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TR4 fuel pump problem


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On the way to Malvern my car came to  halt. Ignition fine, plenty fuel in tank none in carbs. 
Can fill float chambers using priming lever. Car runs till they empty. 

Remove pump top and inspect, nothing obviously wrong, glass bowl half a dozen tiny particles, fuel filter clean, Fuel runs out  freely if end of pipe from tank lowered.
Back home: remove pump, priming lever bit wobbly and moves around when  pumped. Gives hefty squirt.

Today fitted new mech pump. No change, all as above.

Unlikely to have new and old pump with same failure mode so must be in car, 
So what could it be? 

What if I just fit an electric pump  in series to mech pump? [ plus inertia switch?]}
Any suggestions as to best.?

[Felt extremely vulnerable broken  down on fast  main road: lesson - fit  hazard flashers and LED bulbs.]

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Mike  - rubber hose to carbs after pump collapsed due to ethanol in the fuel? I don't think adding to pressure by installing a second pump is agood idea because you haven't found the original problem and may very well create other ones - just my thoughts 

cheers Rich 

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If it works with the priming lever, but not from the cam, I would investigate the ammount of movement the cam lobe is giving. is the pump spaced away from the block at all ? that would reduce the effectiveness of the cam lobe.

Bob

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Unlikely perhaps  -  but when you fitted the new pump are you sure you got the operating lever sitting above the cam?  It is possible to accidentally have it below, in which case the cam doesn't operate the pump lever. 

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thanx suggestions

Rich - pump to carbs seems ok, but I will change 

Bob: The only spacer is paper gasket. Everything was fine until the engine simply cut out no stuttering or missing.

Rob:  I got it below the first time, but its on top now.

 -

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The only thing left then is to investigate whether the cam is moving the pump arm. If you take the top off the pump and crank the engine you should see the diaphragm moving up and down (but if it doesn't move it would be a real mystery).

  It is actually the spring in the pump that drives the petrol.  Using the priming lever or operating the arm pulls the diaphragm down against the spring and sucks in petrol from the tank.  I suppose it is possible you have two pumps with broken springs but the fact you can prime the carbs manually argues against that.  The only other thing is the non-return valves but again they must be working if you can prime by hand.

Edited by RobH
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Same problem on my 4A last year,

it was the additional fuel filter direct in front of the front carb.

It looked well and worked on tickover, but gave not enough fuel to drive.

Edited by Z320
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Noted the pump offer thanx.

AS it happens fuel filter is only  few hundred miles old and looks clear.

Moss catalogue says there is/was a rubber pipe to where the line goes through a cruciform chassis member. 

I checked the pump action and fuel line by jury rigging a 5 litre can straight to pump = no different. So not fuel line, has to be car or replacement pump (Could the cam inside the engine have gone AWOL ?)
 will refit the pump one more time and if that doesn't work switch to electric, if only to get the car to a workshop.

Any further ideas/comments welcomed

 

MIke

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If your timing chain had broken and the cam wasn't turning that's the only way there would be no movement of the pump arm. :wacko:

Stuart

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Have you changed the pipe from the pump to the carbs?

I had a problem that was caused by a bit of rubber from a failed pipe, that was stuck just before the needle valve on one of the carbs, only found it by spinning the engine on the starter with the float chamber removed and a contained beneath it to catch the fuel. You should get a defined spurt of fuel for each revolution of the camshaft.

Pete

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Problem solved.
The cam was not operating the pump lever on either pump. 
On the old pump there was considerable play in  the lever up down, left right and even in out
We surmise the lever slipped sideways off the cam lobe.

In the new one the operating lever also has a fair amount of free play and additionally was slightly bent. Enough to slide off the cam when being wiggled in to place. [Disconcertingly it was possible to bend it straight by hand with a pair of Moles.]

The cam lobe is quite narrow - not much more than the free play on the pump levers.

That explanation sums up 2 hours  this afternoon of head scratching, changing all the pipe rubbers again, blowing high pressure air up all orifices, testing the pumps off car, etc.. In the end the only logical conclusion was the cam shaft not working the pump and a eureka moment after comparing the two pumps side by side. The original pump is only about 4,000 mile old.

