Engine just dies....

A long shot, but did you adjust the float levels? It is a must do when putting a new carb on a Pantera.

Mike

Another even longer shot. It it possible your fuel pump isn't up to the task or is failing? I think Mike is right about it probably being carb-related but in my world, parts like to fail when something unrelated has been changed or worked on.

Good luck.

Mark

My car was giving me alotta' trouble. Every time I go get gas the car would not start at the station, it was flooding for some reason. I had to roll it over until it cleared and blew smoke everywhere. I insulated the carb, regulated the fuel pressure, reinstalled the internal filters, adjusted the floats and replaced the needle/seat... So far, so good...

On this holley, I have the nice glass sights into the fuel bowl and it is full. Again, the car ran for miles without issue. I am not sure if it was a heat issue or ???. Here is the list that I think might be wrong including your feedback:
1) Floats
2) Clogged Filter
3) The "tank sock" debris floats around but after constant suction from the pump, the debris clogs the fuel pick up in the tank
4) Fuel pump can't keep up

quote:

I have the nice glass sights into the fuel bowl and it is full

If the gas is over the sightglass the floats are set to high. Gas level in the bowls should just be visible in the sight glass. With the old style sight screws the gas should have been just at the bottom of the hole, so you could shake the car and a little gas would come out of the hole.
Jeff

Is this your first hot weather with this car?

If so, then it may be nothing to do with the new carb, but something you just have not yet come across due to the weather--- vapor lock?

Larry

My gas is about 1/3 up the glass.

quote:

Originally posted by LF - TP 2511:
Is this your first hot weather with this car?

If so, then it may be nothing to do with the new carb, but something you just have not yet come across due to the weather--- vapor lock?

Larry

This is the first time in hot weather with the car. What are some potential cures?

Check routing of fuel lines to see if they can be moved away from heat sources. Insulate fuel lines. Install non metallic carb spacer.

Mechanical pump? It may have a hole in the pumping diaphragm. Replace?

Installing an electric pump will often cure things, too.

Not quite sure your symptoms are quite right for vapor lock, though. But it sure did come to mind when you said 90 degrees, and I was pretty sure this is your first summer with the car.

Larry

Is it a new carb? You may have to take it apart and clean it out including blowing out idle and other passages. When they started being manufactured outside the U.S.Demon carbs had a problem with metal shavings from manufacturing clogging up the new carbs. Poor quality control. If your fuel level is set correctly and the bowls show fuel when you stall, it's probably not a fuel supply problem. Does your intake slope at an angle?, could be fuel sloshing over when you slow or stop?

quote:

Originally posted by 4NFORD:
Is it a new carb? You may have to take it apart and clean it out including blowing out idle and other passages. When they started being manufactured outside the U.S.Demon carbs had a problem with metal shavings from manufacturing clogging up the new carbs. Poor quality control. If your fuel level is set correctly and the bowls show fuel when you stall, it's probably not a fuel supply problem. Does your intake slope at an angle?, could be fuel sloshing over when you slow or stop?

Brand new carb. The intake looks level to me but I'll put a level on it to see.

Would an engine that is running too rich have this same problem?

If the Carb is the only thing you changed and the symptoms are only apparent on braking then it sounds to me like fuel slosh out of the bowls and into the vent tubes causing the engine to go rich and stumble.

This is often reported as more of a problem on Pantera's with the mid engine design and under braking as fuel from the secondaries sloshes up the vent tubes and floods the engine. You can set the secondaries float just on the low side to help and/or you can get extension tubes that extend the vent tube to help prevent fuel sloshing.

You say your car is running on the rich side anyway, which may be adding to the problem. Did the carb coming appropriately jetted for your engine/conditions?

On the classic Holley carburetor, the accepted method for setting the float level is to run the engine until everything is warm, and with the engine at idle, unscrew the plugs in the sight windows for the float bowls. Raise the float just until fuel begins to escape from the window, then lower the float back down a bit and lock everything in place. So you really shouldn't see any fuel in the sight glass if properly adjusted.

Good luck,
Julian

I had similar issues, and it turned out to be a combination of a few things. One of which was a slightly too high, secondary float, which did flood (will not restart for a good few minutes). As well as a slightly too low primary float that starved... and lastly the most difficult thing to figure out, was that I suddenly got fuel starvation issues due to crud in the fuel tank, that would sometimes partially clog a fuel line, intermittently and cause all sorts of problems.

Clogged fuel filter .. you just bought this car and it was sitting for a ling time ? Or floats need to be adjusted. the clear sight glasses should be removed after adjsuted ..they eventually lossen a fall out and then ...the roof the roof .... is on fire.

Ron

Just a hint, if and when a car overflows or whatever, push the accelerator to the floor and keep it there and keep turning the starter until it starts. When the throttle plates are fully open there's no vacuum to pull fuel through the carb, and as soon as the extra fuel from the accpumps clears (2-3 seconds), it'll start. I've started a few Panteras like that for people in Modena and also a vintage Thunderbird standing in the middle of an intersection, with a worried pensioner behind the wheel...

About your problem, if you look at the link below and take the time to do each step, it may help:
http://www.tuningmadeeasy.com/...a-carburetor-part-1/

How stock is your engine? A 750DP is too much carb for a stock'ish engine IMHO.

quote:

How stock is your engine? A 750DP is too much carb for a stock'ish engine IMHO.

It's not stock. Has an aftermarket intake and cam. Everything else appears to be stock.

I have a working Holley 600 you can use for testing.

Mike

quote:

Originally posted by Pantera 1887:
I have a working Holley 600 you can use for testing.

Mike

Mike...you are the angel of the pantera world. I still have the old carb (650) if I need to switch. It was running a bit rich and my mechanic (possibly former mechanic) convinced me to go up to a 750. Anyway, I need to find me a mentor that can walk me through the carb tuning ritual. I like the tuning made easy site as it will educate me but there is nothing like having an experienced person to walk you through it.

Glad to help anytime.

Mike

Should add that I’ve never had any heat soak problems with my Holley 600 driving in the Southeast and it does not have an insulation spacer.

Mike

Hello Khan,
It looks like your having some fun sorting out your car,
Don't get stuck on the fuel but defiantly eliminate it as a problem.

Also it may be a electrical problem,
Some of the one’s I have encountered are and act the same,

Coil for the plugs would heat up and cut out like no fuel, fix was a new coil and
a resistor wire or ballast resistor rated at approx 1.4 ohms.

Electrical short or break, recently I had a reverse lockout switch on a Hotrod give me problems would cut out when driving.

All easy fixes once you find it!

Mark