Ignition switch issues?, Cranks but won't run with key Options

[trojanhorsepower]

So my car starts fine when I turn on the ignition and run the starter with a remote start switch, but not when the key turns powers the starter? This makes me suspect that the ignition switch is turning off the ignition while in the crank position. Is this a common failure point of these switches? or should I be looking somewhere else?

'74 2l 4lcyl

[Franz_x]

Have you checked what's happening with the solenoid switch when it doesn't start? Is there 12 volts there?
If not, it's the ignition switch. If so, then it's the solenoid. A relay for the solenoid might also help.

Franz

[DC_neun_vierzehn]

I had the same issue for a while. Drove me crazy. Turned out to be a poorly crimped female connector on the yellow wire that goes to the solenoid on the starter. I replaced the connector last year and haven't had an issue since.

[trojanhorsepower]

Thanks guys,
Maybe I don't understand, but the key will turn the starter over, but the ignition (power to the coil etc) is gone until I move the key back to run position from start. I could see this when testing the coil I would get one spark as you let off the key.

Does that make sense?

Peter

[barefoot]

Sounds like your ignition switch is gone bad, do you know how to remove it to do a check ??

Barefoot

[trojanhorsepower]

No. I think you have to take off the knee bolster?

[barefoot]

No. I think you have to take off the knee bolster?

this should help:
https://www.pelicanparts.com/techarticles/9...vrqpJVYxFJmmlxt

barefoot

[trojanhorsepower]

Thanks!

[gereed75]

I have the same problem but with a different twist. My car (70 six) cranks and fires with the key in crank position but stops running in the run position.

This condition is most prevalent in cold temperatures. When below 40 degrees it takes multiple “crank -start-return to run-dies” cycles to get running. Each cycle it runs a bit better in run. Like it starts running on two cylinders, then four and finally 6. Once the engine is warm it will start normally. When it is in crank, it runs on all cylinders and will take throttle - but when the key is released to run, it cuts to 2 or 4 cylinders, stumbles, won’t take throttle and dies, until eventually (after repeated cycles) it “clears” and runs normally

When warm outside it still does this but to a much lesser degree. Typically one cycle of cutting out in run then starts normally, takes a few seconds to clear and then normal (same symptoms as cold but to a much less degree)

First thing I did was change the ignition switch- absolutely no improvement

Can’t figure it out. Fuel pump runs normally through all this. It is definitely ignition related

[emerygt350]

I have the same problem but with a different twist. My car (70 six) cranks and fires with the key in crank position but stops running in the run position.

This condition is most prevalent in cold temperatures. When below 40 degrees it takes multiple “crank -start-return to run-dies” cycles to get running. Each cycle it runs a bit better in run. Like it starts running on two cylinders, then four and finally 6. Once the engine is warm it will start normally. When it is in crank, it runs on all cylinders and will take throttle - but when the key is released to run, it cuts to 2 or 4 cylinders, stumbles, won’t take throttle and dies, until eventually (after repeated cycles) it “clears” and runs normally

When warm outside it still does this but to a much lesser degree. Typically one cycle of cutting out in run then starts normally, takes a few seconds to clear and then normal (same symptoms as cold but to a much less degree)

First thing I did was change the ignition switch- absolutely no improvement

Can’t figure it out. Fuel pump runs normally through all this. It is definitely ignition related

will it keep running if you run 12volts to the coil?

[gereed75]

Thanks for taking the time to give it some thought.

Good question. Never tried it. I assume you are suggesting jumpering 12 volts to the positive coil terminal?

[gereed75]

Spent some time with the six wiring diagram tonight. It appears that the only thing that happens when the ignition switch is rotated to crank is the starter is engaged. All of the same components are energized by the same set of wires that energize them in the run position.

So why does some of the ignition components perform differently in run than they do in crank? Why does engaging the starter improve the ignitions performance?

Stumps me

[Dave_Darling]

Is it the ignition that's the problem?

Test, don't guess. You can try setting up a timing light to see if current is going through the plug wires; you can use an extra spark plug taped against a ground. Some mirrors can help you see flashes if you don't have anyone to help you out.

Also try running 12V directly from the battery to the (+) terminal of the coil. Don't do it for very long without cranking the starter or you might burn the points or kill the condensor or some such.

--DD

[gereed75]

Thanks Dave.

I am running a Crane optical points set up and a Partsklassic “modernized” three pin CD

This is hard to troubleshoot now because the anomaly conditions only seem to last a very short time in warmer temperatures. They persist long enough in the cold to maybe see what is happening. Fall is coming. Colder days will present better test conditions.

What makes this so perplexing is it seems to work fine starter engaged. If it were the opposite it would seem more logical - engaging the starter might cause a testable voltage drop and I would be looking for a short or high resistance in the starter circuit.

But this set of symptoms makes no sense to me !?!?

[emerygt350]

I have run across many cars that drop the coil after the starter disengages. I would suspect a loose wire or that ignition switch. Both can result in unpredictable symptoms. Can you verify your coil/whatever needs it with your setup, is getting 12v when this occurs?

[FlacaProductions]

Greetings - I know very little about the six setups in 914's but I have a 67 911 and have read on the 911S board that the Partsklassic CD boxes enjoy a less than stellar reputation over there.

Sorry for the generalization but it may be a path to check.

[gereed75]

Thanks Emory. Not sure why that happens but the consensus seems to lean towards a coil issue and the symptoms are indicative of a weak spark/ coil issue.

Think I will jumper the coil on the next cool morning and give it a try

I am not 100% confident in the CD. This one went back shortly after install for a repair. Seems fine but…