Mysterious No Start Again

[burner71]

I posted about this awhile back but the problem has slowly started coming back again and I cannot find the issue.

Issue:
Turn the key on, fuel pump primes turn to start and loud click and very small engine turn. Some times it will start the next attempt, sometimes it takes about 20 attempts. Seems to worsen in hot weather.

Things I have done:
Replaced battery, no change. Borrowed a 1000 cca battery with no change

Replaced alternator, no change

Replaced starter actually twice because i was convinced the one i installed must be bad, no change.

Replaced the battery terminals, no change

Replaced key fob battery, no change

Replaced starter fuse relay, no change

Replaced battery ground to frame, no change

Ran a second wire direct to starter from battery, no change

Putting it in neutral or shifting back to park makes no difference.


This really has me stumped. What gets me is that the motor does turn slightly when it clicks, so the signal is getting to the starter solenoid and starter motor.
As an added weirdness, just recently now the radio audio goes out at about half volume, i have to turn it off and back on to get sound back, not sure its related.

any other ideas to try?

 

[Brandon-w]

Put a amp clamp on the big power going to your starter. See what/if it's getting enough power. Just as an experiment try adding power to the little exciter wire. If it spins over hard you knoe it's the exciter voltage.

 

[burner71]

you mean the small yellow wire that clips on the starter? The start signal tab?

 

[Brandon-w]

Yes take that wire off the starter and add power directly to the starter. If it wings over you know it's a signal wire voltage problem. I'd start with an amp clamp on the big wires first.

 

[burner71]

Yes take that wire off the starter and add power directly to the starter. If it wings over you know it's a signal wire voltage problem. I'd start with an amp clamp on the big wires first.

Ok so just short the tab to the red wire connector.
Also as for the amps, whats low and whats normal?
I put an amp clamp at my battery terminal during a start just because i was curious and it was like 330amps

 

[NJMOPAR]

Now that the radio is acting up too I'd be inclined to look towards it being a computer issue.
Seems you've replaced all the hardware and the radio has nothing to do with starting the truck.
Maybe have the dealer reset the factory parameters?

 

[burner71]

I can't, I have handbuilt this motor with a 6.4 cam and ported heads and has a custom tune to make it run right.
BTW it did this with the stock motor as well before i replaced the motor.

 

[NJMOPAR]

Try disconnecting each plug on the computer and check for oxidation. (with battery positive off)
Maybe the ignition module?
Sorry I can't help more.

 

[burner71]

at first i though ignition module, but if it was then i wouldn't be getting a small crank each time.

 

[Brandon-w]

I think amperage is supposto be between 2-400 amps on a warm day. Colder it is the more amperage it takes to crank it.

 

[Brandon-w]

at first i though ignition module, but if it was then i wouldn't be getting a small crank each time.

Do you have tip start or hold to crank? Maybe something is gone wrong with your tip start and it will only give it a bump?

 

[burner71]

No I don't have to hold to crank. It will do its click and small turn or start sequence just moving the key slightly after ON and spring back

 

[Brandon-w]

Hmm sounds like voltage or amperage to me

 

[burner71]

yeah i will check the voltage on the start signal wire tonight.

 

[burner71]

So I got home tonight and started looking things over. One item I had overlooked were 2 main ground wires running into metal blocks connected to the negative battery terminal. I pulled them out and noticed some green growing in the wires. I cut them down and stripped back the jacket and sprayed them down with terminal cleaner then set the back into the junction blocks.
Then I put a meter on the start signal wire and was getting 12.7v when the key was turned so that was good.
Now it’s starting. So far 10 straight starts no clicks. I really hope this was the issue. I’m about to go drive around and heat it up and see how it does.

 

[Brandon-w]

Good! Easy fix

 

[burner71]

Well after I ran it for 20 minutes and parked it did it again.
It’s possibly in that connector block. I’m going to go buy a new terminal for the negative post today and see if that helps.