Won't fire!!

[sacaledus]

So the truck sat over the four day weekend and now it won't start. Turns over but it's like I'm getting no spark. I tried priming the engine by pouring a little gas in the carb and still nothing. Looking on some guidance on where to go next. Thanks!!

[Rons86]

Check for fire at the plugs by pulling one and putting it bakc on the boot and holding it by a ground source (frame), hold it by the boot so you won't get shocked while someone else turns the truck over. If you are not getting spark there check fire at the coil by removing the cap and checking it at the button on top inside of cap. If you ar eont getting fire there check the wire going to the cap for 12 v.

[sacaledus]

Could one plug fire but another not? I'm sure it can what I'm gettin at is should I check each plug like that?

[blazer2007]

is it hei ign.I had the module go right in traffic.

[blazer2007]

I would,t check each one,if one was bad it would,t rev up nice .would miss but still start

[jchav62]

My guess wiould be the module... those go out without warning...

[sacaledus]

As far as HEI how do I tell? Also, on a side note, I have been asked if my truck is w/wo hydroboost. How can I tell that too?

[blazer2007]

I don,t how to test a module,I usually try another one,easy to change,I have a couple dist sitting around.some parts stores have testers you can use

[Keith Seymore]

If it's HEI, then it will have a large distributor cap with the rectangular module in the top (center) of the cap. If you are not getting spark then it won't do any good to pour fuel down the carb...

As has been said, if it's HEI it's probably the module. They can fail instantly with no warning. Alot of guys keep an extra in the glove box (for just such an emergency).

Hydraboost brakes are driven off the power steering pump. There will be a couple hoses that run up to the booster behind the brake master cylinder. It will be a small, black (cast iron) booster, rather than the large diameter relatively flat (cadmium plated) vacuum booster that you might be more familiar with.

K

[sacaledus]

Well I pulled a plug held it by the frame by the boot, had a friend try to start it, and bam started right up. Replaced the plug and gave it a go and it was back to running like a champ. I'm wondering if I flooded it and that's why it wouldn't start. Well, thanks for all the help!!

[Damien]

If you did not have spark, It would not have mattered if the engine was flooded. You probably have a bad module.

[Tynee]

Originally Posted by Damien

If you did not have spark, It would not have mattered if the engine was flooded. You probably have a bad module.

It's not unheard of, from my understanding, for a module to go out, then start again, then the next time you need it, no go again.

Assuming this is an HEI, the next time it won't start, I'd do the spark plug thing again. If you don't have fire at the plug (which I expect you won't), I'd check for 12 volts at the wire that plugs into the driver's (probably) side of the distributor cap, terminal labeled BATT. You will have 12Volts at that wire any time the key is on. If you don't have 12V there, you have issues getting power to the distributor: fuse, broken wire, bad ground, bad ignition switch are all possibilities. You'll have to keep chasing it back through the circuit until you find the bad component.

If you DO have 12V at the BATT terminal, then your problem is inside the distributor. The module is the most common, it is a flat black electronic looking deal about half the size of a deck of cards. Two screw secure it to the distributor base once you've removed the cap and the rotor. It can be tested by most of the chain autoparts stores, I think. I know O'Reilly did it here. This is NOT the most accurate test, from what I've heard. If it tests bad, then that sounds like good reason to purchase a replacement for it.

If it tests good, then I'd check two other components before replacing the module. You have a coil, and you have a coil pickup. The coil takes the 12V from you battery or alternator, and steps it up to the 50,000V (I think) at the spark plug. The coil pickup, as I understand it, senses the rotation of the shaft of the distibutor, and tells the coil when to discharge a spark through the rotor into each contact on the cap. I may be misunderstanding one or both of these parts, I'm sure someone will straighten me out.

Unfortunately, we have reached the end of my knowledge of trouble-shooting an HEI distributor. I don't know any way to know for sure if the coil or the pickup are bad other than replacing one at a time, which isn't the cheapest option.

Good luck, and I hope it was just flooded, and never comes to this troubleshooting scenario for you, as it did for me.