Well I have been having AFR problems forever now and have done a lot of replacing. New MAF, spark plugs, walbro 255, fuel pressure regulator, blew air in the fuel lines, etc. I have scaled the maf up 10% everywhere (AMS intake) and things SEEM to be a little more stable now under WOT, but we'll see. In the past, it has gone a point too lean, or a point too rich, at seemingly random times.

But now I have this stupid and weird problem. It really is only noticeable in 1st, 2nd, and SOMETIMES 3rd gear. My relay switches the fuel pump voltage from 9v to 12v at around 3k RPMS everytime, no matter the load, throttle position, etc. And when that switch happens, my AFR's go SUPER lean. like 16+. it feels like my car momentarily hits a brick wall. like a big stutter or a mini fuel cut.

I really dont know what to do to diagnose this. It's not in my fuel map. My trims seem to be okay.

Any help is appreciated.

thanks!

 

Stupid to ask... but did you replace your fuel relay with Green/Blue relay?

 

Have you disabled trims affecting WOT yet?

Also it sounds like you might need to go back to scaling your MAF, if that is off everything will be screwed up, especially if trims are still affecting WOT.

 

Yes, I have the new blue fuel pump relay and also I have tephra's LT trim disable code, so the mid trim is NOT affecting WOT.

I forget who it was but I read on here somewhere that the AMS intake needs to be scaled upwards of 10% all around. So that's what I did.

 

Just assuming you add 10% to the MAF scaling seems wrong, but I am no pro tuner. You need to log the car after you scale, maybe even on stock injectors and make sure you lifts and everything look right before you continue to make changes.

I am not saying that is the issue, but seems like it might be.

 

you could start by posting injector type, scaling/latencies, fuel maps.

was the car ever running properly after all of these changes?

 

the saga continues.. wait where have i heard that before?

ok so did you resolve the last issue of low fuel pressure?

 

I'm pretty sure the issue with the fuel pressure dropping under boost has been resolved. It has stayed consistently rich, but who knows it might do it again. So now I'm just doing fuel map adjustments and seeing if it stays consistent. Only thing is the problem I'm posting now with the crossover lean thing and also sometimes like after I do a wot run it won't want to decel (keeps injectors on even if I'm off the gas pedal) and sometimes the revs hang. And like If I come to a light, the AFR's will go to like 12.5 and then the STFT's will kick in like 7-15 seconds later and then target 14.7 decently. I think all of that stuff is relatively normal, except for the injectors going super lean at the 9v-12v crossover.

This sucks I'm the only one having these damn problems.

 

here are my fueling related values:



I have the DW 1000 injectors, AMS intake, FP Red, full exhaust, AMS IC pipes, AMS IC, walbro 255, ams fuel rail, and that's about it as far as mods that would be related to this.

 

You have your Closed Loop LT Trim Control table setup wrong.

it should be 350hz in Mid-> High, then 343 in High -> Mid

That could be your problem...

also post up your openloop tables

 

and i think your maf is not scaled properly according to your fuel map.

but lie tephra said try fixing your Closed Loop LT Trim Control table and you might see your fuel table differently.

 

I have the EXACT same problem on my VIII.

Do we have a table that shows the rpm crossover for the fuel pump relay?

In my V7 94171075 there is this table" Boost Control High/Low Gear Range RPM/MPH Crossover " that has an rpm value of 2900. Address is 2204. Could this be mislabled and is actually the switch over point from 9v to 12v for the fuel pump relay #3? ? ? ? ?

 

This is the X section, so I don't think we can help you. Tephra may be able to, and he reads this area.

 

Yes, I realize this the X section. C'mon man I am not a newb. The "issue" happens on 8, 9 and 10 evos.

 

I always wanted to find this table for a double pumper application, but I doubt the table that you are describing is incorrectly labeled... we have it pretty well documented that it is the rpm/mph for gear based boost switching.