[61 389-348]

Originally Posted by 63gpman

Just went through a bunch of your youtube vids. Nice work!!

Thanks

[Keith Seymore]

Sweet Geez Louise!! What is that?! A screen capture off the video, or a regular photo?

Beautiful!

I'm almost tempted to make that my screen saver.



K

[61 389-348]

Originally Posted by Keith Seymore

Sweet Geez Louise!! What is that?! A screen capture off the video, or a regular photo?

Beautiful!

I'm almost tempted to make that my screen saver.



K

Thanks. Still photo by the way. It was a sunny day, late afternoon/early evening. Too bad I can't get it running right.

[Keith Seymore]

With looks like that it doesn't really need to run right.



Just let it sit there and look at it.

(lol)

K

[61 389-348]

Originally Posted by Keith Seymore

With looks like that it doesn't really need to run right.



Just let it sit there and look at it.

(lol)

K

Thanks. Sorta true given that is what may happen, but it ran great before the 112 octane and I will get this figured out. This one is tough though.

]

[Engine-Ear]

I have been mulling this over...you had the carbs rebuilt and all was right with the world before the fateful fill-up. Then problems arose and you have checked fuel pumps, lines, inlet socks, phase of the moon, etc.

Why couldn't something in the gas have deteriorated the carb in some way? I am thinking of solid particles in the fuel that have collected and occasionally clog high-speed passages? Or maybe fuel that has attacked soft parts within the carb?

Mentally plotting a timeline of repairs/rebuilds/upgrades vs. performance (satisfactory to UNsatisfactory (and inconsistent at that!)), I am circling back to a polluted carb as a culprit.

[Ragtop Man]

If there was old rubber in the system that was porous in any way, it is very possible that something went soft and now the problem is exaggerated by the current fuel being used.

If the tank is blown out, you're done with that other than to ensure you have the proper cap that vents appropriately.

Sounds like the sock is okay, or should be considering it has been replaced twice. If you have a spare swap meet electric fuel pump to use, you could try rigging it outside the garage in a tank of non volatile solvent to see what happens when it is exposed to the suction pressure.

Hard lines should remain un-affected, unless perchance something happened to kink one at the track, either the feed or return. Might be worth chasing the lines all the way to the ends to make sure they didn't get pinched by a body rocking or a piece of debris, somehow.

I wonder if the race fuel might have softened the fuel line from the frame termination of the hard line over to the fuel pump. When the pump is really...pumping... is it collapsing or pinching that line cutting off the fuel flow? (Cooling systems sometimes have the same issues...) It could have been age, hard to say.

Also, did a wobbly pump diaphragm tear? It would not be an issue at low speeds, but as the need for greater volume came up with rpm... any porosity or damage would then be felt. Likewise, is there a check valve of some type in the fuel pump that went wonky? Don't know them well enough to say, it's just the coffee in me asking.

Likewise, do you have a way to temporarily rig a fuel pressure guage to monitor the pressure that the carb is "seeing?" A drop that coincided with the hesitation would tell you that at least some of the problem is 'behind' the carb and not in it.

Overall, though, it sounds to me like the bowl is just plain draining, and the rest of the system can't keep up for whatever reason

An ignition issue seems remote, however there are episodes where older charging systems cannot supply enough voltage to the Petronix system to put full voltage to the secondary. Did a belt glaze over or get hot while dragging and then cause a mystery problem?

[Deadhead]

Don't know what carb you are currently running, but if you have a the Carter with the filter at the inlet, that could be clogged. Like EE says something could have disolved, broken loose when you got in on it at Norwalk and gotten caught up in there.

[61 389-348]

Originally Posted by Engine-Ear

I have been mulling this over...you had the carbs rebuilt and all was right with the world before the fateful fill-up. Then problems arose and you have checked fuel pumps, lines, inlet socks, phase of the moon, etc.

Why couldn't something in the gas have deteriorated the carb in some way? I am thinking of solid particles in the fuel that have collected and occasionally clog high-speed passages? Or maybe fuel that has attacked soft parts within the carb?

