Fox Temps on my tfi module relocated

Mindseye007 said:

Took my 1991 5.0 coupe for a nice ride to today it was so sunny and beautiful. when I got back I decided to check the TFI temp with a temp gun now that is is relocated.
The first pic on the left is where the dummy TFI is mounted where the stock TFI used to go on the distributor and it read 157.6 F .
2nd pic the temp of where the Stock TFI is mounted in its new location, it read 95.4 F . you can see more in the 3rd pic how I mounted it. so sweet, I am using the McCully Racing Mk3 TFI Relocation AND Extension kit https://www.mccullyracingmotors.com/

Click to expand...

Pretty snazzy....I had a buddy that bought one of those setups to stop the TFI modules from burning out and didnt realize that if the TFI module gets hot theres a reason other than heat behind it and just pushed the problem up into the ECU as the reasons behind the TFI module failing is a myth no matter the lawsuits as its real reason for failure was Flyback and the fix was adding a starter solenoid that contained a diode...........





If your diode doesnt have a silver foil sticker that says "Diode Supressed" it doesnt contain a diode.......



I just use bubblewrap with a mylar layer to keep the heat from rising up and heatsoaking the TFI module even though with my full ball bearing distributor and 180 degree thermostat my TFI module has no issues with getting hot but I still figured Id give it some extra insurance seeings I removed the clutchfan and added an electric one....





Another thing youll be surprised about is how the TFI module cooling plate is backed up to plastic so the actual cooling is quite moot due to the cooling gel that encapsulates the IC's...............

The TFI mounting plate popped off when the module hit the ground but you can see where the plate mainly grounds the IC's inside as most of the heat transferred into the module comes from the heat of the engine up into the distributor..........




Most vehicles that have TFI module problems get them from either advancing the timing past the 10* btdc or from the Halls effect trigger misfiring from the lower bushing in the distributor body going bad or the 22kohm resistor shorting to "OPEN" and feeding the IDM circuit on Pin #4 with raw unfilered power also the starter solenoid lacking a diode.....

View attachment 722636

Food for thought in case the problems start up again but something tells me the car with the issues isnt well driven like mine which is driven every day...............



Good Luck

Its been awhile since I contributed to this thread and want to show my twist on the TFI relocation kit that the McCully kit doesnt touch upon and feel that it should of..

When I studied the way they designed the setup I see the most weakest areas are :

1. A lack of shielding which is very very important.

2. Has a pretty long drawn out way to get the job done.

When I made my TFI module relocation kit I actually went a slightly simpler route although similar....

1. I took apart an old TFI module and cut off the 6 pin connector and drilled a couple holes to feed the 3 wires through to solder the wires to.



2. The wires were pre-shielded but I wrapped them with copper wire to give it extra shielding and make ground-able with a grounding terminal



3. After that I gave it super -shielding by wrapping it all in copper tape.



4. Then I covered it in EMI resistant shrink tubing and filled the TFI module body with 2 Part Epoxy..This thing is protected against a mega EMP blast......






5. I went low budget and used all of the stuff i had readily on hand and so the faulty distributor I had was put to good use by becoming my heat sink aswell as a good way to mount the 3 pins on the TFI module by using a terminal block from a non functioning Halls Effect Sensor..




6. This thing is a lil more simplified and ultra protected against noise and false triggering........



7. In keeping with the ultra low budget and use what i had on hand part of the project I topped off the distributor body top with some foil tape and a heat sink from an old PC...........


I have mine installed on my F250 with A9L ECU swap on a 351w engine. I also have MSD 6 box and MSD TFI coil and a Moates QH.



Luckily for me I didnt have to cut and modify the TFI part of the harness.



One of the things I had to do afterwards was remove the distributor pull the shaft out and shim the distributor to have .005" of play as the total extra movement before shimming was .038"..The range is .005" to .015" and while I was doing that I also installed a brand new halls effect sensor.

The determining factor of it all was the quality of the graphs in my logfiles which showed how much noise that hinders performance was eliminated.

The orange tracer is the spark...Notice how much advance and retard was recorded due to the amount ot extra lateral movement in the shaft which transfers to erratic spark at idle.............



You can see how much taking the time to properly shim the distributor has on how smoothly it functions and stays almost in a perfect tracking...

Tried a bunch of "new" TFI's (many different brands, some of them touting "upgraded")
a couple years back, including new motorcraft and one of the remote kits.

None of them seem to run as well as the original TFI's I have from back in the day.
Even an original 1984, 3.8 V6 stock TFI runs better than the new one's I bought

Will have to dig into the shimming. Forget now if I used reman'd distr, on either fox.