I have a 94 wrx jdm and have a problem with fuel cut
At the moment im running a Hks boost controller and type of bleed vale device that’s been modified and fitted to the feed to the map sensor
The purpose of the bleed valve is to drop the pressure to the map sensor to try and reduce the fuel cut
The modification I have done to it is to fit a spring and ball bearing to act like a pressure relief valve and to stop any vac problems the unit its self is adjustable via a screw cap
I have a boost gauge fitted and piped to the high pressure side of the turbo before any other devices come off apart from the sensor pipe to the Hks boost controller which comes of at the same point
The thing is if I wind the map sensor bleed valve in so as not to bleed any pressure of the fuel cut comes in at .6 psi
With the bleed valve wound out I hit fuel cut at .92 psi
Basically the fuel cut seems to come in .6 psi left to its own devices which leads me to think the map sensor is faulty
Has any one else had a similar problem and what was causing it
Thanks

 

Have you tried removing your ball and spring contraption, setting your boost controller to a sensible pressure and seeing what happens then?

 

I presume you mean .6 and .92 bar not psi. If so then .6bar will be the actuator pressure and .92bar will be the standard ecu boost/fuel cut limit. I dont understand the bleed valve set up to the MAP at all, but if you are running the standard ECU then it will nearly always cut at the standard limit, i think Someone will correct me if im wrong

 

Sorry I do mean bar not psi
If I remove everything and pipe the map up correctly I can only run .6 bar before hitting fuel cut
The idea of the ball valve thing if to fool the map sensor into seeing less boost than it is
I have tried putting every thing back to standard and trying it again but still hit fuel cut as this is why I fitted the boost controller in the first place and found I had to turn the boost controller of but still got fuel cut just on the actuator pressure

 

This is a receipe for disaster , you do not want to be fooling the map sensor and using a boost controller without monitoring devices such as a knock link and afr as you will end up blowing up your engine , you are best removing everything and getting car to run properly , then get a remap or aftermarket ecu . Car should be running at 0.8 bar standard boost and fuel cut should be set at about 1 bar to protect engine as car is not mapped for fuel/ignition timing ,for running higher boost.


Mark

 

The only cure is a cold shower and hiding its Liberace records.

 

I don’t think any one understands what im saying I fitted the boost controller to get the boost back under control because for some reason it started boosting to as you say 1 bar and hitting fuel cut instead of .8 to .85 bar as it use to
Once I fitted the boost controller to turn down the boot not up the fuel cut has moved from 1 bar to .6 bar if I re pipe it all back to standard I wont be able to use it as it will just keep hitting fuel cut at .6 bar not 1 bar hence the reason im asking if my map sensor could be giving fouls reading to the ecu