1971 LT1 TI Ignition System--Won't Start

[Clem Z.]

Re: 1971 LT1 TI Ignition System--Won't Start

When I prop the butterflies open and clean all the visible gas out and try to start it it starts for just a second and then dies. Must be in the carb. Trying closing the jets all the way down and cleaned gas out--it starts again for just a second on the first crank and then dies. Any suggestions?

sounds like the ignition resistor bypass is working but when the ignition goes onto the resistor circuit you are getting no ignition voltage.

[Paul C.]

Re: 1971 LT1 TI Ignition System--Won't Start

Clem--please explain what that means?????

[Terry M.]

Re: 1971 LT1 TI Ignition System--Won't Start

Clem--please explain what that means?????

Paul,

I think you need Duke's ignition seminar, but you probably don't want to wait for the National in San Diego. I know Duke could explain this a lot more elegantly than I can, and I am struggling from a long day at work and the need to get out of Dodge prior to the "ass crack of dawn" (as my daughter puts it) to get to the Illinois Chapter Meet Tomorrow.

Briefly: if I can -- the ignition system (officially called the Kettering system after the inventor) has two wires feeding the + side of the coil. One wire provides 12 volts to the coil only during cranking. The other provides a reduced voltage (around 9 volts, I believe) during engine run. The battery voltage is reduced by a "ballast resistor" on C2 and earlier, and by a resistance wire on C3 and newer. This reduced voltage makes the points last longer, but the full 12 volts intensifies the spark during cranking (when the system voltage is depressed by the energy needed to crank the motor) for more rapid start. The points (I know you don't have points -- just bear [or is it bare, Reba ] with me for a moment) provide a path from the - side of the coil to ground when they close. The current (be careful: current is the flow of electrons -- think of water flowing in a hose) induces or causes a high voltage in the big wire on the coil to go to the distributor where it is routed (if all goes well) to the appropriate spark plug wire and then to the spark plug.

Clem is suggesting that there is 12 volts to the coil during "crank" but the 9 or so volts is not there when the ignition system goes to "run." This change from crank to run is controlled by the solenoid on the starter motor, but if the 9 volts is not there (at the coil) it could also be a broken resistance wire. If the engine will not run it is difficult to test for the voltage at the coil during "run" -- and at the minimum you will need a good multimeter and an assistant.

Now that I went through all that -- I am not sure what effect the TI has on that system. I know that when TI is installed one of the low voltage wires to the coil is taped back in the harness, but I don't know which one and there is another wire from the TI harness that goes to the coil. I learned this from the 1969 K66 page in the AIM, and some editions of the 1970 AIM have the same page stamped "cancelled" on it. Given you have a 1971 I don't expect you would have either of those references. Someone more familiar with the TI system, or perhaps Dave Fiedler's web pages, can take on explaining hos the TI system interfaces with the Kettering system. It is beddy bye time for me.

[Paul C.]

Re: 1971 LT1 TI Ignition System--Won't Start

Problem solved!!!!I knew it had to be something simple because all the parts are new or have been rebuilt.The connector to the C.E.C. solenoid was loose--pushed it on and car started first time. I also cleaned several other TI connections. I will keep you posted if it fails again. Thanks for all the help--I sure learned alot and appreciate everyone taking the time to respond.
Paul

[Michael W.]

Re: 1971 LT1 TI Ignition System--Won't Start

I can't imagine why the CEC connector would make any difference, that only inhibits vacuum from reaching the distributor advance can. Possibly one of the other connectors you touched is the key, or just bumping wires around.............

[Paul O.]

Re: 1971 LT1 TI Ignition System--Won't Start

I would agree with Mike many 71s ran around for years with the CEC totally disconnected with no problems. Your problem is located at some other point in the TI system.

Paul 18046

[Paul C.]

Re: 1971 LT1 TI Ignition System--Won't Start

I agree--I read up on the CEC and it would have no effect on starting. It didn't start up perfectly this morning but it did start. I adjusted the carb and took it out for a run and it ran fine. Turned it off 4 times and it started right up each time while hot. Maybe it's just having trouble when cold. I did clean some TI contacts. The bottom line is I have no idea why it doesn't start sometimes. I will let it cool down and then trying restarting. This just proves don't let your car sit for over a year and only start it once or twice. Still open to suggestions.

