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Registered
Join Date: May 2001
Location: San Diego
Posts: 940
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Back firing? Is it bad for a motor?
I have a 3.8 with ITBs and Electomotive tech3. After hard acceleration up through the gears and then down shift with no throttle (Foot on Brake) my motor back fires a few times. Is this bad for the motor?
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05-15-2007, 08:24 PM
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PRO Motorsports
Join Date: Nov 2001
Location: Burbank, CA
Posts: 4,580
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Not bad for the motor, but not great for the exhaust system.
It's likely caused by no fuel shut-off on over-run, so you're dumping fuel into the the muffler. There's occasionally enough oxygen to cause a secondary combustion in the muffler or pipes, usually due to a short, unrestricted exhaust system.
__________________
'69 911E coupe' RSR clone-in-progress (retired 911-Spec racer) '72 911T Targa MFI 2.4E spec(Formerly "Scruffy") 2004 GT3 |
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05-16-2007, 11:50 AM
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Moderator
Join Date: Dec 2001
Posts: 9,569
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Don't you have a throttle position switch that will cut off the fuel?
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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05-16-2007, 12:21 PM
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Registered
Join Date: May 2001
Location: San Diego
Posts: 940
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Yes, but I am not sure it is cutting all the fuel off. I am going to have the motor put on the dyno soon to dial things in more.
Thanks for the replies. |
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05-16-2007, 12:48 PM
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