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Gtr 32 Not Making Boost - Further Suggestions?

dorifticon

By dorifticon,
in General Maintenance

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dorifticon Community Regular

dorifticon

Posted
Posted

Well, I imported an GTR32 and as is usual with imports, it was running pretty rough when it came off the boat. So anyhow, tracked down and fixed a couple of boost leaks and associated issues, and it now is idling cleanly and starting sweetly, but not making any boost.

Now, a couple of people have posted up similar problems, but they seem to associated with misfiring and/or various colours of exhaust smoke, which is not consistent with my experience. Also a lot of the other posts seem to be correlated with ‘catastrophic events’ or other sudden failure, whereas mine has just kind of always been shite.

Basically, it is running like a 2.6 n/a with a low static compression ratio (not very impressive). It revs out and doesn’t hesitate, just doesn’t make any boost. It doesn’t blow any kind of smoke (either black or white/blue) and doesn’t seem to consume oil.

So far I have:

1) run an air/fuel meter, which returned 14:1 (pretty much where I’d want it, yeah?)

2) checked the timing – was advanced to about 25 deg, so reset it back to 15 deg BTDC (i.e. what it says on the bonnet)

3) disassembled the intake (passenger) side of the motor – a couple of the rubber hoses to the wastegates were looking a bit worse for wear, so I replaced them with high-pressure efi hose and clamped ‘em down real good. I also took the opportunity to really tighten off all associated hose clamps, as well as replacing the very large rubber pipe that comes off the collector (the one that connects to the pipe that is stamped “twin turbo” – my one had a minor split).

4) examined turbos – the compressor wheel didn’t seem to have any excessive shaft play or damage, but then I’m no expert. I haven’t had a look at the exhaust wheels yet, haven’t removed the dumps – that may be the next thing. The wastegates seemed to have a ‘normal’-ish kind of resistance to them, and everything seemed to spin reasonably well. Nothing jumped out as being seriously wrong.

5) examined plugs – all sparkplugs looked fairly clean, very little carbon or any kind of damage there. But then it wasn’t misfiring at all so that makes sense.

6) here is the wild card – when I got the car, something called the ‘PCM valve’ (small valve kind of behind the battery area) was unplugged. Now, the actual plug was ziptied out of the way, so it doesn’t look like this was accidental. Anyway, I just plugged it back in. Having searched, it seems the PCM has something to do with the EGR system, but that’s all I know.

Anyway, the next thing I’m going to try is looking at the cat converter to see if it’s somehow collapsed or something equally ridiculous.

If there is some vacuum related issue on the D/S I would probably prefer to yank the motor rather than attempt to remove the inlet plenum with the motor in the car (search has told me the inlet is a PITA to remove in the car). I have the engine crane and other tools, and the will, to remove the motor if required (although have not done engine removal on a 4wd setup like the r32).

At this stage I’m really just looking for clues or suggestions on where to go. In particular

1) what is the PCM valve, what does it do and why would someone unplug it? Is this the solenoid people modify to increase boost to 1 bar, and if so wouldn’t plugging it back in simply return the car to factory boost (as opposed to zero boost)?

2) can the car have a boost leak and still idle cleanly and maintain normalish AFR’s even under various load/RPM conditions?

GTRsean Grand Master

GTRsean

Posted
Posted

Ceramic turbines are well known to fail and then you get next to no boost.

See if there is any ceramic turbine remains in the exhaust before the cat converter.

Soleniod behind battery is the stock boost control solenoid.

dave32gtr Contributor

dave32gtr

Posted
Posted

This wont help at all but. I did have my car stop making boost for anout 5 min once. Don't know what happened. Then it just cam back befor i got to where I was going. That was about 5 years ago, and it has never done it again.

dorifticon Community Regular

dorifticon

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Posted
Ceramic turbines are well known to fail and then you get next to no boost.

See if there is any ceramic turbine remains in the exhaust before the cat converter.

Soleniod behind battery is the stock boost control solenoid.

GTRsean = teh winnar!

I was also kind of right, the cat converter was blocked - with this (see pic)

Oh well, just means its HKS ball bearings for me (stand by for dumb questions about turbo upgrades)

post-45795-1219461818_thumb.jpg

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