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no fuel after having the front of the car on stands

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Hi, guys. Here I'm going again. So, after successfully changing the lower inner suspension bushings, with the pride of an accomplished job, I hop on the car for a test drive. As it had been some weeks since I last started the car, I primed the fuel pump by pressing upwards on the small lever it has. I am surprised, as the lever goes up but, rather than feeling some resistance as the fuel is pumped, it goes up. And I don't see any fuel coming into the inline fuel filter. I then try to start the car and it doesn't (my TR4A has always started on the first attempt). I checked there was spark, just in case, and everything seemed fine on the ignition department. I then checked the carburettor fuel bowls and the second one was empty, with the first one half full. Pipes to.the fuel bowls unobstructed. I poured fuel in the bowls and car starts immediately, dying after less than a minute. Fuel bowl empty again. I think the issue can be traced to the fuel pump or the fuel hoses from the tank. Now, the front of the car has been for almost a week on axle stands, for the suspension job. Can this be related?. Maybe sludge from.the tank has obstructed the pipes due to the car being with the front up?.the transparent fuel bowl in the pump is full of fuel, with a sediment of sludge, but when I try to open it I get fuel dripping, suggesting that the fuel is getting there from the tank. Can the pump have been damaged fro being dry?. How can I check the pump without filling my garage floor with fuel?

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Is the fuel pump a repro as I have heard problems with them failing. I have fitted a repro to a TR4a and will be sending the original off for rebuilding as soon as.

Regards Harry.

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Not pertinent to your fault but the pump does not pump when the lever is raised, that is when it sucks in fuel from the tank. It pumps when the lever goes back down as the diaphragm is driven by the return spring (the strength of the spring determines the fuel pressure - which is pretty low for SUs. ). You will never feel much resistance as you raise the lever by hand.

 

Probably the only way you can check the pump itself would be to disconnect the feed pipe from the carb and run it into a jam-jar while you operate the pump by hand.

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Although it would seem that your pump is not working optimally and could benefit from refurbishment, you could pressurise the tank so as to push the fuel to the pump.

How?

Open the fuel filler, get a plastic funnel and stuff it into the orifice. Stuff a length of hose down the funnel so that it jams in the narrow part.

Operate the pump's lever whilst your assistant (preferably a brass player from the local band) blows down the tube.

 

Sceptical? I've done it, and it worked.

 

Ian Cornish

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Phil, the stands were placed under the front cross member, so no piping there, but good point.

Harry, I am not sure if the pump is original or replica it looks original to me and was perfectly fine to date, hence my suspicion that the failure is related to sludge in the tank having got into the tubes and pump due to the front of car being on stands for some time.

Rob, I already checked that the pump is not sending fuel by operating the lever and seeing that there is no fuel getting to the transparent online filter that is before the carburettors, but I will check again disconnecting the pipe from carburettor.

 

I have drained the fuel tank as much as I could and will put the car on stands again (front end), so I can clean the sediment bowl and dismantle the pump to check it with, hopefully, a minimum spill (if a lot of fuel is spilled in the garage I may not need to drink tonight to get high...).

If the pump is good, then it has to be the tubes from the fuel tank. I can use your suggestion, Ian, but I was wondering if it may be easier to do it the other way round (ie: blow from the pipe that goes to the pump, so that any sludge than.may be blocking the pipe goes back to the tank).

Thank you all for your replies. I will.keep you posted.

If anyone has ever dismantled the fuel pump, his experience and do's and don'ts will come in handy. My idea was to try to check the membrane on site (ie: without detaching it from the engine block, which I have read is tricky, as the inner bolt is a b... to get to) by undoing the top screws...

Merry Christmas to all TR4ers!

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If only the front of the car was raised it is likely that any blockage will be near the tank so blowing backwards down the fuel pipe seems a good idea. Is it possible that your in-line filter is the problem? Might be worth taking that out to check before starting to dismantle the pump.

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Check one part at a time, firstly put a clamp on the rubber inlet hose to the pump, then remove the hose from the pump, with a pot close by upclamp the hose and see if fuel flows from tank,

If not then try blowing through to tank. A car footpump with an adaptor is good for this.

If there is fuel flowing through from tank then as already suggested remove the filter. Check filter by blowing through it, visual checks tell you nothing.

