So I bought a 79 several weeks ago and it ran fine just needed some new brackets for the clutch. Got the clutch straightened out and went to test drive but now it wont start.

Cranks and cranks, but never fires. I've verified that its getting fuel, and it has a fairly new cap/rotor.

Based on other threads I used a test light and the pos coil is always hot...and the neg coil does NOT flash. I bought a brand new ignition control module and the same thing with the neg coil wire. My test light does light up when I connect to pos batt and neg coil, but doesnt flash like it supposed to.

Any ideas? I had a mechanic friend tell me my distributor stator could be bad? I'm pretty mechanically savvy, just never worked on these trucks/engines.

Thanks!

 

Nobody??

I'm about to just go buy this and see if it fixes the issue...

Distributor Pickup Assembly by BWD - Part ME12Z - Advance Auto Parts

Or this...

Distributor by Cardone - Part 30-2893 - Advance Auto Parts

 

Take your ignition module out and take it to your local AutoZone and have them test it. The modules are natorious for working one minute and not working the next. When you reinstall it place a 1/4"-20 nut under each mount point to raise it up from the inner fender a bit to help with air flow for cooling.

 

Even the brand new on I just put in? o.0

 

You've got to give people more than a couple hours to respond. Just to double check, when you did the flash test, you're saying you did not see it flash when the test light was connected between the coil negative terminal and ground, correct? That's the way to do it. If it's not flashing, the ignition module is not firing the coil. If you've had the same problem with a couple different modules, then (1) the module is not receiving power or (2) the module is not receiving a fire signal, which could very will be the distributor pickup.

You can do a brief go/no-go test by checking the resistance between the ORANGE and PURPLE wires on the pickup and verifying that it's between 400 and 700 ohms. Unfortunately though, a resistance check won't identify all modes of failure. Therefore it's possible for the pickup to ohm out fine, but still not function (it's a Hall effect sensor). You should also verify that the module is receiving power under both START and RUN.

 

Thanks for the reply. I wasnt thinking about what day it is...my weekends run thurs-sat, and I was hoping to go pickup the parts before too late if anybody replied.

I did hookup a multi-meter between the purple and orange wires before reading this, and while cranking the numbers seem to pulse(digital) but I wasnt sure what setting to use on the multi-meter so I tried several till I got normal appearing numbers. Now I know what to look for so i'll try it again. Do I do the ohm test while cranking?

 

No, unplug the connector and test the two wires on the distributor side.

Josh

 

I'll try that next Josh, thanks.

But I checked under the hood again to get a better idea of the wiring, and now i'm even more confused.

The coil should have 2 wires coming off of it correct? Where should each of those go?

The silver box's 4 wire plug should have 3 wires going to the distributor and then 1 to the neg coil, right? Its also my understanding that a tach would hookup to the neg coil, so that might explain the multiple wires there, but I also have multiple wires on the pos side...

I'll get this thing figured out eventually!

 

Also, this thing started like a champ when I first got it...and as soon as I get the clutch straightened out it acted up, so I know the way its wired up was working, but think I mighta move a wire or something inadvertently when i was monkeying around in the engine bay.

 

The coil negative terminal should have a green wire that goes back to the module, which is what fires the coil by switching ground. It can also have a tach connection, as you described. The coil positive terminal should have power that goes back to the dash; it gets power through a ballast (long resistor wire) or straight 12 volts depending on the position of the key. The positive terminal can also have a connection for a filter capacitor which serves to attenuate high-frequency noise from the ignition that can get picked up on the radio. So it's possible to have between 2 and 4 wires total coming from the coil.

 

Update...truck runs! Sorta....

Apparently the coil was wired up backwards from the get-go based on fmc400's post. Rewired that, and traced all the others, everything looked fine.

It would sometimes puff a few times when I first start turning it over, let off, start again and i'd always get 2 puffs but no start. This lead a friend to tell me to push the distributor an inch in each direction and try starting. Tried counter-clockwise with no results...but when pushed clockwise it started right up and purred along real nice!

Jumped out and straightened out a few things i'd tried, jump back in and its a no go. Get back out move the distributor more clockwise and tighten down the tie-down and it fires right up again, purrs perfectly. Shut it off and put all my tools away so I can take it for a spin and now it wont start up again, it seems to puff real rough until it actually starts, then runs perfect.

So, it appears to be a timing issue, but new distributor? New timing chain? New motor? Sell it and buy a different truck? I'm about lost b/c I havent driven this thing since I bought it!

 

Well, you know your timing is not right, because you have moved it a couple of times. Put a light on it and set at the factory setting. See what that does for you, and go from there.

 

How can I set the timing if it wont start?

Also, cant say i'm 100% on the timing procedure :S

 

Sounds like a wire could be chaffed and going to ground as your moving things around. Would have to start tracing wires to see? Did the new module have the same color grommet as the original? My Ford mechanic insists on these modules coming from dealer only. He said the aftermarket ones aren't full function and can fail very quickly if not right out of the box. Many parts he tells me to get uptown and get cheaper but this isn't one of them.

 

Is there any way for you to tell if the distributor is actually staying put after you tack it down? It just seems odd that you can turn the distributor and get it to fire, but as soon as you come back to it, you have to turn it again (if I'm reading this correctly).