70 Challenger R/T won't start after warm up

[Montana Mopar]

When I came back home from Military Service, my engine was stolen and sold, along with all of my shop tools, by my brother who denied it up and down. I recovered just my home made engine stand from the local Pawn Shop. They told me who sold it to them. I replaced the original 383-4 barrel and 4 speed manual transmission with a 400 big block and auto trans out of a Dodge Magnum. Replaced the steering column with column shift steering column from the local Salvage Yard. Not sure what car it came out of. It was in a pile of 60's-70's Mopar steering columns. But it bolted right in. Anyone ever heard of a starter problem like this? Starter goes dead after engine is warmed up. After a few hours, when everything cools off, it will start right up. But, warm up everything, again, won't start. Starter solenoid won't respond, won't even make a clicking noise, nothing. Replaced a lot of parts. Still the same. First, I replaced the starter with a new one from Napa. Then the battery, Sears Diehard Gold. Replaced the starter relay, Napa. Replaced the ignition switch in the steering column, Napa. Nothing works. I asked my Mopar buddies from a couple of towns over (closest other Mopar fans around). They never seen anything like it. I'm thinking of custom, redoing the whole wiring harness and update with a new ATO,APO type fuse block. Also adding a Volt meter gauge.

 

[miller]

First things first...

Thank you for your service!!

Yup, know all about the good 'ol brother's bit. (Ya say the best of enemies?)

Off the top...almost sounds like you might have what I call a 'floating' short. Means a wire has busted, or burned, inside the wrap. Wire heats up, when current flows through it. Cold the busted ends make contact...as it heats up, that break in the wire separates, and breaks the current flow. Only a maybe...

 

[condor74]

It is a very simple circuit and investing in a test light and volt meter will save you money in the long run. I would first check for power at solenoid wires. Try jumping the large wire to starter engage wire. If it cranks over. Check for power with key in start position at starter solenoid start input. If it is good check to make sure the solenoid has ground from the park nuetral switch on the transmission. You can temporarily ground this wire to see if it starts with the key. I suspect your nuetral park switch is the problem as you have already replaced most everything else.

 

[condor74]

First things first...

Thank you for your service!!

Yup, know all about the good 'ol brother's bit. (Ya say the best of enemies?)

Off the top...almost sounds like you might have what I call a 'floating' short. Means a wire has busted, or burned, inside the wrap. Wire heats up, when current flows through it. Cold the busted ends make contact...as it heats up, that break in the wire separates, and breaks the current flow. Only a maybe...

Actually it would be an open not a short. A short is when an insulated or isolated wire makes contact with another wire or ground when it is not supposed to. An open the circuit is broken not allowing current to flow. Your advice was sound just terminology incorrect. I hope I did not offend you.

 

[NOSTRT980]

I would check the battery cables. found out first hand that cables corrode inside.

 

[PurpleBeeper]

It is a very simple circuit and investing in a test light and volt meter will save you money in the long run. I would first check for power at solenoid wires. Try jumping the large wire to starter engage wire. If it cranks over. Check for power with key in start position at starter solenoid start input. If it is good check to make sure the solenoid has ground from the park nuetral switch on the transmission. You can temporarily ground this wire to see if it starts with the key. I suspect your nuetral park switch is the problem as you have already replaced most everything else.

Condor has the right way to diagnose it (when the car is hot & not starting, run his tests). NOSTRT980 has a good point too to check your main cables.

However, I think your problem might be that the starter is getting too hot. Hot starter = high electrical resistance = no start. I've experienced this myself many times, but it usually acts like the battery is almost dead and cranks over super slow. I have never had it "do nothing". Header wrap & heat-shield insulation for the starter solves this problem. All of my Mopars with this problem would start up just fine once cooled off.

Maybe you can put the car up on jack stands, run it for 1/2 hr until it won't start & then run Condor's tests? If everything tests out OK, then I'm right. If I'm wrong, you'll find the problem running the tests. On one of the tests Condor mentioned, you can actually make the starter crank over with just a screwdriver underneath by shorting the big starter terminal with the small one (or hook in a remote starter button from any auto parts store to do the same thing). That test eliminates everything except the main + cable, ground from the starter to the block & the starter itself.

 

[Montana Mopar]

Thanks everyone for your help. I forgot to mention, I did replace the ground side with a new battery cable. I'm just going to replace the positive side with a new battery cable too. I've been slowly getting shop tools again, the first of every month,(Thank you Uncle Sam). Volt meter and test light is next on the list. And, I'm going have to learn how to use a Volt meter tester. Oh, I don't have to worry about my brother anymore. He drank himself to death, not to long after I came back home. God rest his soul.

 

[Daves69]

You might check the bulk head connector. A clean and tighten up of the terminals wouldn't hurt you.

 

[oldbee]

I'd second "purples" idea of jumping off starter relay first thing. That'll eliminate starter,cables, and battery. Just because they are new, doesn't always mean they are good. Definitely get test lite& meter 1st of Nov..

 

[Speedbird]

I can't get enough from your OP to really help. It looks like you have narrowed it down to wiring.
Is the "little" relay on the fender/firewall not pulling in?
Or the "big" solenoid on the starter itself not pulling in?
It may be obvious to state , but if the little relay is not pulling in replacing the starter is not what to look at.
I'm also reading your OP to mean that you hear nothing when the car is hot.
It's "dead".
Does turning the key supply 12V to that little relay?
It should. Then the relay supplies larger wires with current to pull in the stater solenoid.
Since you have put an unknown steering column in the car and replaced other known items, I would suspect the column.
You really just need some help to turn the key while you check power at different points.

 

[Montana Mopar]

Thanks again, everyone. I have my eyes on a Volt meter at O'Riellys. In the meantime, I'm going to try to swap out the stock flex plate and harmonic balancer with after market from Muscle Motors. The two pieces are supposed to be balanced to the "T". The 400 Dodge Magnum engine has a bit of vibration off idle. Gets a little better, after the car picks up some speed, but the vibration is still noticeable. I'm hoping it fixes that problem.

 

[miller]

Your advice was sound just terminology incorrect. I hope I did not offend you.

Naw...not at all. Just got my own ways.