1968 Stalls under Load

[njmop]

I have 289 in my CS that I've put back together after a few years of work here and there.

It stalls under load. I am concerned my distributor is off a tooth or something.

Car runs/idles fine until it is in gear (C4 auto) and throttle punched. It almost seems like it isn't getting enough fuel because I have to pump the gas a bit to start it back up...BUT i can't drive it because just accelerating from a stop sign or into traffic would be very dangerous!

New fuel filter, fairly new carb (44bbl Holley), new fuel pump, new plugs/wires. Fresh fuel. Note on fuel filters, I am running one before fuel pump (clear/looks good) and one after and it looks a bit low too.

Is this potentially a bad fuel pump out of the box or is this a timing/distributor problem?

I've spent a lot on time troubleshooting but it's time to seek advice!

Please help!

Mike

 

[Mosesatm]

Are you running points or an electronic ignition? If you're using points the problem may be a faulty condenser.

 

[njmop]

Points. I don't know much about the condenser. What would that failing produce?

 

[Mosesatm]

Exactly what you're describing, but some other things can also cause those problems.
Check out this thread. http://www.californiaspecial.com/forums/showthread.php?t=7453&highlight=condenser&page=3
The folks also came up with a number of other things to check.

 

[njmop]

Thanks! I'll check it out!

 

[njmop]

Another thing I to consider, I installed power brakes. Can the new vacuum load cause the stalling? Again, car runs fine, throttles up fine until I put it in gear and throttle up. Could the vacuum on the brakes be choking out the carb or fuel in the intake or something?

 

[franklinair]

Block off the booster vacuum line and see if it cures the problem.

Neil

 

[robert campbell]

Your car will speed up and slow down at an idle when you apply the brakes if there is a problem with your vacuum booster. Blocking off is a good thing for a test as Neil suggests.

To me it sounds like water in the gas or a faulty accelerator pump. More than likely gas. Water is heavier than gas so it sinks to the bottom of the float bowl. It only takes a small amount and then it covers the main jets. Water is to heavy to flow up and out of the carb via the venturi affect of a carb. So it essentially blocks off the main jets and the car will idle just fine. But crack the throttle and the car dies. Immediately. No gas.

Carefully take the carb up and off. Keep it level. Now, get one of your wife's glass or steel pie pans. Dump the carb over and capture the gas. If you have water it will show up as a large clear bubble. Sometimes it will be scattered in small tiny droplets and if you tilt the pie plate slightly they will run down and collect. And turn you gas a hazy color.

Now where did the water come from? Most times it is condensation due to a mostly empty tank for a long time. Most times it only takes one carb dump to cure the problem. Add some Heet to the gas tank and you should be good to go.

You next pie may have a funny flavor. Kinda like distilled corn.

Rob

 

[njmop]

I'll block and test that line tonight. Also ordered a condenser and coil just in case. I need to double check the new fuel pump flow too. I just read another thread about water in the carb. Would water in carb allow for idle then die under load?

 

[njmop]

I'll dump the carb too. The tank was very low and your explaination makes me want look for bubbles.

 

[robert campbell]

I'll block and test that line tonight. Also ordered a condenser and coil just in case. I need to double check the new fuel pump flow too. I just read another thread about water in the carb. Would water in carb allow for idle then die under load?

Absolutely. It will idle like a Swiss watch.... Crack the throttle. nada...

 

[njmop]

I blocked the vacuum line off intake after disconnecting the power brake hose. The car ran worse and backfired through the carb. I then reconnected it and pulled the carb and drained it. I didn't visibly see any water in the fuel but don't know if I would anyway. Just put carb on but didn't have time to check. Maybe tomorrow so I'll update then.

 

[njmop]

Note: I should have probably checked the timing with the pb hose off and intake blocked. I really think the new mpb setup might be choking out the engine.

 

[njmop]

Not the gas. Next up coil and condenser.

 

[miller511]

Njmop,

Just a thought, make sure that your new plug wires are going to the correct plugs.

After I put the new engine in my Mustang, it idled. But ran terribly/stalled out in gear. I had based my plug firing order on the 289/302. And when I connected the wires up the same way to the new (HO) small block crate engine, it idled a little rough. And ran terribly in gear.

http://classictrucks.net/small-block-ford-firing-order/

-Jeff

 

[Mosesatm]

That same thing happened to Bill (Nfrntau). The engine builder used a 302 cam in Bill's 351. It ran using the 351 firing order but it sure didn't run well. After a few hours of head scratching and swearing I convinced him to call the builder to find out what cam he put in the car. We moved the plug wires around and it ran great!

 

[robert campbell]

Time to roll up our sleeves.

1. Initial timing. Needs to be set with vacuum hose off distributor. I would set your car at 10 degrees Before Top Dead Center (BTDC). This must be done at operating temperature and a slow idle under 1,000 RPM. For a quick try on your engine just turn the distributor clockwise a bit. The engine should speed up and run better.

2. Idle screw adjustment. Set both screws at 2 turns out for a start point. Again at full operating temp. It would be great if you had a vacuum gauge. Try to set curb idle (screw that opens and closed the primary butterflies on left side of carb down low on the throttle plate) to run at 800/900 RPM in park or neutral. Then try turning the idle screw on one side in 1/4 turn or out 1/4 turn. If the engine runs better repeat with the other screw. Then slow the engine down with the curb idle screw again. Repeat the above until you get the best fastest engine RPM with the curb idle screw the furthest turns out (counterclockwise).

I would get a vacuum gauge soon. You should have around 17 to 18 inches of vacuum at 800 RPM on a stock engine.

Rob

 

[rvrtrash]

That same thing happened to Bill (Nfrntau). The engine builder used a 302 cam in Bill's 351. It ran using the 351 firing order but it sure didn't run well. After a few hours of head scratching and swearing I convinced him to call the builder to find out what cam he put in the car. We moved the plug wires around and it ran great!

Ford changed the firing order on 302's back in the late 80's I think, to the same as the 351 and a lot of builders use cams with the new firing order. I agree to find out what cam was used, it's firing order, and make sure you have it correct in your car before proceeding.