Bronco Forum - Full Size Ford Bronco Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
198 Posts
Discussion Starter #1
First off, I HAVE searched. Alright, a week or so ago I was driving my truck (89 F150 5.0 aod) and driving down the highway the truck hiccuped and then about a mile later died out. I have no spark, I'm getting fuel, but it isn't being burnt. I had it towed home and have been slowly working on it. I thought maybe the coil but the primary and secondary resistances on it checked out. I tried it in my g/f's truck (96 bronco) and it started her truck up fine so I have to assume that isn't the problem. The resistances and voltages in the coil plug checked out and the resistance from the ignition module was in the range it should be, so I'm assuming it isn't a broken wire from the module. Any wires or connections in plugs that didn't look good I fixed or cleaned. My father asked some guys he works with and they said maybe the pick-up coil. That made sense to me so I picked up a new distributor and there is still no spark. The distributor also came with a new tfi module so that shouldn't be it.

Now my question is, even if the dizzy is 180* degrees out then I should still be getting spark, just not at the right points to start it, right? What else could be causing this? Bad Computer? Any help is much appreciated. Thanks
 

·
Registered
Joined
·
1,485 Posts
Is there 12V on the positive side of the coil? Do you have a tachometer? If so does the tach register any RPM when cranking? If no tach use a DVM that also measures frequency, attach it to the negative side of the coil. Set the meter for frequency, see if it displays a frequency when cranking the engine. I just did this last night on my gas powered skidsteer. Works like a charm to verify if the coil is being told to fire. In your case it sounds like no power or a broken wire(s). Another simple test, turn the key to ON then momentarily ground the negative side of the coil, you should get a spark out of the coil. If that works then it is something related to the PIP/ICM circuit.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #3
I have 12v on the positive side of the coil. I don't have a tach and my multimeter is with my father right now, but I did use a test light. I grounded the light and stuck the probe into the coil tach. With the key in the run position and when it is cranking the light stays on and doesn't flash like I imagine it should as the circuit opens and closes. I also took a wire and and grounded the negative side of the coil with the key on and a spark plug in the coil wire and there was no spark at the plug, but there was where i connected the wire to the coil. Both the ignition control module and the pick-up coil are both new, but I suppose they could be faulty out of the box. The fuel pump comes on so it I'm guessing that means the computer is good. Anybody have any suggestions?

Thanks, Joe
 

·
Premium Member
Joined
·
23,563 Posts
if memory serves me right the injectors are fired by the computer when the TFI senses the engine is rotating.

I would verify with the cap off that your rotor is spinning.
 

·
Registered
Joined
·
633 Posts
I agree. If you swapped in a new distributor and you feel the coil is good, you probably should remove the cap and make sure the rotor is spinning.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #6
The rotor definitely turns as I crank the motor. That was one of the first things I checked.
 

·
Registered
Joined
·
633 Posts
Well if it was 180 degrees out, it should still fire but sound like crap. At least it should pop or backfire. But I suspect you have another problem if you replaced it and are chasing the same problem.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #8
I guess I'm going to recheck all of the wires and make sure there are no shorts. I'm also going to test the icm. Does anybody know if there is a way to test the pick-up coil?
 

·
Registered
Joined
·
633 Posts
Well if you changed the distributor, that means you already had 2 PIP's in it. Doubtful they are both bad. Maybe you should doublecheck the firing order. If you mis-wired it just right, I guess you could cause a "seemingly" no-spark condition. The order should be 1-5-4-2-6-3-7-8. I believe the Haynes manual should have the procedure for testing the ICM.
 
1 - 9 of 9 Posts
Top