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View Full Version : Dura Spark Stator Testing, Diagnoses TBI Conversion



EagleMark
09-29-2011, 06:12 PM
Many people do TBI conversions to other make vehicles and one of the ignition options is to use a Duraspark Stator also known as pick up module, magnetic pick up or? It's the electronic ignition that replaced the points. It sends proper signal to the GM EST module also nown as EST or ICM.

Today I worked on a TBI conversion done to a 302 Ford engine with this ignition. Origanally it was said to start and run fine but do to a lumpy cam they wanted me to tune it. Upon arrival I found it not to be running correctly, timing was not set properly nor would it? Reving the engine up would bring out the problem and while checking timing it was all over the place and when it started to miss and sputter the timing light would stop flashing. Leading up to a brand new stator that was faulty. Here is the test procedure from the Ford Manual. It has a part about vacuum advance which would be disabled for an EFI conversion.

To test the stator (also known as the magnetic pickup assembly), you will need an ohmmeter. Run the engine until it reaches operating temperature, then turn the ignition switch to the off position. Disconnect the wire harness from the distributor. Connect the ohmmeter between the orange and purple wires. Resistance should be 400-800-. Next, connect the ohmmeter between the black wire and a good ground on the engine. Operate the vacuum advance either by hand or with an external vacuum source. Resistance should be 0-. Finally, connect the ohmmeter between the orange wire and ground, and then purple wire and ground. Resistance should be over 70,000- in both cases. If any of your ohmmeter readings differ from the above specifications, then the stator is defective and must be replaced as a unit.

JeepsAndGuns
10-01-2011, 04:54 PM
The AMC engines use the motocraft distributors and ignition systems. When I first swapped on my system and I locked out the mechanical advance, I installed a new pickup coil because the old one, the plastic around the pickup was cracked, and I didnt trust it. I cant remember what brand I got, but was just a regular parts house type one.
I went through absoulte hell chasing down a god awefull backfiring problem. As soon as it started, it would backfire badly and constantly, no matter what you did. You couldnt even drive it. If you started it with the bypass unplugged (to set base timing) it would quit. But plug it back up, the backfiring came back. I chased wires, re routed wires, replaced the coil, ignition module, checked, double checked, and triple checked base timing, tried diffrent bins and even a diffrent ecm. I was at my wits end when I finally decided to try another pickup coil. I bought the most expensive one I could find at napa (and it was actually made in the USA!!) Put it on and the problems disappeared. All that trouble was from a faulty new pickup coil (it was made in china, go figure) and all that time I never suspected it because it was new.

EagleMark
10-01-2011, 05:53 PM
It's realy a pain when a part works, kinda... easy when it fails completly. The one I did would start and run and idle, but could not accelerate. What lead me to the pickup was after I swapped out EST (or ICM) still the same. I knew it was ignition because as sson as it started breaking up popping and back firing the timing light went nuts. Only thing left was to find how to diagnose the pickup. So I posted it here.

This is now on my list of glitchy parts, I hate glitchy parts! The only other one from a TBI system is the EST! Everything else either works or does not. This pick up part is not even from a TBI system but commonly used in the conversion.

Hope it helps others not waste hours of life in frustration! :thumbsup:

JeepsAndGuns
10-02-2011, 06:50 AM
Exactly, learn from my fail....lol
This is one part I would reccomend buying the highest quality you can find. Pay the extra money.