Which ignition to go with? HELP - MAJOR PROBLEM!

[1974dodgecharger]

Digital or analog 6AL?

sorry about that BD I meant stock mopar ECU...I have a hard time with the MSD unit.  On a cold start its awesome, but once the car gets up to temp. and I shut it off it wont start again  It has to do with hot starts for me.

I can start my car with mopar ECU drive till up to operating temp shut it off and rewire for MSD and it wont fire one bit, just cranks over and over and over and kills starter, but then switch back to mopar ecu and if fires right up.

[firefighter3931]

It sounds like an excessive voltage issue to me. Have you measured the voltage Dan ?


Ron

[1974dodgecharger]

Alright Dan I figured mine out after 4 to 6 months playing with this.  Reluctor to gap pick up coil distance.  Mine was .014 plus with brass gauage. I read online from a old msd forum back in 2002 that msd likes .005 or smaller.  The msd tech that tried to help didn't know or something multiple of them.  U can say this old school stuff people who have knowledge don't know old stuff.


Anyways, my car now fires right up no issues with msd unit. 

[BananaDan]

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[BananaDan]

It sounds like an excessive voltage issue to me. Have you measured the voltage Dan ?


Ron

That's what I assumed too Ron and that's what MSD Tech support said after they said "our boxes do not fail". Yeah, whatever, read the internet buddy. I spoke to Pat Collins at Tech West Racing about my problem. He came up on some Moparts threads as an MSD repair/upgrade guy and overall expert and isn't associated with MSD. He told me to check my voltages too but his suspicion is RFI interference. These digital boxes are extremely sensitive he said. He told me moving to an analog box would solve my woes. He laughed at what MSD said to me.

I have non-resistor plugs and FireCore wires so I'm sure there's plenty of RFI interference under the hood.

I am at the car now and just took voltage readings. All readings were taken directly from the battery except for the last one. I checked the starter relay stud as well and the readings there matched the battery.

Voltages
Off 12.75
Starting 11
Running 13.2 - 13.7
Started at 13.2 and crept up to 13.7 after about a minute. Held at 13.7 for 5 minute test.
Running (alt stud) 14.2

I am now going to cut out the digital box and install an analog a friend gave me.

[BananaDan]

Well I did the following today. I fired the car up with digital box #4 for about 5 minutes to take the above voltage readings. No issues found, the charging system appears to be operating properly. I'm installing a voltmeter tomorrow in the car from AutoMeter to go along with my mech. oil pressure gauge and water temp gauge.

I cut out the digital box's harness and wired in a 6AL analog box I got from a friend. I also found a possible problem with the ballast resistor bypass done on the initial installation (see pics). A wire was soldered inside of the ballast resistor but the resistor itself was left and the wire looked really crispy (was only installed in September and I've driven maybe 250 miles on it). In addition, one side had barely any solder contact and the slightest tug pulled the wire off. My multimeter showed resistance during a continuity test of between .7 - 1.0. Not good. I don't think this would have fried the digital boxes (who knows, maybe it would?) but it could have been the cause of the weak sparks that made me think that first coil was bad. So I gutted the ballast resistor and soldered in a new piece of 8g wire. Continuity test showed 0 afterwards.

I also replaced the starter relay. I'm not sure it was bad, but considering the pieces of the car the digital boxes were connected to, it was one of them. I also burnt up a starter when the first box failed so for $20 I replaced it to be safe.

The car started up after all of this work and fired right up as if she was running 5 minutes ago. I ran her for about 20 minutes mostly at idle but also revved her up a few times pretty good. I took many voltage readings and everything was in-line with my earlier readings. At this point it's a waiting game to see if the analog box dies. I have no way of telling if the problem is solved other than time and putting miles on her so we'll see. If the car is good from here on out, I'd have to agree with all of the warnings I was told up front (and didn't listen to unfortunately). These digital boxes are terrible and way too sensitive and unreliable.

[myk]

So if that's the case, what am I supposed to buy when my analog unit bites the bullet?

[BananaDan]

Theres plenty of them on eBay now, even new in the box. Pat Collins at Tech West Racing does repairs also.

[BananaDan]

Back at it again today. I removed the VR and sanded the surfaces where it mounts to the bracket to make sure it has a good ground. I tested the VR mounting bolt to the body ground on the rad support by the battery and got 0.000 volts. I've read that is how to test the quality of a ground? Someone please correct me if not true. I also got my new volt meter installed and I fired her up. She started right up again and ran for about 20 minutes. I had a quick bit of a scare because the new volt meter showed almost 15v. I ran over to the VR quickly and realized I forgot to hook the field wire connector back up after the work I had done. After plugging it in the volt meter came down to 13.5v which I confirmed at the battery with my multimeter. I guess that was another good way to verify that the VR works fine.   

After running her for 20-30 minutes, I took her for a test drive. I put about 30 miles on the car and she seems to run fine. No problems noticed and the good thing is she didn't fail. I might be through this chapter finally.

[firefighter3931]

Great news Dan ! 

Hopefully the issues are behind you and you can go out and enjoy your car 



Ron

[BananaDan]

Fired her up again yesterday and ran her for about 20 mins. Still looks good on the analog box. No issues.