Petrol draining back .............. is this common, gents?

[Linegeist]

Stone me! I hadn't thought of that lot .............

Now you lot have gone and given me a headache! This time yesterday, everything was soooo nice 'n simple.

Bunch of mad scientists you lot are!

[mat_fenwick]

Will the eletric pump free flow if not in use?

Good point - if it doesn't you could bypass it with a length of pipe so that the mechanical pump always has an unobstructed path to the tank. That may need to have a non return valve in it to prevent fuel being pumped in a circle and not to the engine.

[KevR]

I was thinking of heating the air in the airbox of the diesel to assist with cold starting

Blimey, you do like to over-complicate things, don't you...

If the battery and the glow plugs are fine and the engine's in reasonable nick, it should start on the button way down below any temperature you're likely to encounter (and/or are likely to want to go out in). Below that the diesel will probably have frozen anyway and the oil will be like treacle so you'd be better off heating those (pre-heater for the sump...?) than the air, surely. And given how much air the engine gulps per cycle and how small the airbox is, you'd surely need to heat more than one airbox-full in order to make any difference, which would presumably need a hefty heating element in order to keep up, and if the battery can cope with that at the same time as running the starter and glow plugs, it ought to start the damn thing easily enough on its own!

There must surely be more pressing issues to which you can apply yore grate brane...

[electrokid]

Blimey, you do like to over-complicate things, don't you...

You're not wrong there Kev

There must surely be more pressing issues to which you can apply yore grate brane...

Indeed there are which is one reason I haven't even got around to fitting the new glowplugs yet Another reason is I want to modify that bit as well to provide a current monitor for each glowplug.

I think we've come full circle back to...

Blimey, you do like to over-complicate things, don't you...

[electrokid]

Will the eletric pump free flow if not in use?

Probably - it's likely to be a turbine. Easy to test - try blowing through it.

[Linegeist]

Will the eletric pump free flow if not in use?

Probably - it's likely to be a turbine. Easy to test - try blowing through it.

I'm a sucker for turbines........................

Erm .......... I'll just get my coat.... OK?

[Nat]

wrong place sorry

[Linegeist]

Why? I know this isn't exactly a haberdashers - but still ......

[Linegeist]

Okayyyyy - got the drainback problem sorted at last - by fitting the electric fuel pump in series with the existing mechanical pump.




Then it was a simple matter of wiring in a relay actuated by a small discreet press-to-make switch (Maplins = 95p) which I mounted down by the door mirror switch, taking the pump and relay feed from the fuel shutoff feed (amps to spare)



Now, after the car's stood for a few days/weeks, all I need to do is turn on the ignition and press the button for 5 seconds to 'prime' the fuel system. You can hear the pump chattering away until the line's full, then it shuts up, whereupon the car then starts on the first turn of the key after a single pump of the loud pedal to prime the manifold with the accelerator pump. The mechanical pump then takes over drawing the fuel through the now 'off' electrical pump. Sorted!

Finally, the starter motor can take a well deserved break. Recommended mod this one!!!

[MULLEY]

Hope you've declared this mod to your insurance co

[electrokid]

Nice one Bob

hear the pump chattering away until the line's full, then it shuts up,

So it's probably a diaphram pump (like an SU) rather than a turbine ?

[Linegeist]

So it's probably a diaphram pump (like an SU) rather than a turbine ?

It looks like it Brian - there's certainly something making an SU-like sound. I doubt it has points 'n stuff (they went out with the Mk IV chariot if memory serves ) hence its manufacturer's claims that it's solid state.

If it packs up, I'm going to dissect it - just out of curiosity.

Again, out of curiosity, would it not be possible to mount one of these in-line into the BX diesel system upstream of the HP pump, between tank and filter, say? It seems to me that it would make priming a whole lot easier than having to stand there doing the kinky massage thing on that weird rubber bulb! It'd make bleeding/purging and diagnostics simpler too as, with the flick of a switch, you could pressurise the whole LP delivery pipework to about 6psi or so.

Wow! That was an idea!! I think I need to go and lie down ...................

[electrokid]

Thanks for the info Bob - I was looking at one of these as an alternative to the cylindrical type which are a bit more expensive - I'm thinking ahead to what I want to do with the petrol 4x4 - in fact thinking way too far ahead since I need to get on and fettle it and get it through its MOT etc but the fuel system needs some work anyway.

a whole lot easier than having to stand there doing the kinky massage thing on that weird rubber bulb!

That's something I don't normally mind doing except when the weather is like it is today - 'raining on the just and the unjust alike' - actually more like pissing mightily on our heads - then it really does look silly - and I get wet !

I think I've found the intermittant air leak - the accelerator control spindle on the pump is worn and wobbly and there's a hissing sound if it's pushed slightly to one side - I've got a Bosch spindle recon kit (£90 + ! !) but I've had more interesting things to do so it's still in the pack

hence its manufacturer's claims that it's solid state.

Possibly uses a 'hall effect' device - they change their resistance with changes in magnetic field so a small magnet on the moving part could sense the position of the diaphram - or it could be an IR LED and a light sensitive cell where the light path is interrupted or not depending on the position of the diaphram - as you say - loads more reliable than the SU contacts.

Does spoil the fun though in the days of the Morris Minor when it wouldn't start you could get out of the car with spanner in hand as if you were going to do something really technical - then lift the bonnet and bash the fuel pump with the spanner to get it running

[Linegeist]

Does spoil the fun though in the days of the Morris Minor when it wouldn't start you could get out of the car with spanner in hand as if you were going to do something really technical - then lift the bonnet and bash the fuel pump with the spanner to get it running

Oh such memories!!! I had an Austin Healey sprite (same horse - different jockey - same problems) when I was a kid, that required exactly that procedure (usually when the girlfriend of the moment was watching and I had a desperate need to impress). I couldn't afford a new pump on an engineering apprentice's pay of course, and the points had been filed so much they were mere stumps - but, unlike modern, no-fix chuck-it kit, you could always bodge some kind of fix to get you home. S'why I like carbs 'n stuff ............... I can figure out how they work.

Usually.

[electrokid]

I had an Austin Healey sprite

I would have thought that was impressive enough I only ever had 'small engined sensible cars' - until 1989 when I was cured