TFI issues again

[fgross2006]

I have had issues with this prior and there was an older thread I cant find.

I changed my TFI in February with a new motorcraft after it burnt out unexpectedly. Two days ago the new TFI fried on the first hot day here in NY.

I have a TFI relocation kit and when I pulled over I popped the hood and noticed the engine compartment was hot but the TFI mouthed behind the grill was cool. I'm not understanding why they fry every 3 or 4 months. I have swapped this part at least 4 times and always use motorcraft. I don't use cheap parts.

This time I bought a new Motorcraft PIP sensor and had my local machine shop put it in for me. I got a new harness for the TFI relocation from Fat Foxx in case mine has a defect. So I plan to change out the TFI, PIP with brand new Motorcraft parts, as well as put in a new custom extension harness for the relocation to the grill.

Is there anything else I'm missing here?

[Walking-Tall]

I don't think you're missing anything. A suggestion I've seen somewhere is to mount the TFI inside the car somewhere on a big heat sink to keep it cooler. Beyond that, an extra in the glove box is a good idea for these unreliable modules. Like that's a solution, lol Of interest to me (and possibly to others), because I love nothing better than eliminating all nonsense that complicates simple things (AKA sensors), was learning that a TFI module can be triggered with the on/off "digital" signal of a points distributor.

[grabbergreen84]

I've driven around 180,000 miles in TFI equipped cars, and only had one failure. I think that a bad secondary ignition system is hard on them, i.e. bad high resistance wires, plug gaps too wide, worn cap & rotor...

I wonder if you have a dirty 'signal' into or out of it, via one of the wires from the TFI connector. Maybe a bad connection in one of the wires to/from it causing high resistance and unnecessary heat in the TFI. An ohm meter might shed some more light.

[Walking-Tall]

I've driven around 180,000 miles in TFI equipped cars, and only had one failure. I think that a bad secondary ignition system is hard on them, i.e. bad high resistance wires, plug gaps too wide, worn cap & rotor...

I wonder if you have a dirty 'signal' into or out of it, via one of the wires from the TFI connector. Maybe a bad connection in one of the wires to/from it causing high resistance and unnecessary heat in the TFI. An ohm meter might shed some more light.

I don't know how many miles, but same here, and no failures, and those are good points.

[stangPlus2Birds]

Are you using thermal paste between the heat plate of the TFI and the heat-sink?
If so, which thermal paste are you using?

Imho, it seems to be worth it to try to use top quailty thermal paste.
For the external heat-sink, use ~500 grit, then ~1000 grit, then finally 1500 grit sandpaper to make sure that it's clean and has good heat transfer qualities.

You want a thin "paper thickness" layer of thermal paste between the part's heat-sink and the external heat-sink.

For thermal paste, don't screw around, use the good stuff:
Arctic Silver 5 AS5-3.5G Thermal Paste
http://www.amazon.com/Arctic-Silver-.../dp/B000OGX5AM


Also, be aware that fake clones are very prevalent in the automotive parts industry. Places like Autozone, etc have also bought and sold fake parts.
Imho, Amazon or a Ford dealer is where I'd put my trust.
For somethings, I now only trust them from a dealer. Wheel bearings seem to be one of the top fake items. On my FWD Olds, it was going through wheel bearings in less than a year. What a PITA!
I finally broke down and bought them directly from a GM dealer, and I've had these now for over 10 years.

I wish I saw the following article before I went on my PITA wheel-bearing adventure:
http://www.autoserviceworld.com/cars...ronto-airport/


Good Luck!

[JACook]

I'm with gg84, the whole unreliable TFI thing is blown way out of proportion, and I'm not convinced that
some of the things people do to 'fix' the problem don't just make matters worse. My own '85 CFI vert
still has it's original date-coded TFI module, still in it's original location.

I've also been suspicious about the extension harness, and whether the PIP signal lines are picking up
noise, as well as whether the location chosen for the module and heat sink actually see as much airflow
as it might seem. I've seen this problem with external oil and transmission coolers, where locations
that seem like they would have plenty of airflow, don't.

