You know what you could do is have it tuned. Its a new thing people just started doing. :P. Its probably just that it needs a new tune. A fresh motor is gonna make more hp than an tired one, add to the the differnt internal weight and everything.

 

it isnt the tune... maxxing out my fuel map n still running 14 a/f is not the tune then

 

Might as well replace the fuel pump

 

Oh ya I forgot your a tuner

 

im not tuning it someone else is on this site

so i know it isnt me and he is a very knowledgeable guy so i can safely say the tune is def not the problem

 

Have you disconnected the battery to reset the ecu, since after the new tune? Do you have a log you can post up? I know these are basic questions but you have to start at the beginning.

It is strange that it only happens at WOT. Like others are suggesting it seems that if it is not the tune, then the fuel pump must not be getting proper voltage or is thinking about taking a dump. Seems strange for it to go out like that though. Stranger stuff has happened. I guess that swapping it out for another walbro would let you know for sure.

 

yes you can. Ive removed mine, did zero maf scaling and it runs fine.

just make sure you unlock the load limit in the ecu or the load will get capped at 379. after I did all the unlocking and etc i hit a peak of 560 load with my 2.3 and fp black setup at 41psi. going for round 2 in a month or whenever the weather clears up here then switching it to SD and comparing maxed MAF vs SD to see the real world gains and posting results on forum.

removing a restricted screen from the maf does free some power also.. theres no way it doesn't. the screen halts the airflow.

 

Replace the fuel pump, mine did the same thing, except I was running a booster inline pump at the time too. My primary walbro was dying so, my car would go lean only at WOT. Even with only 10psi or so it would happen. Only way to be positive is to measure fuel pressure, but short of buying a 300 dollar electric gauge to mount internally, it would be better just to spend the 90 bucks on a new pump.

 

hope you figure out the issue. i had a similar issue with the o2 sensor and and fpr line not hooked up

 

trims are sitting at -2% with proper latency voltages. (deadtime)

set the map to 7's just for kicks and car still runs ungodly lean.

I would guess its the fuel pump or injectors. I asked him to make sure the vac lines on the FPR, he claims it is.. so i checked that off my list.

recently i had a customer running super lean as well, he removed the fuel pump, cleaned the fuel filter screen and fixed his issue..

so something else there just in case anyone else has this issue that cant figure it out.

anyone else that has ever ran into this problem feel free to join in on helping him.

 

I know someone that had this problem, it was the injector scalings. Just becuase the trims are good doesnt mean ****. you can have the scaling really high an have the latencies high. And still have the low and mid trims +/-5. The maf scalings could be way off.

 

Ya, thats why you start off with factory latency settings recommended by the injector manufacturer and go from there.

As for the injector size scaling itself, yes if you dont log long enough 20minutes between each mid trim adjustment it could drift off in a different position without realizing it.

hes been driving on the final number we concluded to for his injectors and maintained the -2%.

as for rescaling maf.. no need to rescale maf with a silicone intake.

 

maf scalings can make it appear the injectors are dialed in also. say the mid trim is neg then lower the maf scalings for cruise hz. Vola the trims look good but there not. You set injector scaling by afr at wot. latencies by cruise and isle then maf scalings to get the trims even more tight. Also maf scaling can have the same effect for wot, increase the scalings for wot hz.

 

you don't set injector scaling by afr at WOT.

the proper way to get the "injector size scaling" is to drive around and log mid fuel trim.. start by using one of the numbers already on the forum and cruise and the mid fuel trim will adjust every 4minutes. If the trim increases to positive, you decrease the injector scaling. If the trim goes to negative you raise the injector scaling.

To get the latency voltages settings you do that idling the vehicle. on an evo 8 you would reset the battery after every tweak and let the vehicle idle for 4minutes and watch the low trim shift.

maf rescaling isnt ever usually required. is it good to do? yes.. if you want a proper tune you confirm everythings in order, but not required.

also say the cars idling 60hz so it never leaves mid fuel trim making low trim impossible to tune (injector latency), there are tables you can add to your xml to change these settings also.. so for example the mid > low is set to 43hz, but your cars idling at 56hz.

you would change that number anything over what youre idling at to force the car into low trim usage at idle.

 

So if a car is running lean at wot vs what the map says it should be what would you do? Just lower the number in the fuel map? fuel map says 11.5 but that actual afr is 12.5.

For the example just say its definetaly tuning related.