no spark?

[chuglife]

small problem here... was on my way to work this morning, truck was running fairly well for such a cold morning, (i thought?) got on the highway and brought it up to about 45 mph, it backfired and started running on what seemed like 5 cylinders... i pulled off to the side.

when it got down to idle again it started running fine. i sat for about 5 mins, testing the rpm range and seeing how it was gonna run, but as soon as i went to leave it died again. (as soon as i put a load on it.)

at that point i was late for work and called in for a ride. came back on lunch break, checked things out, tried starting it up again and it won't. i'm getting fuel, its turning over fine, doesn't seem like i'm getting any spark. its not catching at all.

what do you guys suggest checking first? i already trailered it home and i'm hoping to get in there and at least diagnose for tomorrow so i can have it for thursday.

i've searched the forum but didn't really find anything that matched my symptoms, it was running fine, backfired and lost a cylinder, gained the cylinder back at idle, then died under load. truck is a 73, with stock F. i believe it has a header. please help

 

[JohnL]

First, you should make sure you swear at it for a while. Then go out to your truck, take a pic of the fuel line plumbing around the cannister on the pass side and post them on my other thread here. https://forum.ih8mud.com/showthread.php?t=25592

Then I will tell you the answer.


just kidding. First, what did you do to check if you were getting spark? That is one clue to chase down first, if you can verify you definately don't have spark.

john

 

[chuglife]

well, i haven't actually checked if i have spark or not yet. the only way i know of is to hold the plug wire close to the block, but i can't do that and still reach the ignition...

i went out a few minutes ago and checked the fuel again (flows, carb float good), tried starting it, no dice. you don't want to see my fuel line setup, either, its an electric pump mounted on the inside of the fender caused me nothing but problems.

 

[CruisinGA]

run a 12v jumper to the starter solenoid from the battery.
rigged remote start is what it is.
if you want to get fancy add two alligator clips and a pushbutton and you have a real remote starter.
now test for spark.

 

[e rock]

I had similar symptoms once. I was pretty sure I had a vapor lock problem since I was coming down from the mountains after about 2 straight hours of freeway speed.

It turned out to be the coil. That's how I learned that I needed a ballast resistor.

 

[burnt03]

I had something somewhat similar happen to me, the starter would turn over but the engine didn't seem to want to catch.

Try to jumper it w/ an alligator clip from the + side of the coil to the + battery terminal. If that works, you know that something is wrong in the circuit between the ignition switch and the coil.

If it doesn't.... well, I'm sure someone else will jump in with some other suggestions

 

[chuglife]

thanks for all the suggestions guys, i got a buddy over and we figured it out. after testing the coil out on the block and battery, we tried a coil off his VW and thats when we realized the pickup from the diz wasn't hooked up to the coil, vibrated loose i guess course by that time the battery was almost dead from cranking runs now. thanks again guys!