Hey ladies and gentlemen, I picked up a non running 1974 FJ40 with a 1979 2f in it. As far as I can tell the distributor is the stock 1979 dual vacuum advance dizzy that should be on the motor. For some reason, I can't get a very good spark out of it.
When I first got it, it had a mini truck coil and igniter on it. It seemed to be wired correctly but I could not get any spark from the coil wire. I swapped in a known good igniter for a 1979 FJ40 and now I get no spark while cranking but as soon as you let off the key there is a single spark. I swapped in a known good distributor signal generator (pick up coil) and got the same result.
I have tested the coil by hooking 12v to the positive and then temporarily grounding the negative and this will give me a weak spark so I am pretty sure the coil is not the culprit. Also since I am getting the single spark I think that would mean the coil is definitely good.
I have five wires coming off of the igniter:
black = negative coil post
green = grounded to the igniter body (I also have a ground jumper running from here to the negative post of the battery to make sure I get a good ground)
red = to red wire coming off of distributor signal generator (pick up coil)
white = to white wire coming off of distributor signal generator (pick up coil)
The following power wires coming off of the igniter originally went to a two prong connector together. I didn't have the factory connector for it to plug into so I clipped it and ran two 12v wires to these two wires
tan (goes into the igniter) = 12v when the key is in the run position (pulled from the BY wire coming off the ignition switch)
yellow (goes to the positive side of the coil) = 12v when the key is in the start position (pulled from the starter terminal)
I also tried switching the tan and yellow wires (ie: tan gets 12v from the starter and yellow gets 12v from the ignition but it didn't make a difference)
I know that originally the igniter was supposed to get 12v in the start position (from the starter terminal) and then when the key goes to run, the coil gets voltage through a resistor from the BY wire off the ignition switch. However, during searching the board I read that in many conversions these are both hooked up to full 12v with no ill effects on engine running or component life. Besides, I am still using the mini truck coil which, if I understand correctly, can handle a full 12v all the time.
I tested the voltage at the positive coil post and I get about 12v while the key is in the run position then it drops to about 9v while cranking.
I also hooked a jumper wire directly from the battery positive post to the positive coil post and ignitor's tan power wire but that gave me no spark at all. The ignitor did get hot to the touch (it may have already been warm though so I don't know if it was a result off the jumper wire) so hopefully I didn't mess it up.
An interesting note with this is that as I was hooking up the jumper wire the coil wire was hooked up to the coil on one end with the other end laying on the fender. When there was intermittent contact with the positive battery terminal I got a spark from the coil wire to the fender.
After I tried the jumper directly from the battery, I hooked the power wires back up as I described earlier and got the same result as earlier; no spark while cranking and then a single spark when you let off on the key.
I really thought the known good parts would cure my problems and I am about out of ideas. Any help would be appreciated.
Richard
When I first got it, it had a mini truck coil and igniter on it. It seemed to be wired correctly but I could not get any spark from the coil wire. I swapped in a known good igniter for a 1979 FJ40 and now I get no spark while cranking but as soon as you let off the key there is a single spark. I swapped in a known good distributor signal generator (pick up coil) and got the same result.
I have tested the coil by hooking 12v to the positive and then temporarily grounding the negative and this will give me a weak spark so I am pretty sure the coil is not the culprit. Also since I am getting the single spark I think that would mean the coil is definitely good.
I have five wires coming off of the igniter:
black = negative coil post
green = grounded to the igniter body (I also have a ground jumper running from here to the negative post of the battery to make sure I get a good ground)
red = to red wire coming off of distributor signal generator (pick up coil)
white = to white wire coming off of distributor signal generator (pick up coil)
The following power wires coming off of the igniter originally went to a two prong connector together. I didn't have the factory connector for it to plug into so I clipped it and ran two 12v wires to these two wires
tan (goes into the igniter) = 12v when the key is in the run position (pulled from the BY wire coming off the ignition switch)
yellow (goes to the positive side of the coil) = 12v when the key is in the start position (pulled from the starter terminal)
I also tried switching the tan and yellow wires (ie: tan gets 12v from the starter and yellow gets 12v from the ignition but it didn't make a difference)
I know that originally the igniter was supposed to get 12v in the start position (from the starter terminal) and then when the key goes to run, the coil gets voltage through a resistor from the BY wire off the ignition switch. However, during searching the board I read that in many conversions these are both hooked up to full 12v with no ill effects on engine running or component life. Besides, I am still using the mini truck coil which, if I understand correctly, can handle a full 12v all the time.
I tested the voltage at the positive coil post and I get about 12v while the key is in the run position then it drops to about 9v while cranking.
I also hooked a jumper wire directly from the battery positive post to the positive coil post and ignitor's tan power wire but that gave me no spark at all. The ignitor did get hot to the touch (it may have already been warm though so I don't know if it was a result off the jumper wire) so hopefully I didn't mess it up.
An interesting note with this is that as I was hooking up the jumper wire the coil wire was hooked up to the coil on one end with the other end laying on the fender. When there was intermittent contact with the positive battery terminal I got a spark from the coil wire to the fender.
After I tried the jumper directly from the battery, I hooked the power wires back up as I described earlier and got the same result as earlier; no spark while cranking and then a single spark when you let off on the key.
I really thought the known good parts would cure my problems and I am about out of ideas. Any help would be appreciated.
Richard