Ignition module failure..?

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Moparbaker

Moparbaker

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Got me a "MSD blaster 2" coil (as some of you already know) cuz I thought it was the problem & I tried it out it worked good, but I only tried it in the garage for a short while... Today I drove out & after a while the engine started cutting out with shorter & shoerter intervals & I noticed then that it would run on idle & even the slightest gas caused it to cut out.
So what d'ya all think; is it the ignition module that's quitting?
 
Sounds like an electrical related issue but could be fuel or a combination. You really need to determine what is good and what isn't before throwing parts at it. More than once I have replaced a part only discover the "new" part wasn't good either.
 
It DOES sound like ignition BUT, what is the history on the fuel, if that fuel has been sitting around, it could be a problem. Today's fuel doesn't last like the old days. Rule out bad gas first, then proceed.
Sometimes you can smell when fuel has gone stale or starting to varnish, but that would be hard to show you from here.
Joe
 
Which ignition module is it? If it's a Chrysler electronic replacement box it's probably junk and when it gets some heat in it, it takes a dump.
 
yellow rose said:
Which ignition module is it? If it's a Chrysler electronic replacement box it's probably junk and when it gets some heat in it, it takes a dump.
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That is true but usually when they go they go all the way at least in my experience
 
70chall440 said:
That is true but usually when they go they go all the way at least in my experience
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I've had a couple (one on my motor home) both did that. And you are correct, usually when the module goes T.U. they just quit. Somethings they go intermittent just to make you crazy.

I'm not a fan of electricity. It doesn't like me either!!
 
I forgot to write that it's no fuel problem.
Every time I've had this problem before it's been the coil but that's new now.
When I put this car together I got this module that's chinese made, the guy in the speedshop said "it's the same stuff in all of them"...
 
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My buddy had a 360 in his A100 pickup that would run great for a few minutes, then it would stumble, fart and stall out. After it cooled for a bit it would re-start then the same scenario would play out.

After A LOT of troubleshooting I discovered the 2 wire harness that plugs into the distributor was crushed when the previous owner installed the engine. I made and installed a new 2 wire harness a the truck ran fine.
 
Start by checking spark. Do so on the starter with everything wired normally. Do NOT use a resistor coil wire. "Rig" a spark gap with a solid core wire. You should get at least 3/8 hot blue spark and typically 1/2" when cranking with the key. Do not test by cranking the engine by bypassing the starter relay. This does not provide full 12V to the system

Next with engine running, check coil + voltage. It should be somewhere between 8 and 12V with the alternator charging at 14. In other words check the battery voltage, coil should be 2-3V below the batt voltage

Make sure module is WELL GROUNDED.

If you have another coil you might try that. This is typical of a coil going bad. "New" does not mean "excellent working condition"
 
Well it does actually run exelent for some minits, even by reving before it starts to quit with shorter & shorter intervals, but then it still runs if I don't give gas... & like that I never had it with coils; either they just died & stayed dead or they would (also) work after cooling down but never work if I left it idling...
 
Check the magnetic pickup. Test with an ohm meter and rotate the distributor. It should fluctuate each time the wheel passes the magnet.
 
halifaxhops said:
pickups get intermittent also.
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Last month I tried to start my duster for the first time. New motor, coil, module etc... for the distributor. I pulled it from a running car I had for a HEI swap. Trying to get it started I chased everything. Would crank and fire a few seconds then nothing. I swapped new coils, wires, ECU. Traced and traced wires. Finally I had an ephianny. Pulled the distributor again and checked the pickup. Got almost nothing. This came from a known running engine that I drove for a long time.
Electronic parts take chits at any given time for no reason.
 
