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01-02-2013, 12:32 AM | #1 |
Scooby Specialist
Member#: 311781
Join Date: Feb 2012
Location: Canada
Vehicle:2003 WRX w STI V8 |
Could a 10-15% leakdown and low compression cause a slight hesitation?
Hey Guys,
So my motor needs a new set of rings and a hone. Hopefully I can get away with that. Currently they are 99.75, worst case I go to 100mm if need be. I do have a question, I've always had a slight hesitation on my built shortblock and was wondering if it was because of the high leak down and compression being low. Cylinder 1 = 117 Cylinder 2 = 117 Cylinder 3 = 105 Cylinder 4 = 105 Cylinder 1: 5% Cylinder 3: 12% Haven't done the remaining cylinders but I assume the worst. CP 8:2:1 Forged Pistons Manley Turbo Tuff I Beam Rods Nitrated Crank MAP H11 head Studs New Gasket/Seal kit Rebuilt heads FIC 1100cc injectors The hesitation is off boost at 2-3k rpm. If I go into slight boost its a dream to drive. A/F are a solid 14.7 while this hesitation occurs. So it always baffled me and I always tried to tune it out. Its a 2004 STI swap, no air leaks (smoke tested), Fuel trim under 2%. So I'm leaning towards the bad motor build. Also, might as well ask. Cylinder 4 sparkplug has a slight white residue, compared to the other cylinders that are brownish. I haven't checked the leak down on that cylinder. Usually people have issues with cylinder 1 and 3. Could be the injector being lower in cc, I'll get those cleaned out and retested (bought used). It could be the injector for all I know. Any thoughts would be awesome! If I missed any crucial information, please ask. I'll edit the first post. Thanks!
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01-02-2013, 11:46 PM | #2 |
Scooby Specialist
Member#: 311781
Join Date: Feb 2012
Location: Canada
Vehicle:2003 WRX w STI V8 |
bumpers
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01-03-2013, 10:39 AM | #3 |
Scooby Specialist
Member#: 245218
Join Date: Apr 2010
Chapter/Region:
South East
Location: FL
Vehicle:2013 STI Limited |
yes, yes it could
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01-03-2013, 10:57 AM | #4 |
Scooby Specialist
Member#: 175565
Join Date: Mar 2008
Chapter/Region:
MWSOC
Location: KCMO
Vehicle:2014 Sport Premium Satin White Pearl |
Most people have issues with #4 cylinder, not 1 and 3. Before my rebuild I was getting blow by and that was causing hesitation as well. Assuming it was a reputable shop and their good at what they do, take it back and ask them.
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01-03-2013, 03:27 PM | #5 | |
Scooby Specialist
Member#: 311781
Join Date: Feb 2012
Location: Canada
Vehicle:2003 WRX w STI V8 |
Quote:
Regardless I'll send the injectors back for a clean/retest when the sb is pulled. |
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