Whoops ... 1JZ turbo blown?

[BabyZ]

OK, time to drag this thread up from the murky depths ...

I ran out of time to do anything before rego was due, so to get the pink slip, I just threw it all back together and hoped. No changes to anything at all. (The 'new' turbos I got + plugs, etc are still sitting on the shelf!!)

Drove carefully around for a while (no boosting at all) and it behaved fine. So I drove it to town for its rego inspection - I knew the inspector would drive it like a granny for the brake test too. Brought it home, still no problems! This is about 30-40km of sedate driving. No smoke, no roughness, no nuttin!

So today, I thought I'd try some boost and see what happened. Started, warmed for ~30 seconds, drove for ~30 seconds: smooth as normal. Boosted to only about 5PSI for about 3 seconds and instantly it's running like crap again for the rest of the drive, like it's missing on 1 or 2 cylinders the whole time.

Surely that's symptomatic of something that a Toymods guru would recognise?!?!?

Maybe a plug breaking down under boost? I can't imagine a coil pack doing that (it's more likely to die when hot, right?) Dodgy MAP sensor flaking out as soon as it gets pressure? Some other thing? ...

All suggestions welcome

[Mr DOHC]

sounds like its getting a fault code and making it run like shit

[Ribfeast]

The fact that it is making 5PSI means the turbos should be OK. If one as blown, you get no boost at all, cos it all leaks out through the dead turbo.
Maybe a boost leak, or even the map sensor has the vacuum line popped off it?
Pull the ECU codes and see what errors it has logged.

[The Real Roadrunner]

Looking at the inlet manifold, there is zero oil in there (ruling out simple plug fouling) but it smells like it's full of raw fuel even after sitting for weeks. I think I'm looking for a fuelling and/or failed spark issue that arose independantly of the turbo problem. The two may not be related at all. (Hell of a coincidence though ...)

I'm going to measure the injector pulses and check the caps in the ECU (plus test the coil packs when I work out how). Any other ideas where to look?

have you checked all these yet? ie coils+ecu?

cheers
linden

[BabyZ]

Argh!! Went to check the fault codes tonight and someone (not me) had left the ignition on - dead flat battery = reset ECU!! I thought I had checked for fault codes before (and found none), but I can't find any reference to it in my notes, so it's definitely worth another drive to check them again.

Ribfeast, I agree on the turbos - I felt they they would have easily boosted more too, I just didn't want to overdo it when it was a) cold and b) in dubious health

Would a boost leak make it run like crap off boost too? I would have thought not ...
The MAP sensor line was/is connected and clear of blockages.

Roadrunner: I haven't worked out how to test the coils yet (other than visually). Any tips? I ran out of time to dismantle the dash to pull the ECU, but it is the next logical step. And a pretty straightforward fix if the caps are leaky.

Thanks again for the help, guys

[The Real Roadrunner]

use some thick heat shrink on the coil extensions to stop it arcing if there cracked,(i dont think this is the real prob as the symptoms aren't right,but fix it anyway)

it sounds like the caps are leaking coz they normaly drop 2 cyls intermtently and use shiteloads of fuel when it happens.

its not a boost leak, if it was it will still run fine but be down on power.

cheers
linden

[1JZ~lux]

The other night I blew a intercooler hose off and the engine kept on accelerating, just a bit slower then normal. I didn't run rough so I doubt u have a boost leak.

So today, I thought I'd try some boost and see what happened. Started, warmed for ~30 seconds, drove for ~30 seconds: smooth as normal. Boosted to only about 5PSI for about 3 seconds and instantly it's running like crap again for the rest of the drive, like it's missing on 1 or 2 cylinders the whole time.

I had a similar thing to this and it turned out to be a loose connector on injector 1.
This may not be your problem but it's still worth checking.

[Ribfeast]

Also check your coilpack plugs/connectors, make sure they are making good contact with the coilpacks. And are wired the correct way around. The coils will still spark when wired with the opposite polarity, but the spark will be a lot weaker.

[BabyZ]

Looks like it's the leaky cap problem ... not huge leaks (like there were on my PC motherboard), but definitely some electrolyte escaping there. So - I'd better send an order to Farnell and get soldering! (Unless someone knows a supplier for the 15uF 35V cap, otherwise I'm going to have to do the 10uF + 4.7uF trick)

I'd taken it for a couple of runs, and even at full boost it refused to play up again. No codes or anything, but I don't trust it yet. I'll do the heat-shrink on the coil packs too, and hopefully all will be well.

No idea what the deal was with the one-off oil leak from the turbo. Maybe a backfire put some back-pressure on an oil seal or something???