Possible Bad RPM Relay? Car starts but immediately dies after Coil swap.

[Bitsyncmaster]

Your not getting voltage on the white wire to the resistor or the resistor is bad. That is how I test the bypass circuit. I pull the white wire, start the engine and it will die when you release the key.

[Beachdrifter]

So onto the ballast resistor . Is there a specific test on it to tell if it's good or bad? I took it out and have a few pics of the tips. One tip looks burnt in the center but not sure if that's normal.

Thanks.

[hmcelraft]

You can run a hot feed (like a jumper from the positive battery post by the coolant reservoir) to the coil wire feed from the ballast resistor and the engine should run all the time if there is an issue with ballast or the run feed to the ballast. While the key is in the run position you should measure the voltage of the run feed to the ballast. It should be battery voltage.

Harold

[hmcelraft]

If you run the engine in "ballast jumper" mode for too long it may damage the coil and distributor cap. I would keep it to 5 or 10 minutes at a time - tops.

Harold

[Beachdrifter]

Your not getting voltage on the white wire to the resistor or the resistor is bad. That is how I test the bypass circuit. I pull the white wire, start the engine and it will die when you release the key.

Thanks Dave and Harold. I measured the voltage to the resistor with key on , at the top right ballast prong and measured about batt voltage. The prong just below it was about half... probably the resistor doing its job?

Of course the left prong was negligible since its only on during cranking...which works because car does initially start.

I will try doing the jump test tomorrow to see if it will start and stay on.

Thanks.

[Bitsyncmaster]

Thanks Dave and Harold. I measured the voltage to the resistor with key on , at the top right ballast prong and measured about batt voltage. The prong just below it was about half... probably the resistor doing its job?

Of course the left prong was negligible since its only on during cranking...which works because car does initially start.

I will try doing the jump test tomorrow to see if it will start and stay on.

Thanks.

Something is wrong. Yes the left side only gets power during cranking but it still will show voltage since it should be an open circuit on the wire but the resistor connects it to the right side. But about half voltage on the right side is correct.

You should have read about 3/4 of battery voltage on the left side. Maybe your meter probe did not make connection.

[Beachdrifter]

Something is wrong. Yes the left side only gets power during cranking but it still will show voltage since it should be an open circuit on the wire but the resistor connects it to the right side. But about half voltage on the right side is correct.

You should have read about 3/4 of battery voltage on the left side. Maybe your meter probe did not make connection.

Thanks Dave, yes you are correct I do get some voltage on the left side as well with key on, sorry.

So today I will try to jump the coil to see if it stays on. Curently the car starts everytime but will not stay on and dies after 1-2 second. I also have a new coil (but tried on my old coil too and same).

And at this point I'm seriously thinking I have an Ignition ECU malfunction. Looking for one to swap out with.

[Bitsyncmaster]

Thanks Dave, yes you are correct I do get some voltage on the left side as well with key on, sorry.

So today I will try to jump the coil to see if it stays on.

And at this point I'm seriously thinking I have an Ignition ECU malfunction. Looking for one to swap out with.

If your engine starts, I don't think your Ignition ECU would be bad. Now you may have an intermittent problem. So even though you read correct voltage on the resistors now, sometimes those readings may not be correct.

I had an intermittent when I first bough my car. That problem was the connector on the distributor pickup wire. It was the worst corrosion problem I've ever seen. I removed that connector and spliced the wires.

[rdarlington]

Probably not related, but my car was doing something similar a while back. The electrical connection on the this thing was causing me grief:

http://2.bp.blogspot.com/-ZGi3uhzgoN...0/IMG_3910.JPG

When connected, no problems. When disconnected the car would start up and then immediately stall. It would not run at all. The electrical spade connectors were pushed up inside the rubber boot and making intermittent contact. I've since slid them out and gave em a little squeeze to tighten em up. This connector is easy to knock loose if you're back there pulling at other things.

-Bob

[Beachdrifter]

Probably not related, but my car was doing something similar a while back. The electrical connection on the this thing was causing me grief:

http://2.bp.blogspot.com/-ZGi3uhzgoN...0/IMG_3910.JPG

When connected, no problems. When disconnected the car would start up and then immediately stall. It would not run at all. The electrical spade connectors were pushed up inside the rubber boot and making intermittent contact. I've since slid them out and gave em a little squeeze to tighten em up. This connector is easy to knock loose if you're back there pulling at other things.

-Bob

Thanks for mentioning it. What actually goes connected on those two little prongs? They look like electrical connections. I checked my car and I don't have anything connected to them.


My ignition ecu swap did nothing to change my situation and seems nothing is working.

I'm at a dead end, and worn out for now. If anyone else has experience the start and die issue, I'm willing to try anything.