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MG TD TF 1500 - Do I have a fuel pump problem?
|When I restored my early TD twenty years ago and changed to a negative ground, I installed a new "solid state" fuel pump. After being off the road recently for some time (12 months), I began having what I thought was carb problems. I would turn on the ignition and both fuel bowls would fill. However after driving the car less than 1/4 mile the engine would start running rough. I would turn the car off and checking the fuel bowls, I would find the front bowl empty. I checked everything and even replaced the gross jets. Still the front carb's fuel bowl runs dry.|
Now I'm wondering if is a fuel pump problem. I disconnected the fuel line from the back carb and ran it into a bucket. I turned on the ignition to see how fast the fuel pump will pump. It makes a "click" and squirts out a stream of fuel (maybe 1/2 oz)--stops for about 2 seconds, makes another click and pumps out another stream of fuel. Is this how the pump should work? Should these short spurts and 2 second pauses be enough to keep both carb bowls full?
|2 seconds seems like a long wait between pumps, if my memory serves me right my pump will pump faster than that when pumping into a bucket. But I would start by looking to see if your front bowl is leaking. Check the cork jet washer and see if fuel is getting past it...|
|Geoffrey M Baker|
|It sounds more like a stoppage in the discharge of the pump,, is there a filter at the discharge of your pump that might be plugged up ?? If the fuel flow is stopped, the pump will stop pumping. As the fuel seeps past the blockage, it will start pumping again..|
|When the fuel is being pumped out (after the click) it is a full and forceful stream--it does not dribble out. It comes on for less than a 1/2 second and then cuts off smartly. But I seem to remember in the past the clicks were much more frequent --perhaps 3 or 4 per second.|
|It sounds like there is a blockage somewhere in the pump. It could be filter, valves, or a venting issue. Is the pump fully electronic or do you still have points?|
20 years without regular cleaning and maintenance is a long time, so it sounds like a good overhaul is in order.
There are a few of us who rebuild the SU pumps. I am one, Dave DuBois is another, but Dave only does them in the winter months. I do them anytime. I've just rebuilt 12 in the last two weeks.
Contact me off-site for more information at
lew (at) roundaboutmanor (dot) com
|Sounds like your fuel pump is having prostate problems it happens at our age|
|S E Bryan|
|Thanks guys for the good advice. I think I'll take a peek inside the pump and see if anything is obvious. An yes, SE Bryan, you have a good point about the prostate. I had proton therapy 4 years ago and never thought about bringing my fuel pump into the radiation chamber with me. Perhaps I could have avoided this "flow" problem if I did....|
my bet is on a plugged filter,,,
|Doesn't sound like a fuel pump problem. I'm assuming only the front bowl is dry and the rear one is full. Therefore it is most probable that the screen filter at the front carb bowl is (partially) blocked or there is a blockage in the fuel line going to the front carb.|
|Joe - You can check the fuel pump by removing the fuel line going into the rear carburetor and directing it into a quart jar that is marked at the1 pint level. Turn on the ignition and time how long it takes to pump 1 pint of fuel in 50 seconds. If it doesn't pump that much fuel, I would start by looking at the filter in the body of the fuel pump first, then look at the filter on the outlet side of the fuel tank. ?Cheers - Dave|
|I would replace the flex fuel lines. I bet they are all breaking down internaly.|
Thanks for giving me an idea how long it should take to "Pump a Pint." I pumped it for a full minute and got exactly 1.5 oz. I guess I will be checking those filters (I didn't know there was one inside the pump) -again thanks all.
|I second Sandy's recommendation. If you don't know the age of the flex fuel lines, replace them - they break without warning and will then spray fuel all over the manifold... happened to me...|
|Geoffrey M Baker|
This thread was discussed between 10/09/2015 and 11/09/2015
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