1JZGTE Missfire running bad at higher rpm

[Highway Dancer]

Hey all

Having lots of trouble with a 1jzgte from a jzx90 that we have put in a landcruiser

Starts and idles sweet as, but when you rev it up about 3-4 thousand rmp it hits a wall of back fires and poping, and just runs bad at da higher rpms

Pulling our hair out trying to figure it out.

One thing is that it was diesel and we have used the diesel fuel tank with an in line bosch 044 pump, with the breather from the diesel tank as the return. is this the problem?

Things we have changed so far:

ECU x 3 auto and manual
Ignitors
MAP sensor
Coils
Cam angle sensors
Crank angle sensor
Spark Plugs

Any suggestions/ideas would be great

Thanks Heaps

[1JZ-Rolla]

when you changed the coils, was it for a new set, or another second hand lot?

does it misfire only under load, or also free-revving or running it out in gear at light load?

[Highway Dancer]

They were second hand but from a running motor

[Highway Dancer]

it misses and carries on when free reving with no load

[1JZ-Rolla]

pull the boots/insulators from them and check them REALLY well under a bright light for cracks in the body/stem

[Highway Dancer]

They came from a running motor with low kms, and it does it with no load at all. its not as bad when you dissconnect an intercooler pipe but still misses and doesnt want to rev that well

[waldo]

That diesal tank could be a problem.

Diesal is bascically an oil and will decrease your knock resistance (although Im not saying this is the problem). First reading your post it reminded me of my 180sx that developed a similar problem. I changed a black-fuel drenched fuel filter and the fuel pump. And bingo, a new car!

If you can, change your filter, use a temporary tank (I once used a coke bottle, although do this at your own risk) and plonk your 044 into that to test. Since you dont need to drive, this can be done easily with the dodgeist oif setups (cheap) within reason of safety limits of course. It will probably need to be purged quite well too (if it is the problem) before it runs well (dont fuel feed your return back into the temporary tank, feed it back into another coke bottle).

Waldo

[midnight_purple_GA70]

sounds to me like the nsw or sta wire needs to be grounded...

had a similar issue with a soarer 1jz into a supra before...
gets to about 4k and then wont rev any higher and breaks down... basically goes into limp mode...

if you grounded one of those wires it would rev fine... cant recall which one though

[Highway Dancer]

yeh it does sorta seem like that but have used both auto and manual ecus still da same.
Its not a limit more a missfires almost like antilag

[midnight_purple_GA70]

but have you specifically grounded 1 of those 2 wires... auto or manual ecu wont make a difference

[Valkyrie]

My brother is having a similar issue to you. Have you checked your plugs? Are they white? My brothers are, and it has a brand new Bosch fuel pump in it.

[Highway Dancer]

Haven't specifically grounded those two wire will give it a go tho.
Have done a couple of 1j conversions and have never grounded them.



I think the plugs were black nt to shure tho, it's a weird problem
Running out of things to replace/ swap

Any more ideas on Wat to try next would be great
We Goin to try another fuel pump to nite Jst in a bucket of fuel

[midnight_purple_GA70]

was looking at wiring diagrams last night while wiring a 2j conversion

my hand written scrawl said splice to ground STA wire...

this was on a conversion using a jzz30 soarer auto engine gearbox loom and ecu...

might work or might not...

[Highway Dancer]

Have fixed this issue finally

Its was the STA/NSW wire in the end

Jst earthed both out in the end and it fixed it straight away

Funny cause i have never had this problem before and have wired a few of these up
thinkin there must be some difference between looms, or is it because i chopped the plugs off the end of the loom.


Thanks for all your help every one

[1JZ-Rolla]

well done Midnight_Purple, sound advice