Lean Misfires at 2700-2800 rpm

[markoverclock]

question bob. if our cars in closed loop ( engine fully warmed up ) strive for 14.7
when we install a emanage or any other type of fuel controller will it overide it?

then if so what is the point, your tune will never stay at you set it at. computer will always take over. or do i have this totally wrong? how do you properly set your cruising speed to 13.8 and wot to 11.5-12 without the computer trying to get the low loads to 14.7 ( fuel economy )

looking for help if anyone knows the answers.

[keithmac]

You can force the car into running 13.8 or lower instead of stoich by bottoming out the O2 correction as Bob mentioned earlier, you have to add enough fuel to overcome the "lowest" trim and the keep adding some to reach your desired AFR. You could also pull the o2 feeds to the ecu, reset it and tune from there, with no valid o2 signal it won`t try to find stoich (but will throw a CEL).

WOT fuel mapping with the emanage on the 1st gen cars is fine, because the ECU ignares all fuel trims when you go WOT (or even just out of closed loop I`ve found).

For me the 14.7 regions haven`t been a problem, WOT is fair game without fear of correction and I`ve richened the real lean cruise sites up, it`s a different car!.

If you could produce an o2 dummy box, that constantly fed a happy stoich o2 signal to the ecu you can have no CEL and no corrections by the ecu?.

[markoverclock]

reason i ask is because its not on our 3kt cars its on a vw. nightmare to tune. and it does set the check lite when i go rich and keep going.

i would deff. be interested in fooling the computer if anyone has any input on doing that i would be in. but i know it switches from below ,400 to ubove ,700 in the voltage anything out of that range and it sets a cel. i work on cars for a living just not tuning them yet. im not sure if anyone knows how to reproduce that ill just make a post and see what happens. if anyone knows chime in.

[keithmac]

What VW is it? My other car`s a Mk2 Golf GTI 16vG60 (a hombrew project) and it runs very well on Megasquirt.

[DoctorDex]

Originally Posted by keithmac

I beleive the ECU used airflow + air temp to get an air mass reading, then references against rpm and throttle position to calculate the actual engine load. What does your TPS signal look like while you`re logging the miss?.

I'm sorry but I don't have a log handy and at the moment I don't have access to my car because its in storage.

[keithmac]

Fair enough. Just a thought, I`m using a MAP reference to alter the Airflow adjustment table not TPS, may have a bearing on why mine`s worked and yours hasn`t?, or your bigger injectors are causing the issue?.

If all else fails to could fit an Emanage Ultimate with MAP sensor and ditch the MAS completey, or run a Megasquirt in fuel only mode?.

[TurboBob]

Originally Posted by keithmac

If all else fails to could fit an Emanage Ultimate with MAP sensor and ditch the MAS completey, or run a Megasquirt in fuel only mode?.

...... or a MAFT Pro.....

[keithmac]

Yeh sorry Bob, forgot about that!. I`ll have to have a look into your setup, wideband afr tracking is a very handy tool to have.

[badass3000]

mine still does it with both (all) O2 sensors unplugged.
It feels like something is holding the car back untill 2800 then wham.
almost like turbo lag but definatly not since Im not trying to build any boost.

[keithmac]

Badass, have you added fuel in at the point of missfire?, mine`s been working like a charm, hits 15.5:1 where it would have been >16:1 and missfiring on the stock map..