1jz-gte major power taper beyond 5000rpm

[SL666]

Its probably not actually dropping the vac in the manifold that much.. probably just in that line.. it would still be screwing up your idle though

[urantia]

You legend wiso! plus rep, this could be what solves my problems. will report back with results.

SL666 just saw your reply. I wouldn't of thought a small vac hose could do much either. But could it be enuf to play silly buggers with the turbo's working harder to keep 10psi of positive pressure?

[urantia]

seems my motors vac fittings are much different to your wiso. Is that a soarer 1jz in the pic by any chance?

I took the pipe of the charcoal canisterand blocked it up idles much better and revs much nicer too. haven't taken it for a drive yet. havnen't reset ECU either which i should prolly do for it to recalibrate things. (before i had to really rev the guts out of it to get teh negative vacuum to come up to above zero, now its really easy)

just looked over your pic again wiso, where the canister is hooked up with those "metal lines that go somewhere", well i wonder where they go to? lol

My motor doesn't have those metal lines that yours does.

[SL666]

i think those metal lines go the the TB on mine.

[wiso]

seems my motors vac fittings are much different to your wiso. Is that a soarer 1jz in the pic by any chance?

I took the pipe of the charcoal canisterand blocked it up idles much better and revs much nicer too. haven't taken it for a drive yet. havnen't reset ECU either which i should prolly do for it to recalibrate things. (before i had to really rev the guts out of it to get teh negative vacuum to come up to above zero, now its really easy)

just looked over your pic again wiso, where the canister is hooked up with those "metal lines that go somewhere", well i wonder where they go to? lol

My motor doesn't have those metal lines that yours does.

nah man, i got mine from a jza70 halfcut, she's all standard supra spec.

hmm, intersting, i'll have a look again in the light tomorrow but i think sl666 is right, as far as i can see those lines go to somewhere around the TB then i loose sight of them, but bofore those lines, just after the top where my hand is it T's off and goes through a gap int he manifold i think.

like i said, will trace them better tomorrow and let you know

[urantia]

cheers wiso, well i should probably save you the effort. I reckon your both right in that those metal lines end up plumbing into the throttle body. My 7m was the same with those metal lines.

The best thing i guess for me to do is tommorow morning take it for a drive to work with the charcaol canistor not connected to the throttle body and see how it performs. Should at the very least solve the idle issue.

Also when boosting i can really hear the charcoal canister going off it's head, or some kind of air leaking noise happening. Anyway enough speculation i will report back with my findings.

Cheers all.

[Endless]

Just had a look at mine and on the top of the canister its got 3 outlets and the words PURGE CARB and TANK nexto them.
Purge goes down to near diagnostic port and tee's off, Carb is blocked off with a cap and Tank seems to go down underneath car and i'm guessing to the fuel tank.

[Endless]

Here's a quick pic i just took for reference.

[wiso]

my canister is differant to that, mines a square one, has the fuel line and vac line out the top, and it has a breather line out the bottom.


but yeah by the sounds of it urantia, you may have issues with where you vac line for the canister is tee'd into

[wiso]

hey dude here you go, that metal line does go to the TB, but looks whats in that line, a one-way valve

[urantia]

sorry for the late reply, Thanx fella's yep i do have those metal lines, found that there was already a vac hose connected to it hanging down in the motor bay. So hooked it all up as per your diagrams and started her up idles perfectly. vaccuum is sitting at minus 20 where it should be. Haven't test driven it yet, i had my gearbox oil draining and couldn't find any where to fill the gearbox oil (execpt thru the shifter hole in teh cabin.)

[urantia]

Well SL666 you were on the money. Made SFA difference with power. But fixed my idle.

*grumbles*

[SL666]

bugger

its not using any more fuel than before or anything is it? (the computer isn't thinking the engine is cold all the time or something silly)


anything strange happen (or did you change anything) in the weeks before this started happening?

[urantia]

fuel consumption seems about the same, i should know after a week of driving to work but i just switched to BP 98octane @ $1.55/litre which doesn't seem to go as far.

It used to idle up to 2000rpm on cold starts then settle down to 650rpm after a few mins of light driving. Seems to drop down to a wam idle rather quicky now, not sure if i'm imagining this or not, need to remember this next time i start it.

The whole conversion was done in 2 weeks from start to finish had to get it on the road drivable before holidays were over so i could get to work. No doubt my rushing the conversion is the problem. Just getting around to fixing my mistakes now.

I'm pursuing my air intake and intercooler next i think. My stock intercooler is dented to buggery on the bottom, thats how it was on the halfcut, it doesn't leak but could be restricting flow, as could my crappy air intake setup lol. (no intake at all with the halfcut had to patch one up on the cheap).

[SL666]

if boost is stable and its a very noticeable drop, its probably unlikely.

it was a manual cut wasn't it?

sadly i think you are going to have to take it to someone who knows what they are doing

maybe you could get a friend to follow you (get some CB's) and you could check for clouds of black smoke out the back (hmm that will be difficult to tell from normal 1j operation though)