1JZ Has Smoke After Back-Off

[jak]

Ok, so we have had this problem for a while now, but put up with it until now.

we recently blew our old 1j into the sky and thought "great, this will get rid of the smoke". Well, it didnt. and we are basically stuck on what is causing it.

Symptoms: When its on positive boost and you back off, there is alot of smoke come out of the exhaust. It used to only be when you were on posotive boost and back off, then accelerated again.

We changed the turbos a few months ago to try and fix this problem, as we thought the turbos were on there way out. We then found a pipe which goes to the oil lines on the turbos that had been 'mutated' due to the hot oil running through (used wrong hose) and we replaced it with the factory pipe that goes there. This reduced the smoke by heaps but didnt fix the problem.

We have just changed the engine, and have swapped everything from the old motor onto it as it was a long motor. As you can imagine, we checked that everything was in good order before putting it on the new engine.

the old motor had a worked head. this one is stock, unopened. the turbos are fine, there is no shaft play.

the pipe that comes out the turbo side of the rocker covers goes to a catch can, not the inlet pipes. And the valve which is on the inlet side that has a pipe connected to the plenum has been changed with no improvment.

we have one theory, that we are going to check on this weekend. We think it has something to do with the pipe that we replaced before, maybe a cloged bit of oil line somewhere? We will have a close look and clean everything out this weekend.

then new 1j has 87,000 k's on it and goes like a dream. but still blows the smoke.

Any ideas guys? Anyone else had a similar problem?

Cheers,
Jak

[Kyosho]

Don't back off...

Problem solved...


What colour smoke?

Blue = oil
Black = fuel/carbon
White/grey = water.

[jak]

its blue smoke.

dont want to end up in the sand now

Jak

[Kyosho]

Blue would be dictating turbos, and by the sounds of it, it's being pressurised somewhere, and only escaping once the boost pressure disappears.
If it only did it before when you hit the throttle, maybe oil was being let into the exhaust/turbos, and then hitting it again forced it out.
Now it's leaking worse.

You may have a blocked return line to the sump on the turbos, this would be my thinking (And it's only this, I've never experienced anything like it) but that's where I'd be looking...
I'm just thinking, on hard RPM oil is being forced into turbo and can't get out, when you back off it can manage to get into turbo and then gets burnt in the exhaust...

[Dieseltrain]

Kyosho is making some sense there.

Why dont you get rid of the Catch Can and run the standard Pipework for the pvc's and such... WOuld eliminate that also.

UNder acceleration everything is getting burnt once you back off crank case pressure rises beyond beleif and pushes oil back into the engine or the turbos....

Just a suggestion...

Btw.. I didnt know the Head was modified on the old engine? I thought it was a complete stocker....

[jak]

Yeah, that return line was our next point of call.

There was a fare bit of oil in the cooler pipes aswell. i.e more than normal.

I suggested that we drive aroud with a bit of pipe coming off the place where it now connects to the catch can, and shuv it out a half shut bonnet and go for a test run.

logically, it is within that area somewhere.

yup, had mild headwork.

Jak

[Ribfeast]

Valve stem seals?

[jak]

in 2 heads?

pretty sure it has been transfered from the other motor.

found all the other set of turbo oil pipes and have cleaned them out. so we will get them on soon and see if thats the problem.

Jak

[byteme]

does it also happen upor start up ? if so it'd be valve stem seals. pretty common problems for 1jz and 2jz motors.

[Ribfeast]

Most 1JZ and 2JZ motors are getting pretty old now, so it's more than likely the problem.
I get a big puff of blue smoke when I start mine up. Maybe that is why I am down a bit on cyl 5, that seal might be slightly more worn.

[Dieseltrain]

I get the same Ribfeast... Not massive but it does for a couple of seconds then clears!

Been doin it ever since i installed the Blitz Ecu... Maybe a little bit of oil and lotsa fuel?

[Ribfeast]

Probably...
Or the oil seals on the turbos are leaking once the turbos cool down and contract. But my turbos are only 12 months old, so unlikely (china turbos though).
Meh...car still goes hard, I'll just drive the thing til it dies and keep changing the oil every 3000kms lol