why low af when I release the gas.apex mcx 290

[nytro-king]

it runs fine all the way, until i get off/release the throttle.and then it gargle a little when hitting the throttle again. any idea?
thanks.

 

[tjc]

Do you have a blow off valve?

 

[nytro-king]

Yes. And it works.

 

[msrx700]

you switch to negative pressure in TB when you close it...so it's normal is tend to 13-14.7

need some delay for receive positive pressure after you push throttle and another delay for piggy back ecu to compensate

 

[nytro-king]

Its way too rich. Too much fuel. And only when i release the gas. It gargle when hitting throttle again.

 

[tjc]

always been like this or did it just start?

 

[gsxr]

Are you using Mcx kit ? and his programing ?

Have you added the lower pressure blow off spring ?

 

[nytro-king]

has always been like this. after the turbo mount.
not a lower pressure spring.

 

[msrx700]

so injector continue to put fuel after realease throttle...

maybe your map sensor tube or something like that is bend or kink

 

[nytro-king]

yes. have checkt all hoses. has there been any problems with the mcx box. ? dont understand why it gets more fuel after realease the thottle.=/

 

[gsxr]

Blow off valve not working properly
Fuel is constant and you let off throttle , air stops = very rich

 

[gsxr]

What year mcx290 kit , mid or rear mount ?

 

[FLYBYU]

It's not burning the fuel complete. Check your plugs. Where is your fuel pump mounted? Hopefully not on headlight frame with the msd pump cooking the fuel above the fuel tank level. Those MSD pumps aren't meant for pulling fuel uphill. Put them down in front of the battery on the delta box. Let gravity assist you in getting fuel to the pump. Doesn't sound like blow off is working correctly. When you let off throttle there should be zero pressure in intercooler and mcx box knows that and stops adding fuel. Since map sensor is behind TB's it goes negative pressure. And yes you will always go rich after quick throttle close with a piggyback