ignition problem - next step?

[turpentyne]

No luck yet getting this truck started.

It's a 1973 C20 pickup with 454 engine, after-market HEI distributor.

Today I checked the compression, everything seems within 135-150 range except for cylinder 8, which came in at 120 psi.

The spark plugs looked pretty dirty, covered in a bit of oil. I replaced those, and the spark plugs and I replaced the ignition module in the distributor. Still no luck.

Turns over, just doesn't start.

 

[350runner]

have you verified that you have 12 volts going to the distributor?

Sent from the dust in front of you!

 

[PrairieDrifter]

Have you checked spark? Other than just putting new plugs in?

 

[firebane]

You should try and keep all your threads together...

But with that said you need 3 things... Air, Fuel and Spark.

Do you have fuel? Do you have spark? As stated does your distributor have 12v? Take out the plug and grab the voltmeter and check the voltage. Like I said if it was converted from points to HEI you may not be wired properly.

 

[turpentyne]

I feel I should reiterate... I don't have somebody here to turn the engine while I do anything. Everything is a one-man job.

I did go get a multimeter so I can test some stuff. I just haven't really messed with one before.

I pulled the bat wire from the HEI and touched it against the firewall and got spark there. Last night, somebody did stop by for a second, and I got them to crank the engine, while I had a screwdriver in the end of the plug wire, and I tried to touch that against something to check for spark. No sparks, but with the screwdriver handle in the way, I'm not sure I quite got it touched.

I can check to see the wiring is wrong to the distributor, but I honestly don't know what I'm looking for.

I fear I may have to just replace the entire distributor.

I don't have a way to check the fuel, with nobody here for the rest of the day. I suspect the fuel is fine. but if somebody has a way to check this alone? My thought this morning was to stick a long paper down to catch the carb jet spray, then pull it out after pumping the gas to see if there was some there.

 

[PrairieDrifter]

Take the fuel line off of the carb and turn it over and see if gas shoots out of the line, you can run a hose over the fender so you don't make a mess on your motor and you can see it easier.

You can just take the plug wire off of the plug and set the wire where it will arc to a solid piece of metal like the block or frame,and crank and see if you see a spark.

Meters are simple, if you are testing for power, find a good ground for the black lead and the red lead to the place you're testing for power. Try not to touch wires with battery voltage to them against metal, arcing them like that could fry components, it's way more important in newer cars but still something you shouldn't really do.

 

[firebane]

I feel I should reiterate... I don't have somebody here to turn the engine while I do anything. Everything is a one-man job.

I did go get a multimeter so I can test some stuff. I just haven't really messed with one before.

I pulled the bat wire from the HEI and touched it against the firewall and got spark there. Last night, somebody did stop by for a second, and I got them to crank the engine, while I had a screwdriver in the end of the plug wire, and I tried to touch that against something to check for spark. No sparks, but with the screwdriver handle in the way, I'm not sure I quite got it touched.

This alone tells me you really either need to do more reading or have some experienced be helping you. Touching a live wire to a metal surface is a quick way of either causing an explosion or blowing fuses.

It also proves nothing regarding power.

 

[chengny]

The first test to do when diagnosing a non-start condition (with starter cranking capability) is to provide a temporary fuel source.

Get a can of starting fluid from the gas station. With the air cleaner removed, spray a 5 second blast of the starting fluid down the carb throat (open the throttle manually while spraying it).

Quickly - before the ether (starting fluid) can evaporate - jump in the truck and crank the engine. If the motor fires (it won't run long) you have a fuel supply problem.

Knowing that, you can stop troubleshooting the ignition system and concentrate on getting fuel into the engine.

On the other hand, if the engine does not fire on starting fluid, that would indicate an ignition (no spark) issue.

BTW - these results:

Today I checked the compression, everything seems within 135-150 range except for cylinder 8, which came in at 120 psi.

are good.

 

[turpentyne]

funny enough, I just came in to check updates on here after doing something to that effect. I ran the fuel line into a glass jar, and only got a little bit of gas - no strong squirt, like previous posters suggested would come out. I poured a little gas into the carburetor and it fired right up, but died within 2 seconds.

So, is this a gas problem them? Fuel pump, or maybe clogged filter?

 

[chengny]

Best to always provide a bit of history when asking for help.

