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MGB-GT Latest on '67 GT Woes

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tony barnhill

tony barnhill

Great Pumpkin - R.I.P
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* New SU fuel pump w.soft lines & banjo bolts & banjo unions
* Carburetors completely rebuilt w/ new air filters
* New clear in-line Fuel Filter

Fuel pumping into clear fuel filter (but not filling it) & into carb fuel bowls (but not filling them)

SU fuel pump never stops pumping....

No leaks anywhere....

So, I'm guessing the hard fuel line from rear of car to front is partially blocked....ergo, the fuel pump is pumping properly but can't pressurize flow fuel to the front of the car

(Oh, I can pump the tank dry with the fuel pump)

???????????????
 
Clear the fuel line from the pump to the tank. If that does not work remove the fuel line at the tank and clear the tank.

In fact I would blow out the fuel line from the pump to the tank just in case then the tank its self.

When was the last time you had the tank cleaned?
 
Silly question but are ye sure it's pumping and not sucking? I did this in my Jag and thought the same thing. I told my parts guy and thats what he told me. Turns out I had the lines crossed.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Silly question but are ye sure it's pumping and not sucking?[/QUOTE]

Rear end's up in the air again...

Yep, its pumping...when I disconnect the line at the pump & turn the pump on, it'll fill a bucket real fast.

I'm gonna blow the line out but I might as well drop the tank & take to the radiator shop for cleaning & lining.....I've had this car since 1998 have never had the tank out (but I've also never had any problems of this nature either!).

It has to be a fuel delivery problem though - & one that's keeping the fuel pump from pressurizing the system.
 
I'd love to see the inside of that tank after 9 years.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I'd love to see the inside of that tank after 9 years. [/QUOTE]

Well, I will in about an hour - that's how much longer I figure it'll take me to get the sucker out!

Back under the car.....
 
Well, looking down the filler, the inside of the tank looks brand new! Its been lined at some time in the past, by the PO.

.....& it is flowing strong out of the pump!
 
Thats cool. I wanted to see it cause my tank was the same age and looked like the titanic inside. I was able to have it lined so I'm not a DCO.
 
then I'd try to blow air thru the fuel lines. I told you not to fix that clock. If Laura was up to it, I'd drive down and get one of them running for you
 
I second Nial's vent check.

And try this: disconnect it at the carbs and put your thumb over it... Does the pump quit ticking or just rattle its brains out? It may be sucking air somehow instead of gas.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I told you not to fix that clock.[/QUOTE]

That was on my '79 Vermillion Red, chuck...you don't even want to know about it (#5 pushrod jumps off the rocker - no matter how many times I put it back on & adjust the valves!)...so, its sitting under a car cover in the middle row of cars until I get back from Europe in July...then, I'm gonna tackle its 102,000 mile never opened engine!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Float bowl vents OK?[/QUOTE]

Yep, best I can tell. They were clear when I rebuilt the carbs Friday & the overflow lines from both float bowls are the originals & are unclogged.

I've just finished reinstalling the new fuel pump after removing the hard line from the tank to it to make sure the line was clear.

Only thing left is cleaning out the line from the pump to the front of the car...can't believe that's the problem but its the only thing I've not checked....

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]...get one of them running for you [/QUOTE]

Seems this summer all my MG's are boycotting me...I want to drive my '79 Vermillion Red, my '67 GT, & my 74-1/2 GT this summer/Fall & they're all taunting me.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]disconnect it at the carbs and put your thumb over it[/QUOTE]

I'll try that tomorrow if blowing the hard line from front to rear doesn't do the trick - that line's already disconnected at both ends.

I've decided that my January 2008 trip to Korea will be the last Army trip for me...its time for younger men to take over....& I need to devote my time to 6 cars a year - that gets them all roadworthy in about 3 years.

And when I was at the body shop last week, they were ready to paint the fenders & tub of my '53 TD - when that's finished we'll need about a solid week to put the body back together so I can bring it home.

And I leave for Europe 27 May!

Plus, I've gotta get my '63 Midget ready for Spridget 2008 in Missouri & the last time I backed it into the garage in the Fall, the clutch was on its final leg.....the engine/transmission has to come out of it this Fall!

You guys with only 1 MG - think twice about buying another!

So, tomorrow, I drive the 380SL! Can't lose all this top down weather!
 
Tony, the fact that the pump never stops pumping is the killer. If the hardline was plugged to the front, the pump would build up pressure and stop pumping UNLESS the valves in the pump were leaking the entire flow backwards into the tank. I suspect the hardline being plugged is only half of your problem, a weak(leaky valves) fuelpump is the rest
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]a weak(leaky valves) fuel pump is the rest[/QUOTE]

Brand new SU right out of the box, Gerry...
 
That's no guarantee nowadays. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

If it'll pump a pint+ in a minute but keeps ticking when you block the outlet hose, something is allowing it to either suck air or as Gerry said, the checkvalves are somehow FUBAR'd.
 
Durn Tony, pump is bad right out of the box. You did not say it was a new pump. Gesh. Get another box off the slelf.
 
If the suction poppet valve was leaking through every time the pump made a stroke, gas would be pushed back into the suction line. The pump would never see the high pressure needed to bog it stroke down. With little or no back pressure on the discharge side the pump would pump forward all day long without a problem but would not buck and resistance, such as a pair of closed float valves, if you added it to the discharge pressure, but instead would leak backwards through the suction valve and just keep on running, just pumping the same gas back and forth through the pump. Visualize a single cylinder trying to run when the intake valve never fully closes enough to build up compression pressures. When the plug fired, the flame would travel back into the intake manifold rather than push the piston down with enough force to sustain the running of the engine
 
<u>Sunday afternoon late:</u> So, this afternoon, I replaced the filler to tank hose (the old one was hard) & blew out the gas line from the front of the car to the rear....then I added 2 gallons of gas & - VOILA - turning the key on, it filled the fuel filter & carb bowls & pressurized the system so the fuel pump stopped clicking!

I'm charging the battery right now so I can see what's been disturbed while rebuilding the carbs & doing a tune-up to the ignition system...I'm probably gonna have to do some minor adjustments to the carbs & static timing tomorrow.

However, progress!
 
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