I believe we discussed this before in connection with this problem, but in any case, it bears repeating.
Fords with TFI do not use the same style starter relay as Fords with points or Duraspark ignition. The
relay used on the TFI cars has an integral suppression diode across the relay coil. (Early on, some
Fords did use the older style relay, with an external diode). The diode is there to suppress a reverse-
voltage spike that happens whenever the relay is de-energized. That spike can cause problems with
the TFI module, including forcing it into 'start' mode for the duration of the drive. In start mode, the
TFI module retards ignition timing, and it also sets a fixed, longer dwell time. If the TFI stays in the
start mode, that longer fixed dwell, can end up damaging the module.

The more I think about this, it seems the TFI failures, the intermittent IDM codes, and the poor fuel
mileage, may all be related to the TFI running in start mode. If so, the big question is whether this
is being caused by a bad starter relay snubber diode, or electrical noise on the start wire to the TFI.

[fgross2006]

I'm with gg84, the whole unreliable TFI thing is blown way out of proportion, and I'm not convinced that
some of the things people do to 'fix' the problem don't just make matters worse. My own '85 CFI vert
still has it's original date-coded TFI module, still in it's original location.

I've also been suspicious about the extension harness, and whether the PIP signal lines are picking up
noise, as well as whether the location chosen for the module and heat sink actually see as much airflow
as it might seem. I've seen this problem with external oil and transmission coolers, where locations
that seem like they would have plenty of airflow, don't.

I believe we discussed this before in connection with this problem, but in any case, it bears repeating.
Fords with TFI do not use the same style starter relay as Fords with points or Duraspark ignition. The
relay used on the TFI cars has an integral suppression diode across the relay coil. (Early on, some
Fords did use the older style relay, with an external diode). The diode is there to suppress a reverse-
voltage spike that happens whenever the relay is de-energized. That spike can cause problems with
the TFI module, including forcing it into 'start' mode for the duration of the drive. In start mode, the
TFI module retards ignition timing, and it also sets a fixed, longer dwell time. If the TFI stays in the
start mode, that longer fixed dwell, can end up damaging the module.

The more I think about this, it seems the TFI failures, the intermittent IDM codes, and the poor fuel
mileage, may all be related to the TFI running in start mode. If so, the big question is whether this
is being caused by a bad starter relay snubber diode, or electrical noise on the start wire to the TFI.

I do have a Standard starter relay. Do you know the Motorcraft part number for an 84 CFI? Id change it just to be thorough.

Fat Foxx send a small tube of Artic Silver with the kit and he gave me a new tube with the replacement harness he sent me. I had the new Motorcraft PIP installed in the distributor and I got another Motorcraft TFI. I plan to install the parts and new custom wire harness this week.

I know the custom harness to extend the PIP to TFI is wrapped in foil, but the TFI plug was extended with new wires as part of the install process. I didn't do it so Im wondering if the TFI wiring from the engine harness to the TFI plug is supposed to be wrapped in foil all the way to the connector? and if so would any type of foil be suitable to use? I know its wrapped in foil in the original harness but Im not sure if it was wrapped in foil around the extended part of the wiring.

Just to restate a few things;
the symptom occurs first with an intermittent cut off of ignition for a second or two. After a while it will buck and stall out. After a few minutes I can drive a block or 2 and stall again.

Replacement of TFI eliminates this issue but it has returned for the 3rd time apparently giving me relief for 3 to 5 months at each replacement. its not an instant failure so I don't know how a short could be the issue since I would imagine the issue would recur frequently. In days, not months.

At my last TFI failure last week, the engine bay was hot, the TFI was cool, Again, I don't see how a thermal overheat could be happening if the TFI is actually cool to the touch being right behind the grille.

[84StangSVT]

I'm not much help here besides finding the past threads where you have had this issue and others that have addressed some of your current questions.

http://vb.foureyedpride.com/showthre...probolem-again

http://vb.foureyedpride.com/showthre...-in-CM-returns

http://vb.foureyedpride.com/showthre...-while-driving

Good Luck!

[Haystack]

I've had 11 86-87 fuel injected tbirds and cougars and I've seen one aftermarket msd tfi module fail and I've probably got well over half a million miles on these cars. At 318k miles, my 86 still appeared to have the original which I swapped out while troubleshooting a fuel pump issue. I have never had to swap out or replace one on a car that I've owned.

[fgross2006]

So here's where I'm at with this TFI issue.

I finished splicing in the new extension harness FatFox sent me. Took my time with it. After putting the battery back in I tried to start the car and now have a no start no spark condition. I noticed now when I reconnect the negative battery cable there no click of the ECM that I always hear every time when reconnecting the negative cable.

