71 Cuda ignition problem.

When I try to start the car the car cranks. When I let go of the keys it starts. If I touch the key all my gauges stopped working including tack. New ignition harness. New key cylinder. Removed all bulkhead connections cleaned greased. Changed all pens on dashboard harness for ignition plug . Anybody have any ideas thanks

Welcome aboard. the loose connection is right there when you touch it, it makes/breaks the connection (in the ign1 run terminal I would assume).

Not sure what you mean. [censored] switch?

when you bump the ign switch by touching it with the key (if I am reading it right), the loose connection would have to be right there, the slight jostling is makeing/breaking the connection/terminal that is slightly loose.

Thanks. i'll keep Tryan

check / test ballast resistor

I think RR is much closer to the likely source.
Check the wiring diagram for your year to be sure what I say here applies.

The instruments and the ignition are both fed power from the Key switch's Run Terminal. On an earlier car the wire to each are crimped together on the same connecting terminal. On your car with the key switch in the steering column the connection may be done differently.

Regardless, the one thing both have in common is the connection in the key switch. So look at the wires and or look at the wires along with the diagram. If they share a terminal on the connector, start there. If not, then its probably in the switch.

Put the key into run position, and with the ground lead clipped to a ground screw or clean metal, probe the back of the connector cavity with the wires going to ignition and instruments. If its not at battery voltage and the one to accessory is, then the situation is as I posted above.

another place to check is the connection at the bottom of the steering column that connects to the harness going to the bulkhead. many times this connection gets corroded, or brittle from age. resistance builds up, then heat, causing this connection to melt. have repaired many at that spot, even after ignition switches have been replaced.
just somewhere else to look. let us know what you find please.

Did that first. Same thing. Thanks

That was the second thing I did. Pulled all bulkhead connections off clean replaced as needed. Same thing with dash highness. Thanks will let you know if I get to the bottom of it.

They don’t share in the column. Maybe by the bulkhead connection. Have to check that out. Thanks let you know.

OK. Not too surprising considering the switch change.



Somehow I missed this part when I replied before.
Could be timing, could be the Ignition 2 wire isn't getting power during start.
To test, clip the voltmeter neg to ground and the positive to brown wire connection at the ballast resitor. When you turn the key it should show low voltage in Run and battery voltage in Start.

If it doesn't show battery voltage in Start, then stick the positive into the bulkhead connector cavity. Keep working back until it does.

To save on battery while doing this testing, disconnect the neutral safety at the starter relay. That way you won't be spinning the starter.

PS. I often make up my own schematics of just the circuits I'm trying to understand (ie Having problems with). it makes it so much easier for me to see and understand.
Althoug I don't use tracing paper, that's basically what Chrysler suggested to their tech.
http://www.imperialclub.org/Repair/Lit/Master/247/Page04.htm
I either hand redraw, or use the computer to copy and past to digitized scans or photos into MSDraw or IRFAN and then start coloring, erasing, and moving things until I just have what I need.

I also mark up any corrections in the manual vs. real lift observations.

Tried a different switch I had laying around. Fired right up. Who makes the best replacement any ideas. I know I saw it year one.

Tried an old switch I had. Fired right up. Now I need to find a replacement. Thanks for your time

Good.
Was just looking at the 71 book (mymopar download).
Instruments are spliced into the accessory circuit, so different splicing than pre 70.

Can't answer who makes good or best. All parts seems to be a crapshoot these days..

How true that is junk is junk. The switch is about 13 months old.

That was too easy!

Doesn’t always work like that. But it’s nice when it does. 😎🇺🇸

Yes, it makes up for Mr Murphy.

Actually a damaged ballast won't start up ever if car is electronic ignition. Just will allow to fire up with points setup while cranking, but will stall when coming back to RUN

^^^ correct, ECU will not get fed in ign2 (crank)

glad the cause was found !

Me too 🇺🇸. Just trying to figure out who sells the better ignition switch. The one that’s in there is from standard. Put it in 13 months ago. Nothing is made here anymore. Junk is junk. Thanks again for your help!

believe or not, I have replaced some parts on my car with used parts from JYs than looks somehow WAY BETTER than new replacements

Agreed quality is down but I think with another switch you will be OK. EDIT & if going to a yard is practical I think that would get you a good used one in hand.

Just picked up another standard made switch not too impressed with the way it's built.

Just realize where you were located. I will be in Aruba for Flag Day. LOL

Just picked up a new switch made by standard. We'll see