55.2-59 Not sure what my Trucks issue is - HELP!

[2bo.c10]

Hi Everyone - having an issue with my 1958 Apache with a i6 235. At idle, it runs ok but has some crackling and I can rev it and it doesnt "die" when I depress the gas pedal. When I put the truck into gear, however, and give it gas, it wants to backfire, sputter and cough and die. I have to engage the clutch and feather foot the gas to prevent it from dying. Here is a video of my truck and what it sounds like.

https://youtu.be/chzixjkwW7s


Here are some points / things I've tried:

1. DISTRIBUTOR: I went to HEI a few months ago and it didnt like it so I went back to my original distributor and points. Truck seems to like it better. When I originally removed the distributor, I didnt mark it or do any of that smart stuff - I just pulled it. Same when I removed the HEI. To get it to fire up, I had to find TDC, the white BB on the fly wheel and make sure theyre in sync. I think I did this right but I may not have. I used a timing light to set the timing to the white BB. As I mentioned above, it sounds like its possibly misfiring. There is a popcorn sound in the exhaust at idle and when it revs. See youtube video link to hear the truck. Someone suggested I may be 180* out of timing. Does this sound like it could be the issue?

2. CARBURETOR: I had the carburetor professionally rebuilt at a place that has carburetor in their name. I assume they did it correctly, but open to the possibility they didnt do it right as I get a little bit of gas leaking from the front of the carb and the gasket seems to protrude a little.

3. VACUUM ADVANCE: Vacuum advance and advance line is brand new.

4. SPARK PLUGS: Spark plugs are brand new and through a spark plug tester, I confirmed spark to all spark plugs.

5. FUEL: New fuel pump and in-line fuel filter. Gas is visible in the filter and seems clean and has no particulates in it.

6.INTAKE LEAK: I put new intake and exhaust manifold gaskets in last week. Today I tested to see if there was an intake leak by spraying WD 40 a the intake ports to see if it would make its way into the manifold and "rev" the engine. It did, but tightening the bolts holding the intake and exhaust manifold fixed that.

7. COIL: - Coil is brand new High performance coil.


I'm really at a loss of what to do. It sounds like it wants to run when I rev it, but once I try to get it to go anywhere it loses power and wants to die.

[MiraclePieCo]

Sounds like retarded timing. Advance it a bunch while idling and see if that helps. If you were 180 out it wouldn't run at all.

Look down the carb throat and verify that your accelerator pump is giving a good shot of fuel into the venturi.

Check for vacuum leaks by spraying starting fluid onto all junctions - carb gasket, intake gasket, vacuum hoses, etc.

[Bimus]

I had a shop put new intake exhaust gasket on and they did not put the steel rings back on the intake ports between the head and manifold .

[2bo.c10]

Originally Posted by Bimus

I had a shop put new intake exhaust gasket on and they did not put the steel rings back on the intake ports between the head and manifold .

Steel rings?

[burnin oil]

Install a vacuum gauge and check the reading. Could be a vacuum leak or burnt valve. Has the overhead been run lately? A tight valve can do some wierd things.

[joedoh]

running out of gas in the bowl? sometimes old rubber line collapses under suction from the pump. if you have a clear filter make sure there is gas in it.

[mr48chev]

Originally Posted by joedoh

running out of gas in the bowl? sometimes old rubber line collapses under suction from the pump. if you have a clear filter make sure there is gas in it.

Joedoe hit on some of the simple old truck things that guys overlook.

Restricted fuel line that will feed the carb fine at an idle but the bowl quickly runs out of gas when you speed the engine up.

Old rubber line coming apart inside as he mentioned. This ethanol gas eats the older rubber hoses in anything you put it in. I have gotten to where I specify hose that is ethanol compatible now.

Plugged fuel filter even though it may not be very old if you just started driving the truck after it sat for a long time crud may be breaking loose in the tank or lines plugging it up.

Gas cap= does it have a correct properly vented gas cap. I went though 3 correct number Stant vented caps on my 51 Merc before getting one that was actually vented. If the cap isn't venting it creates a vacuum in the tank that causes the engine to stall but This may not be the case as normally it stalls and acts like it is out of gas but if you open the gas cap you hear air rush into the tank and sometimes if the gas level is slow hear the sides pop back out on the tank.

Spark plug wires in the right order 1-5-3-6-2-4 ?

Valves out of adjustment as mentioned above? Or a burnt valve?

[mr48chev]

A few things when troubleshooting anything:

Never assume because something is new fresh out of the box or freshly rebuilt that it is in perfect working shape.

On something like this check or recheck the simple things.

Timing
Firing order
Look inside the cap for cracks, carbon tracking or damage
Check the fuel system from cap to carb and if you did any work on something in close proximity to the fuel line anywhere on the truck check the line in that area.

If you have an inline filter take it off and tap the inlet tube on a flat surface and see if crud comes out.

If you haven't done a compression test recently I would suggest doing one to make sure that you do have decent even compression in all cylinders.

Lastly an quite important do not make more than one change when changing or checking things. I've seen too many cars that guys changed all too many things on trying to fix a simple problem and still don't have it fixed. One change at a time and then test it and decide on the results.

[Bimus]

The steel rings fit in to the intake port on the head and half of it sticks out and in to the port in the manifold with out them the gasket will fail in a short time.

[MiraclePieCo]

Whatever it is, be sure to report back and let us know. I hate it when we're left hanging and never get to know!

[dsraven]

Like the others said. Dont assume its good cause its fresh. Start over like youre seeing the truck for the first time. Check everything and write it down for comparison to specs.get a baseline for reference, timing and vacuum included before you change anything. Use a timing light to check if advance moves as revs increase etc. Try running engine in a dark area or atnight to check for crossfire between ign wires or from coil tower etc. Also, to make sure its not just some water in the carb, remove the air filter and start the engine. Rev the engine up full throttle and at the same time, Using a big rag, cover the carb throat completely for a sec. Not enough to stall the engine, just enough to subject the carb to high vacuum. Thaf can be enough to draw contaminants through the jets if that is the issue. Do it a couple times.then see if the engine runs better. You could have a dirty fuel tank allowing contaminants through to the carb.
Fuel pump pressure and output, before cracking fuel cap, for baseline specs
All fuel and vac lines including tank vent cap
Fuel filter contents
Accel pump output and stream aim. Sgould aim at edge of butterfly valve
Valve adjustment and condition on rockers/shaft. Check oiling of top end as well. Worn shafts and or rockers can affect valve adjustment
Condition of spark plugs and color check
Resistance across points, condition etc. Dwell reading for baseline
Ensure internal connections in distributor are not rubbing ground etc when advance happens and things move
Centrifugal and vac advance check
Condition of rotor, cap and wires
Condition of coil, look for obvious discoloration spots indicating overheating, cracked wire tower or areas around the studs for connections
Check ballast resistor if equipped
Check for good cable connections at battery, engine block, ign switch etc. Wiring is only as good as it's worst connection.
Compression dry and wet

Remember, a lean mixture is harder to ignite so spark will find another path if one is available and that can also change timing. You could start the truck, have someone rev it till it acts up then clamp the rubber fuel line right when it acts up. Shut it off and pull the top off the carb to see how much fuel you have in the bowl. You could also then see if there are contaminants in the bowl as well. Even a bit of water will cause havoc because it wont go through the jets.