I am sure there's a no ground condition to the ECM but I don't know where or why this happened. The physical ground line between the negative battery cable into the engine harness is intact no breaks.

I took the new Motorcraft TFI out and ran over to Autozone and it tested OK so its not a bad TFI. I'm thinking maybe the PIP sensor I just had installed in my distributor is bad or wrong for my car. The PIP is Motorcraft DU-30-C. I had the Standard PIP removed to try to keep the system all Motorcraft. I just noticed the box says contents made in Mexico. So much for better quality American made parts.

The car was startable when I pulled into my driveway last week. Now the ECM wont engage. Any suggestions what to try to remedy this? I'm thinking to pull the distro again and have the machine shop put the Standard back in. I don't know where else to start.

I'm attaching pics of my work running the new TFI extension harness today.

Attachment 101073Attachment 101074Attachment 101075Attachment 101076Attachment 101077

[fgross2006]

Also, I ordered a new TFI connector pigtail from Autozone. Mine was put in 2 years ago but this kit has been in and out so may times the connector looks beat up already. The Autozone TFI connectors (and everyone elses) have all black wires. Does anyone have or sell this connector with correct color coded wires?

few more pics from today.

Attachment 101080Attachment 101081Attachment 101082Attachment 101083

[JACook]

The no-spark condition doesn't have anything to do with your ECU, other than the ECU symptoms may
be an indication of the primary problem. If the ignition system is correct, you should have spark, even
if the ECU is disconnected.

Have you verified the work that was done on your distributor was done properly? For that matter, is it
even spinning when you crank the engine?

Have you ohmed out the new PIP harness, to make sure it's good? It's a low probability, but I don't
assume anything is good until proven, even (or especially) if it's new.

[fgross2006]

The no-spark condition doesn't have anything to do with your ECU, other than the ECU symptoms may
be an indication of the primary problem. If the ignition system is correct, you should have spark, even
if the ECU is disconnected.

Have you verified the work that was done on your distributor was done properly? For that matter, is it
even spinning when you crank the engine?

Have you ohmed out the new PIP harness, to make sure it's good? It's a low probability, but I don't
assume anything is good until proven, even (or especially) if it's new.

The distributor doesn't spin when cranking. There's no crank when turning the key.

The ECU doesn't click when I re-connect the battery cables as it always does. I know from past experience that if the ground to the ECU isn't good the car wont start. Right after I got my car 2 years ago I found the blade connector in the ECU ground to be green and corroded.

I just feel like the ECU isn't connected because of a bad PIP to TFI connection or bad PIP. Ill test the PIP harness tomorrow. What should I see when I check ohms?

The PIP was installed by my local machine shop. Same guy that put in the Standard PIP last winter. Im gonna recheck all connections tomorrow and if it still doesn't start Im gonna ask the machine shop to swap the PIP back to the Standard to see if I got a bad PIP.

I wish I had a spare distro to try for troubleshooting. I do have an old TFI I may try direct to the distro to see if it starts.

Today I replaced the TFI connector. I did replace that 2 years ago but its beat up and had barrel connectors. I soldered this one today with shrink tubing. I hate the all black wires. I wish I could find one with correct color wires.

I showed Ray at Fat Foxx pics of my wiring and he said I strung them correct

[Haystack]

If the engine doesn't crank because you added an extension wire, you really messed something up. Essentially all you did was re-do one connection that has nothing to do with starting the car or the computer.

[Walking-Tall]

Now not even cranking? I'd back way up now, checking battery voltage and cables. Not even any starter solenoid clicking?...

[fgross2006]

So today I re-did all the connectors on both ends of the TFI extension harness. I thought the male connectors that plug into the PIP were lose so I got bigger ones that I had to trim a bit to make a snug fit. I also replaced the female connectors that plug onto the TFI's 3 prongs. Also got female connectors that were smaller so they fit on nice and snug.

I replaced the TFI connector and soldered the connections as opposed to barrel connections I used last time I swapped the TFI pigtail. I put new wire loom on wires that needed it. I replaced the distributor collar because one of the spring clips that hold the cap on had no spring to it and kept falling off.

