boost issue?
 

Around 4k as the turbo starts 2 wind up im getting the engine management light flash and fuel cut?
I had the maf and boost solenoid changed as process of elimination (didnt buy mechanic changed and reverted back 2 originals). no fault codes are logged on the laptop as the eng man light isn't staying on?
Being a novice what pipes should i check for splits holes or other potential problem areas?
car/mods-jdm hawkeye type 20 kit.

oh, i did have turbo gaskets changed approx 2 months ago due to boost leak?
any info would be great, cus its doing my nut in :(

Fuel pump?

Is that a question or a statement? If the latter it's not correct not correct. Provided you are running a Subaru ECU if the CEL is coming on, there will be a fault code stored. If it goes off again as the car is being driven the code will be moved to the historic (as opposed to current) section of the ECU's error memory.

As such, if you're claiming no fault codes are stored, you can't be diagnosing the ECU correctly. In this case it'd be worthwhile going back and seeing what you can do different, as the DTC will be there, and it will help you diagnose this problem.

Dunno, did you?

splitpin excuse my useless grammar and lack of mechanical knowledge :)
I took the car to extreme scoobies in boreham, the guy there replaced the maf and boost solenoid which had no affect on the problem? he also plugged his laptop into the car and the only 'history' was idle control system which was erased a time ago and he said that was nothing to do with the current problem. he said further investigation is required.
ive just taken off the intercooler and checked all pipes and jubilee clips, everything looks fine visually. put all back together and its still doing it?
The car was mapped by powerstation with ecutek.
Any suggestions?
thanks for your reply. :)

I wasn't sure that having the gaskets changed recently may have something to do with the problem?

No probs. With that habit you have of ending every sentence with a question mark, I just thought you were Australian. ;)

So, since the car was last on the laptop, has the check engine light recurred? If so it'd be worth calling back there (or somewhere else) and diagnosing again.

Do you have a boost gauge fitted? Also, have you tried taking the boost control pipework off the wastegate actuator and/or turbo compressor bleed outlet and either cleaned them out, or checked for oil contamination? If not, take the pipe off the compressor outlet, roll up a piece of white tissue and shove it in. When you pull it out, does it come out white and pristine, heavily tainted with oil, or...?

Also, you say this happens "as the turbo is winding up at about 4k", and yet you are driving an MY06 JDM car. Are you saying that the turbo is spooling at that engine speed? And does this problem happen every time you plant it, or just occasionally?

Ill do my best to answer your questions :)


So, since the car was last on the laptop, has the check engine light recurred? If so it'd be worth calling back there (or somewhere else) and diagnosing again.

The cel is still flashing up

Do you have a boost gauge fitted? Also, have you tried taking the boost control pipework off the wastegate actuator and/or turbo compressor bleed outlet and either cleaned them out, or checked for oil contamination? If not, take the pipe off the compressor outlet, roll up a piece of white tissue and shove it in. When you pull it out, does it come out white and pristine, heavily tainted with oil, or...?

No boost gauge fitted and no haven't cleaned the above.
Ill give that a whirl.

Also, you say this happens "as the turbo is winding up at about 4k", and yet you are driving an MY06 JDM car. Are you saying that the turbo is spooling at that engine speed? And does this problem happen every time you plant it, or just occasionally?[/QUOTE]

The problem occurs under accelleration for e.g 1st gear pull away normal, squeeze the throttle the car speeds up starts to spool then CEL/FUEL CUT into 2nd gear squeeze throttle and same as above through all gears. in 6th gear 4K Revs at say 70 mph(think thats about right mph/revs) you squeeze the throttle slowly and it spools up and holds boost with no CEL/FUEL CUT. ????

If you can make sense of that please reply if not just tell me to book it in with a specialist :)

The ultimate answer is always to book it in with a specialist. ;) In this case, given that the CEL keeps lighting up, and given also that the problem is recurrent and seemingly consistent, I'd get the thing diagnosed - and I don't just mean a fault code sweep, I mean looking at the live data out on the road. Will probably isolate the issue in a couple of minutes. If Extreme Scoobies can't do that, find someone who can.

What you're describing sounds a lot like boost spiking - and quite pronounced at that. First thing to check is as above, boost control pipework with significant quantities of oil in it. If the tissue test comes out oily, take all the control pipework off (making careful note how it goes back) and spray it through with brake cleaner. See what difference that makes.

While you're at it, check the sump oil level when the car is warm (i.e. about 5 minutes after switching off). It shouldn't be above the full hole.

Cheers splitpin for hanging in there :)
ill do what u said tomorrow and book it in this week sometime.
any recomendations? im nr lakeside, thurrock, essex
thanks again, Luke

Extreme Scoobies would have been the first name I'd have thought of given where you are. Probably worth a look in the appropriate regional forum to see what the locals have to say, but if all else fails you could take it back there, ask them to do another DTC check, and, most importantly, monitor it in real time on the road.

Right, well, that's the obvious potential explanation ruled out. In this case the quickest way to sort it is likely to be some on-road diagnosis.

Hmmmm, so sounds possible that you accidentally corrected the fault, which then came back. This is only a wild and tenuous guess but it's simple so probably worth a look before you book your appointment: If you've changed the pitch stopper, you must (assuming you're running one) have taken the TMIC off, and, as a matter of course, will probably have disturbed/moved the wiring loom in that area in some respect while doing so. Maybe it's moving that wiring around that temporarily fixed your problem (it probably isn't but like I said, worth a look).

The MAP sensor on a newage is on the top of the throttle body, and a misread from that will cause fuel cut/limp mode. So's the idle speed control valve (which of course you had an error report for, albeit the one the mechanic claimed was "ancient" history). Also around that neck of the woods should be the sensor ground - bolted to the inlet manifold. Have a good look around the wiring in that area - check for damaged or loose wires. Give them all a bit of a pull and manipulation. Try unplugging the MAP sensor and checking the connector for damage/moisture ingress. Do the same with the ISCV and throttle position sensor. And make sure the ground is bolted tightly to the manifold, as that can cause all sorts of weirdness if it's loose.

Once you've had your fiddle, plug it all back in and go for a drive. It it doesn't make any difference, you just wasted 5 minutes of your life, but at least you know you need it looked at. If it does make a difference, you know you're onto something so need to give that area a closer look.

If you end up taking it (back to ES or) anywhere, get them to do both a trouble-code sweep and an on-road diagnosis. It should be pretty obvious from the sensor inputs what's causing the "cut", even if the stored DTCs don't give it away.

Cheers for the reply splitpin ill have a butchers tonight, fingers crossed :)

Now being told it's potentially an ECU problem.......under voltage on 'idle control valve' (ICV) terminal on ECU?
ICV flashes up after 'fuel cut' every time (after being erased from ecu memory)
It seems a coincidence that ICV flashes up, how can this be related to 'fuel cut' and the MAJOR PAIN IN THE ARSE im experiencing?
Any info greatly appreciated, Ta

Hi subeyman. Im having the same issues but with a v3 classic sti with a power fc. It might be a coincident but this started for me a week after i fitted a fmic and remapped. I Was thinking it could be a mapping problem but the car was fine for a week.
I also find the cutting out issue sometimes goes away but then returns on next drive, Did you find that?
Did you fix your problem? ta