Engine Troubles

[Shane@DBPerformance]

Originally posted by EclipseTurbo@Jan 22 2004, 11:14 AM
Not always will the bigger injectors or a bigger pump CURE it. It will help it though, or raise the psi it will cut at.

No, it won't help at all, unless you remove airflow signal with a fuel controller. Putting in a bigger fuel pump will not change where it fuel cuts at. The reason why you fuel cut when its colder out is because 14psi when its 75 degrees out is not the same as 14psi when its 30 degrees out. Colder air is denser so when its cold out the ECU sees more airflow at the same boost level than it does when its hot out. Which causes its fuel cut routines to kick in earlier because they are based off airflow not boost psi or running lean.

As far as the MAFT, it uses the same tricks that an AFC does. It is no better nor worse than using an AFC to get around fuel cut, so you need to use larger injectors in conjunction with it for it help fuel cut at all.

[JiN]

How exactly do you hack the MAS?

[Enes]

Originally posted by JiNMaXimus@Jan 22 2004, 01:16 PM
How exactly do you hack the MAS?
definetely not thru ssh

[A//// Guy]

I dont know, differnt threads say differnt things, FAQ says differnt things and when I have posted in the past about fuel cut why did you guys tell me to get 550s? Oh well.

So does the Mas read fuel DC based on airflow or is it real dead time for the injectors? If DC has nothing to do with fuel cut then why when you get up past 100 or so it will fuel cut?

Im confused.

[Shane@DBPerformance]

Originally posted by EclipseTurbo@Jan 22 2004, 12:41 PM
I dont know, differnt threads say differnt things, FAQ says differnt things and when I have posted in the past about fuel cut why did you guys tell me to get 550s? Oh well.

So does the Mas read fuel DC based on airflow or is it real dead time for the injectors? If DC has nothing to do with fuel cut then why when you get up past 100 or so it will fuel cut?

Im confused.
Well, even if it is tied to pulse width (duty cycle is just a logger calculated value from pulse width, rpm, and dead time), pulse width is directly tied to airflow. If you put in a bigger fuel pump, you ECU won't change its duty cycle/pulse width to compensate for more fuel because if has no way of knowing that there is more fueling available.

Here is some info on the fuel cut routine in the ECU's code from a post by Keydiver.

On my flight out to LA
last week, I spent some time looking at the disassembly, and noticed
what I'm pretty sure is the correction being put into the raw
airflow, a 16-bit value, to make the corrected airflow value L0057
for the fuelcut check. The routine takes the raw airflow, multiplies
it times one address, divides it by 128, multiplies it times another
address, and divides by 128 again. I'll bet anything that the one
address is the barometric pressure, where 1 bar (sea level) is 128,
and the other is the intake temperature. I don't have my notes in
front of me now, but it looked very simple.

[AJ]

Originally posted by JiNMaXimus@Jan 22 2004, 12:16 PM
How exactly do you hack the MAS?


honeycombs. No not the cereal.

[Shane@DBPerformance]

Originally posted by JiNMaXimus@Jan 22 2004, 12:16 PM
How exactly do you hack the MAS?
People don't hack the 2G MAS very often. They can handle 3000hz and 450whp stock. You have to start hacking the 1G MAS pretty early on if you want to continue to use it and make any power. It likes to start overrunning when you get close to 2000hz. On a 1G MAS, the first steps are to remove the lower honeycomb and back out the calibration screw. If that isn't enough then you can start removing some of the lower half of the MAS with a dremel. People often at that point also solder a resistor or potientiometer into the intake air temp sensor line to fool the ECU into thinking it's colder outside and adding more fuel to compensate for the added airflow that it won't be reporting to the ECU. You don't want to hack the MAS more than you currently need because you can run into timing/knock problems and it gets hard to tune the more it is hacked. You also never want to remove the main honeycomb, without the main honeycomb it won't meter the air worth a crap.

[JiN]

Personally, im not so sure if it's fuel cut anymore. I think it has to do with my BOV venting to the atmosphere.

[A//// Guy]

Fuel cut feels like the car basicall hits a wall for a second. Your face should almost eat the steering wheel.

[Miranda]

I know! Downpayment for a house! :P