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

Forgot car is 03 sti jdm modded
Md321h twinscroll
Pe 650 injectors
Rcm trumpet
Walbro 255 pump
Full decat

don;t look too far out.

has a mappper/specialist looked at it yet?

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

find a better mapper would be my advice

Car was mapped by andy f but hes fully booked till end of august now

ah right, need to find a decent specialist then who knows em inside out :(

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

has it missfired when hes been plugged in? if he only see's it when its fine hard to trace intermitent fault

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

Plugs gapped correctly?

.65 heat 7s replaced just incase but no difference

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?

He had it 5 days mate said he couldnt find fault

hmmmmmmm, need to def find a decent specialist in yoru area then

Its trying to find one thats the issue

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.

Did you do the test wet and dry ?

Compression Test done dry and he did leak down test said leak down was fine

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

Those readings are low, and as its across all 4 cylinders its doubtful its rings, id look more at the engine timing etc.

Could just be a ****ty tester.

Thinking that mate as other than cold issue car runs fine running 1.65 boost