Erratic50 and I have been fighting issues with TFI modules on my 86 GT Vert for a little over a year now. When it all started, I had a bad radiator, and a duralast module. Needless to say it got cooked... We replaced the radiator and put in a Motorcraft TFI module I got from Oreilly, and (I thought) my problems were solved.
This past spring/summer came around, and with it some more fun with modules. It started out fairly simple. I'd drive my car to say, Taco Bell. The car would run great, stay cool, etc. I'd park it and go in to eat. I'd come back out 15 minutes later and jump in the car. Won't start. So I'd open the hood and wait 10 minutes for the module to cool off and then I'd drive home.
I ran with the car like this for a while, I had bigger priorities at the time, and it really only did it on 100+ degree days.
But then it eventually resumed doing it on the interstate, in the middle of intersections, etc. So needless to say it was time for it to get some more attention.
I code scanned the car, and of course got a pip circuit code. On a whim, we popped the cap off the distributor to find a fair amount of oil inside. So we pulled the distributor and I took it to autozone for a lifetime warranty replacement. While we had it apart, erratic50 found this article: https://therangerstation.com/tech_li...agnostic.shtml and copy/pasted the TFI Module Resistance Test #5.
I got out the multimeter, and tested all 3 modules I have on hand. (One brand new duralast one, The Motorcraft one I got from Oreilly, and a motorcraft module from a distributor I nabbed off a cat eyed lx in the local junk yard).
All 3 modules passed these tests with flying colors. I figured I'd just put my Oreilly module back on and call it a day. But then I saw the table at the very bottom of the page, and opened excel.
First I tested the module from the junkyard. The farthest out of whack it ever was was maybe 1000 ohms on something that was supposed to be 13.7K, for example. I figured A) There was some gunk on the connectors I ended up scrapping off, but B) The module was used for who knows how long, and that may have just been because of that. I called this module a pass.
Then I tested the module off my car, the one from Oreilly. Honestly I have no f***ing clue how the car was even running at all. Most of the readings were between 2x and 10x what they were supposed to be, and some of them would just max out my meter and not give me anything. I concluded this module would be good for a paper weight, or maybe a door stop, but it would definitely NOT be my first choice for a module for my car.
Then I tested the brand new duralast module. A lot of readings were actually way UNDER the expected values. I thought part of this might be the fact that it is brand new. But also the article states: "These values may be valid only on an OEM module, but may apply to aftermarket".
So while I can say I'd never run a duralast rotor, I can't just call their ignition module a POS. It might actually work fine, who knows...
I just thought it was interesting I pulled a module off my car that passed those initial tests, and then turned out to be complete junk. Big thanks to Oreilly for only providing a 1 year warranty, that has just barely ran out.
Anyway, hopefully my car will at least take a moment to consider behaving itself now. If anyone here is having similar problems, I think that article might be of some help.
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