Transistorized Ignition woes

[robert leazenby]

I drove my car last night for the first time on the rebuuild. It ran fine up until the moment I was pulling back into my shop. About ten feet from the door it just died. It would then crank but not fire. Checking the coil wire for spark I found it to have spark intermittently. Not off and on, rather on one start attempt it would produce spark, on the next it would not.

My understanding of transformers is, they are either bad or good. Usually will not fluctuate from good to bad. It is the original TI coil.

I understand there may be other coponents causing the trouble. Any suggestions on how to isolate.

[Bill Clupper]

Re: Transistorized Ignition woes

I would start by checking all the connections in the TI wiring system, especially the grounds. Also chack the distributor mag-pulse setup for signs of a cracked impulse coil. If that doesn't improve things, I'd suggest Dave Fiedler at TI spectialties. He advertises in the riveline" and does excellent work.

[Bill Clupper]

Re: Transistorized Ignition woes

I would start by checking all the connections in the TI wiring system, especially the grounds. Also chack the distributor mag-pulse setup for signs of a cracked impulse coil. If that doesn't improve things, I'd suggest Dave Fiedler at TI spectialties. He advertises in the riveline" and does excellent work.

[Jack layton #896]

Re: Transistorized Ignition woes

www.tispecialty.com
Dave Fiedler
765-962-4265
1631 Pheasant Run
Richmond, Indiana 47374

[Jack layton #896]

Re: Transistorized Ignition woes

www.tispecialty.com
Dave Fiedler
765-962-4265
1631 Pheasant Run
Richmond, Indiana 47374

[Wayne K.]

Re: Transistorized Ignition woes

Had this happen to me once. Turned out to be the unit by the drivers side front inner fender (wheel area) wasn't grounded good.

[Wayne K.]

Re: Transistorized Ignition woes

Had this happen to me once. Turned out to be the unit by the drivers side front inner fender (wheel area) wasn't grounded good.

[robert leazenby]

Re: Transistorized Ignition woes

I went through everything again, connections, grounds, especially at the unit up front. Works fine now so evidently there was a bad connection/ground. Thanks.

[robert leazenby]

Re: Transistorized Ignition woes

I went through everything again, connections, grounds, especially at the unit up front. Works fine now so evidently there was a bad connection/ground. Thanks.

[Duke W.]

Re: Transistorized Ignition woes

I experienced two TI failures during the 60K miles I had one on my SWC. The first was a broken lead on the main power transistor. This transistor is mounted to the heat sink and the three leads loop to the circuit board. Once I removed the amplifier and took off the rear cover, the problem was obvious to visual inspection. I soldered the transistor lead back into its via (hole).

The second problem was with the amplifier connector. Moisture intrusion had corroded a terminal on the harness. I was able to carfully remove the terminals from the harness plug, clean off the corrosion, and reassemble. (I might have also used a bit of solder, too.) If this is your problem use some silicone dielectric grease to reinstall the terminals in the plug. This will aid in reintalling the terminals back in the connector boot and help prevent future moisture related problems. You should thoroughly inspect the amplifier connector even if the immediate problem turns out to be something else.

Another problem that can develop is failure of the two leads from the pickup coil. Constant movement of the breaker plate in response to the vacuum advance will eventually cause the wires to work harden and break (HEI systems experience this same failure mode.). Check for the pickup coil continuity while moving the plate or wiggling the wires.

The other responders comments are also very good. In particular, be sure the grounds have continutiy.

Duke

[Duke W.]

Re: Transistorized Ignition woes

I experienced two TI failures during the 60K miles I had one on my SWC. The first was a broken lead on the main power transistor. This transistor is mounted to the heat sink and the three leads loop to the circuit board. Once I removed the amplifier and took off the rear cover, the problem was obvious to visual inspection. I soldered the transistor lead back into its via (hole).

The second problem was with the amplifier connector. Moisture intrusion had corroded a terminal on the harness. I was able to carfully remove the terminals from the harness plug, clean off the corrosion, and reassemble. (I might have also used a bit of solder, too.) If this is your problem use some silicone dielectric grease to reinstall the terminals in the plug. This will aid in reintalling the terminals back in the connector boot and help prevent future moisture related problems. You should thoroughly inspect the amplifier connector even if the immediate problem turns out to be something else.

Another problem that can develop is failure of the two leads from the pickup coil. Constant movement of the breaker plate in response to the vacuum advance will eventually cause the wires to work harden and break (HEI systems experience this same failure mode.). Check for the pickup coil continuity while moving the plate or wiggling the wires.

The other responders comments are also very good. In particular, be sure the grounds have continutiy.

Duke

[Clem Z.]

Re: Transistorized Ignition woes

the best way to make sure the ground stays put on the amp.is to make sure there is no paint on the amp where the ground wire goes to the mounting bolt. also i always install longer mounting bolts and use nuts on the back side of the amp case to keep the ground wire tight then i install the amp through the holes in the fiberglass and use nylon lock nuts to secure the amp to the fiberglass panel. that way the ground wire will always be tight because the fiberglass panel is not that good a mounting surface.

[Clem Z.]

Re: Transistorized Ignition woes

the best way to make sure the ground stays put on the amp.is to make sure there is no paint on the amp where the ground wire goes to the mounting bolt. also i always install longer mounting bolts and use nuts on the back side of the amp case to keep the ground wire tight then i install the amp through the holes in the fiberglass and use nylon lock nuts to secure the amp to the fiberglass panel. that way the ground wire will always be tight because the fiberglass panel is not that good a mounting surface.