Won't Run

[toms69rr]

Here's the problem
can't keep the bird running, as soon as she starts I release the key to the run position the car dies.
I have replaced the Key switch, replaced ballast resistor,chrome box, voltage regulator, the instrument panel is new from redline, the panel has been in for a couple of years now though.
the car will run if I hold the key between run and start, any suggestions?

HELP

 

[george68hemirr]

Here's the problem
can't keep the bird running, as soon as she starts I release the key to the run position the car dies.
I have replaced the Key switch, replaced ballast resistor,chrome box, voltage regulator, the instrument panel is new from redline, the panel has been in for a couple of years now though.
the car will run if I hold the key between run and start, any suggestions?

HELP

I WOULD GET A TEST LITE AND START CHECKING THINGS TO SEE WHERE YOU HAVE JUICE AND WHERE YOU DONT WITH THE KEY IN THE ON POSITION AND GO FROM THERE.....COULD BE THE NEUTRAL SAFETY SWITCH POSSIBLY

 

[toms69rr]

Thanks George for the input, I have been trying to chase the culprit down with my meter. no luck yet. going to crawl under the dash and see if I can spot a short, although I did ring out the harness when I was redoing the car. the front engine harness and rear harness are new,all the wiring is new except the main harness and it is as good as new, never hooked up the neutral safety switch

 

[Basketcase]

check the coil. my truck did this to me last week. would statr(sometimes,run like crap untill I released the key). swapped the coil off the bird and whamo.

 

[Big John]

I know you've already changed it, but it sounds like a ballast resitor. Check that for continuity first, then for voltage at terminals.

 

[mac]

bulkhead connector?

 

[toms69rr]

John, I have continuity across the ballast but no volts this is while the key is in the run position. I do have all the equipment inside working though, radio,heater etc. Mac It could be the bulk head connector, I will start checking that next.
Did I say I hate electrical problems? :brickwall: :brickwall: :brickwall: :brickwall: :brickwall:

 

[toms69rr]

Dave I didn't think about the coil, I have one of those laying around here, I try that too
Thanks guys :cheers: :cheers: :cheers:
Keep it coming

Tom

 

[glhcarl]

I have to agree with Big John, classic "ballast resitor" failure!

 

[Basketcase]

I've owned Mopars since '84. In all that time, I've only had one go bad. I was leaving in my '68 Charger, and the throttle cable broke. I grabbed a spare, swapped it out, then the car did the run while the key was on. swapped the ballast, and haven't had another go bad since then, and that was in '84. when the truck wouldn't start last week, that was the first think I thought of, but it doesn't have one, so the coil was the next thing I thought of, and I haven't had one of those go bad for about as long.

 

[Big John]

John, I have continuity across the ballast but no volts this is while the key is in the run position. I do have all the equipment inside working though, radio,heater etc. Mac It could be the bulk head connector, I will start checking that next.
Did I say I hate electrical problems? :brickwall: :brickwall: :brickwall: :brickwall: :brickwall:

With continuity across the ballast resistor, then the resistor is good. No voltage with the key in run means there's some issue with the wiring going to the ballast resistor. I'd trace back to the bulkhead connector and check voltage there. From there, trace back to ignition switch. My hunch is it's in the connector.

If you want to, you can run a jumper wire to the power side of the ballast from a 12 volt source (the starter relay is a good spot). The car should start and run if everything else is good.

 

[moparstuart]

I have to agree with Big John, classic "ballast resitor" failure!

take the resistor off and scrape some paint off the fire wall to get a good ground , also get some of those star or what i call biter washers to bite into the metal

 

[toms69rr]

Rang out bulk head connector this morning, everything seems to be good, Dave I threw a coil on it this morning no luck. I think I still have a bad key switch, I check both of the switches I have with a meter. they both seem to work correctly, I have continuity on the run side, switch key to the start side I have continuity and drops the run side release the key I have continuity back on the run side.
John I,m going to give the jumper a shot and see if that works. one good thing coming out of this I'm getting a lot of good spare parts to carry around with the car

 

[toms69rr]

Well the jumper wire works the car runs, from switch through the bulk head connector is must be bad. I checked N and Q on the bulk head connector to back of switch plug in (connector) I have continuity, Must be the switch, agreed?
I must not understand how the start circuit runs on switch or it different when power is run through the switch and I'm not seeing it when out of the car checking on the bench.

 

[Big John]

The start/run circuit is pretty simple. You turn the key, it sends 12 volts to the starter relay and 12 volts directly to the coil. The car starts, you let off the key and the starter disengages and now 12 volts is sent to the ballast resistor. The ballast resistor drops the voltage to the coil down to approx 6 volts.

The principal is this... more voltage to the coil for easier starting and less voltage is needed as it runs.

 

[Big John]

I have to agree with Big John, classic "ballast resitor" failure!

take the resistor off and scrape some paint off the fire wall to get a good ground , also get some of those star or what i call biter washers to bite into the metal

Don't need to ground the resistor.

 

[toms69rr]

Took one of the two switches apart that I have, separated the crimped part from the casting and insulator and look at the contacts internally, some old dried up grease and corrosion on contacts. took some light sand paper and cleaned up the copper disk also cleaned up the contacts on the insulator. Used some dielectric grease reassembled. that seemed to do the trick. will see.
Thanks for the help so far, I'll let you know how the test drive comes out here in a while :drive: :drive:

 

[mac]

if you had the switch apart, you can get a new switch from napa that fits 1968. use the new switch parts with the original key part and you are all set. this is what i ended up doing for my car.

http://www.napaonline.com/Search/Detail ... 56+2056018

 

[toms69rr]

Mac Good info, I'll go get that today!! :yesnod: :yesnod: