1JZ Misfiring

stevo332

New Member
Jan 13, 2010
7
0
0
New Zealand
Ok Ive got a mk3 supra running a 1jzgte and r154. Basicaly when i first brought it it was smoking (blue) once it had being for a drive and didnt have much power once on boost, so i tigtened all the intercooler piping and it ran alot better but still has a misfire. So I pressure tested the intercooler and all the piping and it showed up pretty good. Checked the engine fault codes and it displayed 14 (Turbocharger Pressure) and 24 (Intake Air Temperature Sensor signal). When the engine is cold in runs really well has loads of power and dosent misfire but once it warms up it starts missing and runs not as good. I installed a boost guage and it runs 12 psi, im not sure what the stock boost is something like 10.5? might have dodgey vaccume hoses or it may have had wastgate mods, I will check it out once I get some time.

So I was wondering if anyone would have any idea what the intake air temp sensor is doing. Could it be beceause its running more boost and the standard intercooler cant cool the air. or is it not working at all and dosent detect the motor has warmed up and runs the motor richer. Any ideas on what I have to check and where? Thanks a lot
 

johnd

Supramania Contributor
Dec 4, 2007
278
0
0
Ont. CA.
Sounds like your engine is running in limp mode, thus causing the blue smoke and lack of power, misfiring.
I would rule out the ic, unless it has a hole.
When does it misfire, wot,idle?
 

MKonmac

New Member
May 2, 2009
128
0
0
40
Salem, Oregon, United States
1. Check your spark plug gap and gap them to .028
2. check your coils for cracks> when they get hot the crack may make spark escape to your valve covers
... if there is cracks an easy fix is to use some clear finger nail polish and put a few layers over the cracks.
hope i helped!
Matt'!~
 

suprahero

naughty by nature
Staff member
Aug 26, 2005
14,971
0
36
54
Roll Tide
I'd replace the IAT sensor. I think it's shot it's wad. I'm pretty sure I used one for the MKIV and I got it at Advance.