Trying to help out someone. Has a 6 speed coupe that has had a consistent problem since we got it going last year. It was his Dad's car and had been sitting awhile.
If the car stalls it will not crank and he has to disconnect the battery and then it will restart. He has been teaching his girlfriend to drive a standard and it has made it less than optimum as she loses confidence.
It has had the same thing happen when going to start the car but only randomly and infrequently. Usually start right up and this mostly happens in a stall situation
I did install a new RCM last year and had it resoldered before installing. He did throw the old RCM back in and it did the same thing
The battery has been replaced. Ground cables replaced
He does drive it daily. So not sitting around
He has spent fair dollars getting maintenance up to date including having the plugs and wires changed but nothing else electrical
The fan is not running on high when key turned to on after 30 seconds.
Only post I could find remotely related was something to do with the Engine control relay but don't understand how it would be the same with his original RCM and new RCM.
Also how disconnecting the battery each time would correct it.
He has an off/on turn switch on his battery as it was not driven much by his father. He says he shuts the battery off for a bit then on and it will start.
He says that over the last year and a half it has done this nearly fifty times and rarely takes more than one shut off to reset it and start up.
I have another new RCM to try but thought I could give him a little confidence if someone could give me a clue where to look if it is not the RCM
I am not a mechanic or electrical guy but have done 15+ sticky keys and other fixes but can't figure this one out.
I have searched for months and not found anything so maybe Mark pizzaguy or DJ Tighed1 could give me some direction. Questions and suggestions appreciated. Thanks, Ron

 

I'd remove that and restore the factory wiring and see how it acts. If that fixes it, it fixes it. If not, then we can move on.
THing is, as I read all thru this, it sounds like the ECU is "hanging up" for some reason - and corrupt electrical power can cause that.

Quote:

If the car stalls it will not crank........

If that means, and I'm sure it does, that the starter won't engage, but it engages and the car starts up if the battery is disconnected, then I'd damn well restore the battery wiring to factory.

I admit that may not be it, but you have hit about every other suspect so.........................................

ON THAT NOTE: SOME of those disconnects are effective and safe to use. Ambulance and Fire trucks often use them to be sure the rig starts.
But if you have one of these on there, get it the hell off the car before you end up buying a SKREEM, ECU or TCU.

 

Thanks Mark, I was thinking about that too but thought if it starts it should be ok. I will have him remove and see what happens.

 

Sorry Mark as usual when I try to make it clear it is in my head only.... Just to clarify - he has to disconnect the battery and wait a minute then reconnect battery and it will start

 

Oh My. Thought I better update this no matter how embarrassing. He thinks he figured it out.....
So he removed the battery cut-off and it happened again while his girlfriend was driving and stalled the car. He thinks his girlfriend was more than likely not pushing the clutch in all the way! She is a new manual driver and has short legs!! Waiting to see if that was really the only problem!! Glad he's a good kid cause I racked my brain on this one, Thanks for your help Mark. Will let you know if this happens again.