For example:

Did this problem happen all at once or slowly over time?

Did you just buy the truck (in a non- running condition) and so you have never even heard it run?

Stuff like that.


Don't be offended but - there is plenty of gas in the tank, right?


Just so you'll know when the fuel pump is working correctly, here is the GM test procedure (Cliff Notes version)

With the gas line disconnected and led to a container, crank the engine for 15 seconds. The container should have about 8 ounces of gas in it.

In reality, you don't have to crank for 15 seconds. Just crank for 5 seconds and pro-rate the amount.

 

[PrairieDrifter]

The pump can still be working but it doesn't mean that its pumping enough fuel (volume) for the motor to run. It could be a weak pump, a restriction in the system, or an air leak in the system that is sucking in air.

I would check your fuel lines for kinks or cracked hose even if the hose looks alright it may have deteriorated to the point where it collapsed inside, if it were me I would just replace the pump and all rubber hoses along with an inline fuel filter, and you should have a small filter in the carb where the fuel line goes in.

I would just do all of this regardless if its your problem or not, its pretty cheap for all of the pieces and you'll know you have good flow and clean fuel going to your motor with no leaks.

But since you got it to fire up off of some gas in the carb, its probably safe to say its fuel related.

 

[turpentyne]

I generally do give a full breakdown of what happened. believe my mistake is that I intentionally focused on the electrical, because I was sure that was where the problem is. I didn't mention how the problem arose, because I thought i knew for sure it was an electrical issue.

It's pretty straight forward. I came out to start the truck one morning, it fired right up, then died and hasn't started since. No previous problems. I didn't have the loss of power and rough running that warns of a failing fuel pump. So It didn't seem like that would be the problem.

I bought the truck about 3 months ago, as is and running. I've been driving it daily since. The only thing I've replaced before yesterday was the coil. That's pretty much it.

Right now I'm replacing the fuel filters. there's two - an inline filter and the one in the carburetor. The gas tank is half full.

After that, I'll tackle the fuel pump. Man, I really thought this was electrical!

 

[PrairieDrifter]

Sometimes there is no warning of a failing fuel pump, you drive it one day and the next day it wont start!

 

[firebane]

I generally do give a full breakdown of what happened. believe my mistake is that I intentionally focused on the electrical, because I was sure that was where the problem is. I didn't mention how the problem arose, because I thought i knew for sure it was an electrical issue.

It's pretty straight forward. I came out to start the truck one morning, it fired right up, then died and hasn't started since. No previous problems. I didn't have the loss of power and rough running that warns of a failing fuel pump. So It didn't seem like that would be the problem.

I bought the truck about 3 months ago, as is and running. I've been driving it daily since. The only thing I've replaced before yesterday was the coil. That's pretty much it.

Right now I'm replacing the fuel filters. there's two - an inline filter and the one in the carburetor. The gas tank is half full.

After that, I'll tackle the fuel pump. Man, I really thought this was electrical!

No point in 2 filters. I have one after the fuel pump and none in the carb.

 

[turpentyne]

Yeah, I was on the phone with my dad and that's what he said he does (drives same truck, but 350 & 2-barrel. He took the filter out of his carb and put an inline filter underneath.

I went ahead and put the in-carb filter in, since I'd bought it. Then I replaced the one underneath, out end toward carb... and noticed there's even a THIRD inline filter for a later add-on gas tank (That I haven't been using)

I hope there's not something goofy with the switch over valves. I hadn't messed with them, and I've only used the factory tank. But I wonder if I kicked them and caused a problem. (Yes, you read right.. plural. Instead of one switch valve there's a separate switch for each tank )

My day is ending for now, so I guess next weekend I'll have to tackle the fuel pump. I'm running out of things to check! (All needed stuff, anyway - considering I just bought it ) But if there's any other stuff to check, let me know. It now seems narrowed down to fuel pump though, I'm assuming?

UPDATE: I fiddled with the two gas tank levers, and loosened the fitting to the new fuel filter underneath to see if I was getting fuel there. And I did. I tightened things down, started up the truck, and it ran for about 20 seconds before running out of fuel. I think I'll replace that third filter, put some gas in the second tank, and try it again before I go replacing the fuel filter - just to see what happens. Thoughts?