1JZ GTE hesistation at 3000 rpm to 4000 rpm

[Cressid@]

Hi all, I have 1jzgte slightly modded. (exhaust, front mount, steel wheels twins running at 18psi, exhaust cam gear 8 degrees retarded.)
On a cool night, it hesistates only from 3000 rpm to 4000rpm. From idle to 3000rpm is quick and smooth and anything after 4000rpm it picks up right away.
any comments are welcome thanks.

cheers,

[EldarO]

plugs or cracked coilpacks.

ECU might be a bit spasticated too, but seeing as it seems to be consistent, id look at the other two potential problems first.

[pandaah]

how tight is the timing belt?.. my mates skyline starting going gay like that and turned out the timing belt was out, maybe your exhaust cam is a little too retarded?

[chris davey]

stock ecu then? no piggybacks?

I would be looking into coil packs (including connectors) if that is the case.

Also, try bring the cam gear back to say 6deg. This has seen good results on other 1j's. Out of curiouity, have you had it on a dyno to get to your 8 deg figure or just pick that one?

[Cressid@]

stock ecu, no piggy back!
Dialed the cam gear back to 6deg, doesnt seem to helps. I think the coilspack are on its way.
But it has been repaired (electrical tape and heat shrinked).

Or could be just that is how it is? turbo full boost at 4000rpm above that is why it feels much harder after 4000rpm, but at 3000rpm it just slowly boosting?

Off topic. does it matter if you turn the crank anti-clockwise when marking TDC? well toyota TSRM said always turn it clockwise! I read the TSRM when it was all done. lol

[pandaah]

yeh it does cos turning it anti clockwise loosens the timing belt cos its spinning the opposite way, as the timing belt tensioner is preloaded to tension a belt turning clockwise...

if your belt is worn turning it anticlockwise (theoretically) could make it skip a tooth and you wont have the true top dead centre

[EldarO]

i had my 1J hesitate slightly on cold mornings cause the gap on my plugs was too small.

i gapped em down because it was too big at the standard .8mm, cause the coil packs were so broken and busted, but i fixed those with heat shrink, and opened that gap back up, runs like a dreammmmm