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Join Date: May 2002
Location: Up North
Posts: 1,449
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High idle after engine warms up...
Hi,
I run into a small problem that really bugs the h*** out of me. After the engine warms up, AND you drive it for a while. After I remove my feet from the accelerator (say stop at a light), the idle will most of the time go from the normal ~850 to around 1300rpm. It might stay there for a long while then drops back, or sometimes it will just stay there. I though it might be a sticky throttle linkage, but it seems to return to normal position everytime. Any thoughts? thanks...
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87 930 K27HFS/B&B/Twin-Plug... Megasquirted 
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08-23-2002, 11:09 AM
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Registered
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,468
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below the intercooler is a deceleration valve. the large round gold thing. remove the small hose from the middle of it and plug the hose. then see if it makes a difference.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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08-23-2002, 11:42 AM
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John, my car does the same thing. Can you permanently bypass this valve?
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It's not important to be the best, just do your best. |
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08-23-2002, 01:01 PM
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Location: MA USA
Posts: 2,938
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Yes you can get rid of the decel valve if you want.
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Dean 911 SC turbo, 3.0L 930 motor, G50, 930 brakes, DTA EFI, 352 RWHP DynoDynamic dyno, |
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08-23-2002, 05:40 PM
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Crotchety Old Bastard
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What is the effect after elemination of the decel valve?
What function does it serve in the stock application that is not needed by the enthusiast?
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds '78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8 |
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08-23-2002, 05:45 PM
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Location: MA USA
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I think the decel valve was put on for emissions. With the valve removed you idle will go down to normal much faster. Like a car should.
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Dean 911 SC turbo, 3.0L 930 motor, G50, 930 brakes, DTA EFI, 352 RWHP DynoDynamic dyno, |
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08-23-2002, 05:54 PM
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Join Date: Jun 2001
Location: Sweden
Posts: 5,911
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Is this decell-valve???
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Thank you for your time, |
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09-11-2002, 06:33 PM
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Crotchety Old Bastard
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Yes, that's it.
Mine is history. We'll see how she runs without it.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds '78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8 |
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09-11-2002, 06:51 PM
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Join Date: Nov 2001
Location: AUSTRALIA
Posts: 3,492
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Guys, I take it this is the same or similar setup on an NA 3.2? Mine suffers similar symptoms.
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Audi B7 S4 |
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09-11-2002, 07:52 PM
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Formerly bb80sc
Join Date: Aug 2001
Location: Hollywood Beach, CA
Posts: 4,361
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JW et al,
I recently unplugged the decel valve on my 80SC. I notice a bit of popping on decleration, I assume this is now considered normal? Also, some folks refer to *smashing* the decel valve a few mm to cure the high idle problem. Is there an actual procedure to do this? TIA -Brad 80SC |
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09-11-2002, 08:29 PM
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Allright this was really interesting!
If I want to unplug the decel valve should I just plug the tubes or should these be connect together so the flow passes by? /J
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Jocke Andersson Reach me on ICQ - 317860713 Porsche 930 -77 SOLD Modified, one of a kind in Sweden. Check out my car @: http://members.cardomain.com/jocke |
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09-11-2002, 10:48 PM
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Location: MA USA
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If you want to take the decel valve out you should plug the openings, not connect them together.
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Dean 911 SC turbo, 3.0L 930 motor, G50, 930 brakes, DTA EFI, 352 RWHP DynoDynamic dyno, |
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09-12-2002, 06:20 AM
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Registered
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Quote:
But the smaller tube "on the decel valve"must be plugged?, have I understand it right then? /Jocke
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Jocke Andersson Reach me on ICQ - 317860713 Porsche 930 -77 SOLD Modified, one of a kind in Sweden. Check out my car @: http://members.cardomain.com/jocke |
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09-12-2002, 07:06 AM
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Location: Sweden
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Is it enough just to disconnect the middle-hose on the picture and plug it w/o removing whole valve and plugging two hoses behind?
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09-12-2002, 07:35 AM
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Location: MA USA
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Unless your valve is blown. Then you have to take out the unit and plug the ports. I would take the whole thing out anyway. It cleans up the engine compartment and saves about 1/2 lbs. Woo-hoo
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Dean 911 SC turbo, 3.0L 930 motor, G50, 930 brakes, DTA EFI, 352 RWHP DynoDynamic dyno, |
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09-12-2002, 01:36 PM
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Join Date: Jun 2001
Location: Sweden
Posts: 5,911
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Hmmm...
I heard stories of flames belching out on high-rpm lift-off when deccel-valve is plugged...True?
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09-12-2002, 04:36 PM
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Location: MA USA
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I wish I had flames. It doesn't happen on my car. The only thing that I notice is that the idle returns like it should and the exhaust burbles alot.
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Dean 911 SC turbo, 3.0L 930 motor, G50, 930 brakes, DTA EFI, 352 RWHP DynoDynamic dyno, |
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09-13-2002, 04:14 AM
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1977 Porsche 911 S 2.7 CIS 
78 Porsche 911SC 3.0L, 3.3Turbo soon. 
1977 Porsche 930 3,0L Turbo
