OK, so I got the old truck running but In need to make some changes.

It is an 86 F150 4x4 with the 300 six.

Originally equipped with an "engine control module", this had been taken off by the previous owner ( and most of the wiring ).

It still has the original distributor with it's TFI module attached on the side.

My understanding .... and please correct me if I am wrong .... is that the engine module sends a signal to the TFI module to set the spark timing.

Sine the engine module has been removed, I assume there is no signal being sent to the unit and thus no advance on the spark.

The easiest solution I can see is to install an earlier distributor with a vacuum advance ( ebay $38) and a duraspark II model.

The distributor will take care of the advance the the module the spark.

I would even consider going back to points if I could find a good distributor but I am not sure how far back I would need to go and if I could find one cheap that would fit my 300 engine. I think Ford has used the duraspark ( I, II then III) since 1974.

The one question I have ( other than any advice you guys may have on doing this ) is what is the difference in all the duraspark modules?????

I gather there is a difference in the I and II ( I read the I need a ballast resistor as it runs on 9 volts and the II no resistor since it runs on 12 .... is this correct ) is minimal and both wire the same and should work.

The problem I see is that some say they are for the 2.3L four, some for the 302 eight, some for big blocks ...... WHY??????

If all they are doing is picking up the signal from the pick-up coil and switching on and off the coil to make a spark then what does it matter which one I use ????? Why are there different ones ???????

Any help would be greatly appreciated !!!!!!!!!!

Mike

 

You need to look in the stickies at the DS-II conversion info. Much, MUCH has been written on that and there's no need to redo that. But, once you've read it and have further questions then ask.

However, a couple of things. First, you said "I read the I need a ballast resistor as it runs on 9 volts and the II no resistor since it runs on 12 .... is this correct". That is wrong. If it has a round coil it needs a resistor. But the ones that came with the round coil had the resistor built into the wiring harness. I don't know if the others did.

Also, there's lots of info out there on the modules themselves, but the key is the color of the grommet through which the wires come out of the front of the module. Blue is what you want, and any other color isn't. It is that easy.

Now for the tricky part. If you have the truck running and you are sure there is no ECM then you must have a partial, if not complete, DS-II conversion. I say that because w/o the ECM the trucks that came with one will not run since the ECM tells the ignition when to fire. No ECM and no spark. So you need to ID what you have. Maybe post some pics of the dizzy, the box, and the wiring, and we can help.

 

You need a Duraspark module with a blue plastic grommet where the wires enter.
It doesn't matter what vehicle or engine it is sold for.

Gary is not entirely correct.
Earlier Duraspark I (with dwell control) did not need a ballast resistor, but it did still have a canister style coil.
Gray (push start)TFI modules will run without a computer. This is what happens when you remove the spout, it locks the timing.

If looking for an aftermarket coil to use with the Duraspark II system it will mention "for electronic ignitions".
This will require the ballast resistor, as all DSII ignitions do.

The cheaper way out is to use a GM ignition module on a heatsink with your DSII distributor.
These controlled dwell so you do not need a ballast resistor in the coil hot wire.
There are a number of threads on this setup.
http://www.carbdford.com/tech/HEI/hei.htm

Good luck Mike!

 

The TFI distributor gets its timing signal from the under dash computer via input from the MAP sensor on the right side apron. As long as that is still hooked up electrically and with a vacuum line, you'll get advance through the rpm range. At least thats how its been working on my 86... ~Bill

 

He says the ECM has been removed and the wiring hacked...
How can you control advance without a computer?

 

Well there goes that option... ~Bill

 

Hey!

Yes, the computer has been removed. As ArdWrknTrk said, from what I read, the TFI will still work without a computer but without a spout connected, the timing is "locked".

I gather this means I have not advance right now.

I will definitely look into the gm vs duraspark since you say either will work off the ford pick-coil.

I truly appreciate all the information !!!!

This is an old truck but it is all I have to drive right now and I want to keep it running as long as possible. Body is rough but did pass it's yearly inspection once again. The frame is great ... the previous owner(s) sprayed it with oil each year .... smells bad as it is all over the exhaust but it did the trick, minimum rust for 28 years in Vermont.

Thanks again ..... Mike

 

Jim - Thanks for the corrections. I forgot about the DS-I's. And I didn't realize the TFI's would work w/o a computer. Good to know - for however long I can hold into it.

 

Mike,
You're correct, without a Spark Out signal from the Engine Control Module you are running locked timing.
The $38 distributor you ordered can give you advance and a GM ignition module on a properly grounded heat sink will work with your existing low ohm, 12V TFI coil.

The other solution would have been to purchase an 'all in one' HEI style distributor.
But -as I found out recently- the inexpensive $48 ones are not available to fit the 300, like they are for all the Ford V-8's.
DUI wants stupid money for one of these things because they seem to be the only company marketing one for the venerable 300 I-6