The pickup inside the tank has a kind of filter so it doesn't try to pass
big bits through the pump. Maybe your chap got his sealant onto the pickup
and now it is severely restricted. A suction side blockage can make the
pump go faster, but not as fast as an air leak i.e. when you run out.
Remove a pipe from a carb and direct it into a container and switch on the
ignition. You should get at least 1pint per minute. If you get less than
this try blowing through the lines from pump to carbs and from pump back
into the tank, neither should show much resistance, and the latter should be
accompanied by much gurgling as air blows out of the pickup below fuel
level. Another cause of a suction-side air leak is perforation of the
pick-up pipe above fuel level, and this can cause symptoms just like having
run out even though the tank is still half full. If so, it's scrap.
You say if you take the gas tank off the car it starts? Do you mean that?
Or the gas cap? A 68 presumably has not charcoal canister and hence should
have a vented gas cap. A non-vented gas cap will cause fuel starvation, but
usually not until after the first few miles.
PaulH.
----- Original Message -----
From: "John" <John@all-the-facts.com>
To: <mgs@autox.team.net>
Sent: Friday, November 28, 2003 3:23 PM
Subject: Gas Tank Obstruction
> I have a 68 MGB. My gas tank was leaking from a rust through hole. I
pulled the tank off and hand it sand blasted which showed several more holes
and then took it to a guy who refurbished tanks with a POR-15 gas tank
sealer.
>
> I put the tank back on and my fuel pump went crazy. My shop manuel said
that it was a "suction side" air leak. I cleanred out the line from the tank
to the fuel pump (and for good measure, I replaced the carbuertor lines with
the stainless steel braided lines, it look great!)
>
> So now the car with idle very smoothly at 1000 rpm but when I accerlate it
will cut out and stall. If I take the gas tank off the car will start.
|