>
> 1. Install another electric fuel pump close to the fuel tank,
> probably a 5 to 7 psi one.
We have a switchable electric pump immediately after (in terms of fuel
flow) the tank switch. We have never needed it unless something adverse
happens to the fuel delivery system.
>
> 3. I already have vents at the rear corners of the motor box. I am
> considered putting in some 4" dryer ducts behind the grille to force
> more air into the motor box area.
We have a 4" duct from the grille that does a 90 degree turn and blows
on the distributor. Without this duct, Ron and Gina's neighborhood tends
to eat our ignition modules, when towing car trailers in the summer.
This failure once perfectly mimiced fuel delivery problems, and since we
*did* drain about a half pint of water out of the filters, and
commiserated with two other vehicles that had come to rest on the
roadside with water-filled injectors after filling where we did, we
wasted about 6 hours trying to "fix" the fuel system before we finally
changed the module.
Last July, we got about two quarts of water and mud from what looked to
be a brand-new station in southern Colorado (no extra charge). We left a
trail of clogged fuel filters from Pueblo to Salt Lake City. Our tank
selector switch never again allowed enough fuel through to pull the
trailer up a long grade. We also had to install a new carb deck gasket
before the GMC ran good again, since the backfires ate a chunk out of
the previous one.
I don't know if it's true of all, but our GMC *always* first announces
any malaise with a backfire. Consequently, we are very experienced at
changing manifold and carb deck gaskets.
We have about an inch of urethane under the floor and hatch in the
engine bay, and Reflectix above the floor. We use a large A/C condensor
for an auxiliary tranny cooler, and the biggest, most dense radiator
core we could install. We have stainless, uncoated headers, and are
usually towing 4,500 to 9,000 pounds of enclosed trailer, so we do make
some heat in the engine bay.
We have almost always run the original quadrajet, with the original fuel
delivery, except for two of the biggest fuel filters we can find in each
line from the tanks, the auxiliary electric pump after the tank switch
(for emergencies), and a third filter before the mechanical fuel pump. I
have usually not had the quadrajet's inlet filter installed. We have
been running many times in near 120 degree temps, and up to 11,000'
AMSL, but I don't really know what the worst case for
altitude/temperature is that we have seen. Our GMC has gone from central
Texas to at least Phoenix on I10 every July or August (or both) for the
last four years.
Walt Taylor
Austin, TX
'75 Eleganza
> 1. Install another electric fuel pump close to the fuel tank,
> probably a 5 to 7 psi one.
We have a switchable electric pump immediately after (in terms of fuel
flow) the tank switch. We have never needed it unless something adverse
happens to the fuel delivery system.
>
> 3. I already have vents at the rear corners of the motor box. I am
> considered putting in some 4" dryer ducts behind the grille to force
> more air into the motor box area.
We have a 4" duct from the grille that does a 90 degree turn and blows
on the distributor. Without this duct, Ron and Gina's neighborhood tends
to eat our ignition modules, when towing car trailers in the summer.
This failure once perfectly mimiced fuel delivery problems, and since we
*did* drain about a half pint of water out of the filters, and
commiserated with two other vehicles that had come to rest on the
roadside with water-filled injectors after filling where we did, we
wasted about 6 hours trying to "fix" the fuel system before we finally
changed the module.
Last July, we got about two quarts of water and mud from what looked to
be a brand-new station in southern Colorado (no extra charge). We left a
trail of clogged fuel filters from Pueblo to Salt Lake City. Our tank
selector switch never again allowed enough fuel through to pull the
trailer up a long grade. We also had to install a new carb deck gasket
before the GMC ran good again, since the backfires ate a chunk out of
the previous one.
I don't know if it's true of all, but our GMC *always* first announces
any malaise with a backfire. Consequently, we are very experienced at
changing manifold and carb deck gaskets.
We have about an inch of urethane under the floor and hatch in the
engine bay, and Reflectix above the floor. We use a large A/C condensor
for an auxiliary tranny cooler, and the biggest, most dense radiator
core we could install. We have stainless, uncoated headers, and are
usually towing 4,500 to 9,000 pounds of enclosed trailer, so we do make
some heat in the engine bay.
We have almost always run the original quadrajet, with the original fuel
delivery, except for two of the biggest fuel filters we can find in each
line from the tanks, the auxiliary electric pump after the tank switch
(for emergencies), and a third filter before the mechanical fuel pump. I
have usually not had the quadrajet's inlet filter installed. We have
been running many times in near 120 degree temps, and up to 11,000'
AMSL, but I don't really know what the worst case for
altitude/temperature is that we have seen. Our GMC has gone from central
Texas to at least Phoenix on I10 every July or August (or both) for the
last four years.
Walt Taylor
Austin, TX
'75 Eleganza
