Adjusting the fuel pump

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Oscar
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Adjusting the fuel pump

Post by Oscar » Thu Sep 08, 2005 12:49 pm

Hello

Tom mentioned recently getting 55mpg after fiddling with his motor. Anyone able to give me an idiot's guide to turning down the fuelling on the (LucasCAV) pump? I need to achieve better mpg than I'm getting, and can afford to lose some top speed.

BTW, on Andyspares when I asked this question, Turbolag replied to the effect that the desired effect could be achieved by taking my foot off the right hand lever in the driver's footwell. This was funny, but not much help : )

Thanks for all contributions.

Oscar
(Red BX 1.7TZD ("Well, it is a style icon" - Tom Sheppard)) "Was", Tom, "was"

Stewart (oily!)
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Post by Stewart (oily!) » Thu Sep 08, 2005 6:11 pm

I have a set of instructions for doing the opposite, let me know your email and I suppose you could read them backwards :D , exactly how much fuel is it using? have you got dragging brakes or something?
Stewart
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Xantia Td estate, going soft

jeremy
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Post by jeremy » Thu Sep 08, 2005 7:00 pm

A diesel engine works on the principal of free air and has an unobstructed intake. The power output is therefore entirely dependant on the amount of fuel supplied - and the pump simply controls this. The amount is controlled by your right foot. The pump can deliver too much - in which case the car will emit black smoke caused by incomplete combustion. The timing can also affect the combustion efficiency and can result in white smoke and or excessive noise.

Good combustion needs clean filters and an engine that is in good condition.

Jeremy

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Oscar
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Post by Oscar » Fri Sep 09, 2005 11:33 am

Jeremy

The point is well taken and I pay attention to speed now, but your message and Stewart's contradict each other, so I will tinker a bit and feedback. This is after all, a long-term process of learning experiment for me, so all experience is useful.

O
(Red BX 1.7TZD ("Well, it is a style icon" - Tom Sheppard)) "Was", Tom, "was"

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cavmad
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Post by cavmad » Fri Sep 09, 2005 12:51 pm

If you do find out could you please post up the details? My estate is using more fuel than I`d like-o.k it`s a bigger engine and a bigger car than my 1.7 diesel hatch but any saving is a good one. I`ll have a go at replacing the air filter and possibly the fuel filter and ease off the right foot too but any extra is a bonus.

The prinicpal of free air interests me, does anyone think it would be worthwhile having a larger/better air intake? I`m thinking similar to the plastic pipe supplied with K+N type air filters which clips onto the grill and has a larger bore to increase the amount of cold air fed in?
Vauxhall apologist.

Stewart (oily!)
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Post by Stewart (oily!) » Fri Sep 09, 2005 3:32 pm

I once ventilated the standard black plastic airbox on my old TD BX, I peppered it with inch and a quarter holes, to my mind the thing did breathe a little easier but it sounded like an old two stroke commer breadvan, these days I run the standard airbox but with a foam panel element made by scorpion, theres a little more inlet noise and a bit more go, ot improve economy try the ebay under pedal brick :D
Stewart
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Xantia Td estate, going soft