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Thread: More TFI issues

  1. #1

    Default More TFI issues

    Hello:

    In January my 86 GT died on me. Safely pulled over, and eventually towed home, no problems. I went through the shop manual and the rest of the ignition system checked out. I have a stash of TFI modules. I replaced it with a Ford unit and problem solved. Car runs just fine. The module that died was itself replaced about two and a half years ago when the car overheated. Well, the dash gauge didn't go to the H but close to it. Fortunately it was in a parking lot of a minimall with a parts store in it. Fixed in five minutes and got home. Replaced a faulty water pump. All systems go until this past January. I noticed the tach gyrating around while driving but no engine problems until shutoff.

    Here we are in Spring. Tach showed some gyrating again even though temp and coolant level and water pump are fine. Only gyrated once and not as severe as previously. Engine purred fine. No hesitation. I do have a coolant leak that will need addressed. Its minor and tolerable but I'm thinking new factory water pump. I did flush the system and seems OK. Some minor debris. Car didn't overheat during the flush.

    The engine runs hot since I've had it rebuilt back in 2000. I'd like to pull it and address the coolant leak and two minor oil leaks. Drain plug and low oil sensor connector. Plus some gaskets as they are weeping oil- mostly valve covers. The coolant leak may be the timing cover, not sure yet.

    Here's why I am confused and thanks for reading thus far. If the TFI quits when hot, doesn't it run hot? And if heat is the real culprit, could the distributor stator also need to be replaced? It was about ten years ago and I have another. I also have some idle issues when cold but not always. Otherwise, it runs great. Don't want to get stuck anymore.

    Am I on the right track or should I consider relocating the TFI. I have two left in my stash. Want more mystery? I checked the module and it passes all tests even though it stranded me three months ago. The one that died two years ago doesn't test OK. Neither will be going back on the vehicle, of course.

    Thanks for the advice and ideas.

  2. #2

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    I checked my stash of 2 new modules, plus old ones that failed. Two years ago the replacement was from BWD. Lasted until either too much heat cooked it or who knows. The one I cooked back then was part number E3EF-12A297-A1A. The current module on the car is the same as one more spare, part number E6SF-12A297-A2A. They both came out of Motorcraft boxes marked E43Z-12A297-A/ DY-425. Seems they aren't the same and maybe this might be a problem?
    What is correct for a factory 86GT with the 5 speed? I thought I had E43Zs but apparently have E6SFs. Maybe I'm too picky but if this solves the problem...

  3. #3
    FEP Super Member webestang's Avatar
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    Best thing I ever did was relocate my TFI to the inner fender. Mine used to cut out all the time when on the dizzy. Ford knew they messed up mounting that on the dizzy and on later models moved it to the fender. My engine never overheated and I used the grease on the back to mount but it still got hot enough to quit on me. This is on my 85 2.3 and I guess I've been lucky with my 88 5.0 so far the factory one has held up, now I type that it will cut out.....LOL


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  4. #4

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    Is the tach aftermarket? If so it could be a loose ground or signal wire. Same with a stock tach just not as likely. I replaced one tfi in my 5.0. The new one has been great. I was generous with the dielectric grease on the back and put some on the terminals that plug into the distributor. No problems.

    Sent from my 5017B using Tapatalk

  5. #5

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    Quote Originally Posted by Jackthemind View Post
    Is the tach aftermarket? If so it could be a loose ground or signal wire. Same with a stock tach just not as likely. I replaced one tfi in my 5.0. The new one has been great. I was generous with the dielectric grease on the back and put some on the terminals that plug into the distributor. No problems.

    Sent from my 5017B using Tapatalk
    Correction! It was not dielectric grease on the back. Just the prongs.

    Sent from my 5017B using Tapatalk

  6. #6
    FEP Super Member erratic50's Avatar
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    I've had TFI heat problems based upon distributor clocking. If it's in time with the wires facing towards the right from fender, no problem. If it's a cog on the dizzy advanced the wires face forward and the TFI gets too hot.

    Just my experience.

    Moving it is a good fix. I haven't needed to on mine in all the miles I've driven it including Wichita summers.

    I would run a new ground block to K member or firewall. The stock grounding straps go bad and cause all sorts of trouble.

    I would also move the stock ECU and ignition grounds so they go direct to the battery. Cut the piece of junk spade connector that corrodes out. Wrap the new wire plus the bundle of 4 wires with a loop connector cut into a C then wrapped around or use a hog ring. Solder everything up. I used a second nut and a loop connector at the battery for this ground lead. Once you know for certain your grounds are awesome start checking connections at the relays, etc. ECU and ignition relays and ignition switches do go bad.

    A tell of a bad ignition switch is if you remove the memory lead from the radio and there is ANY power draw from the battery while the car is off. My car would eat a 1100 CCA battery down below the ability to start the car in 2 weeks before I put in a new ignition switch. Now it is fine for months.
    Last edited by erratic50; 04-23-2017 at 07:19 PM.

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