I am doing a "over the phone" analysis of a spark problem on my son's 84 I-6.

After driving for 2 hours he stopped for food and the van would not start...... no spark.
After throwing some parts at it (new coil, cap, rotor, wires & plugs), still no start.
The van will start after letting it sit for 3 or 4 hours or overnight, runs great for 5-10 minutes and dies as if the key was turned off.

He has good spark from the coil first thing in the morning, no spark after it dies.
It does have voltage to the + terminal of the coil when ever the the key is turned on.

I'm a little in the dark not being able to look at the distributor (he lives several hundred miles away and has all the service manuals).

He says it doesn't have points, some sort of electronic pickup that looks like six legs hanging down from the rotor.

It sounds like it might be a distributor pick up problem (is this the 'control modual')
if so ... can you check something first (volt/ohm wise) before he throws any more parts at it.

Thanks,
Jim

 

Sounds like the ignition module (metallic box bolted to the driver-side fenderwell). When they are on their way out, heat can shut them off pretty easily. When they cool off, the truck starts back up and runs without a problem, until they get hot again. Autozone has a test rig that can test these modules, although it's not foolproof. Replacement modules from parts stores tend not to last as long as the originals. You can still get them through the dealer, which are the best ones, but they're really expensive. I got one from Napa a couple years ago and so far it hasn't had any problems.

 

If the box on the fenderwell tests good, it will probably be the pickup coil inside the distributor. I'm predicting the pickup coil because it has happened twice to my old bronco with the same symptoms. By the way, you could pour cold water on box by the fenderwell after it quits running. If it starts up immediately, then it is that box. If it's not that box then the pickup coil is the only thing left that could cause that.

 

"six legs hanging down from the rotor" sounds like the tfi system, which in 84 has the module mounted to the side of the distributor. also, the tfi has no vacuum advance, and the duraspark II for that year does have the vacuum advance diaphram thing, which could help you determine what he has.

so, if he has the tfi, one thing that is hard to troubleshoot is the connection between the tfi module mounted on the outside of the distributor and the pip module inside the distributor. the pip module has a hall effect sensor which detects the magnetic field which is affected by the six legs hanging down.

the problem is this: if that connection is bad, like it was on my 84 f150, to change the pip side (the female side, which can get loose over the years if the tfi module is pulled and replaced), you have to pull the distributor and disassemble it.

the general consensus in the 80's forum is that the tfi system is inferior to the duraspark II, and lots of people make that changeover.

 

OK, I got the van and the service manuals in my garage now.

Same problem as before, has good spark and will start when cold, runs for 5 min and shuts off. Does not have spark and, of course, will not start.

It looks like it has the TFI-IV distributor with the control module built into the base.
The service manual has a 10 test trouble shooting guide for distributor & coil. The first problem I ran into was with the wiring to the ignition module connector, the book shows only 3 wires going into this 6 port connector, I have 6 wires going into this connector. I need to know what the 6 termals are for, there should be 1 to the ignition coil, 1 for the run circuit and one for the start circuit, what are the other three for?

My plan is to make sure I have voltage while operating the starter, if so I will go for a new control module and ignition pick up, I hate to throw parts at it but I can't scratch my head all day. Any better suggestions? Which one first?
Also, the inside of the distributor is a little rusty, could that have somethng to do with it?

Thanks, Jim

 

For some reason I can't edit my own posts, but I now have a correct wiring diagram for the above post. My 1984 emission and engine electronics shop manual has all the tests outlined but shows the wrong connector (3 wire). The 1984 engine shop manual shows the correct connector (6 wire) but not much detail ..... looks like I will have to fake it.

 

sorry i didn't reply yesterday. if you are looking at the module on the distributor, the wires are as follows, starting at the top:

1. pip: timing signal from distributor to computer. this comes from the pip module inside the distributor, and tells the tfi module and the computer where the crankshaft is. each of those six legs (vanes) interrupt the field of a permanent magnet, so that the hall effect sensor either sees a strong or a weak magnetic field, and generates a voltage signal for the tfi to send to the computer.

the connection between the pip and the tfi has 3 wires. that's probably what you were looking at in the manual. viewing the tfi module with the 6 pin connector on the right, and the pip pins on top, those 3 wires are ground, power (+12v), and pip. i'm not sure if the signal on this pip pin is identical to the one coming out of the tfi module. it might be amplified at that point, by the tfi module, but i'm not sure.

