Another fuel cut question - but different!!!
 

Right,

Still hitting fuel cut in my MY96 STI. It boosts to around 0.8-0.9bar (as per gauge) until around 5k rpm. At that point I can see the needle rising slowly on my gauge until it hits 1.1bar, then fuel cut!!!

I fitted a Dawes and set it to 0.8 bar. Guess what? It still happens, rises slowly from 0.8bar to fuel cut.

Could there be a leak in the vacuum hoses?

Could I have a faulty MAP sensor?

I'm awaiting delivery of a ScoobyECU type chip from ESL. Hopefully this might remedy the problem, anyone?

PLEASE PLEASE HELP ME!!!!!

Anyone????

Remove the fuel cut or eliminate the boost creep.

Removing the fuel cut would just mask the problem.

And how to eliminate the boost creep, that's what I want to know how to do!!!! Am I best just replacing all of the vacuum hoses? Are these vacuum hoses meant to be very tight fitting?

Anyone?

Cheers!;)

You shouldn't be getting fuel cut at 0.8 bar on an STi. It's set at about 1.1bar on those IIRC.

Measure the voltage output from the map sensor, at idle and full boost.
I have the pinout and expected voltges if you need them.

Someone speak english please :D

Scott, he states that he hits fuel cut at 1.1bar

Nick why not say that in the first place, you'll need to port the wastegate enabling it to flow a little more to prevent creep.

Try cleaning the boost solenoid ;)

cheers

Why would he need to port anything. No-one else seems to have this problem.

Have you still got the restrictor in the boost control return pipe ?

Must be a vacum/boost leak somewhere then.

Actuator too tight ?

Was done by AS Performance a couple of months back!

Before or after the problem ?

Scott - Would I need to get rid of this restrictor? It's in the slightly thicker hose from the Boost Solenoid isn't it????

Are the vacuum hoses meant to be tight fitting? I can easily pull the vacuum tubes off their connectors. Especially this vacuum hose that is attached to my Dawes. IIRC it comes from the wastegate or something, its a larger bore, then goes to a plastic reducer to a small bore (normal) size vacuum tube.

Should all of the vacuum tubes have clips or clamps on them?

Thanks!!!!:brickwall

The restrictor in the bottom hose needs to be there.

Yes all hoses should be tight and held on with tie wraps or metal spring clips.
Any marginal leak in these hoses will act as a bleed valve and increase the boost.

The ones on the reducers should be OK without clips if they are tight (they don't normally have clips on these).

After and it still happens!

Leading to increased boost then fuel cut????

;)

Cheers Scott! I'll check them over on Tues and post back on here!

;)

Ok, been to the local motor factors and got some hoses to replace the vacuum hoses.

The hose I got was not specific for vacuum hoses though, will this make a difference? It's the hose used for diesel return from the injectors!!!

Do the hoses have to be the exact internal diameter as the ones I'm replacing? As some of the hoses I've bought have a slightly smaller ID, therefore a tighter fit (and hopefully no leaks!!)

Anyone? Please help as these will be going on tomorrow!

Nick ;)

Anyone? Are these hoses OK to use?

Shouldn't make a great deal of difference.
I changed some of mine to Samco type hose without any ill effects.

Can't remember the internal diameters, but probably a set of 5mm and 3mm. I think there are usually some on ebay.

http://cgi.ebay.co.uk/3MM-ID-QUALITY...QQcmdZViewItem

These aren't silicone though! I'd imagine that silicone would be better as they wouldn't collapse.

I needed some ASAP so the only ones they had were 1.5-2mm thick walled rubber hoses with a weave of material over them. Will these be OK and not collapse?

Cheers.

They sound like fuel lines, so should be fine to try. Swap to something fancier if it solves the problem