Igniton Modules, again

[Mavawreck]

right now, i have a 1986 iginition module wired in, i just spliced in the old connectors, this afternoon on my way home the engine started missing an acting in the manner that it usually does when the module is about to fry, its done it enough times that i can tell from the way its runnin that its about to go. it died at a stop light but i got it goin an back to the parkin lot. Is there something I missin here, this is my third one in two months,5th since Dec. 26th of last year. one was an MSD box. This last time i wired a freakin 12 volt cooling fan an mounted it on top of the DA#M box to cool it. Do yall have any suggestions? I have TFI, MSD Blaster 2 coil, a new starter,new starter relay, 8mm wires and plugs have about 8k on em. I just dont get it.

[Serious Johnson]

Who knows? My Jeep lacks a spare tire, but doesn't go anywhere without a spare ignition module. Hot, cold, wet, dry, off-road or Interstate, they seem to crap-out at times of their own choosing no matter what you do. I just duct-tape a junkyard replacement to the main one for quick plug-&-play. Good, clean grounds seem to help a little.

:-

[ November 23, 2003, 08:36 AM: Message edited by: Serious Johnson ]

[Joe Guilbeau]

Your power and grounds are not correct.

What is the alternator putting out at full charge, half charge?

These boxes are pretty stout, lots of other folks use them and have no trouble.

Therefore it stands to reason that something in your vehicle has an effect on these electronic units.

When troubleshooting electronic items, always check power and ground first, they will not operate without proper voltage and good grounding.

Your alternator "Might" have leaking diodes, which will cause ripple voltage on the power it sends to components.

A rusty bolt on the grounding mounts "Might" cause excessive heat build up.

These days. upi pretty much have to have a good Multimeter to keep ahead of the curve. Sears sells a nice unit that is about $50 dollars.

[Mavawreck]

the grounds are clean, we redid all that crap about 2 weeks ago, are there any tell tale signs of a alternator that goin?

[sloop]

get a multimeter on it and see exactly how many volts it is getting supplied

[Marvin Gates]

HEI!!!!!!!!

[jode]

Originally posted by Joe Guilbeau:
These boxes are pretty stout, lots of other folks use them and have no trouble.

Therefore it stands to reason that something in your vehicle has an effect on these electronic units.You said it all - it hasta be somethin else...somethin...somewhere...sux

I hate it when people on the forum dont have better answers in situations like this, but there hasta be a short, or another malfunctioning part, or you screwed up the wiring somewhere...and it is gunna be tough to diagnose online.
Most autoparts stores these days will run the diagnostics on your alternatro for free

:confused: :(

[TexasJ10]

The investment in a multimeter will be worth it. You smply can't figure out electrical promes without it. I have a nice radio shack one, but frequently pull out by $10 Harbor freight model that I keep in my tool bag. It seems to get to the bottom of most of the common stuff fine. A while back I had something going on with my alternator overcharging. I got great advise on here once I was able to post the voltages.

[The Anti-Chrysler]

Are you using new modules, or old ones??? If new, then you should be able to claim on the warranty. When I bought my first new one, it has a lifetime warranty. There were 2 or 3 choices I think, and I got the "best" one. I didn't think the cheap module was a good idea.

[vic]

for what it's worth, I went thru something similiar two weeks aqo. tfi coil, 8mm wires, etc.
had a BAD NEW module. It happens. Also the modules do not like too much current running thru the switching transistor to the ground side of the coil, thats why they run a resistor wire in the circuit to limit current. Some people say you need it, some people say you don't with the tfi coil. The stock module NEEDS it to stay alive for any length of time. Compare heat build up in the module with and without the resistor wire and you will see what I mean. I re-installed the resistor wire and a new module and problems disappeared. Hope that helps.
Good luck. vic
p.s. the bad module made the engine run rough with the alternator hooked up, but when run off the battery direct without the alternator in the circuit, it was okay. Led me to replace the alternator before I found that the "new" module was fried.