Lean under throttle after adjusting AFPR

[DeadlyScone]

Figured out my base fuel pressure was not set correctly(50psi) when i was tuning my car. so i got it set to about 37-39psi. i adjusted the global fuel to what it should be with 660cc's and started tuning again. under any throttle any gear in closed loop causes the car to totally lean out 16.0-18.0 afr i adjusted the maf sliders in accordance to the STFT at the specific MAF Hz and it seemed to help some, but sometimes it still leans way out.
I've tried everything i could to try to get it right, but just keep getting no where. I have a log with the current tune and everything. Tell me what you think i should do, I almost want to put the base fuel pressure back up to 50 where it was before.

 

[huafist]

How did you adjust it? You realize that you should set the fuel pressure to 37psi with the vacuum line disconnected from the regulator, right?

It has to be in the tune somewhere though. Even setting the FP with the vac connected wouldn't yield a lean spot (rich actually, as the base FP would be higher than intended). I know it's stupid, but be sure it's rising 1:1 with boost.

 

[DeadlyScone]

How did you adjust it? You realize that you should set the fuel pressure to 37psi with the vacuum line disconnected from the regulator, right?

It has to be in the tune somewhere though. Even setting the FP with the vac connected wouldn't yield a lean spot (rich actually, as the base FP would be higher than intended). I know it's stupid, but be sure it's rising 1:1 with boost.

i set it correctly, pull off the vac hose and put your thumb over it and adjust it that way. but the problem is happening while in closed loop and not under any boost.

Also my gauge for my FP sits on top of my fuel filter if it makes a difference.

 

[huafist]

i set it correctly, pull off the vac hose and put your thumb over it and adjust it that way. but the problem is happening while in closed loop and not under any boost.

Also my gauge for my FP sits on top of my fuel filter if it makes a difference.

If it's happening in CL, then it HAS to be in the tune somewhere. It would suck, but have you tried starting with a fresh tune and just adjusting the global to see if it comes back in line?

 

[turboglenn]

Like huafist said, if it's happening in closed loop and the fuel trims aren't maxed out then it's either in the tune or it could be in the o2 sensor that's feeding the ECU it's information (are you reading a wideband that's seperate from the sensor feeding the ECU it's information???)

Fuel pressure can make large changes like that..

In a regular speed density setup like i run, i can have major changes in AFR"s and to largely different degrees from cruising closed loop to wide open open loop. For me though i have it kinda easy to trouble shoot because i don't tell the ECU a desired AFR to shoot for under open loop, i tell it exactly what to put out in pulsewidth at any given cell (one feature i wish ECMlink could do but becayuse it piggybacks the stock ECU it must follow the stock ECU's way of "thinking" and this is something i doubt can be changed or implemented)

Anyway... Check the o2 sensor (front one)

HOld up...i went through your log and the only lean spots i can see where it's not just doing the typical .20 to .80 up and down cycling which is normal, is when you've let of the gas and are sslowing from a higher RPM and in that case lean is normal, because the ECU cuts fuel on deceleration for economy. Can you point out a specific time in the log you think something is wrong so i can examinue it?? nothing looks wrong to me but then again i'm no ECMlink expert, but based on what i see coming from a general tuning standpoint there's nothing i can find wrong

 

[DeadlyScone]

I simulate the narrow through my WB. i put a picture of "these" type of spots where my car goes supper lean and it feels like my car is trying to tow a 2 ton bag of bricks.

EDIT: i also suspect a tiny exhaust leak after the WB at where the down-pipe and O2 housing bolt to each other. Will that cause a weird reading even though it is after the WB?

 

[turboglenn]

OK, did you unplug something or leave a wire off when you messed with the AFPR? reason i ask is how can you be trying to accelerate and the boost est be at -21psi, it should be near 0 or in the positive range unless you're at steady cruise or decelerating.. Ithink you may have an issue based on wiring and not so much the tune..

post a copy o that log so i can see that area and the sensor values second by second if you don't mind

Also, is the AFRest the real reading from your wide band?? I wish there was just some univeral way to log thew AEM wideband as it's 0-5v signal in ECMlink where people like me can know that everytime we see that value it's going to be just the direct output from the sensor

 

[DeadlyScone]

OK, did you unplug something or leave a wire off when you messed with the AFPR? reason i ask is how can you be trying to accelerate and the boost est be at -21psi, it should be near 0 or in the positive range unless you're at steady cruise or decelerating.. Ithink you may have an issue based on wiring and not so much the tune..

post a copy o that log so i can see that area and the sensor values second by second if you don't mind

Also, is the AFRest the real reading from your wide band?? I wish there was just some univeral way to log thew AEM wideband as it's 0-5v signal in ECMlink where people like me can know that everytime we see that value it's going to be just the direct output from the sensor

the log that you are looking at is the same that is posted at the top where i first posted.

 

[turboglenn]

Weird, ok I found that spot in the log, but the values i'm seeing in your screen grab must be live engine data then because i can't come up with the same values under that area in the acual log, I have no idea what could be the issue based upon the log because the only thing i can find that don't look right is that the boostESt reads 10psi and the thing is still in closed loop..

