69 L71 will not fire off

[Lawrence S.]

I am working on the above car with TI ignition. The car ran fine and last week when I tried to move it in the garage it just would not fire off. The car turns over, getting gas, but will not fire. Acts like it is not getting any spark. I went to check the wire connection at the distributor and the wires broke off at the connector. The wires are short at the distributor I connected longer wires so I would have room to connect back to the harness. While connecting the wires I noticed that the wires coming from the distributor are silver and the wires (which I used from an old 67 harness) are cooper? I guess this is fine? I have connected everything back up and expected the car to start. Still nothing. I am not getting any spark it appears. This is my first C3 more familiar with the C2's. Any idea why I suddenly would not be getting any spark? By way of background this car is unrestored had been sitting in Ca for some years. it had several loose connections when I got it which I simply fixed and things started working. I am thinking perhaps there is a loose connection somewhere in the harness that is causing this grief? Any ideas?

Thanks

Lawrence

[Joe R.]

Re: 69 L71 will not fire off

Lawrence,

Sounds like the TI module may be at fault. TI's will not tolerate much sparking with bad wires.

JR

[Mark E.]

Re: 69 L71 will not fire off

To diagnose an ignition, I typically start at the spark plug and work "up stream".
- Spark at spark plug?
- No => spark at coil to cap high tension cable?
- No => Primary voltage ok?
- ... and so on.

This will methodically trace down the root cause of the problem.

[Edward B.]

Re: 69 L71 will not fire off

Larry, check the TI ground wire that's attached to the radiator support. If it's not connected, or isn't grounded very well, the car won't start.

Ed

[Lawrence S.]

Re: 69 L71 will not fire off

Previous owner installed new plug wires, coil, and D. Cap. Don't know the condition of the TI module, but some one has been working with it due to new fasteners holding it to the inner fender.

Lawrence,

Sounds like the TI module may be at fault. TI's will not tolerate much sparking with bad wires.

JR

[Lawrence S.]

Re: 69 L71 will not fire off

Thanks Mark. I agree with your method, but at the moment don't have a helper. May get my wife out there to help!

To diagnose an ignition, I typically start at the spark plug and work "up stream".
- Spark at spark plug?
- No => spark at coil to cap high tension cable?
- No => Primary voltage ok?
- ... and so on.

This will methodically trace down the root cause of the problem.

[Lawrence S.]

Re: 69 L71 will not fire off

Thanks Ed. Will check it out.

Larry, check the TI ground wire that's attached to the radiator support. If it's not connected, or isn't grounded very well, the car won't start.

Ed

[Lawrence S.]

Re: 69 L71 will not fire off

I found a ground wire coming out of the TI harness that looks as if it is attached to one of the TI module fasteners. Per the AIM, I see how the ground wire attaches to the radiator support. Does this ground wire come out of the TI module, or does it act like a ground strap and just grounds to one of the TI module fasteners?

[Edward B.]

Re: 69 L71 will not fire off

Larry, the ground is part of the harness and not a separate wire. And yes, since the TI amp is attached to the inner fiberglass fender, it supplies ground to the TI box via the radiator support.

Ed

[Duke W.]

Re: 69 L71 will not fire off

Go through the TI troubleshooting procedure in the '69 CSM, which is also in any manual for years it was available. A prime suspect is the pickup coil wires. There is a nearby thread on the same subject.


Duke

[Jack O.]

Re: 69 L71 will not fire off

Larry,

See my thread 'L68 with TI No Spark". I'm going through the troubleshooting procedures Duke mentioned but have some questions about them which may also help you.

Jack

[Lawrence S.]

Re: 69 L71 will not fire off

Thanks Duke.

Just read Jack's post. My TI harness wires were fatigued and the plug basically just broke off the wires in my hands. I suspected that was my problem. After installing new wires and connecting everything up I still have no spark. I will do the voltage test at the TI plug and look for a voltage pulse coming from the pickup coil.

Go through the TI troubleshooting procedure in the '69 CSM, which is also in any manual for years it was available. A prime suspect is the pickup coil wires. There is a nearby thread on the same subject.


Duke

[Lawrence S.]

