Fuel Tank Issue
Thread Starter
Pro
Joined: Mar 2008
Posts: 552
Likes: 2
From: Dubuque Iowa
Fuel Tank Issue
I have a 1987 Z52 with a Manual trans. When my fuel gets just under half a tank my engine will sputter while ecellerating hard around corners. It is very annoying! I plan on running someday at a track for a few hours, and want to be able to run for more than half a tanks worth...
Anyone have any idea what the problem could be??
If the tank is above half, I have no problems what so ever!
Anyone have any idea what the problem could be??
If the tank is above half, I have no problems what so ever!
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
The filter sock on the end of the fuel pump is uncovered and the
pump is drawing air instead of fuel.
It is possible that the fuel pump assembly is not extending as far
downward as it might. Two tubes run down from the filler plate,
the pump is on the end of one and the sock is intended to sit
within the walls of a shallow tray that runs fore/aft slightly above
the tank bottom. Bends in the tubes can be manipulated to lower
or raise the elevation of the sock, relative to the tray.
Caution: fuel vapours are highly flammable. Flash photography
in the vicinity of the fuel tank may cause ignition of fuel vapours.
The simple solution is to ensure that the fuel level is sufficiently
high so as to prevent starvation while cornering.
.
pump is drawing air instead of fuel.
It is possible that the fuel pump assembly is not extending as far
downward as it might. Two tubes run down from the filler plate,
the pump is on the end of one and the sock is intended to sit
within the walls of a shallow tray that runs fore/aft slightly above
the tank bottom. Bends in the tubes can be manipulated to lower
or raise the elevation of the sock, relative to the tray.
Caution: fuel vapours are highly flammable. Flash photography
in the vicinity of the fuel tank may cause ignition of fuel vapours.
high so as to prevent starvation while cornering.
.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
fuel slosh (dammed gravity again) takes the fuel away from the pump...several avenues of attack:
1) visit your circle track parts vendor and spend $100 for "fuel cell foam blocks"...remove your pump/sending unit, squeeze the foam blocks and insert into tank, arrange blocks so they expand against each other to leave a space at the pump...(foam blocks will significantly slow fuel migration to tank corners while cornering)
2) get two "duck foot" fuel pick-ups from local circle vendor (see ATL fuel cells online), install second fuel pump, one duck foot at each rear corner of fuel tank to respective pump...mercury switch cut-off of pump power may be needed if track turns cause extended "dry run" of pump.
3) install low pressure pump inside fuel tank, feeding to new vertical configuration, limited capacity, "day tank"...day tank to contain high pressure pump for efi service and be of sufficient capacity to meet engine demand during cornering.
1) visit your circle track parts vendor and spend $100 for "fuel cell foam blocks"...remove your pump/sending unit, squeeze the foam blocks and insert into tank, arrange blocks so they expand against each other to leave a space at the pump...(foam blocks will significantly slow fuel migration to tank corners while cornering)
2) get two "duck foot" fuel pick-ups from local circle vendor (see ATL fuel cells online), install second fuel pump, one duck foot at each rear corner of fuel tank to respective pump...mercury switch cut-off of pump power may be needed if track turns cause extended "dry run" of pump.
3) install low pressure pump inside fuel tank, feeding to new vertical configuration, limited capacity, "day tank"...day tank to contain high pressure pump for efi service and be of sufficient capacity to meet engine demand during cornering.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
I used to have to run 10+ gallons to prevent sucking air during launches. After installing a 5 gal fuel cell, no problem. The rear sump at the bottom of the tank and the internal foam eliminate starvation. Larger ones with different pickup locations for tracking are available also.
Thread Starter
Pro
Joined: Mar 2008
Posts: 552
Likes: 2
From: Dubuque Iowa
I used to have to run 10+ gallons to prevent sucking air during launches. After installing a 5 gal fuel cell, no problem. The rear sump at the bottom of the tank and the internal foam eliminate starvation. Larger ones with different pickup locations for tracking are available also.
You would think GM would have tackeled this problem durring pre-production...
