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Car starts only with key in start mode

Ron H

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This could be one of those occasions where more than one thing decides to go to crap at the same time. Having my dash bezel redone twice, I encountered problems with my gas and temp gauges not working. Figuring a ground I rechecked this and had gauges working for a few minutes. I'm thinking the harness now as it's been unplugged and re-plugged many times. Question: Now my Plymouth won't start unless holding the key in start position; let go of key engine stops. This had been cropping up for awhile; but after some tries engine ran. Thought it was due to being stored for months. Sounds like it must be the ignition switch; but before I replace it wondering if any of yuz guys found other culprits? Thanks!
 
That is usually a problem related to the ballast resistor or the wiring associated with it.
 
I have a spare one, mine as well give this a shot...thanks. There's a ton of ignition switches on eBay for cheap; but wonder if it's china chit...
 
With a voltmeter check at the coil for voltage with key in the run position. You know you have voltage in the start position because it runs. You could also run a wire from Positive post of battery to coil to get it to run if you have no voltage in run position from the ignition switch. When jumping coil don't run too long or you'll burn out coil.
 
You have voltage drop between the ignition switch and the ballast resistor....I had this problem a while back.
 
Had the same issue. Check the wiring to the ignition switch. Probably loose.
 
Lots of time it's the bulkhead or the ballast.

Simple test, put the key in run, test the side of ballast not connected to coil. No power, bulkhead or switch is a likely culprit. If you have power, test other side of ballast. No power, bad ballast.
 
I need to remember that!
 
My guess also is I had done a lot of messing around with wiring being cautious not to eff up wires between cluster in and out in and out and also ran new wires to bypass the BH to reconnect the Alt gauge. But decided to let this alone for the summer season for a next winter project. Somewhere a wire could have been disconnected...the ignition key operates a little weird now as I have to 'lift' the key in the lock to get it to the run position. The smooth action is gone. Maybe no relevance but among the things to check. Thanks.
 
After testing the key switch and ballast (also had a spare ballast I put in for extra measure) things checked ok. The car still has this weird problem though not every time. I have an early model mopar electronic ignition system I put in years ago and some years back had to replace the brain box after ruling out other culprits to have car running fine again. The thing is, car wants to run when the key is held in start mode....let it go engine dies instantly. So the typical culprits looked ruled out. I thought there could be some relationship with the neutral start as among the 'think of anything' checks, I had pressed the trans buttons (push B trans) and reset to N to have the car start fine. This was a flash in the pan. The safety switch seems to function fine no start in gear and besides, I think a safety switch malfunction wouldn't allow any run/start or start in any gear. As the car has headers, a mini-starter was installed and this is like a year old. All wires look fine tightly connected. Well, any other ideas to be had? thanks again.
 
Need to say for the audience, a bad ballast would start up maybe with points ign system while cranking but NOT with electronic ignition, because module is feeded throught the ballast also while cranking up via the ign2 circuit.
 
the ignition key operates a little weird now as I have to 'lift' the key in the lock to get it to the run position.
Sounds like the ignition switch is wore out, not making good contact. Maybe a 'complete' new switch.
I'm not up on the electronic ignitions, so wonder if the ballast resistor is the correct one, for that ignition? Was it working before?
 
as mentioned on some reply, need to check for power on each ignition switch stage and if some stage it gets missed the power then check every point.

you can check at ballast for power with a test light. Will light up full on brown wire side when cracking and dimmed while key is un RUN. Checking at blue side will be of course the opposite, Full light while in run and dimmed while cranking. You will be checking the ballast condition at the same time making that test getting checked on both sides.

If checking at blue side you miss the power while key is in RUN you have the blue line broken between ignition switch and ballast plug, could being the bulkhead or even the ign switch itself... or a broken wire?

Same about brown side but while cranking.

If you don't have a test light, any tester will work, with full reading should be 11-12 volts, and dimmed power could be anything between 4 and 9 volts
 
There is a plus checking procedure on this. IF you put the key in RUN and the brake light ( with emergency brake pressed )&/or oil ligh if idiot light present doesn't turn on when key is in RUN then could be very well the ign switch since that is sourced before the bulkhead.

If lights up and turns off when cranking, the brown line is broken, included a damaged ballast, since these lights gets a feedback from the ign2 circuit throught the ballast
 
I am having the opposite problem with my 73 Charger. I seem to have no power to the coil in the start position while the car is cranking over, but when I let the key go to the run position the car starts and runs. The car does have an aftermarket alarm system in it,so I suspect that it may be causing the problem. I have disconnected two power sources to the alarm system and it is still working. Any ideas on this issue would be helpful.
 
I am having the opposite problem with my 73 Charger. I seem to have no power to the coil in the start position while the car is cranking over, but when I let the key go to the run position the car starts and runs. The car does have an aftermarket alarm system in it,so I suspect that it may be causing the problem. I have disconnected two power sources to the alarm system and it is still working. Any ideas on this issue would be helpful.

Check my replies
 
There is a plus checking procedure on this. IF you put the key in RUN and the brake light ( with emergency brake pressed )&/or oil ligh if idiot light present doesn't turn on when key is in RUN then could be very well the ign switch since that is sourced before the bulkhead.

If lights up and turns off when cranking, the brown line is broken, included a damaged ballast, since these lights gets a feedback from the ign2 circuit throught the ballast
Thanks all, I pulled the ignition out and tested fine, checked ballast and also tested fine so could be deeper as you say. Oil light comes on with key. My checks will look for a bad wire; all the putzing with the dash in and out and running two wires for alt bypass I might have messed something up...
 
Oil light comes with key but... dims out while cranking or turns off ?
 
Well guys regurgitating my old post here as I'm still have the same f-ing problems again; but seemed to subside for awhile now back with a vengeance. Right at this moment I'm supposed to be in a cruise and later a show and be damned if tonight is actually nice around here for once. I've checked everything that is 'supposed' to be suspected culprits and all check fine! Ig switch good, ballast good, and put another on for good measure. Wiring all looks fine/connected. It's a new engine harness in the car for about 16 months now and had run fine. My guess right now is the ECU...I installed a 1st gen mopar electronic ignition some 15-18 years ago and this is the 2nd box. I had replaced it after doing all the checks and finally put in a new one and car started right up (it had been a no start issue then). So wondering if I should put in a 3rd box for the 30 bucks as all else seems to check fine. I don't like the look of the back as the epoxy has partially separated on one end...no clue if this is any issue as I've been grabbing straws at this point. Frustrating as the 99% culprits are ruled out. I'll add, since my car is a button shift, it seems to rock as if needing an adjustment; but hell I had that before and didn't cause this problem...any advice is appreciated.
 
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