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MG TD TF 1500 - Fuel line need to be primed?

I came home 'on the hook' (flatbed actually) the other night after getting my TD on its feet for the 1st time in 4 years.

I'd taken it on about a 10-15 minute jaunt around the neighborhood and all went well, so later in the evening I planned on taking it on a 4-5 mile run to heat everything up and burn the stickers off the new SS exhaust system I'd installed earlier in the day. I only got that two miles before it died. Right before it died I had turned on the marker lights when 400 yds or so later it started to sputter and die. I pulled off into a driveway as it completely died on me. I tried to restart in the driveway but didn't have enough charge to get it to turn over (I had not charged the battery for more than 45 minutes or so, and when it started easily I assumed I was okay). That made me think my problem was the charge. AAA came, brought me home on a flatbed and I charged the battery fully the next day.

Today I came out, popped the bonnet and turned the ignition to let the fuel pump do it's thing as I'd smelled fuel upon the car being pulled up onto the flatbed (and seen a puddle). When I turned the key the inlet side of the fuel pump started leaking. I turned the key off, removed the fitting coming to the inlet from the fuel tank and inspected. Nothing seemed unusual so I reinstalled and the same thing happened. I removed and reassembled again, and thinking maybe there was a blockage down stream, removed the line from the pump to the 1st float bowl and dropped the carb end of the line into a beer bottle to observe the fuel coming out of the line. My thinking was that if there was a blockage in the carbs, that might be creating the pressure at the inlet side of the fuel pump, causing excessive pressure and a leak. When I turned the pump back on I got about an ounce of fuel into the beer bottle, and nothing more. And no leak at the inlet side of the pump. But no more fuel after the 1st ounce.

Thinking maybe I now had something in the line from the tank to the fuel pump I shot a quick blast of air up the fuel line toward the fuel tank until I heard the bubble in the fuel tank (I had released the tank cap to allow the pressure to get back there). Confident that there wasn't anything clogging the line, I reassembled everything to the point where I had the line into the beer bottle again and turned on the pump, only to get nothing other than a running pump, but no fuel. Just in case it needed pressure on the outlet side, I reconnected the outlet (pump) line to the carb bowls, and nothing happened as far as I can tell because the pump ran for far too long (it usually stops when the bowls are full, BTW - Important to note I have a newer German fuel pump installed by the PO) and also after turning it off I checked for fuel in the inlet side and it was just as dry as when I had reassembled it, so I'm assuming no fuel got to the pump.

Any ideas what I have going on? Does the line need to be primed between the tank and the pump? It seems gravity would fill it all the way from the tank to the point just below the pump where it turns to come from under the car up the firewall.
Stan Griffis

check the filter in the fuel tank.
TRM Maine

Stan, These pumps are diaphragm type, self priming. If you disconnect the inlet pipe and put your finger over the inlet fitting, you should feel considerable suction when you run the pump. If not, it is possible that the check valve might be unseated by a foreign particle (or the diaphragm might be ruptured). In the SU pump, the check valve consists of a brass disk resting below the inlet fitting.
If you decide to replace the pump, I suggest that you consider an origional type SU. They are readily available new or rebuilt, and add a nice touch of origionality. They are also quite reliable. I opted for the solid state type-identical on the outside, but even less maintainance.
Steven Tobias

Stan - First thing to do is to tighten the inlet fitting into the pump body. Really reef on it to get it good and tight (it will take a tremendous amount of torque before stripping the threads, so don't be very gentle). Once that fitting is tight in the pump body, do the same on the outlet side (loosen the line between the outlet of the pump and the carburetor first) to insure that you have a good air tight joint and follow up on the filter plug on the bottom of the pump. Reconnect the fuel lines on the inlet and outlet (use two wrenches so the fittings in the pump don't turn), then try the pump again. If you still don't get any fuel pulled through, then there is a check valve issue in the pump. There is no clog between the pump and the tank as long as the pump continues to run. A clog on the inlet side of the pump will cause the pump to stall and if the power is left on, the pump will start getting hot. Cheers - Dave
David DuBois

