toneh

iTrader: (1)

What plug gaps are you running
My bug will cut and miss like a pig at 0.7 at various points and loads at 12psi + but at 0.65 it's spot on everywhere up to 20psi
Just read through again 0.8 seems way too big a gap

Merko

I'm not sure what you mean exactly by silencer pipe in the rear exhaust box? The only thing I can think of is the muffler, which hasn't collapsed. I'm running a 3" turbo back exhaust which is in good condition. The only old exhaust parts are the exhaust manifold and up pipe.


Wouldn't running the Power FC make the car work regardless of the speed sensor condition?


The plugs I'm using are recommended by a huge amount of WRX owners. They are platinum and you can't gap them. Regardless, plugs aren't the problem. I changed them yesterday and had no improvement. And I don't think the car would've worked properly for so long with the same plugs and then suddenly stop.

jason_2013

What about the Turbo, take it off and make sure the wastegate housing isn't cracked?

Merko

Turbo is fine. Has less than 40,000km (25,000 miles) on it. And this doesn't behave like a turbo issue at all.

toneh

iTrader: (1)

The plugs I'm using are recommended by a huge amount of WRX owners. They are platinum and you can't gap them. Regardless, plugs aren't the problem. I changed them yesterday and had no improvement. And I don't think the car would've worked properly for so long with the same plugs and then suddenly stop.[/QUOTE]

Yes you can gap platinum plugs ,( carefully ) I have to do mine as do many others
Mine gapped at 0.7 led to weird misfires and random cuts , sometimes it would some times it wouldn't , sometimes it would pull cleanly right through
IMHO a 0.8 gap is not helping your issue at all ,

Merko

Replacement plugs with 0.6mm gap made no difference. Plugs are not the problem.

toneh

iTrader: (1)

I'm not being funny mate but you said you can't gap them and now replied you've tried them at 0.6 ?

Merko

No, I said I have replaced them. I gapped the replacements to 0.6.

Stefen1

iTrader: (1)

[quote=Merko;10920847]
The inlet manifold ground is fine. I'm not sure where to check the ECU grounds though? I understand where the pins are on the ECU, but where do the wires actually ground?
quote]

Forget about where they ground, there may be a break somewhere in the loom. Put the earth to the pins on the ECU that was mentioned in this thread, that will bypass the loom. It's quite simple.

Also you could plug in EVOScan and see what voltage the ECU is seeing, and also will be able to log when the power cut is occuring.

Merko

Update: Auto electrician couldn't find problem... probably because they couldn't do any testing with the car actually cutting as they don't have a dyno. Apparently they checked all they could with the car stationary but saw no issues.

FFS

jason_2013

Have you checked that the one way valve mod in the map sensor is still working as a one way valve and not blown through?

Merko

Yes I replaced the valve when it first started cutting and I thought that it was overboost fuel cut. No fix. And even if the valve was shot it wouldn't be cutting at 10psi seeing as the ECU fuel cut is 15.85psi

Merko

Problem solved! For anyone who might have a similar issue, the problem was the following:

As the VF34 doesn't have the 90 degree elbow that the stock TD05 has, we put in this rubber elbow. Seems it was a bit too soft as the high vacuum from high boost was sucking the hose shut and stopping the flow of air. Though the bloke that put it in has used it in many other rexes with no problem. I must be unlucky! Anyway, I put on a hose clamp diagonally as seen in the pic, set it to 15psi, and BOOM IT REVS ALL THE WAY!

lord shaun 83

i have same problem, an issue i have been trying to resolve for some time now.. changing this that and the other to no effect... just that mine is using a silicone pipe from maf to turbo. could this be perished in some way coursing it to do what yours was doing?
i cant see it closing up but then my car is stationery under no load when i check it. how did you find out it was doing that? cheers shaun

Merko

It could very well be that yours has the same issue. Silicone hose or not. It won't suck the hose shut when it's not under load, there won't be anywhere near enough vacuum for it to happen unless it has a good deal of boost. The only way to check it stationary would be on a dyno.

I found out this could be the issue after someone on NASIOC said they had this happen to them. I checked all my rubber intake hoses, saw no signs of damage from being squashed shut, but I wasn't convinced :P I put 3 hose clamps on various parts of the hoses to reinforce them, took it for a drive and like magic, it worked. I suspected it was the after market rubber hose that was collapsing, so I removed the clamps from the hose with the ports for the blow off valve, PCV valve and head breathers, and this narrowed it down to that rubber hose in the pic.

Only way to find out without a dyno is to get a few hose clamps and start clamping rubber intake hoses for reinforcement. There probably won't be evidence of the hose collapsing on the hose itself. Mine had no damage or creases or anything. Just try it and see.

Andy Gilmore

Hi Merko

i am having the same issues as you have had as shown this thread. Would you be able to share the photo you referred to in this post showing the relevant boost hose which was causing the problem?

best wishes,
Andy

1509joe

iTrader: (2)

Thread is nine years old.

bunsofsteeeel

iTrader: (1)

It will be the induction hose that feeds the turbo

Steve Whitehorn

iTrader: (13)

Cheaper induction hoses collapse under pressure.
Harvey fitted a Perrin hose to my car years back and I have never looked back