85hp Chrysler Power Pack is good, now what? Update

[prater]

I have no spark, replaced power pack and coil, engine started. A few minutes later it quit, no spark. I tested the power pack and got a strong spark, which points to the points or preamp. I have no idea where to turn now.

 

[Frank Acampora]

Re: 85hp Chrysler Power Pack is good, now what?

Re: 85hp Chrysler Power Pack is good, now what?

Really need to know the year of the engine!

Motorola CD ignition with distributor? Big finned aluminum black box on the side of the engine.

Check the wires where they pass under the flywheel to be certain they are not rubbing while running and popping the circuit breaker. If it is the steel can it will reset itself.

Do you have points or pre-amp? Points will be a single wire to the distributor and pre-amp will have two. Points are set at .018. There is no way to test for a defective pre-amp besides installing a known good one.

 

[prater]

Re: 85hp Chrysler Power Pack is good, now what?

Re: 85hp Chrysler Power Pack is good, now what?

1978, Magnapower Ingition, white box on side of engine with coil attached. Two wires on distributor one black/white and one blue. I think I got it going, started and ran strong, found the battery ground wire on the breaker panel was loose. Not sure if that would cause it to crank but not run. Heres a question though.

Before the problem I was having was no spark most times, sometimes it had spark and would start at which time the tach would go crazy shooting straight to 6000rpms and staying there even at idle. I tested the power pack and coil and found that one of them was bad, but I didn't know which one, so I replaced them both. Now the tach is operating normally and the engine seems to be running great since I rechecked all the grounds. But I still don't know if the coil or the power pack is bad. I'd like to know so I'll know which of the old parts I took off is still good. Any ideas?

 

[Frank Acampora]

Re: 85hp Chrysler Power Pack is good, now what?

Re: 85hp Chrysler Power Pack is good, now what?

When a coil goes bad, it is usually a short or a broken internal wire. This would be no spark at all times. More likely it is the CD box that is not functioning correctly. However, you can check the primary and secondary side of the coil for resistance--I don't remember the numbers, but low resistance on primary and high on secondary. Secondary is grounded through the same ground terminal as the primary so check center post to ground.

Sometimes a transistor inside the CD box goes bad and it delivers multiple sparks instead of one. Depending upon where the tach takes its signal from, yes, a malfunctioning CD can cause erratic tachometer operation.