I may be off the T series issue, but I had a related fuel problem in 1968 when I was stationed in Guam. I had a really ratty looking TR-3 but mechanically was a treat. I used to go to a native village way off base as they had some excellent bars with exceptional young women frequenting them. One night I must have upset some of the villagers, and soon decided it was time to get out of Dodge. Something about sisters? As I left town I found I was being persued, and heard gunshots. Gunning the TR-3, it started choking from fuel starvation, and before it completely died, I drove into the jungle and cut the lights. They passed and I spent the night in the jungle as it would not restart.
The next morning, I checked the fuel pump (mechanical with a glass sediment bowl) and found what appeared to be rubber bands in it, so I cleaned it, it started right up and I returned to the base.
To shorten the story, after many breakdowns of this sort, I removed the fuel tank and found that someone had dropped a golf ball into the tank and the fuel eventually rotted the ball and let go of the never ending winds of the ball to the fuel pump.
Just part of 45 years experience with British cars and one of many strange happenings. Bob
R.AF. Robert Finucane

Thank God that it wasn't lead as in bullet lead, not lead as an additive. John
John Hambleton

Robert - Now you've got me worried about golf balls.

I have a story, too long to relate here of my then 3 year old son dropping a golf ball into a location in a daily driver that had me and my mechanic hundreds of dollars down the path of a CV joint replacement before I discovered the ball rolling around in an under tray.

Maybe he's back up to his golf ball tricks? I hope not at 17.

I'll be checking the pump tonight to see which of these recommendations fault isolates the problem.

If it's the filter, am I correct in assuming I'll be emptying the tank? If so, at that point what do you all think of just acid washing the insides and 'slushing' it while I've got it empty?
Stan Griffis

Its not hard to remove (harder to put back on), you might just take to a rad shop and have it cleaned and coated....worked for me 5 years ago...!

So, Robert, you've got Stan worrying about golf balls. Me? I'm worrying about sisters. Thanks for the heads up.
G.E. Love

Stan - Cleaning and sealing the tank is not a bad idea, just as a general precaution. That said, the problem you are experiencing is not the filter in the tank. The filter will not cause an air leak. If it were getting clogged, it would stall the pump, not cause it to run continuously. Cheers - Dave
David DuBois

So it turns out that the German fuel pump installed by the PO (ticked like an SU though) cannot have the inlet line tightened too much as the plastic (yup, plastic) threaded inlet on the base will break completely off (Grr.....).

I'm looking on Moss' website for the correct SU Solid State pump and the one that says "MG TC-TD-TF to (c) 1509 Pos. ground" should be the right one for my Nov '51 manufactured TD (#11889), right?

I'm thinking this might be why it wasn't drawing fluid; if it had a crack there, it would suck air at the inlet pipe crack and never get enough pressure to pull from the tank (fingers crossed as I type this hopeful assumption).

Stan Griffis

Stan - Are you sure that the pump is German? The plastic pumps are generally from New Zealand. If I had known that your pump was plastic, I would have warned you about it.

"I'm thinking this might be why it wasn't drawing fluid; if it had a crack there, it would suck air at the inlet pipe crack and never get enough pressure to pull from the tank (fingers crossed as I type this hopeful assumption)."

You are exactly correct.

The pump you are quoting is the correct one for your car. cheers - Dave
David DuBois

David - No worries. If I hadn't cranked on it to that degree I'd have never found that it was split at the base and I'd have chased the problem around (assuming this is actually it - we'll know more after the new pump arrives).

I'm quite certain it's German. My father (the PO) confirmed he put it in, sometime in the 70's I think, when I was telling him what happened. Now I'm going to see if I can find a new base for it so that I'll have a solid state pump as a spare.
Stan Griffis

In the late 70's Moss or JC Whitney or somebody suppliled a SU clone (Harting I think) that was made in Germany and was plastic. George
George Butz

"Golf Ball"...took me back to one I forgot about long ago. Working on car lot as a kid in 67 ...bought a 62 Tempest Convertable for $25.00. Very cheap as the whole service department had tried to fix this one carb, new fuel lines,ect. Nobody wanted this "cursed little car". It would run fine unless you "got on it"...then it would just die. Had a ping pong ball in the tank that would "suck" against the fuel outlet. Took off the tank, rolled out the ball and drove it all summer before selling it for $700.00.
Cheers, & thanks for the "jog"
David 55 TF1500 #7427
David Sheward

This thread was discussed between 03/06/2009 and 06/06/2009

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