Ca18det rebuilt low compression HELP.

[shelbe]

i recently rebuilt my ca18det with forged pistons total seal rings, full balanced rods pistons crank flywheel,block honed/bored/decked, clearances were all right, steel headgasket, arp studs, and head decked, set timing to 17 degrees idles fine but struggles through 3-4thousand rpm then picks up after and goes smooth but doesnt pull as hard as it should put new plugs in swapped and cleaned coilpacks, just checked compression tonight and its sitting at 120 across the board dry and my vacuum is at about 16 at idle can anyone help me.

[bradt]

EDIT

Thanks Gabby, I shouldnt cruise NICO after having some drinks, lol.


Modified by bradt at 11:16 AM 12/11/2008

[ca18detgabby]

Drop resistor issue maybe?

What would something that drops the Imp of the injector pulse have to do with compression or even vac for that matter......

120 is not good..... time to do a leak down test and see where you are leaking.

did you recently rebuild it or is this something? is this the first time you fired it up?

PS check your FSM for specs on vac, is that 16 once it is warm? likely a small vac leak.

[D_Stirls]

17 degrees is a fair bit advanced, the JDM base timing is 10 degrees and the Euro base timing is 15 degrees. Also did you do the compression test on a hot or cold engine? i wouldn't worry about the low reading as they are all equal, admittedly the engine is probably getting a bit tired (if the test was done hot) but since they are all equal just keep driving it till it dies.

[boost_boy]

i recently rebuilt my ca18det with forged pistons total seal rings, full balanced rods pistons crank flywheel,block honed/bored/decked, clearances were all right, steel headgasket, arp studs, and head decked, set timing to 17 degrees idles fine but struggles through 3-4thousand rpm then picks up after and goes smooth but doesnt pull as hard as it should put new plugs in swapped and cleaned coilpacks, just checked compression tonight and its sitting at 120 across the board dry and my vacuum is at about 16 at idle can anyone help me.

I don't like it when it starts out low because now you're dealing with a hit or miss. You really shouldn't be exciting yourself about compression just yet. Put about 1500 miles on that motor and then get back to us about your compression. What method you used for break-in? 120psi per is low for a refreshened motor, but drive it some more.

Dee

[shelbe]

well when i put the timing to 10 degree it hated it at around 3-4 it wouldn't even move going down the highway just sit and misfire and if i downshifted and went it felt powerless its really hard to get a reading when there is snow outside. i advanced the timing to almost 20 no knock and it ripped why cant we advance the timing on the ca18. the car has been tuned by a company but idk if they adjusted the cas. also i'm reading no codes on setting 3 and 5. when i timed it the intake and exhaust are 39 teeth apart i pulled the cover of and made sure again. also for break in i ran the car for about 45 min making sure no leaks and let it idle and held it at 2grand for 20 mins dumped oil put in rotella diesel oil 15w40 because of the awesome break in additives and did hard pulls from 2-5 grand up hill and let of and went through gear in vacuum for about 200k then dumped oil and put in 10w30 castrol with a acdelco additive for break in. and now im at 530km.

[boost_boy]

well when i put the timing to 10 degree it hated it at around 3-4 it wouldn't even move going down the highway just sit and misfire and if i downshifted and went it felt powerless its really hard to get a reading when there is snow outside. i advanced the timing to almost 20 no knock and it ripped why cant we advance the timing on the ca18. the car has been tuned by a company but idk if they adjusted the cas. also i'm reading no codes on setting 3 and 5. when i timed it the intake and exhaust are 39 teeth apart i pulled the cover of and made sure again. also for break in i ran the car for about 45 min making sure no leaks and let it idle and held it at 2grand for 20 mins dumped oil put in rotella diesel oil 15w40 because of the awesome break in additives and did hard pulls from 2-5 grand up hill and let of and went through gear in vacuum for about 200k then dumped oil and put in 10w30 castrol with a acdelco additive for break in. and now im at 530km.

Bad boy No playing with the timing, especially on a newly built motor or you will be sorry. This motor isn't like the SR20DET which loves timing; the ca is the opposite. Please put your timing back to 15* BTDC or your compression will be lower from you cracking the piston ring lands. You did not hold your rpm at 2kRPM for 20 minutes? If you did, you just condemned your build. Newly built engine should not be left to idle unless you've put some miles on it and even then. The only to do now is be patient and see if the compression comes up. Don't waste too much time testing stuff and adding stuff becaus you're only going to frustrate yourself. Be patient and get back to us when you've put some more mileage on the car. Did you put the compression rings on right?

Dee