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RobertN
Joined: 19 Apr 2015
Posts: 142
Location: Lisburn Co Antrim
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 Posted: Tue May 17, 2016 6:27 am Post subject: Cold idle problem |
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Hi Guys, got the emissions done 1.0 and passed the MOT. Good for another year 
Next morning she fired up but was very lumpy and struggled to idle at 950 until almost running temp. I had to hold the accelerator pedal slightly to keep her from stalling.
Could she be running too lean or too rich?? How do I maintain good cold idle if my hot idle is perfect!
Thanks.
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Robert.
Porsche 924 N/A 1984.
Electrical Engineering Sales to Control panel builders. |
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Ozzie
Joined: 12 Mar 2005
Posts: 4448
Location: Townsville, Qld. Australia
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| Posted: Tue May 17, 2016 7:56 am Post subject: |
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it could be a little more rich.
I think the maximum for MOT is 2
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Tue May 17, 2016 9:14 am Post subject: Re: Cold idle problem |
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| RobertN wrote: | | Could she be running too lean or too rich?? How do I maintain good cold idle if my hot idle is perfect |
Not answerable until: a) intake has been tested for leaks on a smoke machine, and; b) fuel pressures have been verified with a proper tester.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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RobertN
Joined: 19 Apr 2015
Posts: 142
Location: Lisburn Co Antrim
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| Posted: Wed May 18, 2016 2:15 am Post subject: |
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Thanks guys. Emission pass here is 4.5 CO and 1250 HC.
Yes need to invest on a cis tester.
Btw the idle screw is 6 full turns out from its seating point?? Too much?? Idle is around 950 hot.
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Robert.
Porsche 924 N/A 1984.
Electrical Engineering Sales to Control panel builders. |
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scm924s
Joined: 22 Oct 2010
Posts: 296
Location: Gloucester UK
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| Posted: Wed May 18, 2016 5:30 am Post subject: |
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Your emissions are too low IMHO, these things are best around 2 to 3%, I normally aim for 2.5, but it does vary car to car.
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1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold |
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RobertN
Joined: 19 Apr 2015
Posts: 142
Location: Lisburn Co Antrim
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| Posted: Wed May 18, 2016 6:07 am Post subject: |
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| scm924s wrote: | | Your emissions are too low IMHO, these things are best around 2 to 3%, I normally aim for 2.5, but it does vary car to car. |
You think I have messed the cold idle as a result of low co adjustment? She was always good before!! When warm she runs really well and starts perfectly.
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Robert.
Porsche 924 N/A 1984.
Electrical Engineering Sales to Control panel builders. |
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scm924s
Joined: 22 Oct 2010
Posts: 296
Location: Gloucester UK
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| Posted: Wed May 18, 2016 6:25 pm Post subject: |
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Poor cold start can arise from a number of problems, CSV or WUR not operating correctly, but my first thoughts in this case would be too lean a mix at idle
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1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold |
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RobertN
Joined: 19 Apr 2015
Posts: 142
Location: Lisburn Co Antrim
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| Posted: Wed May 18, 2016 7:11 pm Post subject: |
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csv okay. How do adjust the mixture from lean to rich? Clockwise turn??
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Robert.
Porsche 924 N/A 1984.
Electrical Engineering Sales to Control panel builders. |
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scm924s
Joined: 22 Oct 2010
Posts: 296
Location: Gloucester UK
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| Posted: Wed May 18, 2016 10:23 pm Post subject: |
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Yes, but VERY small adjustment has a large effect! Ideally a CO2 meter should be used.
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1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold |
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RobertN
Joined: 19 Apr 2015
Posts: 142
Location: Lisburn Co Antrim
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| Posted: Wed May 18, 2016 10:26 pm Post subject: |
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Cheers. I have a Gunson gas tester which I use for the mot tests.
Thanks again.
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Robert.
Porsche 924 N/A 1984.
Electrical Engineering Sales to Control panel builders. |
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