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Help Please. My TR6 conked our yesterday. When stopped I could hear the fuel pump in the boot whizzing away ( it doesn't usually make that noise. But the car would not start. After one hour the AA turned up and when I tried to start the car it fired up with no whizzy noise from the pump and I drove home 3 miles without a problem. An idea what' wrong? Thanks

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If you have PI and the Lucas original it is almost certainly fuel vaporisation leading to cavitation.

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I had a similar problem last year, having circumnavigated the Paris Peripherique in scorching weather. Gave it a while to cool down & it restarted. No problems since so I suspected cavitation.

 

I have a Bosch type pump (not Lucas) & although it tends to make a bit of noise after a couple of hours constant use I've had no further problems with it

 

Steve

Edited by Percy TR6
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these cars vary a lot !

 

my last TR6 did not like to run below a quarter of a tank, and made horrible noises when the pump got hot.

this was with a '996' bosch pump and then one of the replacement setups from a reputable supplier.

 

Current car will happily run right down to empty without a murmor, apart from on left hand bends when it is staved of fuel.

 

this again has a '996' pump.

 

nonetheless the 'keep the tank half full at least' advice is a sound, but I'd look into your pump, electrics to be confident they are all ok.

 

steve

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Cooling coils, and Bosche pumps recipe for disaster,

all it does is make the situation wuss. hidden by keeping a full tank.!!!

 

bigg filters are what ye need,

 

one before the pump, to get rid of frothy petrol, which has come frae the PRV / return , beofre it gets to pump,

and will also act as a swirl pot too

 

one after pump, to get rid of any cavitation froth, an theres alott of it .

 

one near the MU, to get rid of the same, beofre it gets to injectors, an stops em work,n

 

one on the return to tank

 

one frae the PRV to tank

 

pumps need a liquid to pump, they no like pumping air, air is in the frothy petrol.

this meks pump run hotter, then it meks petrol froth even moer, a vicious circle

 

moer so on a PI, as opposed to EFI where its a electric signal opens em.

as its pressure that opens the injectors, air less petrol cant be compressed, thats why the injectors open

frothy air riddled petrol can be compressed, hence injectors no open.

 

dee this, there no probs at all, what ever pump yer running.

im running 4, and never suffer any of the probs that folk keep going on aboot on here.

even when doon to last dreggs of petrol

 

M

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Hello Roy,

you don't say what setup you are running. It is the original Lucas, or a replacement 'bosch' type pump?

Also how long have you had the car? i.e. if you've had it for years has it normally run fine and is now suddenly giving problems. Or have you just bought the car and getting used to its normal behaviour?

As Steve D mentioned, these cars seem to vary a lot.

 

In short, I'm quite sure you have pump cavitation due to the fuel vaporisation. There are two main reasons this can occur:

1) the fuel filter is becoming blocked. When this does a small vacuum is created on the suction side of the pump, so making the fuel more likely to vaporise.

2) Or the pump is getting too hot (due to long duration running, and/or a long day)

 

For the second case if you are running the Lucas pump, my view is DO consider a cooling coil but make sure the returning petrol is put back into the tank NOT back into the CAV filter (that is a recipe for problems as the fuel short-circuits round a loop getting hotter and hotter!)

 

First case - I'd check you fuel filter and change that, make sure you buy a petrol filter, some suppliers incorrectly supply a diesel filter as that same filter housing was also used on diesel motors of the same vintage.

 

Myself - I'm running Lucas pump (rebuilt), with cooling coil and so far in my 2 years of use have not had issues even on hot days and low tank levels.

 

finally if you didn't know, for an expert on all things Lucas PI contact Neil Ferguson, he's on here as K Raven smith. He can rebuild pumps, injectors and Metering Unit 's.

 

Hope that helps,

James.

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  • 2 weeks later...

Thank you everybody for your help and advice. I am a new TR6 owner. It has a Bosch fuel pump but I had no idea about fuel cavitation - totally new to me. SO I shall check / replace the filters and perhaps fit a cooling coil. You are a marvellous bunch!

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Roy, if you have a bosch pump you can't fit a cooling coil (that's only for the lucas).

Bosch pump and motor run with fuel passing through them in the canistor design.

 

Yes start with new fuel filter first and look at how dirty the old one is. Will be an indication if it was the likely problem.

 

Good luck...

James.

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I remember taking a left hand bend last summer shortly after finishing the car when the tank was low and the engine conked out.. I didn't know about this issue so sat there in the middle of the road for about 30 seconds.. thought about the fact I had a little fuel.. thought about the side of the tank the feed was on, light bulb went off in the air above me and I tried the ignition, started straight away.. I always try to keep the level up now, if not I take left hand bends veeeeeery slowly :)

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Help Please. My TR6 conked our yesterday. When stopped I could hear the fuel pump in the boot whizzing away ( it doesn't usually make that noise. But the car would not start. After one hour the AA turned up and when I tried to start the car it fired up with no whizzy noise from the pump and I drove home 3 miles without a problem. An idea what' wrong? Thanks

Hi I fitted a second fuel tank in boot well it's fill from gravity only and is all ways full of fuel since doing no more problem with fuel

I posted a picture of this under (fuel in tank ). On this site

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