71 LT no spark
Thread Starter
Racer
Joined: Sep 2011
Posts: 381
Likes: 90
From: Portland, the original!
71 LT no spark
The car has never failed to start during my ownership of ~5 years. Ran and started fine 2 weeks ago. Plenty of crank, no start.
A quick check showed no voltage at the coil (electronic) with either the key in "on"" or in the "start" position.
I guess I'm in for some quality time with my multimeter. I'd like to get the car to my neighbors open barn to facilitate any work. I was wondering if I could run the car with another source of 12V to the coil just to run it down my street to the barn.
A quick check showed no voltage at the coil (electronic) with either the key in "on"" or in the "start" position.
I guess I'm in for some quality time with my multimeter. I'd like to get the car to my neighbors open barn to facilitate any work. I was wondering if I could run the car with another source of 12V to the coil just to run it down my street to the barn.
Race Director
Joined: May 2006
Posts: 18,737
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The car has never failed to start during my ownership of ~5 years. Ran and started fine 2 weeks ago. Plenty of crank, no start.
A quick check showed no voltage at the coil (electronic) with either the key in "on"" or in the "start" position.
I guess I'm in for some quality time with my multimeter. I'd like to get the car to my neighbors open barn to facilitate any work. I was wondering if I could run the car with another source of 12V to the coil just to run it down my street to the barn.
A quick check showed no voltage at the coil (electronic) with either the key in "on"" or in the "start" position.
I guess I'm in for some quality time with my multimeter. I'd like to get the car to my neighbors open barn to facilitate any work. I was wondering if I could run the car with another source of 12V to the coil just to run it down my street to the barn.
Then you mention electronic coil do you mean you have the factory TI ignition system?
If you do have the TI it does not normally direct 12 volts to the coil based on the wiring diagram below.
Wiring diagram
Thread Starter
Racer
Joined: Sep 2011
Posts: 381
Likes: 90
From: Portland, the original!
Yes, LT-1 with the TI ignition box. So that may make trouble shooting a bit tougher. That said, in the schematic, (great pic thanks) it sure looks like a black/white wire runs from the TI box to the coil + to me. That's where I'll be starting. Unfortunately not terribly accessable.
So the title mentions LT, is that LT1?
Then you mention electronic coil do you mean you have the factory TI ignition system?
If you do have the TI it does not normally direct 12 volts to the coil based on the wiring diagram below.
Wiring diagram
Then you mention electronic coil do you mean you have the factory TI ignition system?
If you do have the TI it does not normally direct 12 volts to the coil based on the wiring diagram below.
Wiring diagram
Race Director
Joined: May 2006
Posts: 18,737
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Yes, LT-1 with the TI ignition box. So that may make trouble shooting a bit tougher. That said, in the schematic, (great pic thanks) it sure looks like a black/white wire runs from the TI box to the coil + to me. That's where I'll be starting. Unfortunately not terribly accessable.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Not sure about the TI system, but does that system get its power from the starter solenoid (like a points system does)? If so, you may just have a defective starter solenoid. (Nothing to do with the starter, itself.)
Race Director
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It shows the R terminal on starter going to TI amplifier.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If the R terminal has no power when the ignition is turned to RUN (not START), that's your problem. (starter solenoid or the wire between solenoid and TI unit. Measure the voltage AT the solenoid terminal to determine which is at fault.)
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Thread Starter
Racer
Joined: Sep 2011
Posts: 381
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From: Portland, the original!
I think the K66 ignition is the same through all the years. Great step by step, thanks. Pretty sure no power into the amplifier, no power out! If power in, then it's the box.
Guess I'll have to get out the floor jack to get the car up on jack stands to do this. Sure I wish I had decluttered the garage!
Guess I'll have to get out the floor jack to get the car up on jack stands to do this. Sure I wish I had decluttered the garage!
Thread Starter
Racer
Joined: Sep 2011
Posts: 381
Likes: 90
From: Portland, the original!
For sure, but the power from the "R" terminal is only a voltage boost to distributor when key is in "start", no? I also have no power at Coil + when key is in "on/run".
Race Director
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If you have only 1 wire on the positive terminal of the coil there is no voltage boost like on a points distributor. Look at the wiring diagram it shows one wire with the resistance symbol.
Thread Starter
Racer
Joined: Sep 2011
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From: Portland, the original!
Clearly there's a wire from the starter to the amplifier. Maybe just an "exciter" wire maybe for the amplifier then? That wire only has power with key in "start" position. Coil and amplifier need power to run and presumably comes from the ignition switch lead
as seen below. Once I can get the time, and get under the car, the culprit should make itself quickly known.
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
If you don't have power to the amplifier box from either the ignition switch or starter solenoid, I would first check the harness connector going into the box to see if the connector/connection is bad.
Thread Starter
Racer
Joined: Sep 2011
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From: Portland, the original!
Thread Starter
Racer
Joined: Sep 2011
Posts: 381
Likes: 90
From: Portland, the original!
Melting Slicks
Joined: May 2002
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From: Laporte, IN
An area that is prone to failure is the pole piece white and white/green wires as they enter the distributor. Because the movement of the advancing plate in the distributor can cause the wires to be cold worked and fail or break. This also can cause a no start condition.
Tech Contributor
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
The R terminal is the ballast Resistor bypass line that provides sufficient current to the TI module or points coil during the lower battery voltage in cranking mode. The R terminal is only electrically active during cranking, and open circuited at all other times.