At my wits end with the car, can't seem to get to the bottom of an issue(s)! Problem seems to have started after a rad hose on my Process West kit shat itself, dumping coolant everywhere.

In short, the car won't make peak boost in the lower gears (1-2-3), in 4-5-6 it seems to be fine most of the time - making the 22psi it should.

It also wants to stall/sometimes does stall when I depress the clutch, coming up to junctions etc. Sometimes when I stop for a second (at lights, or to go into reverse to get into a parking spot) the car starts to idle incredibly funny, almost like a hunting. It previously had an issue with mentally advancing the timing after an ECU reset - it sounds similar to this when it happens.

Idle is pretty rough.

So far I've changed, to no avail;

MAP sensor - old one was reading 7psi at idle on Romraider!?
MAF
All 4 coil packs
Spark plugs - old ones seemed to be fine when they were removed
Camshaft position sensor - a few months ago, but changed nonetheless

Really stumped now. The car spools up fine and holds boost well (between 15-18psi in lower gears - should be 22 from 2nd onwards) leading me to sort of rule out a turbo/boost control system issue.

There are no present or stored codes on the ECU.

What's next, minus a compression test, as that's in the pipeline?

Mildly modified 2005 Wide Track JDM STI.

 

I would have thought maf or iacv but you changed maf

 

Aye that would be my first thought! I'm quite stumped to be honest! I've a spare gasket for the ICV here, so may give that a clean, see if it helps.

 

Neutral position switch on top of the box

 

I've stumbled across this a few times on various threads. I'm by no means a genius, but it did look like it was functioning on Romraider - i.e the value was changing as I was moving it in/out of gear.

I guess it can't hurt to change it! You able to elaborate further, like why the NPS causes symptoms like this - for my own knowledge?

 

https://www.scoobynet.com/general-te...on-switch.html

 

Cheers Banny, now understand why it can cause flatness and lack of 'oomph'.

Although, in your opinion, do you think it would still make boost in higher gears with a gubbed NPS?

 

I would imagine it would still make full boost in the higher gears but feel flat with the avcs not working

 

By way of an update...

Car is still idling like a pig, although she feels better under half throttle and seems to boost 'cleaner' (makes 20psi fairly regularly if less than full throttle) this way.

She feels 'boggy' when maintaining a constant throttle pressure - for example at 50-60mph in 6th.

AFR was all over the place at idle - bouncing between 11s-16s.

Popped the timing cover off on the nearside, timing notches are not perfectly aligned on the pulleys - a couple of mm difference in them being perfectly aligned, although I'm told this can be normal on AVCS cars? Belt was also not completely taught, but not overly slack. Slightly slack.

Neutral position switch confirmed as working - registering when in gear and when in neutral in Romraider with no dramas.

Still no compression test, as I haven't had time to get down to my mates garage.

I'm still torn between possible valve issue, duff injector or (if it's possible) the timing belt slipped?

 

Have you done any data logging?
How does your LTV look and what's your IAM ?

 

Another wee update. Had the compression test done. All relatively low - circa 110, with the exception of number 3 at 60psi. Guess that's my question answered - best guess would be that I've burned a valve or possibly the HGs are failing due to the coolant hose bursting and her running hot.

Rebuild time when I return from foreign climes at Christmas...