Dying turbo maybe?

[SteveH]

After a great day at Japfest I decided I would fit my new boost gauge when I got home. All fitted fine and dandy so I took the car for a spin to see what the gauge reading was. Well I'm consistently getting well over 1 bar and it seems to hold it, it was my thinking that this was too high for our cars?

However I had noticed the car has been smoking a little over the past few weeks, not always just every now and then. But now it seems to have developed a new problem, when I floor it I'm getting bit of stuttering and coughing. Plus what sounds like tiny stones hitting the bulkhead. When I back off everything goes back to normal and the car runs fine and pulls hard other than when I completely floor it where its playing up. I decided to turn the boost down via the manual controller, it didn't seem to make any difference although I did notice that there is oil seeping from the tap. To top it off, on one floor down attempt I lost power but the engine was still going for it and boost pressure was holding.

I know that's a bit of a list of things there but does anyone have any ideas or pointers for me?

[Nick Mann]

Are you sure it is all plumbed in right? If you have a leak in the control pipework the car will overboost. Have you got a flashed ecu on it? I'd expect you to be hitting fuel cut if not once you are hitting over a bar of boost. The loss of power could be over fuelling, which would tie in with a small air leak, or could be plugs or leads breaking down.

[SteveH]

Do you think maybe the bleed valve leaking could be just the leak to cause over boosting? It was already on the car when I got it so I don't have the T piece that would have been on the car originally. I don't think the car has a flashed ecu.

Interesting that you mentioned plugs as the car is due it's service.

[VR457]

How about turning it down to 0.8 bar, resetting the ecu and see what happens?

Davezj had a thread about boostleak testing, he tested his kit on my car and it turned up good.

[SteveH]

I tried turning the valve down, it doesn't seem to make any difference. I'll try an ecu reset tomorrow aswell, try and strip the valve down to clean too.

[Nick Mann]

That's part of the reason I wondered about a control pipework leak. Bleeding pressure off the control system will make no difference if there is a big leak in there!

[SteveH]

stupid question maybe. My bleed valve is a brass tap with a ball and spring inside, i'm guessing its wind in for less boost?

[VR457]

Isn't it loose = less with these things?

[SteveH]

its just like this one if that helps?

http://www.ebay.co.uk/itm/MANUAL-BOOST-CONTROLLER-200SX-S12-S13-S14-S14A-S15-T28-MODIFIED-TUNED-VALVE-/290709608354?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43afa497a2

[SteveH]

Right i've stripped the valve down and cleaned it out. Decided to wind the control knob all the way out and back in a few turns. Went for a drive and got .5 bar, wound it in a little more and now have .8 bar. All seems well with the car now. Found some perished pipes while fiddling so sorted them too. Ecu is resetting as we speak as i now have a really low idle at about 400 rpm.

[VR457]

You can search for threads on adapting the ecu which basically involves (afai can remember) running the a/c, headlights etc for 10 mins and then idling for another 10 mins.

Sounds like you have a result. Your controller is like the one i have. You have to tune back down in winter but that is a while away.

[SteveH]

Low idle was caused by another pipe popping off. So many bloody pipes on these cars.

[Davezj]

when you say you have changed some of the pipe work, please ensure you have not changed the pipe with the restricor in, you need tthe restricor in it if you ever go back to using the factroy boost valve.

[SteveH]

when you say you have changed some of the pipe work, please ensure you have not changed the pipe with the restricor in, you need tthe restricor in it if you ever go back to using the factroy boost valve.

I haven't changed any pipes, just cut the bits off that were perished. All the bad bits were around the connectors so i'm hoping all is ok. However, you've got me worried now as i don't remember seeing any pipework with a restrictor in it. Which pipe is that?

[Davezj]

I haven't changed any pipes, just cut the bits off that were perished. All the bad bits were around the connectors so i'm hoping all is ok. However, you've got me worried now as i don't remember seeing any pipework with a restrictor in it. Which pipe is that?

the restictor is inside the pipe with the red tip or the one that goes to the factory solonid. if the restrictor is not in place the factory solenoid is overwhelmed by the volum of air and can't control the bleed off, but with the restrictor in place all works fine.

the restrictor is exactly what it sound like, it is a hard bit of plastic that sits inside the pipe and has a smaller hole in it than the pipe originally has. so it restricts the volume of air.
nothing more than that.
you should be able to see a slight bulge in the pipe surface where the restricor is and it will not be flexible unlike the rest of the pipe.


the only reason why i mention the restrictor is that there have been a few threads resently that have all been down to people doing a replace all the vacuum/boost pipes with nice coloured ones to make the engine bay look nice, have caused the boost control to fail as they have been using the factory boost solenoid to control the increased boost, and unknowingly removed the required restrictor.

[jjayokocha]

With an ebc fitted though & the std boost solenoid bypassed is there still a need for the restrictor red tipped pipe?

[Nick Mann]

That depends on the EBC I'd guess. Some solenoids can cope with a large volume of air, some can't. I am pretty sure it depends on the way the solenoid is set to work - the stock VR4 solenoid bleeds the pressure from the system, others limit the pressure getting into the system. If you bought the EBC new, it should have said what to do about pipework. If you didn't buy it new, have a look for the instructions online.

[jjayokocha]

mine is an old blitz e sbc and i cnt find a manual anywhere for it, wud i be safer plumbing in the std boost solenoid aswell to allow it to bleed off and the red tip pipe bk in?