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Author Topic: MK2 GTI 8V idle speed drops  (Read 2048 times)

Offline PIPKIN

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MK2 GTI 8V idle speed drops
« on: 09 February 2011, 21:21 »
Hi all

Just a quick question when I remove the oil filler cap when the engine is running the revs drop.

Is this normal and if not what could be the problem.  If this is a problem how can I identify the specific concern.

Cheers

Paul
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Offline Khare

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Re: MK2 GTI 8V idle speed drops
« Reply #1 on: 09 February 2011, 21:26 »
It's normal. Engines run on a pressurized system, if you let the pressure out, they don't like it  :smiley:
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Offline rubjonny

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Re: MK2 GTI 8V idle speed drops
« Reply #2 on: 10 February 2011, 09:40 »
vacuumised ;)
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Offline Khare

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Re: MK2 GTI 8V idle speed drops
« Reply #3 on: 10 February 2011, 12:05 »
Quote from: rubjonny on 10 February 2011, 09:40
vacuumised ;)
dam! I was going to use that rather than pressurized but I didn't know which one, so I took a gamble!  :grin:
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Offline rubjonny

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Re: MK2 GTI 8V idle speed drops
« Reply #4 on: 10 February 2011, 12:30 »
if it was a turbo you would have been right  :grin:
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Offline Khare

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Re: MK2 GTI 8V idle speed drops
« Reply #5 on: 10 February 2011, 12:39 »
Ahhhh, NA runs on a vacuum, turbo on a pressurized system. Got it :afro:
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Offline rubjonny

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Re: MK2 GTI 8V idle speed drops
« Reply #6 on: 10 February 2011, 13:54 »
aye engine is in effect a rather big vacuum pump, as the cyls move down they suck air and fuel in so the intake is under vacuum. turbo puts the inlet under +ve pressure to cram even more air in there :)
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Offline Khare

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Re: MK2 GTI 8V idle speed drops
« Reply #7 on: 10 February 2011, 14:20 »
Makes sense  :smiley:

Top man as usual RJ :afro:
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Offline PIPKIN

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Re: MK2 GTI 8V idle speed drops
« Reply #8 on: 11 February 2011, 17:19 »
Cheers for the pointers and assuring me that a bill is not on the way.

Paul
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Offline javalin

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Re: MK2 GTI 8V idle speed drops
« Reply #9 on: 14 February 2011, 16:33 »
worth pointing out that the crankcase on both turbo and non-turbo shouldn't be pressurised, but under a slight vacuum.  The air intake is pressurised on a turbo though (boost) and slight vacumm on a non-turbo (upto the throttle butterfly of course).

J
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