Not reaching full boost - Page 5 - Perth-WRX.com

Rossco · #41 15-04-2009, 11:17 PM

Quote:

Originally Posted by dazzabozza

The bad stuttering/hesistating disappeared a few weeks back after another visit to the workshop.

The car drives pretty smooth at the moment and the idle has improved since the lines were replaced and the ECU reset. Main prob now is the delay/lag and some very slight power cuts (or knocks) through out the rev range.

Before I could accelerate through corners, roundabouts etc and really feel the car gripping with heaps of power/torque at lower-mod revs. Now I put my foot down and the car does does nothing until about 20metres after the corner LOL.

Daz

What did they do to correct the stuttering?

Could also be a blocked / smashed cat converter blocking the exhaust, bottomed out on anything recently?

daggyboy · #42 15-04-2009, 11:21 PM

Quote:

Originally Posted by LegacyRS

What did they do to correct the stuttering?

Basically re-sat everything, checked connections, leads, piping etc. Unfortunately they did this before roadtesting so never saw the car at it's worse.

Quote:

Could also be a blocked / smashed cat converter blocking the exhaust, bottomed out on anything recently?

The car is quite low so it's possible. No major bottoming out that I can recall, mainly just scraping.

Daz

Rossco · #43 15-04-2009, 11:22 PM

Quote:

Originally Posted by RichX

Ross knows more than me around boost controllers, but if you've been Verso'd then if there were any issues there originally the retune should have ironed all that out as your boost is controlled via the ECU like my car.

I think there is a gain setting on the boost controllers which can increase/decrease how the car comes on boost but not really sure about that, Ross?

Yeah the gain basicly delays when the wastegate begins to open, bringing the boost on earlier than stock, the down side is that running a high gain also sets your engine up for nasty boost spikes that can occur before the system reacts to them........ BOOM!

daggyboy · #44 24-04-2009, 10:50 PM

Update.

Had the car in the shop Thurs/Fri. Sean noticed some oil build-up around the BOV and intercooler. He removed the intercooler and gave the intake manifold? a good clean etc.

The car ran really well over the weekend and Monday morning. Built up boost and accelleration effortlessly (light on the pedal). BOV firing fast and cleanly. This is the first time I actually heard what I think is the turbo spooling down (BOV vent noise and then a higher pitch sound follows).

Monday arvo things turned to poop again. Started the car, had the aircon on, turned it off as I had to pull out in front of traffic. Gave it stick (still warm) and it was below average. Still reaching full boost but acceleration was lacking. The was also a delay after releasing the accellerator, like there is extra fuel it needs to burn off. In first gear if I floored it up to 5000rpm and released the accellerator I'd hear BOV fire (much more faintly), the revs would hold, then drop slightly, hold and drop again. Sitting at the lights I noticed the revs sitting around 1100rpm (in or out of gear). Normally sits around 600-700rpm from memory.

Over the last few days it's gone through different stages, sometimes jerky through the rev range especially when giving it stick. Now I'm pretty sure I'm back down to 6psi, no jerkiness but super slow.

My thoughts is the timing keeps adjusting itself to safer zones. Keep in mind this is running on the same tank of fuel when it was running really well over the weekend.

What's everyone else's thoughts?

Daz

scoobygez · #45 24-04-2009, 10:56 PM

boost solanoid needs cleaning maybe????

look at the simple things first.....

daggyboy · #46 24-04-2009, 11:20 PM

Gday Scoob

First post in the thread the solenoid was replaced as it was originally thought that's where the fault was

Majority of the vacuum pipes around that area has been replaced too (pill retained).

Daz

scoobygez · #47 24-04-2009, 11:25 PM

sorry i should of gone further back with the posts lol

not sure now after reading all the other ideas/thoughts if i think of anything i will post it up though mate

Rossco · #48 25-04-2009, 12:46 AM

Quote:

Originally Posted by dazzabozza

Update.

(warning #1 = Going lean)Still reaching full boost but acceleration was lacking. (warning#2 = false Maf output to ecu, ecu pumping extra fuel for false (high) airflow)The was also a delay after releasing the accellerator, like there is extra fuel it needs to burn off. In first gear if I floored it up to 5000rpm and released the accellerator I'd hear BOV fire (much more faintly), (warning#3 = maf output staying high)the revs would hold, then drop slightly, hold and drop again. (warning#4) Sitting at the lights I noticed the revs sitting around 1100rpm (in or out of gear). Normally sits around 600-700rpm from memory.

(warning#5 = Going lean @ random) Over the last few days it's gone through different stages, sometimes jerky through the rev range especially when giving it stick. Now I'm pretty sure I'm back down to 6psi, no jerkiness but super slow.

My thoughts is the timing keeps adjusting itself to safer zones. (the ecu is getting confused and going into limp mode to prevent further engine damage) Keep in mind this is running on the same tank of fuel when it was running really well over the weekend.

What's everyone else's thoughts?

Daz

AIR FLOW METER!!!!!

Everything I've bolded in the quote above are the classic signs of an air flow meter failing, especially the random high idle when the engine is warm.

Does it feel like the car continues to pull when you lift off the throttle completely when cruising?

Get it checked ASAP.

A Fucked MAF sensor will cost you an engine if driven on boost.

RichX · #49 25-04-2009, 08:36 AM

Sounds awfully like the MAF .. Especially the high idle. Surprised it hasn't thrown a CEL but. Rip it out and give it a good clean, Otherwise Russ on these forums has one for sale which you could try out.

Try disconnecting it while the engine is running, the car should almost stall and throw a CEL if it's engine is seeing a signal from it, but that's not to say it's 'partially' damaged, and not broken enough for the ECU to see a fault.

As i've mentioned before though, if you're not running a super oiled pod filter, i'm surprised that it's dying if that is in fact what it is.

Change it out and see what happens - Did ASG mention anything about the MAF/AFM?

daggyboy · #50 25-04-2009, 09:42 AM

Quote:

Originally Posted by LegacyRS

AIR FLOW METER!!!!!

Does it feel like the car continues to pull when you lift off the throttle completely when cruising?]

Occasionally yes. More obvious when I put my foot down and then release.

Just to confirm I'm looking at the right thing... the MAF/AFM sensor screws into the top of the intake tuble between the filter box and engine? By unplug I assume you mean just the electrics?

No menion about faulty sensors from ASG as yet.

Daz