This my first time, so please bear with me. I just changed cams in my 440, it was rebuilt about 8 years ago and driven on the weekends without problem. Then the cam was wiped out. Why is not important. The cam was changed. Now, I was having trouble with the engine starting and running. Finally, thought I had discovered the hot wire for the coil (+) which goes through the resistor was shorted out. I ordered and replaced the ignition because I could only get .223 volts out of it. WELL, the new one is no better. The engine will start, but not run. Later today, I checked the (+) on the coil and it is reading -11.00 volts? That is with the negative cable removing from the battery! Can someone help me trouble shoot this problem? I just put a MSD unit in line to up the preformance. This is in my 71 Challenger.

Check your block to body and negative to block grounds?

Okay, I just put the old wires back on before this problem. Will check it next. Thank you

Checked both grounds. No problem. The thing I find strange is that with both ignition units, the new one and the one in the car which is not more than 10 years old, the power coming down the brown wire, the one going to the resistor doesn't show more than a .223 volts +-. The wires that provide 12 volts to the rest of the car with ignition on, i.e. the dash and other units in the car and under the hood are fine and showing 12 volts okay. Does anyone know which wire going into the voltage regulator under the hood is the field. I want to be sure that power is going through the regulator right.

Thanks, this helps alot. Now if I can only find the short.

You might check your voltages at the ign sw terminals ign1 (run) & ign2(crank) & especially pull apart the bulkhead & check your voltage drops there also.

My new msd street fire unit sends two wires to the distributor by way of the magnetic pickup. One is violet, the other Green. There is no way to figure out which is which on the distributor. Could these wires be backwards therefore not allowing the engine to run?

I think it'd run but not right. iirc the green MSD wire (neg) goes to the black oe wire (neg) on the Mopar dist.

Okay, that is the way I hooked it up. Next question. Is the 14 gauge brown to black wire that goes to the (+) terminal on the coil the starting circuit? If I am looking at this correctly, the juice goes through this wire from the ignition switch to the resistor, (which is taken off with the MSD) and then goes to the (+)coil orginally. Now, MSD wants it to go to it's small red wire that I thought would need an ignition-on switch for power. I can not trace an -on- wire for the MSD if the resistor is disconnected. In other words, without the resistor hooked up, or straight wired, there isn't any way that power can get to the MSD to indicate that it should stay on AFTER starting. Is that make sense?

I'm not sure because I've never had a MSD & the dist pickup polarity just stuck in my head & I prefaced it with an iirc as I was not sure. I do think the large (MSD)red/black leads go directly to the battery then a small red switched 12V to energise it. I better stop there as I did not pay close attention as I figured I'd be too poor to ever afford an MSD (but I'd like to have the multispark).

Thanks rapidrobert. I have been going back to another of your discussions a few days ago. Putting everything together, I think that the MSD is not getting continuous voltage AFTER the starting circuit. I have tried to write to the MSD people without an answer. But, I think that it needs power from the ign 1. On the other two cars, I have a resistor on each car in the standard location without problems. So, that is what I am going to do after recharging my battery again. I agree that the MSD cost more than a ECU, but, added together, it isn't that much more. I probably don't really see a big difference, but, my engine doesn't run as well with the new cam as it did before, so I thought I would try it. I am beginning to think the heads aren't big enough for this cam. BUT, I can 't get the car to start/run with the new MSD. I am ready to go back to the old ECU if this doesn't work. Thanks for your help.

Well guys, I was right. No power through the resistor to the ignition wire while in run. It was only running the day before with the Chrysler control unit. Ran voltage test, resistor would not allow any voltage through it with the ignition on, (not in start mode). Backed up by removing the MSD unit, and reinstalling the Chrysler control unit. Still had trouble once started. Still haven't figured out the timing, but I must have moved it 20 plus degrees once the engine started and was running. Once it was running smoothly, I put the MSD unit back on. Wow, what a difference! I am still having a bit of a pinging problems under hard acceleration, but that is for another time. I spoke with the MSD people and told them that there is no way that the engine is going to run without the resistor hooked up. He was surprized! But, the resistor was bad and it would not allow voltage through it in run mode. Thanks.

Well guys, something is still wrong. Why does the engine start with the distributor at one setting, location one I will call it, run great when adjusted to equal the proper timing, that is; location two, that is with maximun timing without vaccum at 35 plus/minus, vaccum connected shows a solid 52. It runs well, still needs to have the carb adjusted to the larger cam, (I think that is it) but will not start again after shut down without resetting the distributor back to location one that is described above. It will start hard, run rough, then let me adjust it to location two where it runs smoothly agian. Shut it down, and here we go again. I checked the two distributor wires and made sure that the green lead wire from the MSD is connected to the black wire to the distributor. Oh yeah, I switched these two wires and absolutely couldn't get the mark on the flywheel to line up at all with the timing mark. Looks like it was backward. BUT, I am not sure. Any suggestions?

Just an update. It turns out that the distributor has been messing up my trouble shooting assessment. The distributor has been advancing too far forward after adjusting the timing to the mechanical 3000 RPM. I hope you know what I mean when I say this. The engine was way out of position for "starting" timing. It would not start. Since the old distributor, which wasn't causing any problems, has a vaccum adjuster, I am swapping the old distributor for the new one and hoping that this will solve my problems. yeah!!!!