No Start

[Pentastar440]

so, a couple of weeks a go my brake light switch calved. I got another, but in the process of removing the old one, I accidentally nicked the speedo cable. I thought I should replace it. I got a NAPA replacement and installed it. I had to pull out the instrument cluster to do this. Since then, I have had a no-start. I'm scratching my head here. Ballast resistor showing 1.2 ohms. voltage on left side of resistor 10.97 v. other side 4.9v. Pulled no. 1 plug, no spark. Checked ECU ground, installed a ground wire to be sure. Never had an issue like this owning Mopars for nearly 50 years WTF?

 

[Geoff 2]

Check the wires/plug on the ign sw. Say a prayer to Allah.....

 

[Don Frelier]

4.9v is too low something is wrong there

 

[twecomm]

Your brake light switch "calved" ? Think "Calved" is the wrong word...

More info needed.... Does it crank ? What are the voltages across the resistor while cranking ? 10.97 is well below what your battery voltage should be, what is the state of the car when you get these measurements ? When you had to pull the gauge cluster, did you disconnect the alt-amp gauge ?

 

[Pentastar440]

Brake lights started staying on constantly. Remedy, new switch. Yes, it cranks. Battery voltage is 12.6.
I'm going to pick up a remote starter switch today so I can watch for spark at high tension coil to distributor wire. I'll check the ignition harness, maybe it is not making full contact at the plug. I did undo the ammeter wires. They are re-installed correctly, as is every other connection to the cluster. I took my Charger down to a shell and rebuilt it with all new wiring. There are no weird connections or splices. It has run perfectly since 2012, always stored in a heated garage. no visible corrosion on any electrical connections. I also pulled every spark plug, cleaned and dried them off and re-installed them. I should mention I am running a Mopar Performance electronic ignition kit P4120505, and a two pin ballast resistor. The ECU is a 4 pin.

 

[Don Frelier]

Brake lights started staying on constantly. Remedy, new switch. Yes, it cranks. Battery voltage is 12.6.
I'm going to pick up a remote starter switch today so I can watch for spark at high tension coil to distributor wire. I'll check the ignition harness, maybe it is not making full contact at the plug. I did undo the ammeter wires. They are re-installed correctly, as is every other connection to the cluster. I took my Charger down to a shell and rebuilt it with all new wiring. There are no weird connections or splices. It has run perfectly since 2012, always stored in a heated garage. no visible corrosion on any electrical connections. I also pulled every spark plug, cleaned and dried them off and re-installed them. I should mention I am running a Mopar Performance electronic ignition kit P4120505, and a two pin ballast resistor. The ECU is a 4 pin.

Just note that when you use the remote starter right at the relay the key is in "Run" position.
You need to check spark in both Start and Run.
But 5 volts isn't going to do it I can tell you that for sure.

 

[twecomm]

It's possible that the ECU ( orange Box) went bad. It happens. Only solution is to try another ECU. The orange box big front diamond shaped transistor completes the circuit to the ground side of the coil. If you can't get any spark that may be the issue. The 10.97 & 4.9 voltages you stated is not normal..

 

[Pentastar440]

Connected the remote starter and started checking things. Battery 12.7v. Good fat spark from coil. Decent spark on plug wires. I then checked cranking voltage on ECU side of ballast. 10v. to coil 5.5v. As I was cranking it with everything connected it seemed like it wanted to start. I hopped in the car, pressed the throttle a bit and it flashed right up. I have no idea what fixed it but I suspect it might have been a loose plug at the ignition harness. Running voltage ECU side of ballast 12.1, coil side 6.5v. I let it warm up a bit and shut it off. Started and stopped it a few times. Seems ok. Thanks for the help. Its a head scratcher but I'll take it!

 

[Pentastar440]

More to the story now. When it started, the fuel, oil pressure and temp. gauges weren't working. FFS!
popped the cluster out again and pushed on the power supply to those gauges. Buttoned it back up and tested again. Gauges work but no start! I reached down and pushed the ignition harness plug together, flashed up instantly. I think I have narrowed it down to the plug. I'll pull it apart tomorrow and put some dielectric grease on it, zip tie it together, tight! Amazing how the simplest thing can give you fits...