Weird no fire issue

[ncguy89]

Just figured I would come on here and get some others opinions. A feller I go to church with has a 87 chevy c10 305. He said he started it up and drove it down the rd about a half a mile and back and let it idle for about 10 minutes shut it off and let it sit. He fired it up for 3 days and it ran fine. Well I went to his house to fix his brakes and we went to start it up and it wouldn't start but could smell fuel. So I took a spark tester and checked for fire to the plugs and had none. I had to leave so we let it sit over night he went out the next mornin and it fired right up. Anybody know what could be causing this? I checked connections going to distributor and everything is good. Maybe a pickup coil? I haven't had a chance to check it out but any ideas would make the search go a bit quicker as this is his only vehicle now. Thanks in advance!!

[Captkaos]

Nothing is changing between the time it cranks and the time it doesn't.  First thought is the ignition swithch.

[ncguy89]

Nothing is changing! One time it will start up and will be fine for 3 days or 3 hours then it randomly loses spark. He did say it cut off on him today when he drove it down the road and he let it sit for about 10 minutes and it fired right up. Then after that its been fine. I haven't had a chance to take a look at it yet.

[Fairlane514]

HEI ignition module may be bad.

[454Man]

X2

[chengny]

If you go through the whole ignition system and still get no spark (or a weak yellow one) while cranking the engine - check or change the starter/solenoid.

A short to ground in the starter will pull the vehicle's entire electrical system down while cranking.

Everything will check out fine in the static condition. But if there is a heavy draw in the starting circuit, the primary side of the coil can drop below the required 10.5 volts.

A good indication of this fault is; the engine seems to want to fire up when the ignition switch is released back to the run position (as opposed to the key being in the start position).

It's a longshot, but still something to consider if you have checked everything else.

[ncguy89]

Well it was 2 parts causing it. I finally got to his house and within a half hour found out the ignition coil and the pickup coil was bad. He told me when I got there that the truck had sit for 6 years before he got it so I started testing. Thanks for the help guys.