fuel starve in hard cornering.

OK, so this weekend was my 2nd and 3rd events in the truck. After the first outing, I made sure to fill the tank so I wouldn't get fuel starve. Well.... that didn't work. Coming out of hard sustained corners it falls on it's face for a few seconds before coming back and destroying the tire. Quick hard transitions (like slaloms) don't seem to affect it.

I've heard this could be float bowl issues and I've heard it could be mechanical pump/fuel line issues. It's an Edelbrock performer 600cfm (1406).

Suggestions? Thoughts? Dump it all and go LS? (not happening)

How much gas in the tank?

If your pickup is uncovered for 5 to 10 seconds it can lead to fuel starve.

I had the same symptoms in my 78 Malibu. It was the power steering pump pulling the engine down and stalling it. I changed out the pump and the issue went away...

This is really only an issue with an automatic.

I reread. Full tank...

Hmmm.

Where is the pickup for the tank?

Being a C10, it's a long, skinny saddle tank with the pickup in the center. Tank is about 4-5ft long and skinny.

If the tank was full, I highly doubt the issue was the pickup in the tank.

Bobzilla wrote: Coming out of hard sustained corners it falls on it's face for a few seconds before coming back and destroying the tire. Quick hard transitions (like slaloms) don't seem to affect it.

I'm guessing you were on the brakes before the long corners? If slaloms aren't affecting it, then I don't think it's (strictly) the lateral g-load affecting the fuel pickup.

Were there any tight corners on course with hard braking before them? How did it behave on those?

At the first event, there were approximately 5-6 gallons in the tank. Hard acceleration would cause the starve as well. With the tank full that wasn't an issue.

We had a nice mix of fast sweepers and brake hard sweepers while getting back on the gas. Both had the same effect. Roll back on hte power and it broke up hard for 2-3 seconds before coming back full strength. Makes me think this is a fuel bowl sloshing issue more than a fuel delivery. Unless the lateral load is affecting the mechanical fuel pump.

These are things I am not very familiar with. FI doesn't have this problem. lol

Its the edelbog. Horrible floats for autocross. The problem is in how the floats are hinged, and changing float heights just moves the conditions. There is no good cure that i have found, oth errr than holley with roadrace floats, or efi.

I was thinking that fuel starving with a full tank should be practically impossible, but then wondered how terrible a carb's floats would have to be designed to cause a fuel starve...guess there's the answer.

Dusterbd13 wrote: Its the edelbog. Horrible floats for autocross. The problem is in how the floats are hinged, and changing float heights just moves the conditions. There is no good cure that i have found, oth errr than holley with roadrace floats, or efi.

Yep, for as lackluster as the GM TBI options are, they do have at least one advantage over a carb....

Fix the carb issue and you can worry about fuel tank issues if they crop up after that.

Video of awesomeness All the roll

Dusterbd13 wrote: Its the edelbog. Horrible floats for autocross. The problem is in how the floats are hinged, and changing float heights just moves the conditions. There is no good cure that i have found, oth errr than holley with roadrace floats, or efi.

A quadrajet would likely resolve the issue as well. They saw plenty of use in boats with lots of sloshing, etc. and I've never seen one fuel starve.

The Q-jet has incredibly wee float bowls. I have no fuel starvation issues from the Q-jet in my '77 (had mechanical pump issues, though, but that's a different story...)

A fuel pressure gauge would be an excellent diagnostic tool in this situation.

Or you could spend money upgrading the fuel system for an electrical problem......

Carbs suck you could be running EFI (not throttle body injection).

All the wiring is new. So if there is an electrical problem I'll be pissed. But since it's doing the same thing it did on low fuel and accelerating I'm pretty certain it's fuel related. It also (apparently) blows black smoke when it comes to life again

Bobzilla wrote: It also (apparently) blows black smoke when it comes to life again

This makes me think float bowl sloshing is an issue. When you come out of the corner, the fuel sloshes back the other way and might end up giving the thing a slug of extra fuel.

In reply to rslifkin:

Exactly. Goes from dead lean and starving for fuel to dead rich and almost flooding due to the fuel slosh

And the solution to this is a different carb? I heard of the holley trick of tube off the vents etc. Or a holley made to turn. EFI isn't an option at this time because $$$.

Wow, I ran a Weber 38/38 on my track car for a couple years with no problems and I had no idea carbs could get flaky once you take them off the drag strip.

I just did a 302 swap, and bringing the EFI along with it was a material amount of extra work. I had been questioning whether I should have just gone the carb route.

I don't know a ton about carbs, but if anybody has the time to do a quick run-down of the problem, I'm all ears. But I don't want to put anybody to the trouble unless they're game.

I'd love to just go this route: easy button

Along with pressure check the volume of the pump. Maybe an electric pump closer to the tank would help.

I vaguely remember something about tall vent tubes on early Holleys.

JBasham wrote: I don't know a ton about carbs, but if anybody has the time to do a quick run-down of the problem, I'm all ears. But I don't want to put anybody to the trouble unless they're game.

I can give you a quick overview.

The carb has a float bowl where it holds a small amount fuel (enough for the engine to run on for a few seconds) that is fed to the jets under a combination of gravity and vacuum. The level of the fuel in the bowl is regulated by the carb float which is a floating lever connected to a valve, much like the one in a toilet tank, that allows fuel into the float bowl unless it's completely full. If the float bowl saw any pressure from the fuel pump, the engine would be massively flooded with gas. Fuel delivery must be pneumatically/aerodynamically determined by the vacuum in the throat of the carb alone.

So all kinds of mistakes in the design of the float bowl or carb float could cause it to fuel-starve when driving at a steep angle (common problem in offroading) or under cornering loads. It's much like traditional starvation in a fuel tank, but on a smaller scale and with the added factor that the fuel level could change dramatically due to movement (or a lack of movement) in the float, possibly even causing the float bowl to run completely dry.

The issue is the same for oil pans and any other fluid containers subjected to rapid changes in G-loads.

Some oil pans, carburetors, etc. are better about managing the fluid's movement than others.

Apparently the Performer series carburetors from Edelbrock are known for it. One fix I found with a quick Google search was to fill the transfer channel between the two bowls with JB Weld and keeping the throttle on slightly during cornering. Another solution is to change the carb out for an Edelbrock Thunder series as it is apparently better suited for those situations.

Fill the transfer channel

Lots of hits on Google about Edelbrock Performer and cornering.

Try to fix the carb or replace it.

TBI is less expensive than a new carb if you use take-off parts from a donor. You can always go aftermarket EFI later.

Welcome to a whole new world of fun and frivolity. Miss the Kia yet?

We can tbi swap it for about 100 bucks.....

Assuming stock, low spec cam.

Bobzilla wrote: I'd love to just go this route: easy button

I'm not impressed with those, overpriced and too many dedicated parts that you have to go to them to replace or repair. A TBI unit off a BBC + MS1 will get you there for a fraction of the price and use GM parts, sensors and a cheap and easy to replace/repair ECU. It just doesn't have the fancy "fluff" that Hot Rodders get suckered into (Ooooh Shiny!).