Jump to content
SAU Community

Recommended Posts

Hi guys,

Just a quick question I'm sure:

Basically I've owned my R33 GTR for about 2 months now, I put some apexi pods filters on it and just has a cat back exhaust at the moment otherwise completely stock.

Now my boost gauge use to say -11 ish on idle and boost up to abou 10 PSI, (on both my mechanical boost gauge and stock gauge), and now after a oil change (duno if it could be related at all) sits at about -2 ish on the gauges and only found that its boosting up to about 6-7 PSI? and car just seems a little slower in general..

Now I'm no engine guru but my first thought was maybe there is a leak somewhere in my FMIC piping? but figure I'd just ask here to see if this has happened to anyone else.. sorry if its been answered before but couldn't find anything.

Thanks in advanced,

Leigh

Link to comment
https://www.sau.com.au/forums/topic/335130-rb26-noob-question-regarding-boost/
Share on other sites

yep, most likely a pipe blown off, or vacuum hose off. best bit if you are not sure what to look for is take it to a mechanic and get them to find the missing/split/blown pipe. easy fix.

Ah ok no worries, it must be only small / hard to find if its still getting some boost I guess? I was going to get some parts and a tune by Status so I assume Trent should be able to find it if I cant haha

edit: is there any common places to look?

Ah ok no worries, it must be only small / hard to find if its still getting some boost I guess? I was going to get some parts and a tune by Status so I assume Trent should be able to find it if I cant haha

edit: is there any common places to look?

Does your car have a front mount?

If so, the turbo > first hot pipe, is a common one on aftermarket kits. So is throttle body and first of the cold pipes.

Are you blowing any black smoke and is it idling rough?

Its just got the stock front mount

I will check pipes when I have a chance

It doesn't seem like its blowing to much black smoke if any, the rear of my car gets a little black but seems fairly normal black-ness to be honest.

It seems to idle a little rough sometimes but not at all times, and also seems after I turn the car off for say 5 minutes (get petrol or what ever) get back in and drive off it has trouble when it hits boost seems to missfire a bit? or at least seems like that and also will idle rough at this stage as well.

Used a oil filter removal chain, and then replaced filter with a socket type filter 'Drift' brand.

The only thing I saw near the filter was something going to the front diff? a wire or something from memory

under the inlet manifold there is a vineyard of black vacuum hoses. have a really good look, even use a mirror, its to coincidental that you changed the oil then this happened,

the reason i asked it you used a tool is this would make more sense if you pulled a hose off

yeah trent will be able to find it no problem in 10 mins or so. he would have fixed literally hundreds of skylines with the exact problem you describe.

Yeah i'll try and have a look when i can.. if not fixed I'm sure Trent will have no problems he would be 100x better with this sort of thing then myself :down: I'm more of a I.T guru rather then engine troubleshooting..

And yes! GTR has FMIC! ;)

Happy that its nothing serious

The map sensor for your gauge is located on the drivers side of the engine bay near your brake booster. There is a hose that goes from that to the back of the plenum near the firewall. The rubber tends to go hard, split/crack or just break off the brass pipe fitting that is on the back of the plenum.

You can easily reach it to check the hose. Give the hose a wiggle and squeese where it attached to the plenum. If its hard and cracked it will probably break off completely. Replacing the hose and doing a complete pressure test to identify other failing hoses is your best bet.

Well I feel like a idiot for not seeing this while changing the oil but here was the problem (simple boost gauge T-Piece rubber tube has busted):

Thanks for the help and advice people :ermm: gauge went from -2 ish to -20, and boosted 10psi plus now instead of dropping at like 6-7 psi and just not running well in general.

img0212q.jpg

:D

  • 4 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • From my youth: GTi-R clutch change is a massive pain. The gearboxes are fragile? But the car is super cool and I want one 馃槩 
    • Remember this is 1988 tech.
    • Driveline vibration is resolved. I ended up loosening all my engine mount and trans mount bolts, giving it a good shake then retightening everything and it's gone... Let's just say I was surprised that fixed it.  I've been happily driving it around again but unfortunately put zero time into my direct port/constant pressure WMI setup. I'm on vacation next week, so I'll try and finalize it then.  On a different note, I spent all week fuel/ignition mapping 2x 216L V16 engines. Turbo's were burning glycol and we swapped them out for larger units. We also had planned emissions testing on site, so I figured I'd be there the same week to use their instrumentation and massage any emissions issues out if needed. This was a first for me. Fuel management is similar in certain ways to automotive (i.e air density as load variable) but very different in others. It's all PLC based and AFR's are controlled by air and not fuel. They use a control valve between the turbo and air manifold to control pressure which in turn controls AFR's. Due to this, target AFR tables supplied by the OEM are in pressures and not mass which really through me off. They use air pressure vs fuel pressure tables. I also relied on an O2 concentration sensor the emissions team had in the exhaust. Ignition timing was also all over the place and we were losing a fair bit of power. They're now happily sitting at 16-40BTDC depending on load. We were making about 1600kw at 900rpm at 90% load. Engines were running a lot smoother as well.    
    • heh, aint no R32 ever meeting modern targa cage rules unless the driver is veeeery short OP, good luck with the sale, since its already in the land of freedom I'm sure you will find a good buyer.
    • meh, it was a good video, clear about the issue and how he dealt with it. A bit heavy on the RTV and very brave to put an RB in anything without rebuilding it first, but otherwise I thought it was good Dose, I'm not sure that having the pickup forward is a big issue; yes of course the oil could shift under brakes but the sump should never be empty enough for that to be a problem (unless you also have a higher volume oil pump, and that oil can't return from the head to the sump quickly enough)
  • Create New...