Mentally plotting a timeline of repairs/rebuilds/upgrades vs. performance (satisfactory to UNsatisfactory (and inconsistent at that!)), I am circling back to a polluted carb as a culprit.

Thanks. I bought a Carter 9635 AFB back when I restored the car in 2001 and really have no problems up to the time of the 4 or 5 gallongs of 112 octane. I've since rebuilt and had rebuilt the Carter 9635 twice and still big problems. I replaced that carb with an Edelbrock 1406 and it was mostly ok for a couple of weeks. I'm doing fuel pump #7 tonight or tomorrow. And then it will be time for another carb. None of this makes sense, but I do know I was fine before the 112 octane. I had also suspected that the race gas messed up the carb. This is crazy. I'm long ago out of ideas.

[61 389-348]

Originally Posted by Deadhead

Don't know what carb you are currently running, but if you have a the Carter with the filter at the inlet, that could be clogged. Like EE says something could have disolved, broken loose when you got in on it at Norwalk and gotten caught up in there.

Bruce, There was no filter in the inlet and that was two rebuilds and one carb ago. I checked for the imlet filter up at the track and none in there.

Edelbrock 1406 now and it was mostly ok for a couple of weeks, but now it's back like it was .... open the secondaries and it runs out of fuel.

[Engine-Ear]

You're running out of variables here...I like the idea of adding an accurate fuel pressure gauge with a large enough dial face to read deltas of 1 PSI (or less).

Instead of swapping out pumps (for the n'th time) I would do the gauge first and watch for pressure drops in accordance with the perceived starvation / nose-dive events.

[61 389-348]

Originally Posted by Ragtop Man

If there was old rubber in the system that was porous in any way, it is very possible that something went soft and now the problem is exaggerated by the current fuel being used.

If the tank is blown out, you're done with that other than to ensure you have the proper cap that vents appropriately.

Sounds like the sock is okay, or should be considering it has been replaced twice. If you have a spare swap meet electric fuel pump to use, you could try rigging it outside the garage in a tank of non volatile solvent to see what happens when it is exposed to the suction pressure.

Hard lines should remain un-affected, unless perchance something happened to kink one at the track, either the feed or return. Might be worth chasing the lines all the way to the ends to make sure they didn't get pinched by a body rocking or a piece of debris, somehow.

I wonder if the race fuel might have softened the fuel line from the frame termination of the hard line over to the fuel pump. When the pump is really...pumping... is it collapsing or pinching that line cutting off the fuel flow? (Cooling systems sometimes have the same issues...) It could have been age, hard to say.

Also, did a wobbly pump diaphragm tear? It would not be an issue at low speeds, but as the need for greater volume came up with rpm... any porosity or damage would then be felt. Likewise, is there a check valve of some type in the fuel pump that went wonky? Don't know them well enough to say, it's just the coffee in me asking.

Likewise, do you have a way to temporarily rig a fuel pressure guage to monitor the pressure that the carb is "seeing?" A drop that coincided with the hesitation would tell you that at least some of the problem is 'behind' the carb and not in it.

Overall, though, it sounds to me like the bowl is just plain draining, and the rest of the system can't keep up for whatever reason

An ignition issue seems remote, however there are episodes where older charging systems cannot supply enough voltage to the Petronix system to put full voltage to the secondary. Did a belt glaze over or get hot while dragging and then cause a mystery problem?

It's fuel related and not ignition, but I replaced everything anyway. I ran a Petronix 1 for 12 years without trouble except for long crank times on first start, and replaced with a petronix 2. I have a big ass alternator and have had for years

All rubber fuels lines have been replaced at least twice. I've carefully looked at the stainless lines front to back. They flow freely forward or backwards when i run compressed air through them. Tank has been taken out and dumped twice (nothing in there) and sock replaced twice with the correct Delco TS1000 sock. I've had two more fuel pumps in since I've been back in town and it's just about to get its 3rd. Heading over to NAPA in a few minutes to pick it up.

To make it worse, the problem isn’t all that consistent … sometimes it’s really bad (tow truck) and sometimes it’s somewhat OK.

