Fuel System Issues

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Ian_Fearn
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Fuel System Issues

Post by Ian_Fearn » Thu Nov 16, 2006 9:35 pm

We had a petrol leak the other week on the GTi. Item 10, described at a 'Pulsation Buffer' had rusted through and was leaking.

Its in an extremely awkward spot so i bypassed it with a length of fuel pipe. The car passed its MOT today emissions as follows: 0.71% (max 3.5%) and 177ppm (max 1200ppm) so its running well enough BUT we've lost 6mpg seemingly since i did the mod.

Image

Can anybody shed any light on this? We're now down at 21mpg.
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tim leech

Post by tim leech » Thu Nov 16, 2006 10:18 pm

Im no teccy, but I would get another one stick it on and see if you get your fuel economy back?

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Post by Way2go » Fri Nov 17, 2006 3:32 am

Presumably if it does what it says on the tin then it smooths and makes an even pressure in the injector bar in conjuction with the pressure return valve. When the injectors are closed all pressure surges will be returned to the tank. When the injectors are open any surges from the pump will take the path of least resistance through the open injectors before the return valve opens.

If you check your plugs they are also likely to tell you that you are running rich.
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thanuttiscotsman
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Post by thanuttiscotsman » Fri Nov 17, 2006 9:07 am

Way2go wrote:Presumably if it does what it says on the tin then it smooths and makes an even pressure in the injector bar in conjuction with the pressure return valve. When the injectors are closed all pressure surges will be returned to the tank. When the injectors are open any surges from the pump will take the path of least resistance through the open injectors before the return valve opens.

If you check your plugs they are also likely to tell you that you are running rich.
that sounds right to me. :D
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Post by docchevron » Fri Nov 17, 2006 10:21 am

Yep, you want to be replacing that matey.
Without it the line pressure in the system will be all to cock.
Should sort you're consumption out immediatley.
Your spark plugs will thank you for it and the injectors will be pleased too!

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tim leech

Post by tim leech » Fri Nov 17, 2006 10:47 am

:D

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Post by Way2go » Sat Nov 18, 2006 11:39 am

Have you recovered your lost economy yet? :?
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Post by Ian_Fearn » Sun Nov 19, 2006 3:48 pm

No, i need to get on the blower to Citroen first thing on Monday morning. The dealers round here are useless. They can sometimes take weeks to get BX parts in.
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Post by tim leech » Sun Nov 19, 2006 4:01 pm

And cambelt kids for Xantias! Derbys a bit better than burton but not much.

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Post by Mike E (uk) » Sun Nov 19, 2006 11:04 pm

I had this break on my GTI.

I bypassed it too, and never noticed any difference.

If CO is 0.71%, doesn't that mean it is not running too rich?

21mpg is really poor, are you sure you haven't still a fuel leak somewhere?

Mike

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Post by docchevron » Sun Nov 19, 2006 11:27 pm

That surprises me Mike. Good call though, the emissions suggest that it aint running rich.
That said, without the "damper" present the fuel line pressure will (or at least should be) all to hell, but again, the emissions suggest otherwise?

Interesting! :D :shock: I'd still fit a replacement and see what difference it makes. If it makes non then maybe the pressure reg has packed up but surely too much of a coincidence if it all happened at the same time?

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Post by jeremy » Sun Nov 19, 2006 11:48 pm

I would have thought that a substantial drop in fuel consumption would have shown up as a smelly exhaust, loss of power, black smoke or something - and not to be completely symptom free.

Polyester resin (fiberglass resin etc) used to be proof against leaded fuel - in the long term - and I've used it and some matting to repair rusted out fuel tanks on a number of occasions - and it may be that for test purposes you could repair the unit and see if it makes any difference.

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Post by jeremy » Mon Nov 20, 2006 12:27 am

I would have thought that a substantial drop in fuel consumption would have shown up as a smelly exhaust, loss of power, black smoke or something - and not to be completely symptom free.

Polyester resin (fiberglass resin etc) used to be proof against leaded fuel - in the long term - and I've used it and some matting to repair rusted out fuel tanks on a number of occasions - and it may be that for test purposes you could repair the unit and see if it makes any difference.

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Post by Cornishbx16v » Mon Nov 20, 2006 12:10 pm

several of our guys on 16v.co.uk have bypassed theirs with no ill effects!
i replaced mine when it went as wasnt on the forum then! but was lkess than a tenner from citroen! had i been on the forum i would have prolly bypassed it as the others!!!!
Timmo.

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Post by Ian_Fearn » Mon Nov 20, 2006 4:51 pm

Its £35 now from Citroen. Have ordered one.

We're going down the LPG route with it as we're unlikely to find a better car out there given what we've spent on it already but the fuel consumption makes it too expensive for me to use although the missus does much less mileage than me.
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