New stuff sucks since I am familiar with this. New condensers for example have a 50% failure rate hot, points have crap spring pressure, The ecu's are a crap shoot. Some have a fake transistor on them and a small board inside. Older the parts the better!
 
gliderider06 said:
Check the magnetic pickup. Test with an ohm meter and rotate the distributor. It should fluctuate each time the wheel passes the magnet.
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Another big BIG issue with pickups is the two wire connector. There is NO current through that connector, so ANY looseness or corrosion will kill off the tiny pulse signal. "Work" the connector in/ out several times to scrub the terminals clean, and "feel" for tightness. Inspect with a light/ magnifier for corrosion
 
Moparbaker said:
Well it does actually run exelent for some minits, even by reving before it starts to quit with shorter & shorter intervals, but then it still runs if I don't give gas... & like that I never had it with coils; either they just died & stayed dead or they would (also) work after cooling down but never work if I left it idling...
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This is also a typical engine response to a declining fuel level.
Just because the accelerator still pumps gas doesn't mean the idle-wells are full. Once the fuel level gets down far enough, the engine just can't pull the fuel up any more......... or rather atmospheric pressure just can't push the fuel up and over the top anymore. You may be able to keep it running for a short time, by pumping the accelerator, but eventually the AFR is just too far outta whack.
Jus saying

So in that light, I would do a fuel-pump output test, even if just to rule it out. I mean how many times can you throw coils at it and keep getting the same results.
BTW; If your car is using a factory-type electronic ignition, it will run on any, yes ANY same-type Ecu off any other period Mopar; slantys included the ECU doesn't know the difference.
The pick-up however, is polarity sensitive; you can't run a pick-up, as delivered, from a counter-rotating to yours, engine. But you can swap the leads in the connector, and then it will work.
In my experience; the reluctor gap will work just fine between zero and .030 gap. By .035 some, not all, PUs will start to crap out. It might be ECU related,IDK.. The spec is .008 to .011, I think. What's more important is for it to have a well defined rise and fall on an analog tester and a stable output voltage. I don't remember the peak-voltage, maybe, I'm guessing, .3VAC
It's been reported, that sometimes the vacuum advance mechanism, when it is doing it's job,can cause the reluctor gap to change, messing with the spark. I haven't looked into that, and IDK how that can happen, but apparently, it does.
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I actually use the fuel level, sometimes, to fine-tune a cranky idle.... you know like happens with a low idle-vacuum;like with a 292/292/108 cam, or maybe not enough valve lash, or retarded timing; or whatever.
Sometimes I can get that 292 cam to idle down at 550 in gear (sometimes less) and pulling itself...... with; a manual trans, and 3.55s!
No that's not the only thing I do to make that happen,lol. I can't tell you all my secrets or I wouldn't have a job! Yes I'm kidding,lol; I'm semi-retired and loving it.
 
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Lots of good advice here; however based on what you are saying my first choice would be the ECU; it sounds to me like it is getting hot and when it not working correctly the warmer it gets. I have seen this before on a car I had years ago. That said, if it were me, I would pull the ECU and look at the back for any anomalies (discolored spots, bubbles, etc.), I would also check to ensure that it was grounded well (a very common problem, I install rivnuts in all the sheet metal screw holes in my firewall and inner fenders) and used 10-24 screws with star washers on my ECUs and voltage regulators. You would be surprised how many issues are resolved with good/excellent grounds throughout the car.

Once you have decided that the ECU is probably good, trace all the wiring to ensure it is connected correctly, not broken or damaged. Check the coil, check the ballast resistor, check the gap on the distributor, look at the inside of the cap and the rotor for carbon trails and/or broken parts, check all the spark plug wires to make sure they are not grounding out (it does not take much and if they are anywhere near the exhaust/headers as they get hot it will make the problem increase), check the fuel system to make sure it is functioning correctly.

This is frustrating but not rocket science, the problem is there waiting to be discovered and fixed. If you approach this in a methodical and organized manner you will find it.
 
About the fuel: It runs the same on gas as on LPG.
& about the ignition: It's original MoPar electronic ignition exept for the new "MSD 2 blaster" coil.
Going out to unscrew & check the backside of the ignition module ("ECU"?) now...
 
Done checking it & it looks new on the backside, no bubbles & no difference in color. So pro'ly the pick up...
& I wonder about the bad ground / bad wire connection possibility; shouldn't it be the same if the engine is warm or cold?
 
A quick check on the pickup can be tested on the car, un-hook the two wire connector at the distributor.
Hook a ohm meter up set on amps, and crank the engine, you should see a reading as the distributor turns, you can also bench test the same way by spinning the distributor by hand.
 
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