1jz running like crap. Not sure whats goin on.

[Little_Matt]

So I finally got my 1j running in my S13. It idles rough and has no power. I drive the thing in the parking lot and it hesitates and doesnt have power. Once it starts to rev it smooths out. The throttle isnt very responsive. The air fuel ratio at idle bounces between 12.9 and 13.1. I am not a mechanic so Im not the greatest at diagnosing problems. I am a body man. I make cars pretty.


So the mods I have done are

3'' Y pipe and down pipe
Front mount intercooler with 3'' pipe and Blitz BOV
OS Giken super single
Drift Motion alt, PS, and Water pump pullys
2jz water pump

It is a JZA70 motor and ECU. I have checked the ECU for leaking caps and everything is good.


Help a guy out so I can get it to the dyno for some numbers.

Thanks.

 

[te72]

Well, the a/f thing isn't uncommon, mine bounces around 14.5-15.0 all day long cruising, so I wouldn't worry about that. Things to check though:
-Timing.
-TPS
-ISCV

If all those things check out ok, and are set correctly, that should give you a good baseline to work with. Also might look into fuel pressure... I've never messed with it, but a stock 1j ecu will run pretty much stoich all day long. Are you running bigger injectors perhaps? Like i said, I've never messed with fuel tuning before, so I'm only going off of what comes to mind as being related.

 

[mk3tattoos]

check the map sensor as well, if you can borrow a ecu just make sure it might be a good idea.

what do your plugs look like, what gap and type of plugs are you using?

 

[Little_Matt]

Sorry I should have stated some of the things I have already done. I have replaced the plugs with NGK Iridiums for a 2j, replaced the TPS, checked all the coil packs, unplugged each cam sensor while running and it got worse when unplugged. I also should mention that I don't have that fuel dampner thing anymore. I am running a fuel line straight to the rail.

---------- Post added at 09:07 AM ---------- Previous post was at 09:05 AM ----------

Also what is a ISCV? And where would it be?

 

[92TealSupra]

Sorry I should have stated some of the things I have already done. I have replaced the plugs with NGK Iridiums for a 2j, replaced the TPS, checked all the coil packs, unplugged each cam sensor while running and it got worse when unplugged. I also should mention that I don't have that fuel dampner thing anymore. I am running a fuel line straight to the rail.

---------- Post added at 09:07 AM ---------- Previous post was at 09:05 AM ----------

Also what is a ISCV? And where would it be?

Idle speed control valve on the intake manifold near the back.

 

[te72]

Sorry, could have specified about the ISCV more. They have a nasty habit of sticking on our engines. Try unplugging it and see if it runs any differently. If not, then it's likely stuck open or closed... Also I've read a couple threads in here that some people have issues with the car running smoothly without the FP dampener in place. I guess it's one of those things that affects some, but not all.