I'll read up what you're supposed to do for the dud spares report and see what joy I can get from the supplier. Hopefully they will recognise the wasted hours.

Mike

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Well it's a result I suppose but it does make you wonder.......

After that saga, if you want to go electric I can recommend a Huco pump. 

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1 hour ago, RobH said:

if you want to go electric I can recommend a Huco pump. 

Ditto 

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Well done!

Most problems are solved in your mind and not with tools in your hands.

Currently I drive an original one with cast lever (left side), the pin fixed with clips in both sides, the "play" of the lever is very low.

I bought the TR with a "Made in Canada" pump (right side), now my spare part pump (never needed) this had some play in the lever.

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iMyNSQAFnWWlV5OmiLsAWYhrmFYBI8bloI4ph7lV

To avoid what happened to you I put some DIY shims in, this should be also possible to do with standard shims.

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Q6PX8K_cdF13XBKF1jYM34j91PQiyJbDQhjQ3bl2

Just an idea for an DIY improved pump (all photos are from 2015)

Ciao, Marco

Edited by Z320
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Those pumps look considerably better quality than mine For example the lever  is made from a couple of stampings joined by a single rivet.

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Some of you may know I did a lot of modifications on my TR4A.

But I don't swap to an electric fuel pump for several reasons:

- electric unsafe voltage supply - crash switch needed

- pressure regulator needed

- a further electric part that can fail

- big filter bowl of the mechanic pump is a big benefit

- it does less filter - more separate by slowing down the flow and gravity  

My recommendation is to buy an original old one with a primer lever, alread refurbished or to DIY.

Once simple rebuild (and the lever perhaps shimmed) it will be very reliable.

Perhaps I make a post with old and some new photos...?

Ciao, Marco

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Hi all  - Here are some photos of a genuine AC Delco pump refurbished by Dave Davies. Just to be clear, the lever arm on the pump in the photos is steel which is copper coated - these were fitted to TR2-4.

TR4A ones had a laminated lever which was riveted together which have gained an unfair reputation for failure. Dave Davies told me he had never seen an original laminated arm fail - however there have been examples of repros with a similar arrangement failing which has tarnished the reputation of the original ones.

There are variations to the lever fixing arrangement in the body of original pumps which occurred over time but I'm not aware of any reliability issues concerning the variations.

Hope this is helpful

Cheers Rich

PS Sorry for the orientation of some of the photos - for whatever reason, they turn upside down when I load them and I don't know how to change them!

IMG_3398.JPG - Resized.JPG

IMG_3399.JPG - Resized.JPG

IMG_3400.JPG - Resized.JPG

IMG_3401.JPG - Resized.JPG

IMG_3402.JPG - Resized.JPG

IMG_3403.JPG - Resized.JPG

IMG_3404.JPG - Resized.JPG

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Hi Rich,

it would be GREAT you join with this info an photos my post about the 4 cylinder fuel pump (when I started it - sooner or later).

Perhaps you know what "the flag" is for at the diaphragm? I knew, but sadly I forgot it, because once refurbished this pumps it needs no attention anymore......

Ciao, Marco 

Edited by Z320
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A pressure regulator not necessarily required if you use the correct pressure pump like the Huco mentioned above.

Likewise some of the facet pumps are low pressure rated.

There have been problems with "New" mechanical pumps on and off for years - in your case simply not aligning properly with the lobes on the camshaft but some that simply are not lifted sufficiently by the cam lobe to pump as intended .  It's not just a TR issue - I had a similar issue with a Scimitar Se5A - the replacement pump came supplied with an insulationg gasket. However when fitted the lever barely touched the lever until the peak of the cam lobe. Swapped to a paper gasket and all was good.

Generic pumps with a baseplate to fit the bolt spacings but not an accurate reproduction for the claimed fitment.

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A post script  from me. I found the pump I put away the last time this happened about 10 years ago.. Great news (I think): It' a proper AC Made in England job, so I'll see about getting it done up;

Meanwhile please see picture of my two dud pumps and spot the difference! Can anyone explain why?

Mike

Pumps.JPG

Edited by MikeF
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