday.
I really hope that I do not have to replace the distributor coil.
After charging the battery for a while I tried to start it again. Took several tries but it did start and continue to run. :-) That is a start. Will try it again tomorrow to see if it will start again.
I will let you know what happens. Thanks again for the suggestions.
Drifting
Joined: Sep 1999
Posts: 1,417
Likes: 161
From: Des Moines, Iowa, USA Iowa
I had ignition problems intermittently with my TI system last year and one of the things that I had done was the distributor rebuilt and GM reproduction coil pick-up installed. eBay item 200933569451 is what I bought and that seller is the one rebuilt my dizzy. The pick-up coil was $275 and worth it. Not sure if that is your problem but it appears you have replaced the other main components. A bad pick-up coil can definitely disrupt the system 
Thread Starter
Cruising
Joined: Jun 2013
Posts: 10
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Thanks for the info. I may have to resort to that.
There shouldn't be a lot of wear. Only 43,000 miles.
I have owned the car since 1973. Had 26,000 on it when I got from a girl. Hasn't been ripping up and down the road
There shouldn't be a lot of wear. Only 43,000 miles.
I have owned the car since 1973. Had 26,000 on it when I got from a girl. Hasn't been ripping up and down the road
Drifting
Joined: Sep 1999
Posts: 1,417
Likes: 161
From: Des Moines, Iowa, USA Iowa