Boost and Fuel

[Sports GT]

Got myself an MBC, raised the boost up to 1.0 bar on my 6A12TT.. noticed it starves for fuel along the range and slightly jerks ever so often... so I lowered it to 0.8 bar and still does it a lil but not as bad... anyone have the cure for this? My guess is that its not getting the fuel... I'm running a Walbro 255 but a stock fuel pressure regulator...

P.S.. My friend reset my ECU by unplugging my battery and now its gotten worse

[Gly]

you sure its a fuel problem?
these cars usually run very rich from the factory....

have you tried a new set of plugs or re-gapping your current ones to 0.6mm

my car runs fine on stock boost,
but tends to spit and splutter on anything higher than 11psi,
and get worse as you raise it...

coz the plugs have had it, getting new ones tomorrow.

[Sports GT]

I believe you're right... going to get new plugs ASAP, better heat range ones as well... noticed that the car is running a lil richer than it used so, probably because the O2 sensor is seeing more unburnt fuel in the exhaust

[Sports GT]

Something else I noticed... when the car stutters, the Blow Off Valve opens... like its cutting off and releasing the air... boost cut? at 11 PSI?.. I have no idea, need a lil help.. the plugs need replacing but I don't think that's the problem, no check engine light though.

[Kenneth]

Something else I noticed... when the car stutters, the Blow Off Valve opens... like its cutting off and releasing the air... boost cut? at 11 PSI?.. I have no idea, need a lil help.. the plugs need replacing but I don't think that's the problem, no check engine light though.

maybe you have a leaking BOV. bov shouldn't open if you have your foot planted on the gas (unless you had traction control which was closing the throttle butterfly) as BOVs are designed to work on pressure differential between the intake plenum and pipework pressure.

The BOV opening makes me think its something to do with the BOV. maybe the hose that goes to the BOV from the plenum is cracked, leaks or is bent to the point it is restricting flow

[djb160]

what! TCS messes with the BOV - I'd better whatch my factory one then.

[Kenneth]

what! TCS messes with the BOV - I'd better whatch my factory one then.

um, dont know for sure... but it kills power somehow... i just assume it does it at the throttle body... dont take my word for it as I have never had Traction Control

[OSiRiS]

It sounds like the exact same problem I had.

Your car is actually running richer than 10.9 AFR.

You need to tune your AFR by REMOVING fuel.