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For classic Porsche 911 content

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Boxer6
DDK Seasoned Poster
Posts: 34
Joined: Mon May 15, 2006 5:03 pm
Location: London/Sussex

first post

Post by Boxer6 »

Hello everyone! I've been watching the forums for a few months now with great interest and thought I'd take the plunge - I'll post some pics of my eldest child (gp white 79SC undergoing a savage backdate) asap.

One quick question..... I've noticed the idle drops when I remove the oil filler cap - is this normal? I am about to give the CIS a good going over and wondered if it was some kind of vacuum issue.... where should I start with my CIS rebuild?

Also I've started getting a misfire on warm-starts, is this the dreaded fuel accumulator or could it be something else?

Oh yeah, one more thing - my headlights (in fact all the lights, interior etc) dim slightly as the revs drop below around 1200 - is this normal or does my alternator need looking at?

Many thanks, look forward to joining in the fun!

Tim

PS Hi Andy (lightweight), your front wings are about to go on!!!
sladey
Nurse, I think I need some assistance
Posts: 9397
Joined: Sat Apr 23, 2005 9:08 pm
Location: Nottingham, UK

Post by sladey »

Welcome to the forum Tim

Not sure about the earlier cars but my idle certainly drops when I remove the filler cap - think it does on most cars

On the headlight you perhaps need to pop a couple more candles in there - I like the scented ones meself - doubles the power on full beam :wink:
The simple things you see are all complicated
I look pretty young but I'm just backdated yeah
Viv_Surby
DDK rules my life!
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Joined: Mon Jan 31, 2005 4:52 pm
Location: Cardiff, South Wales

Post by Viv_Surby »

Welcome Tim - hopefully you've been keeping an eye out for the SW London meets too!! 8)
.....AKA the Welsh driving ace - Carlos Monteverdi!

1969 Porsche 911R Homage - 'Prescilla'
Gilbert '71 T
I luv DDK!
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Joined: Sun Oct 03, 2004 9:12 am
Location: N London

Re: first post

Post by Gilbert '71 T »

Boxer6 wrote:One quick question..... I've noticed the idle drops when I remove the oil filler cap - is this normal? I am about to give the CIS a good going over and wondered if it was some kind of vacuum issue.... where should I start with my CIS rebuild?

Also I've started getting a misfire on warm-starts, is this the dreaded fuel accumulator or could it be something else?
Hi Tim

I've not experienced the first problem with CIS before but have heard it on some 3.2's Motronic systems. One thing you could check is the small breather filter canister on the side of the CIS airbox, make sure that's not clogged up.

Missfires can be all sorts of things, ignition or fuel, first thing you want to do is make sure the timing etc is all in spec. next I'd suggest testing your fuel pressure, I had a tester made shown here http://www.ddk-online.com/phpBB2/viewto ... l+pressure if your pressures are not within spec you may have a warm up regulator or pressure accumulator problem, i would expect a pressure accumulator problem to come up on cold starts rather than warm starts though, things like leaving the car overnight may cause the pressure to drop with a faulty accumulator.

If the fuel pressures come out good you could do a volumetric test on the injectors and metering head all in one go. Simply pull out all of the injectors and putting them into beer bottles or 6 containers of the same size and shape, switch on the ignition, remove the airfilter and push up on the airflow sensor plate, all of the inectors should give a nice even spray and let out the same amount of fuel at the same time (Continuous Injection System)

Re the lights dimming, I have a new alternator and voltage regulator and my car still does that a teeny bit, a good check is to see what voltage you are getting at the battery when the engine is running, if you get some spikes over 13.5 volts then it could be a alternator or voltage regulator problem, if you're at a steadyish 13.5 the everything should be ok.

Hope this gives you something to go on, might help you narrow things down.

Good luck :)
Darren
71 911T with C3 motor
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