after my pourus head thread i think i have a different problem instead..

[michael squeak]

i managed to get a compression test done on my c20xe and i got these readings. 1,160psi 2,170psi 3,150psi and 4,240 psi..

does anyone no what minimum pressure they need to run at?

the car still refuses to run right. when i turn the key it revs up to 3000k and cuts out still, and misses like mad..

im thinking the fuel pump might be my problem.. its a 5 bar pump, is this to much and drowning my plugs? causing a miss fire? might explain when i press the acellorator it bogs and dies..

any help apreciated.. im at a dead end now lol

[paul080803]

What are the plugs like? Wet or dry? Colour?

[Lewis.]

I'd expect anywhere between 120psi and 180psi in a petrol engine, exact number doesn't matter so long as they are even.

how are you testing it though? your odd high figure makes me think you are changing variables.

remove all the plugs, test each cylinder in turn, and get 3 readings for each cylinder, which will help eliminate any anomalies. and be consistent with what you do, (i.e. 5 revolutions, wide open throttle every time)

then repeat the test with a little oil down the bore (again, the same amount each time)

[michael squeak]

this is were i get confused. there was water or it could have been wd40 as it was oily liquid down the spark plug holes so i couldnt tell what they would have been like inside the head... the plugs are dark brown/blackish

[burgo]

Number 4 seems way high, other 3 look normal to me

[michael squeak]

I'd expect anywhere between 120psi and 180psi in a petrol engine, exact number doesn't matter so long as they are even.

how are you testing it though? your odd high figure makes me think you are changing variables.

remove all the plugs, test each cylinder in turn, and get 3 readings for each cylinder, which will help eliminate any anomalies. and be consistent with what you do, (i.e. 5 revolutions, wide open throttle every time)

then repeat the test with a little oil down the bore (again, the same amount each time)

thats were i might have gone wrong.. i cranked it untill the needle stopped reading any higher..

ill get another test done in the week and do it evenly.. thanks lewis

[paul080803]

Make sure you do the compression check with a warm to hot engine

[michael squeak]

i still cant get why ive got the miss fire. ive had new leads. idle control valve, plugs, coolant temp sensor.

could my fuel pump be to high pressure for the engine?

or when i changed the tank would it be possible to suck crap up and block an injector?

because when i was cranking the engine i could see the fuel coming out the plug holes on on all cylinders except number 3..

[michael squeak]

i cant do that i cant keep it running long enough lol..

[craig green]

Ideally you would remove the fuel pump relay so as not to be squirting fuel into the cylinders whilst doing this.

To answer your Q about the fuel pump being too high a pressure.. NO the job of the fuel reg is to regulate the rail pressure at a set amount & return surplus fuel to the tank. Unless you have an adj reg set too high you should be fine.

[swedge]

Swap your injectors about and are if the misfire follows the injector if it does you know it's the injector