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Old 03 July 2015, 09:46 PM
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peter zippy reid
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Default compression test results

Hi i have a cold running issue my car stutters chokes misfires whilst driving till warms up got a compression test done heres my results
warm compression test results:
1- 100
2- 110
3- 105
4- 105
all in psi
Could this be my issue
Old 03 July 2015, 09:47 PM
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Forgot car is 03 sti jdm modded
Md321h twinscroll
Pe 650 injectors
Rcm trumpet
Walbro 255 pump
Full decat
Old 03 July 2015, 09:50 PM
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Tidgy
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don;t look too far out.

has a mappper/specialist looked at it yet?
Old 03 July 2015, 09:59 PM
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Yes the guy that did test does opensource he cant seem to find issue says fueling is fine and 02 and maf are within tolerances
Old 03 July 2015, 10:00 PM
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Tidgy
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find a better mapper would be my advice
Old 03 July 2015, 10:01 PM
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Car was mapped by andy f but hes fully booked till end of august now
Old 03 July 2015, 10:02 PM
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Tidgy
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ah right, need to find a decent specialist then who knows em inside out
Old 03 July 2015, 10:04 PM
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peter zippy reid
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I keep going back to 02 and maf as they were off a breaker so dont know if they can be trusted to be working correctly
Old 03 July 2015, 10:06 PM
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has it missfired when hes been plugged in? if he only see's it when its fine hard to trace intermitent fault
Old 03 July 2015, 10:09 PM
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No misfire when he had laptop on it it only misfires if i try to drive through bad stuttering as in apply more throttle instead of just lifting off
Old 03 July 2015, 10:14 PM
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Plugs gapped correctly?
Old 03 July 2015, 10:15 PM
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.65 heat 7s replaced just incase but no difference
Old 03 July 2015, 10:20 PM
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Originally Posted by peter zippy reid
No misfire when he had laptop on it it only misfires if i try to drive through bad stuttering as in apply more throttle instead of just lifting off
dont try to drive through it, could damage the engine. Can you leave the car parked up and go into town and then have him plug in when its cold and doing it?
Old 03 July 2015, 10:23 PM
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He had it 5 days mate said he couldnt find fault
Old 03 July 2015, 10:26 PM
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hmmmmmmm, need to def find a decent specialist in yoru area then
Old 03 July 2015, 10:29 PM
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Its trying to find one thats the issue
Old 03 July 2015, 11:31 PM
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Bob99
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Compression (warm engine, 350 rpm and fully open throttle)

Standard = 142 — 171 psi
Limit = 128 psi
Difference between cylinders less than 7 psi

Your pressures are low and below the bottom limit. Might be worth getting a leak down test done to establish where the problems. Could be piston rings or valves passing.
Old 03 July 2015, 11:54 PM
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Originally Posted by peter zippy reid
Hi i have a cold running issue my car stutters chokes misfires whilst driving till warms up got a compression test done heres my results
warm compression test results:
1- 100
2- 110
3- 105
4- 105
all in psi
Could this be my issue
Did you do the test wet and dry ?
Old 04 July 2015, 02:42 AM
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peter zippy reid
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Compression Test done dry and he did leak down test said leak down was fine
Old 04 July 2015, 07:18 AM
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peter zippy reid
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Started car today sat for 2mins before driving off water gauge reading 43degrees drove fine when andy mapped it he said he didnt get a signal from avcs within the 60secs on start up but said he would get it on the road could this be the issue
Old 04 July 2015, 06:00 PM
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gazzawrx
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Those readings are low, and as its across all 4 cylinders its doubtful its rings, id look more at the engine timing etc.
Old 04 July 2015, 08:59 PM
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Could just be a ****ty tester.
Old 04 July 2015, 09:05 PM
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peter zippy reid
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Thinking that mate as other than cold issue car runs fine running 1.65 boost
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