2. spout: timing signal from computer to distributor. this signal is based on pip, and is advanced/retarded by the computer. if you disconnect this wire, the electronics in the tfi and pip modules can run the motor by themselves, but the performance won't be great. i inadvertently left mine unconnected one day, and at one point could only do 50 mph trying to go up a barely sloping road. the good part is, if your computer dies, you should be able to drive home.

the spout wire should have a cylindrical connector about the size of an AA battery so you can test the pip and tfi: if the motor runs with spout disconnected, the tfi and pip have power and are functioning. if the motor does not run, they *might* be the problem.

3. start... uhhh, forgot what this one means.

4. power to module: should be battery voltage

5. tach: this is the wire that goes to the (-) side of the coil, like the points in old systems: electronics in the tfi module ground this wire to build up current in the coil, then open it to create spark.

6. ground

 

OK, so I am going to put in a new Control module and might as well do the pick-up at the same time.
I marked and pulled the distributor, looks like there is one pin to drive out just above the gear, then it should come apart for access to the pick-up .... right?

Also, the Control Module that is on it is a Standard Motor Parts Unit, I asume this is not the Original Part or it would be a Motocraft....right?

The local parts shop has Niehoff replacement parts. Is this considered an acceptable aftermarket Brand?

Thanks,
Jim

 

i don't know for sure on any of your questions, so i hope someone else will reply. but, here are my somewhat informed opinions. i think you are correct about the gear pin, and are probably correct that the original part was motocraft. as for niehoff, i don't know anything about them.

one thing about this design makes it touchy: you have to pull the exterior module (the tfi one) straight down to disengage the spade contacts, and push it straight up to replace it, or you can damage the female contacts in the pip module inside the distributor. mine stopped working because of a loose connection there, and i wonder it was due to assembly technique.

i don't recommend this, but i actually cut the pip wires, and extended them so that my tfi module is on a fairly huge homemade heat sink on my fender. there are pros and cons here. the pros are that the tfi module runs way cooler, and has solid testable connections to the pip, as each wire has an insulated spade connection a few inches from the tfi module. the main con is that these long wires need to be twisted and shielded properly to avoid picking up electrical noise, and i'm not an expert on that, but mine runs fine so far.

it bears repeating that almost everyone here would swap to a duraspark II system, which is some trouble, but once done it should be much more rugged. i'll probably do it the next time my truck pisses me off.

 

Standard Motor Products is a replacement brand; you're correct, it isn't the original Motorcraft. Niehoff is so-so. I stick with Napa for the major stuff.

 

Back at square one.
During the many tests that I have performed I have digressed from start & run for 5 min then die (no spark) to no spark/no start.
I have gone thru the Service manual's 10 step Preliminary Checkout which tests Ignition coil EEC-IV- TFI-IV, wiring harness, distributor, etc. All tests passed except for the ones that pointed toward maybe a dead ICM or PIP.
I have replaced TFI (ICM) module and PIP (pick up)...... and still have no spark.
The only unusual thing is with a spark tester installed on the top of the coil I will get 1 spark when I hit the start position, no spark during cranking and a weak spark when the key is released. Voltage is present at the + coil terminal during cranking. I have used a remote starter with the key in 'run' with the same results, trying to eliminate a possible ignition switch problem.

Tomorrow I will go thru the basic tests again with the new ICM & PIP installed and look for clues. If you have any suggestions ....I will try anything.
I have scaned it and only get a code 13 ..idle speed control.
Jim

 

was wondering if this issue was ever solved im having exact same issue with same engine in my f150

 

It was a bad TFI unit and/or PIP. Although I had replaced these parts and they passed all the checks they were still bad. I gave up on this rig for over a year ....then started back at square one. Bought (another) new TFI & PIP, put them in and there was spark, and five munutes later the van was running. If you read thru the post I was tearing my hair out and running in circles because I obviously asumed that the new parts I purchased were good .... turns out , not so. The TFI unit is notorious for failing, I would start there...good luck.

 

thank you will try there tomorrow

 

Good Luck, I see you had dug up another one of my posts from a few years ago in another thread. Like I said, this thing drove me crazy. Mine is a distributor mounted TFI. This thing was so bad that there was even a class action law suit against Ford over this item. Keep us posted as to the results.