After all that the ECM still doesn't click when I connect the negative battery cable and still no spark or start. So to cut to the brass tacks I temporarily bypassed the TFI relocation kit and put the TFI right onto the distributor and still no spark/start. So its not the TFI relocation kit or its custom extention harness that's the cause.

I pulled the distributor and took it back to the machine shop and asked them to put the old PIP back in. I just have a feeling that's it. I didn't touch anything else in the engine compartment other then the distributor and the TFI so it has to be a bad PIP.

If putting the Standard PIP back in doesn't correct this than I will have to tow it to the mechanic. Beyond a bad PIP Im have no other ideas.

Some pics from today.

Attachment 101162Attachment 101163Attachment 101164Attachment 101165Attachment 101166

[grabbergreen84]

None of the ignition stuff could cause it to not crank. Except the switch...
Did you pull the red/blue wire at the solenoid, and forget to plug it back in? Battery fully charged?

Also there's the neutral safety switch circuit, if you unplugged anything underneath when messing with the exhaust.

[fgross2006]

None of the ignition stuff could cause it to not crank. Except the switch...
Did you pull the red/blue wire at the solenoid, and forget to plug it back in? Battery fully charged?

Also there's the neutral safety switch circuit, if you unplugged anything underneath when messing with the exhaust.

Honestly Grabber, I only pulled the battery, the distributor and the TFI. I did not touch anything else.

[Haystack]

What is the grounding voltage compared to battery voltage?

There should be less then .1v drop from the battery positive cable to the block. I've seen badly corroded grounds cause a car to not crank. Easy test would be to jump the negative battery post right to the block and see if anything changes.

With no crank, it has nothing to do with the igniting module if the engine doesn't turn over.

[fgross2006]

What is the grounding voltage compared to battery voltage?

There should be less then .1v drop from the battery positive cable to the block. I've seen badly corroded grounds cause a car to not crank. Easy test would be to jump the negative battery post right to the block and see if anything changes.

With no crank, it has nothing to do with the igniting module if the engine doesn't turn over.

This tutorial I found that shows step by step troubleshooting for EFI no start condition. Very informative and easy to follow.

http://sbftech.com/index.php/topic,588.0.html

Last step in this process points to TFI and or Stator (PIP) failure.

Since I have a brand new TFI (Motorcraft) and I ran it over to Autozone to test it and it tests good, the only logical thing left is a bad PIP since the distributor and the TFI are the only things I removed from the car. I had a functioning Standard PIP that I swapped for a Motorcraft last week. I think I got a bad one out of the box.

I dropped off the distributor yesterday to get the old (Standard) PIP put back in. If it fixes the no spark condition that's great. If it doesn't Ill have to tow the car as I have no more ideas.

[JACook]

This is confusing as hell. If the distributor wasn't spinning, and/or the engine wasn't cranking, how
is that a PIP sensor problem?

[dynodon64]

You need to verify the "no crank" to us to clear up things. Does the car crank over with the starter or are you just saying it won't start when cranking over?

I see there is a ground wire hooked to the distributor, where the TFI bolted on, but not one hooked the the heat sink. Where is the ground wire hooked? It needs a ground wire hooked to the heat sink. I wouldn't rely on the chassis ground when the heat sink is bolted to the body. The distributor gets grounded when bolted in place.

You can test the distributor for spark with it out. Just turn on the key and hold or ground the distributor to the engine block and spin the shaft. Use a spark plug tester right from the coil output to ground. It will fire away if everything is fine.

[fgross2006]

You need to verify the "no crank" to us to clear up things. Does the car crank over with the starter or are you just saying it won't start when cranking over?

I see there is a ground wire hooked to the distributor, where the TFI bolted on, but not one hooked the the heat sink. Where is the ground wire hooked? It needs a ground wire hooked to the heat sink. I wouldn't rely on the chassis ground when the heat sink is bolted to the body. The distributor gets grounded when bolted in place.

You can test the distributor for spark with it out. Just turn on the key and hold or ground the distributor to the engine block and spin the shaft. Use a spark plug tester right from the coil output to ground. It will fire away if everything is fine.

No crank means nothing happens when I turn the key, no crank, no click of the starter or battery. Its as if theres no battery in the car when I turn the key. no sound at all. but the lights and radio work so there is power.