[61 389-348]

Originally Posted by Engine-Ear

You're running out of variables here...I like the idea of adding an accurate fuel pressure gauge with a large enough dial face to read deltas of 1 PSI (or less).

Instead of swapping out pumps (for the n'th time) I would do the gauge first and watch for pressure drops in accordance with the perceived starvation / nose-dive events.

"You're running out of variables here"

You got that right. New pump seems to 'fix it' for a short time. Stranger yet!

[Engine-Ear]

While you're at NAPA (or order thru summit, etc.) pick up a fuel pressure gauge rated for an in-car installation and a universal inline electric fuel pump.

Keep us posted.

[61 389-348]

Originally Posted by Engine-Ear

While you're at NAPA (or order thru summit, etc.) pick up a fuel pressure gauge rated for an in-car installation and a universal inline electric fuel pump.

Keep us posted.

And a inline electric pump was next on the list.

[BigAquaBonney]

Originally Posted by 61 389-348

And it is just a little stumble at throttle tip-in and at sustained full throttle, but I had once get so bad that it was the tow truck to get home.

It sure was fine getting back from dream cruise in 2011

http://youtu.be/8wH7F0oCAes

Watched the video, kept waiting for the camera to rise above the dash board. Maybe next year?

Loved the B-52's video you had online. Saw them in '82--crowd looked a little different then.

[61 389-348]

Originally Posted by BigAquaBonney

Watched the video, kept waiting for the camera to rise above the dash board. Maybe next year?

Loved the B-52's video you had online. Saw them in '82--crowd looked a little different then.

It did at the 11 or 12 mark. Had the old girl wound pretty tight. Sure wasn't running out of fuel then.

And in re: the B-52s, yeah, Freddie was slowing down a bit, but it was a bitchin hot humid night so we all were slowing down a bit.

[6T5 Cat]

I had a similar problem one time. It turned out to be the power line to the electric choke was losing contact with the connector on the choke and therefore the choke was not operating properly. Without tension to hold the choke open it would close under hard acceleration and it was just like running out of fuel. I checked everything in the fuel and ignition systems and it drove me nuts for a couple of hours untill I found the problem. I read where you blew air through the fuel lines, but that doesn't neccessarily mean there is not blockage somewhere restricting the amount of fuel passing through the line. It may possibly be allowing enough fuel for part throttle operation, but not enough feul for full throttle operation. I had that problem once also. Blew compressed air through the line and nothing came out except air; I took a roll of .032 safety wire and started feeding it through the line and encountered a partial blockage. I've seen a bad coil fail at higher rpm, but ran normally during normal driving conditions.

[61 389-348]

Originally Posted by 6T5 Cat

I had a similar problem one time. It turned out to be the power line to the electric choke was losing contact with the connector on the choke and therefore the choke was not operating properly. Without tension to hold the choke open it would close under hard acceleration and it was just like running out of fuel. I checked everything in the fuel and ignition systems and it drove me nuts for a couple of hours untill I found the problem.

Ok, now THAT'S interesting. I've had the connector come off before and yes, it did cause trouble. It was easy to spot though because the hot line had fallen off of the connector on the choke. OK, I will check this out in the morning.

Thank you for coming up with something that I had not checked.

"I took a roll of .032 safety wire and started feeding it through the line and encountered a partial blockage"

And another good idea. I've replaced all of the lines multiple times except the main 3/8" stainless line that runs the full length. I've also had three coils on it since I started having trouble. It's not necessarily high rpm. It can be under load anytime the secondaries are open.

[kwt63cat]

61 389-348,
Since you've replaced fuel pumps, filters, carbs, and rebuilt carbs, I'm leaning towards something with the lines. Not the rubber lines since you said that you replaced all of them, but the steel lines. Maybe a kink that you missed but likely a piece of rubber from the old ones stuck at a bend or at the fitting end. Also there is a piece of line from the pump to the inline filter. Did you check that line and the one from the filter to the carb. It's hard to diagnose this sort of thing without having hands on it. It's time to go to a fuel pressure gauge and positively confirm a fuel problem like EE has suggested. Good luck. Ken