Ignition Issues - Car Won't Start Intermittently

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72demon-777

72demon-777

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It first started with what I thought was a linkage issue. My 72 Demon (225 3 on the tree) would intermittently not start while in park. If I shifted into neutral it'd fire right up. I thought my linkage might have loosened up over 30 years of use but figured I'd wait until winter to fix it.

Now it randomly will not start in park or neutral. The first time I start it from neutral it will fire right up but as soon as I shut the car down again and attempt to restart, nothing.

I jacked her up and attempted to adjust the linkage this weekend but there did not appear to be any slack in that connection where the set screw is. I brought up the issue with my Father who is a much older and wiser man than myself. Our two prominent thoughts are either the ignition switch in my steering column or the starter relay.

Has anyone encountered this before and what was the fix? A relay is an easier fix which I might try just to rule that out but I figured someone's had to had this problem before me...

Any help would be greatly appreciated.
 
Check your grounds too. A loose or corroded ground can cause that issue.
 
"The fix" is to find out what is wrong, not start adding stuff. The trouble could be

linkage adjustment

linkage damage inside the trans

a bad neutral switch

loose connection at the neutral switch connector, or damage to the connector or wire

a bad starter relay

bad connection in the "start wire" in the bulkhead connector

other wire problems in the start wire / bulkhead/ ignition switch/ wire harness to the transmission / transmission connector

But since this 'seems' to had been depending on wiggling the linkage, I'd start with the switch itself. If it was linkage adjustment, you should be able to get it to crank by holding the key to start and wiggling the shifter from park through neutral

START troubleshooting by identifying the wire going from the start relay down to the transmission. There will be two push--on connectors on the start relay. One goes down to the bulhead connector, the other goes down the firewall, over the top of the trans, and to the neutral switch on the trans.

Pull that last wire off, and hook a clip lead from the terminal on the relay which you just uncovered to ground. Try starting the car, and be CAREFUL as it will START IN ANY GEAR

Go ahead and start and drive the car long enough / enough times to determine that this temporarily "fixed" the problem. If it works "OK" then this splits the problem---it eliminates the start relay, the wiring through the bulkhead to the ignition switch, and eliminates the ign switch as being the problem.

If that is true, check out the linkage carefully, check the wire harness down to the switch for damage, for breaks, and for electrical continuity,

and then get under the car and disconnect the linkage at the trans so you can manually manipulate the transmission shift lever.

"Clip" your ohmeter or continuity checker from the center terminal of the neutral switch to ground, and see if shifting the trans to park or neutral results in activating (grounding) the switch
 
If I read this right he is running a manual transmission, no safety switch.

Check for 12V to the coil while cranking, sounds more like the start switch is wore out.
 
sireland67 said:
If I read this right he is running a manual transmission, no safety switch.

Check for 12V to the coil while cranking, sounds more like the start switch is wore out.
Click to expand...

In the original post he mentions "park."..............................
 
sireland67 said:
If I read this right he is running a manual transmission, no safety switch.

Check for 12V to the coil while cranking, sounds more like the start switch is wore out.
Click to expand...

It has a linkage, it's an automatic trans.
 
It is an automatic trans and it doesn't click when try to start it and it doesn't successfully start.. 67dart thanks for the tips, that will help me eliminate some of the non-issues.
 
I'll bet my quarter on the neutral safety switch itself has failed.
The brown wire on the starter relay should show little to no resistance to ground when the shifter is in park or neutral. Prop your ohms meter up where you can see it from the drivers seat, operate the shifter. If the reading varies a lot, the contacts inside the switch are the problem.
 
Sorry it's been a while since I replied, life has simply been crazy.

I finally got around to trying some of the suggestions posted here. I disconnected the wire from the starter relay and used a jumper cable to connect that to ground. The car started up perfectly from the 'park' position and subsequently started with no problem repeatedly after that.

I've investigated the linkage and that all seems to be really solid. There was no adjustment that I could make, everything appeared really tight.

It appears as though the problem is then located either in the wiring from the starter relay to the neutral safety switch or the neutral safety switch itself. I find it hard to believe there is linkage damage within the transmission as once I jumped the starter relay the car starts beautifully.

Thanks for all of the advice, next step is getting underneath the car again to look deeper into the neutral safety switch... One step closer.
 
Even easier test... Attach probe end of test lamp to brown wire at starter relay, clip end of test lamp to battery pos+. When operating the shifter the lamp should come steady on every time the shifter goes to park or neutral, since the neutral safety switch is simply supplying a ground path on that brown wire. If the lamp flickers at all in park or neutral positions, replace the switch.
There are a few plastic bushings in the shift linkage pivot points and those can fail and cause similar problems. I'll assume you've already looked at the overall condition of the linkage. Bottom line... no matter if the problem is mechanical or electrical, periodic adjustment should not be required.
 