Re: 69 L71 will not fire off

Update on my situation
As a background, I have following Jack Ottofaro's thread with his 69. Glad he figured it out.
I feel confident I have good grounds on the radiator support, and the coil is grounded well. Now my problem is that when the timing light is hooked up to Number 1 I get one flash from the light every third or so try when turning over the engine. The timing light is not receiving a constant pulse from the the number 1 wire. I have not checked the resistance at the coil as yet due to I thought I had a bad ground. Which apparently have toubleshooted and are sorted out? The coil is a new after market deal that was on the car when I bought it. I will try another coil I have. If anyone has an idea why I am getting this intermittent pulse pmease let me know.

Thanks

Lawrence

[Richard M.]

Re: 69 L71 will not fire off

Update on my situation
As a background, I have following Jack Ottofaro's thread with his 69. Glad he figured it out.
I feel confident I have good grounds on the radiator support, and the coil is grounded well. Now my problem is that when the timing light is hooked up to Number 1 I get one flash from the light every third or so try when turning over the engine. The timing light is not receiving a constant pulse from the the number 1 wire. I have not checked the resistance at the coil as yet due to I thought I had a bad ground. Which apparently have toubleshooted and are sorted out? The coil is a new after market deal that was on the car when I bought it. I will try another coil I have. If anyone has an idea why I am getting this intermittent pulse pmease let me know.

Thanks

Lawrence

For better visual reference you may want to attach your Timing light pickup directly on the HT coil wire.

A few things to try.....

Using your voltmeter, attach meter lead + to coil+ and meter lead - to coil-. Turn ignition switch to ON, no crank...

What is the voltage? It should be 2.5 to 4 volts. Use the troubleshooting flowchart HERE for more detailed info if not correct. If correct, there are TWO other possibilities that come to my mind that may be causing your intermittent/weak spark condition....

Background.....The PU coil generates a very small pulsed DC voltage to trigger the TI Amp module at each rotation of the 8 distributor poles/plug wire positions. The voltage is around 2 volts. It is VERY important that the polarity of the 2 distributor PU coil lead wires to the harness is correct. Since you've had to replace some wires, it is possible someone else before you had the connectors apart, and reversed them, or maybe you did accidentally.

Additionally, certain TI module circuit board designs may be more sensitive to these low input voltages. It has not been determined which of the 3 types of boards are in your system, original Delco, M&H reproduction, or K&B reproduction. You would have to open the AMP Module case to verify. Internal module grounds to the circuit board of course are important as well. You may have to open it up to verify at some point.

I would check the following:

The PU coil WHITE wire connects to the harness PINK wire. This is the source power to both the PU coil AND the TI Module.
The PU coil WHITE/GREEN (or if PU was OTC replaced, the GREEN wire) connects to the harness GRAY wire. This is the PU coil output wire which is the trigger wire to the TI Amp.

If these 2 wires are reversed, it can cause intermittent/weak trigger pulses to the Amp. You may have to remove the dist cap and carefully trace the wire colors inside at the PU coil wire pair down to your repaired external connector.

If those appear correct......

At crank, the PU coil pulses are of short duration, therefore a higher voltage is required at crank as the battery supply is being reduced by the starter motor current draw. This much like a Ballast resistor bypass in a points ignition system at crank. The harness includes a small gauge PINK wire which directs full battery voltage to power the AMP AND PU coil input. This higher voltage is needed to ensure proper supply voltage at crank.

The PINK wire source is the Starter Solenoid "R" terminal. In the engine/forward harness, there is a single plastic plug wire terminal from the solenoid R which connect to the associated TI Harness plug, likely running along the upper hood ledge area. Visually check that is there and verify proper voltage at crank, below.

Connect your - meter lead to ground, + meter lead to the distributor PU coil WHITE/ TI Harness PINK wire. Turn IGN ON, no crank. You will see a reduced battery voltage on the meter as there is a resistor wire in the harness to drop voltage to the AMP. Record voltage reading.

Then while observing the meter, crank the engine and record voltage. It should be higher than previous reading, at or near full battery voltage during crank. As a reference, you can record the battery voltage at the +cable during crank also.

There of course are other possibilities causing your weak spark. These are just a few to try, but should be verified to help diagnose the fault.

Rich

[Lawrence S.]

Re: 69 L71 will not fire off

Thank you Rich those are great instructions for next steps. I will report back.

Lawrence