Paul

[Mike R.]

Re: 1971 LT1 TI Ignition System--Won't Start

Hi Paul I read this thread with interest since I chased my tail for several days with the TI on my 65. What I found and has not been mentioned here is that the contacts can push out of the rubber connector that connects the TI module to the TI harness. Then I had intermitant contact so sometimes it worked and sometimes it didn't. I noticed that one wire going into the connector was longer (from being pushed back inside the connector. Another problem I found was that the solid state module circuit board sits slightly higher than the original so the terminals are closer to the module case. Make sure the terminals are not grounding on the case as mine were.

Mike

Problem solved!!!!I knew it had to be something simple because all the parts are new or have been rebuilt.The connector to the C.E.C. solenoid was loose--pushed it on and car started first time. I also cleaned several other TI connections. I will keep you posted if it fails again. Thanks for all the help--I sure learned alot and appreciate everyone taking the time to respond.
Paul

[Paul C.]

Re: 1971 LT1 TI Ignition System--Won't Start

Mike I did pull the plug and cleaned the contacts because I had also had a problem not pushing the two ends together tight enough. The other contacts you are talking about are inside the module?? That module is a pain in the butt to remove--took me forever to put it back in after it was rebuilt by Dave F.

[Clem Z.]

Re: 1971 LT1 TI Ignition System--Won't Start

Paul,

I think you need Duke's ignition seminar, but you probably don't want to wait for the National in San Diego. I know Duke could explain this a lot more elegantly than I can, and I am struggling from a long day at work and the need to get out of Dodge prior to the "ass crack of dawn" (as my daughter puts it) to get to the Illinois Chapter Meet Tomorrow.

Briefly: if I can -- the ignition system (officially called the Kettering system after the inventor) has two wires feeding the + side of the coil. One wire provides 12 volts to the coil only during cranking. The other provides a reduced voltage (around 9 volts, I believe) during engine run. The battery voltage is reduced by a "ballast resistor" on C2 and earlier, and by a resistance wire on C3 and newer. This reduced voltage makes the points last longer, but the full 12 volts intensifies the spark during cranking (when the system voltage is depressed by the energy needed to crank the motor) for more rapid start. The points (I know you don't have points -- just bear [or is it bare, Reba ] with me for a moment) provide a path from the - side of the coil to ground when they close. The current (be careful: current is the flow of electrons -- think of water flowing in a hose) induces or causes a high voltage in the big wire on the coil to go to the distributor where it is routed (if all goes well) to the appropriate spark plug wire and then to the spark plug.

Clem is suggesting that there is 12 volts to the coil during "crank" but the 9 or so volts is not there when the ignition system goes to "run." This change from crank to run is controlled by the solenoid on the starter motor, but if the 9 volts is not there (at the coil) it could also be a broken resistance wire. If the engine will not run it is difficult to test for the voltage at the coil during "run" -- and at the minimum you will need a good multimeter and an assistant.

Now that I went through all that -- I am not sure what effect the TI has on that system. I know that when TI is installed one of the low voltage wires to the coil is taped back in the harness, but I don't know which one and there is another wire from the TI harness that goes to the coil. I learned this from the 1969 K66 page in the AIM, and some editions of the 1970 AIM have the same page stamped "cancelled" on it. Given you have a 1971 I don't expect you would have either of those references. Someone more familiar with the TI system, or perhaps Dave Fiedler's web pages, can take on explaining hos the TI system interfaces with the Kettering system. It is beddy bye time for me.

if i remember correctly it is tied into the distributor pickup coil as it gives more juice to the system till the distributor picks up speed to generate more voltage after the engine starts. i would check the wiring and connectors on the distributor

[Mike R.]

Re: 1971 LT1 TI Ignition System--Won't Start

The contacts in the module are either grounded or not. I wouldn't go taking apart the module if it has worked at all since it was apart.

Mike I did pull the plug and cleaned the contacts because I had also had a problem not pushing the two ends together tight enough. The other contacts you are talking about are inside the module?? That module is a pain in the butt to remove--took me forever to put it back in after it was rebuilt by Dave F.