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Posted by: worn Aug 10 2014, 05:16 PM

Today at an autocross meet the car was doing great. EXCEPT that after a sharp curve there was a delay in getting power, with he engine running lean. We were running a half tank or less to save on weight and it was suggested that the problem was fuel starvation after a sharp turn.
Having looked inside the tank it don't seem so awfully likely, but it does fit the symptoms. Driving back on country roads I went across several 90 degree bends, and the same durn thing happened! Any thoughts?

Posted by: Mike Bellis Aug 10 2014, 06:04 PM

Carbs or FI?

Posted by: sixnotfour Aug 10 2014, 07:10 PM

oops

Posted by: worn Aug 11 2014, 06:28 PM

A 2056 running stock 2.0 FI. When the power comes on, it's on! Air fuel ratio showed way too lean when it was happening.

Posted by: Mike Bellis Aug 11 2014, 06:35 PM

I would start with a new higher volume FI pump. A fuel accumulator requires a tank and a secondary fuel pump. There should be no need for an accumulator at your HP level. You should also replace the pressure regulator.

Also make sure your supply and return in the tank are not reversed.

Do you have this problem with a full tank?

BTW, I'm running a single pump in the front and a +300hp turbo motor and don't have this issue.

Posted by: SirAndy Aug 11 2014, 08:34 PM

I would start there. If it still happens with a full tank something else is going on.


If it is related to fuel level in the tank, you could try to add some baffle to the tank. That would require opening the tank but should work well enough.

Posted by: worn Aug 15 2014, 08:11 PM

I guess I was wondering if it had happened to anyone before. It is a relatively new FI set of components, and yes, I think it does depend on fuel level. But this is a tank I treated with rust removers and rotary nuts and bolts. I ran it with a bar b q rotisserie for a couple of days and yes, I did count the nuts and bolts both ways. I was impressed by the baffles already present. Any chance the bucket for the fuel return isn't quite enough? I am running at 32 psi, which is slightly high, and I also notice how the tank is very transverse. It is right at the front wheels, so there is good reason for all of the fuel to migrate left or right. Then after the turn - disappointment!

Posted by: Mike Bellis Aug 15 2014, 08:47 PM

I'm wondering if your supply and return are reversed. The supply is the lowest one and should not starve for fuel like you describe. The return sits about 2" above the bottom of the tank. If they were swapped, it could produce the effect you describe.

Posted by: JamesM Aug 15 2014, 08:57 PM

The tank already has some baffles in it, adding more would probably be more trouble then it is worth.

Where is your pump located? Is it an old 3 port or a new replacement?

I had a similar condition but it was not due to fuel slosh but rather shifting and pinching of the fuel supply lines between the tank / filter / pump.

Posted by: brant Aug 16 2014, 07:33 AM

We never had problems with stock tanks. I think something else is causing it other than the tank. I've even had electrical problems related to cornering forces

Posted by: Racer Chris Aug 16 2014, 09:57 AM

When I road raced my car with a d-Jet 1.7L I ran an accumulator fed by a low pressure pump.
Fuel in the tank sloshes around too much for the pump to maintain full pressure for the FI.

Posted by: tadink Aug 16 2014, 10:45 AM

I've got exactly the same issue but ONLY on hard lefties, righties are al-rigthy. Baffled by this for going on a year now - it happened with my 1.7L FI and still happens with the replacement 2.0L FI. tub is a '71 - stainless lines thru the tunnel by McMark....so pretty sure they are hooked up to the correct supply / return at the tank.

I'd like to figger it out as I'm not able to ax with it the way it is....

glad I'm not the lone ranger on here with this issue! maybe I'm not crazy after all?

keep those suggestions coming - its probably something!

td

Posted by: d914 Aug 16 2014, 02:06 PM

expensive but here is one to use almost out of the box..

Posted by: tadink Aug 18 2014, 05:49 PM

ok, so is that a fuel accumulator?? where do you put it? Upstream or downstream from the existing fuel pump? It works with fuel injected set ups, yah?

the pic came thru but not the source....

thanks

td

Posted by: d914 Aug 18 2014, 06:12 PM

low pressure from the gas tank.. high pressure to the fuel rails.. edelebrock, for use with their superchargers..

Posted by: stugray Aug 18 2014, 06:31 PM

I have seen the fuel slosh "chambers" that use trap doors to keep the last bit of fuel in a smaller area for the pickup.

The other way to do it is to use a low pressure in sump fuel pump to pump up to a reservoir (can be in tank or out) that dumps back to the tank (or fuel cell) with an overflow.

Then a HP fuel pumps from there.
That way the HP pump wont ever get starved until the very end.
Using the LPFP in the tank it is less susceptible to damage from being run dry frequently.

Posted by: Racer Chris Aug 18 2014, 06:32 PM

A fuel accumulator is a small tank (1 quart or more) fed by a low pressure pump drawing from the tank, with a return line that goes back to the tank.
The return fitting is at the top of the tank so it stays filled at all times.

The primary fuel injection system draws fuel from the bottom of the accumulator and returns the excess back to the accumulator.

That way the high pressure FI system never sucks air unless the fuel tank is totally empty.

It is well worth the investment if you're chasing trophies.

Posted by: tadink Aug 20 2014, 03:13 PM

Thanks all for the input - but I don't think we still know why the Worn (OP)'s car and my car exhibit the same fuel starvation issues on hard left corners?

is a fuel pump upgrade the way to go?

any other thoughts???

td