1jz breaks up a 4k

[crazygrk3]

i got a problem with my 1jz at around 4k it just sputters and breaks up right when it goes to built boost
heres what i have done so far
new coil packs
new spark plugs
new coil pack connectors
replace one of the two cam sensor pins that were no good

when car is cold will start up and rev out and build boost but once it warms up it wont go past 4-4500 rpm even if i down shift while driving will at 4k and just break up

does any body have any suggestions that can help me out it would be greatly appreciated thank you

 

[Gritz]

Have you checked your temp sensor? Other than that, try to regap your plugs to .26-.32 .. some have break ups at .30 but ran smooth as butter at .28 just try differnent gaps..

I found that my ECU was bad when i had my problems...what codes do you have?

 

[GotTurbos?]

I'm guessing when its cold you're not actually driving it 4500 full boost right? Sounds like it could be a fuel pressure issue. On mine I could rev it in neutral just fine, but put a load on it and it didn't have the fuel pressure to accelerate past 3500 or so. It could also be your ECU.

 

[crazygrk3]

ok im gonna try to regap the plugs but i just got a stock 1jz just FMIC and stock twins with y pipe and full 3 in exhaust what a quick way to check fuel pressure and what should the specs be


and i am getting code 12 which correct me if i am wrong is either rpm signal or knock sensor

and about the ecu is a HKS ecu

 

[crazygrk3]

I'm guessing when its cold you're not actually driving it 4500 full boost right? Sounds like it could be a fuel pressure issue. On mine I could rev it in neutral just fine, but put a load on it and it didn't have the fuel pressure to accelerate past 3500 or so. It could also be your ECU.

well here what i mean last night i changed the cam sensor pins and then started the car and reved it note this is the first time i have started the car all day i reved it and it reved all the way out multiple times i let it idle for about 10 to 15 mins and got on the street to i rev all the way out to 7k and built about 9lbs of boost i drove about a half mile but on my way back to the house it would start to break and sputter right at 4k

 

[91T breezen']

ok im gonna try to regap the plugs but i just got a stock 1jz just FMIC and stock twins with y pipe and full 3 in exhaust what a quick way to check fuel pressure and what should the specs be


and i am getting code 12 which correct me if i am wrong is either rpm signal or knock sensor

and about the ecu is a HKS ecu

An HKS ecu??? What?!!! I have a similar problem, but more around 3200-3400rpm. Also have gone through same check list. The 1J ecu's are notoriously bad, (leaky capasitors) so swap out for a known "good" ecu, and see if that fixes it.

 

[crazygrk3]

An HKS ecu??? What?!!! I have a similar problem, but more around 3200-3400rpm. Also have gone through same check list. The 1J ecu's are notoriously bad, (leaky capasitors) so swap out for a known "good" ecu, and see if that fixes it.

i give that a try thanx alot

 

[crazygrk3]

well now the car wont even rev at idle when i rev at idle it wont past 4k i tried to regap the plugs there were at .30 and i put them to .28 i cleaned them out i also tried unpluging the temp sensor but nothing i also tried to unplug the knock sensor sense im getting code 12 but that didnt do anything either the only other thing i havent checked was fuel pressure and i just noticed on 12mm bolt missing for the fuel rail towards the rear of the engine another thing i noitced was when i would turn on the headlights it kinda felt like the idle would slightly change does anybody any more advice that would be help ful it would be greatly appreciated thank you very much for your time

 

[kozzman555]

pull your ecu out and check the circuit board. my car was having the same probs as you are and i found that i had two capacitors that were leaking onto my circuit board and burning it.

see here for pics of what that would look like
http://www.supramania.com/forums/showthread.php?p=1457340#post1457340

 

[crazygrk3]

i have took the ecu cover to check for that but i saw nothing burnt