I just had the old PIP put back in and its the same condition. I'm very confused as to how this happened because all I did was pull the distro to take to the machine shop to change the stator. And I swapped out the TFI with a tested good one. I replaced the custom extension harness too but I also tried the TFI direct to the distributor with the same result so its not the custom harness.

Last summer I had a corroded ground to the ECM that caused this exact same condition. So I feel like the ECM is somehow not in the electrical system anymore. I don't know how pulling the distro and swapping the TFI could have caused this, but it did. Im out of ideas so im towing the car to my mechanic.

The instructions and screenshots and verbal instructions I got from Fat Foxx is that the drain wire ground goes to the distributor the other end gets sealed into the harness, no need to ground both ends.

Heres a pic from the install instructions from fat Foxx, it shows how its supposed to look at both ends. I did exactly like this.

Attachment 101205

Heres mine
Attachment 101212Attachment 101213

[stangPlus2Birds]

You can take the EEC-IV and distributor out of your car, and throw them off a cliff, and they wouldn't have any effect on if a Fox Stang cranks.
Neither have *anything at all* to do with the starter engaging on a Fox Stang.

A Fox Stang has zero anti-theft and prevent-starting-with-engine-running protection.

See the awesome diagrams that TMoss did:
http://www.veryuseful.com/mustang/te...itchWiring.gif

http://www.veryuseful.com/mustang/te...ng-ECC-EFI.gif

More files:
http://www.veryuseful.com/mustang/tech/engine/


Yea, I need to add thumbnails to the web pages. One of these days...


So....
1) Turn on the headlights.

2) Turn the ignition to on. Does the radio and wipers work? The radio and wipers should work.

3) With the headlights on, turn the ignition to "start". Do the headlights go out? Use a mirror, cardboard, what ever, to see if the headlights stay on, or go out. They should stay on.

4) Turn the ignition back to on. Do the radio and wipers still work? The radio and wipers should still work.



Sounds to me like you may have a bad battery or ground connection. The stock ground connection on a Fox was done because is was CHEAP! :-) Considering how many Foxes are left and only some had ground issues, it wasn't a "horrible" idea - it was just not a good idea.

Also, the starter solenoid may be bad, or the ignition switch may be bad.


Oh yea, you'd need another EEC-IV and distributor for the car to run, if you threw the old ones off a cliff. :-)


Good Luck!

[fgross2006]

You can take the EEC-IV and distributor out of your car, and throw them off a cliff, and they wouldn't have any effect on if a Fox Stang cranks.
Neither have *anything at all* to do with the starter engaging on a Fox Stang.

A Fox Stang has zero anti-theft and prevent-starting-with-engine-running protection.

See the awesome diagrams that TMoss did:
http://www.veryuseful.com/mustang/te...itchWiring.gif

http://www.veryuseful.com/mustang/te...ng-ECC-EFI.gif

More files:
http://www.veryuseful.com/mustang/tech/engine/


Yea, I need to add thumbnails to the web pages. One of these days...


So....
1) Turn on the headlights.

2) Turn the ignition to on. Does the radio and wipers work? The radio and wipers should work.

3) With the headlights on, turn the ignition to "start". Do the headlights go out? Use a mirror, cardboard, what ever, to see if the headlights stay on, or go out. They should stay on.

4) Turn the ignition back to on. Do the radio and wipers still work? The radio and wipers should still work.



Sounds to me like you may have a bad battery or ground connection. The stock ground connection on a Fox was done because is was CHEAP! :-) Considering how many Foxes are left and only some had ground issues, it wasn't a "horrible" idea - it was just not a good idea.

Also, the starter solenoid may be bad, or the ignition switch may be bad.


Oh yea, you'd need another EEC-IV and distributor for the car to run, if you threw the old ones off a cliff. :-)


Good Luck!

I have to disagree. If the ECM isn't grounded the absolutely will not crank. I know because I had pulled apart the blade connector in the stock ECM ground to clean it last summer. The next day I had a no crank, no spark condition. I knew it was the ground because I had worked on less than 24 hours earlier. I found that after cleaning the corrosion out that the blade was very sloppy in the female connector. I got same gauge ground wire from the auto parts store, removed the blade connector and put straight line in and it started right up.

On my car the ECM is essential to starting and running the car. If I replaced the CFI with a Holly, Edlebrock and a vacuum advance distributor I could throw the ECM off cliff, but my setup is still stock.