Sort fuel flow before dismantling pump, there may be nothing wrong with it!

Best of luck.

Chris

Edited by potts4a

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I'm not keen on return sludge to the tank - it's almost inevitable that it will return down the line at some (most inconvenient) time. If sludge is your problem, perhaps it's time to remove the tank and give it the Sloshing treatment (see my article in Section K3 of the Technicalities CD).

 

In 1998, without disconnecting the pump from the engine block, I was successful in removing the top of the pump in order to replace the valves and the diaphragm/seal. It's been working well since then.

 

Ian Cornish

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If you find you do have a pump problem, I have spare nos original diaphragm and gaskets, and for that matter a spare original pump, newly rebuilt by Dave Davies, on the shelf . . . . .

 

By all means send a PM if you do find you need anything.

 

Cheers,

 

Alec

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Mr Ian Cornish, you are definitely a master TR4er... After dismantling the fuel pump and seeing (to my surprise) that everything was fine, y reassembled, filled up with gas, removed the stands and leveled the car, and I tried with your Funnel method. In my case, I had a large O ring from some plumbing job I did long ago in my sink, which fitted perfectly over the rim of the fuel cap assembly and against the Funnel. I did the solo version, blowing like crazy and then rushing to the pump manual lever. In almost no time, fuel was flowing into the glass bowl. Once glass bowl was full, I then took out the fuel hose into the first carburettor and suctioned while at the same time pressing the lever of the pump, until I had the gas flowing. I then reconnected the hose and did the same with the second carburettor. Car started at the first attempt and runs fine. So, after writing 100 times in my whiteboard "you HAVE to prime the fuel pump if the front of your car has been on stands for days", I am now heading to a Christmas dinner that will be merrier knowing that there is nothing wrong with my fuel system.

 

Thank you all. Merry Christmas

 

Enrique

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Great Result!

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I would......disconnect the inlet fuel line from the pump and pressurise the tank by using compressed air ...stuff some cloth in the petrol tank filling hole to help seal the hand blower, that will at first clear any debris from the fuel line and demonstrate correct fuel flow.

Then follow previous suggestions regarding testing pump etc.

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Enrique - I'm delighted that my simple method of pressurising the tank worked for you, too!

 

Keep a close watch on your pump's filter bowl as you may find more particles flowing into it from the tank. If this continues, removal of the tank and Sloshing will be the remedy.

 

Happy Christmas, and continue to enjoy your TR as we move into a New Year.

 

Ian Cornish

Edited by ianc

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Although it would seem that your pump is not working optimally and could benefit from refurbishment, you could pressurise the tank so as to push the fuel to the pump.

How?

Open the fuel filler, get a plastic funnel and stuff it into the orifice. Stuff a length of hose down the funnel so that it jams in the narrow part.

Operate the pump's lever whilst your assistant (preferably a brass player from the local band) blows down the tube.

 

Sceptical? I've done it, and it worked.

 

Ian Cornish

 

Best ideas are always simple ! Do not try this if your car' tank is ventilated by another orifice than the cap itself ;)

 

M2P : I use a roll of bicycle brake sleeve (without its plastic protection) as sweeping a chimney, to run it in the fuel pipe from the tank to the pump

.

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A little while ago I replaced the fuel line under the 4A with one complete run of new metal pipe. I removed the 2 rubber connectors under the car so thereby removing possible leaks/blockages in these 2 sections of pipe. Also installed an in-line fuel tap just before the fuel pump. This is located in the engine bay but below level of bottom of fuel tank. Can now use this to drain fuel tank if I need to and also isolate fuel pump from tank if I need to work on that. Simple modification but found it very useful.

Keith

Edited by keith1948

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I was thinking about adding a fuel tap, too. Definitely useful to clean sediment bowl... just have to remember to turn it on before driving. Alec, thank you for the offer, but everything's fine, so far. And then, Chris, thank you for your tip. Unfortunately I only read it after dismantling the pump, but now " check flow before dismantling pump" will be on the whiteboard alongside "prime your pump after leaving car on standa"

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Sorry me Enrique,

I can´t count how often I lifted the car front up and had it on stands for weeks, without ever any problem.

Guess you mix up two different stories to one rule.

Edited by Z320

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Keep the tap (8 mm) there where you can easy reach it while a repair on the road.

 

 

 

Edited by Z320

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