72demon-777 said:
I've investigated the linkage and that all seems to be really solid. There was no adjustment that I could make, everything appeared really tight.

It appears as though the problem is then located either in the wiring from the starter relay to the neutral safety switch or the neutral safety switch itself. I find it hard to believe there is linkage damage within the transmission as once I jumped the starter relay the car starts beautifully..
Click to expand...

There IS an adjustment on the external linkage

You need to download the free 72 factory manual, this thread here:

http://www.forabodiesonly.com/mopar/showthread.php?t=244981

The key to figuring out whether the linkage is out of adjustment or a bad switch is to hook everything up as "normal" and attempt to start the car

Wiggle the shifter from park through neutral and back while holding the key over into "start." If the starter clicks and tries to pull in, or does so, you either have a bad switch, or linkage out of adjustment.

If you get nada, most likely bad switch or wiring / connection break from switch up to the relay.

You can get the switch connector, if needed, at NAPA along with the switch. Replacing the switch is a little messy, but you can help by jacking the car up with driver side high, or even driving that side up on a curb, etc

Someone mentioned the other day, immediately before you pull out the old switch, start the car IN NEUTRAL (not park) and run for a minute. The hydraulic circuits in the trans cause it to pump out the pan and fill the converter in neutral, lowering the level.

(That's why it's important to check fluid level in neutral)
 
I agree with checking the NSS itself (i.e. right at the switch, not the wire from it). I would add, that you should disconnect the shift linkage when doing this. The transmission itself has spring detents for each position. You want to align these with the spring detents in your shifter. If not, the NSS may be correct that you are not fully in P or N, and is doing its job protecting you. Whenever you bypass the NSS, do not have anyone standing in front of the car when you try to start, because the car may jump forward. If you don't have a multimeter, go to Harbor Freight with a free coupon.
 
67Dart, I own a service manual and the first thing I tried was attempting to adjust that external linkage. I watched as my neighbor shifted the car from park to drive and back again to determine which was it'd need to adjust. Then I loosened the bolt and attempted to adjust the linkage. It was tight, I could not manipulate it any further. That's what led me to thinking it was something in the wiring either between my tumbler, starter relay, NSS, etc. The car is in great condition and the external linkage is no different, it looks solid, I don't THINK the problem is in the linkage.
 
67Dart, Good comment about running the car in neutral, that'll save some mess!

Bill, can you explain your comment? I think that I follow you but I am new to all this. :)
 
72demon-777 said:
Bill, can you explain your comment? I think that I follow you but I am new to all this. :)
Click to expand...
"Detent" means the click you feel and hear when the transmission (or shifter) is in each position (P, R, N, D, 2, 1). If you were to disconnect the shift linkage and operate the lever on the transmission by hand, you would still feel each detent. You would also still feel each detent in your shifter. Your task, should you choose to accept it, is to adjust the linkage so that both align. If so, the linkage should be slightly free at each position.
 
Alright, it's been a while, life has gotten in the way (new kid and a cross country move from NY to GA) but as life has started to settle down I've had some time to investigate this ignition issue a little more.

The last thing I did was jumper from the brown wire connected to the starter relay to ground. This solved the ignition issue as I had been able to start the car without fail every time.

This past weekend I went to take the car for a cruise and when I turned the ignition NOTHING. No clicks, no attempt to turn over, literally nothing. I charged the battery and got her to start again. Took her for a ride and decided that it was time to get the battery checked and replace the starter relay. I just installed the starter relay, made sure I had a charger on my battery and attempted to start her again. Nothing. Put it into neutral, it turned over. So now I'm back at square one, having eliminated the starter relay itself I am thinking that my next step is to investigate the NSS.
 
BIG-B-Barracuda said:
Bulk head check both sides under dash and engine side . Most likely engine side corrosion burnt out :eek:ops:
Click to expand...
Similar issue with mine. Start fine for days then dead, then start, then dead. When it wouldn't start I'd check voltage all the way from the battery to the bulkhead and it'd be fine. Then get inside and check the opposite side from the bulkhead to the ignition switch and get nothing at the bulkhead. Go back to the engine compartment for a second check and get nothing at the engine side of the bulkhead. WTH! An hour later she'd fire right up. When it happened one time and I kept getting nothing I started cutting the tape off the wiring bundle at the top of the firewall and found a butt connector splice, by the PO, and the wire pulled right out of one end. Recrimped it and all was well for a couple of weeks when it happened again. Wiggled the wire at the bulkhead and it pulled right out leaving the spade in the bulkhead. When I pulled the spade out the bulkhead plastic broke. It was melted badly. Gave up and did the bulkhead bypass and alternator mod. No more starting problem since.
 
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