Failure to start

[LG73]

Okay so long story short, did a 4bbl conversion on my 73 Slant-6 Valiant. Ever since I did it though I hasn't wanted to turn over for more than a few seconds at the most and just recently after using some starting fluid it almost turned over but instead decided to make some strange clunking noises. I cranked it again and it backfired through the carb gasket and a little out the top. Cranking sounded normal after that. I'm not sure what exactly what happened but my guess is the carb is a little warped and is really plugged up from sitting with gas in it for a few years. I have fuel pressure to the carb but nothing comes out at part or even half throttle. I've also replaced the distributor because of a faulty pick-up and haven't been able to reset the timing because it won't turn over. Any ideas?

 

[67Dart273]

Let's get our terminology straight:

"Turns over." This should be used to describe that the engine rotates when you twist the key on the starter, other wise known as "cranking."

"Fires" or "Tries to fire" or "tries to start." "Fires" and similar mean that when you "crank" it the engine coughs, sputters, may run on it's own for a second or two or more OR MAY start and keep running

"Starts" Same as above except means actually runs for a short time OR runs and keeps running

"Runs" Good or bad, rough or smooth, means the engine continues to operate on it's own

You sound like you mean that it is CRANKING but will not FIRE or RUN

This could be a number of things.......timing, if you did something that could have changed that, or if something went wrong with the distributor, ignition system, distributor drive, or even camshaft

Could be fuel......lack of, too much, stale/ sour fuel, etc etc.

First thing I'd do is check for both spark and fuel. Use a test gap or plug "rigged" to the coil wire or better yet an extra wire core coil wire

Pump the throttle while looking down the carb throat to see if the acellerator pump is providing fuel. If not, could mean the carb is not getting fuel, could mean there are internal problems with the carb

 

[LG73]

Let's get our terminology straight:

"Turns over." This should be used to describe that the engine rotates when you twist the key on the starter, other wise known as "cranking."

"Fires" or "Tries to fire" or "tries to start." "Fires" and similar mean that when you "crank" it the engine coughs, sputters, may run on it's own for a second or two or more OR MAY start and keep running

"Starts" Same as above except means actually runs for a short time OR runs and keeps running

"Runs" Good or bad, rough or smooth, means the engine continues to operate on it's own

You sound like you mean that it is CRANKING but will not FIRE or RUN

This could be a number of things.......timing, if you did something that could have changed that, or if something went wrong with the distributor, ignition system, distributor drive, or even camshaft

Could be fuel......lack of, too much, stale/ sour fuel, etc etc.

First thing I'd do is check for both spark and fuel. Use a test gap or plug "rigged" to the coil wire or better yet an extra wire core coil wire

Pump the throttle while looking down the carb throat to see if the acellerator pump is providing fuel. If not, could mean the carb is not getting fuel, could mean there are internal problems with the carb

I can almost guarantee that it has stale fuel, it has spark i know for sure, im honestly thinking carb. It's a 1404 Edelbroke 500 cfm with an electric choke conversion. It did start last year with this carb, but it acted like it was out of gas and died after a second. It for sure has fuel pressure, I hooked up a gauge to the fuel line and it read between 5.5-7 PSI. As I'm writing this I'm also wondering if it sunk a float, I've seen newer Edelbrocks rust completely from the inside after only a month or two. As for spark it has a new ICM, distributor, voltage regulator, coil, cap, and rotor and it shocked me pretty good when i grounded it to the shock tower. I think what i'll do is i throw another carb i have at it to see if it'll start. Thanks...heres what it looks like

 

[kiss]

What on earth is that thing connected to your PCV valve? Is that a filter attached to it?
That's not how it works. A PCV valve is a valve to suck the fumes out of your engine so to speak. It doesn't let any are out through it without vacuum (think 1 way check valve). You should hook up your PCV valve ASAP. It attaches to the middle front port on the carb. Without it you are causing wear to your engine and it will rapidly cause oil leaks. Right now your engine is building pressure inside while running with very little ventilation.

 

[67Dart273]

Does it look "wet" down the carb? Pull a couple of plugs are they dry/ wet?

If wet, I would pull the fuel line and plug it to prevent more fuel. Clean, dry the plugs then see if you can get it to fire briefly, use a squirt down the throat of fuel if necessary. This will at least tell you it can fire.

If a float sinks, there will be fuel all over inside the carb, when cranking, it will percolate up through the bowl vents

 

[67Dart273]

What on earth is that thing connected to your PCV valve? Is that a filter attached to it?
That's not how it works. A PCV valve is a valve to suck the fumes out of your engine so to speak. It doesn't let any are out through it without vacuum (think 1 way check valve). You should hook up your PCV valve ASAP. It attaches to the middle front port on the carb. Without it you are causing wear to your engine and it will rapidly cause oil leaks. Right now your engine is building pressure inside while running with very little ventilation.

LOL, comon, he is trying to start it and get it to run. Ignore the PCV for "now". You are right........does not appear to be connected

 

[kiss]

Also looks like the distributor is hooked up to manifold vacuum, it shouldn't, should be at ported vacuum (port on the passenger side). Disconnect distributor vacuum advance while trying to start the car.

 

[LG73]

Does it look "wet" down the carb? Pull a couple of plugs are they dry/ wet?

If wet, I would pull the fuel line and plug it to prevent more fuel. Clean, dry the plugs then see if you can get it to fire briefly, use a squirt down the throat of fuel if necessary. This will at least tell you it can fire.

If a float sinks, there will be fuel all over inside the carb, when cranking, it will percolate up through the bowl vents

the plugs were dry when i pulled them. it seems like there is nothing coming out of the carb

 

[LG73]

Also looks like the distributor is hooked up to manifold vacuum, it shouldn't, should be at ported vacuum (port on the passenger side). Disconnect distributor vacuum advance while trying to start the car.

nope not on this carb. that is the vacuum advance port on this model

 

[LG73]

What on earth is that thing connected to your PCV valve? Is that a filter attached to it?
That's not how it works. A PCV valve is a valve to suck the fumes out of your engine so to speak. It doesn't let any are out through it without vacuum (think 1 way check valve). You should hook up your PCV valve ASAP. It attaches to the middle front port on the carb. Without it you are causing wear to your engine and it will rapidly cause oil leaks. Right now your engine is building pressure inside while running with very little ventilation.

thats just a vacuum elbow i found in a pile of junk parts. there wasn't a pcv on it when it was running just a grommet with a hose going to nothing. I failed to mention when I bought this car it was missing most of the rubber hoses and the carb was leaking so bad i only drove it for 2 weeks. tried to rebuild the 1920 holley but found out that most of the internal threaded pieces were stripped, and to top it off the intake manifold had cracked because of carbon build up in the crossover pipe. what i've mostly done is replace things that were broken and worn out and just dealt with what the last 2 owners didn't do.