I didn't go alll the way to the end last time i had looked at that log so i didn't see the areas where there was lean spots under load.. But the STFT's goes to 17% at the end of that lean spot then it goes back into closed loop,. i think there might be a lot of setup issues in your DSMlink install at this point or the tune and calibration are way off... I mean the ECU is trying to richen things up but i don't understand what you'd have to change in your settings to rchen it up from the start (you will have to richen up for the lower fuel pressure, but again, since you only input a desired AFR and then calibrate everything the last thing i can come up with is the VE tables but i can't remember if that's in effect when running a MAF meter or not.. I"ve tuned some DSMlink cars but they were all moslty setup when i got there or were running SD)

See this is a point where DSMlink confuses me, being that you don't change actual pulsewidth but rely on the ECU to put the AFR's wherethey need to be at anygiven load range (even at WOT) It leaves me thinking about a bunch of calibrations and stuff that i usually don't have to deal with

ok,... ichecked the active MAF comp and there's all the fuel you're lean pulled out in that tab.. maybe i'm wrong but left clicking on that log and selecting "MafCompADjust CombinedFT" and the table it briogs up there's a ton of fuel pulled in the MAF areas from 400 to 1800hz and that's where the MAFRaw readings are putting you while lean

 

[DeadlyScone]

Weird, ok I found that spot in the log, but the values i'm seeing in your screen grab must be live engine data then because i can't come up with the same values under that area in the acual log, I have no idea what could be the issue based upon the log because the only thing i can find that don't look right is that the boostESt reads 10psi and the thing is still in closed loop..

I didn't go alll the way to the end last time i had looked at that log so i didn't see the areas where there was lean spots under load.. But the STFT's goes to 17% at the end of that lean spot then it goes back into closed loop,. i think there might be a lot of setup issues in your DSMlink install at this point or the tune and calibration are way off... I mean the ECU is trying to richen things up but i don't understand what you'd have to change in your settings to rchen it up from the start (you will have to richen up for the lower fuel pressure, but again, since you only input a desired AFR and then calibrate everything the last thing i can come up with is the VE tables but i can't remember if that's in effect when running a MAF meter or not.. I"ve tuned some DSMlink cars but they were all moslty setup when i got there or were running SD)

See this is a point where DSMlink confuses me, being that you don't change actual pulsewidth but rely on the ECU to put the AFR's wherethey need to be at anygiven load range (even at WOT) It leaves me thinking about a bunch of calibrations and stuff that i usually don't have to deal with

ok,... ichecked the active MAF comp and there's all the fuel you're lean pulled out in that tab.. maybe i'm wrong but left clicking on that log and selecting "MafCompADjust CombinedFT" and the table it briogs up there's a ton of fuel pulled in the MAF areas from 400 to 1800hz and that's where the MAFRaw readings are putting you while lean

so maybe it would be wise to adjust my BFP back up to say 45-50?
what are the repercussions of having a bit higher base fuel?

 

[Calan]

so maybe it would be wise to adjust my BFP back up to say 45-50?
what are the repercussions of having a bit higher base fuel?

A better question is why would you run it at something other than stock?

The only reason to not run stock base fuel pressure is if you have raised or lowered it for a very specific reason, such as trying to extend injector range or get more volume from a pump.

 

[turboglenn]

so maybe it would be wise to adjust my BFP back up to say 45-50?
what are the repercussions of having a bit higher base fuel?

NO the proper thing to do would be to take the negative units out in the "MafComp Adjus (CombinedFT)" setting found when you left click on the datalog (that's how i find it anyway but i'm not ECMlink expert)

High fuel pressure is a band aid of sorts and really isn't something you should do unless you just need a slight adjustment in your fueling at the track or if you don't have any of your tuning equipment on you, or are out of injector and needthat little bit more temporarily

Porblem is if you have fuel pressure at 50psi bse and are running 30psi boost thn you've got 80psi fuel pressure under WOT and that's a LOT, not only does that high pressure make your pump flow less, but italso makes it harder for the injector to open (increasing the dead time also) and sometimes if there's not enough voltage and there's too much pressure the injector might not open at all..all of this can cause dangerous lean conditions and engine failure

Typically people when running on the edge of their fuel pumps output but having plenty of injector left will lower the BFP so the pump can flow more and they just have to turn up the pulsewidths in the top end to make up for lower pressure, but with the pump flowing more they can now do this..

A better question is why would you run it at something other than stock?

The only reason to not run stock base fuel pressure is if you have raised or lowered it for a very specific reason, such as trying to extend injector range or get more volume from a pump.

Exactly, i would like to know or say that the owner/OP needs to state why the ful pressure was so high to start with, was this a band-aid cure for some other problem? if so what was the problem?

Calan, you're more savy on the ECMlink than I, does that sound right to you on the MafComp adjust? I mean i know it's usually calibrated to get fuel trims correct right? but his logs show that he's lean the exact amounts that the MafCompis in the negative range by,

Buyt my big question is, since you don't have total control over all teh puslewidthsd and stuff on ECMlink, will the ECU learn what it needs to change to get the AFR"s correct in closed loop like it does normally?

It just confuses me or makes less sense to me to have a VE table and a desired AFR table both in use at once, I can see the desired AFR being needed in MAF but in SD you should just have a "fuel table" where load and RPM are crossed adn a cell is looked up and a value from it used... when the ECU is using the AFR and VE tables in SD what's teh operation of lookup to decide the fuel output in pulsewidth???

I would think VE table since it's Load x RPM but then what does it do if the desired AFR isn't met, and how can they call this open loop operation if the ECU looks up an AFR and tries to meet it?? that's closed loop operation to a T!!!!!!!

 

[DeadlyScone]

The original owner of the car had it set that high, and among other things i have found that were not correct either. I have been trying to adjust the maf sliders but it still under different conditions makes it run lean, sometimes. the fuel trims will say -6 or -10 so i will take away -4% or -6% to see if it changed at that Hz, Then what happens is all the sudden at theat Hz it the STFT is trying to add 10%+ its just a big headache. Its hard to drive the car because whenever i give it gas over 20%(just my guess) it goes 16-18afr then after like 1-2 seconds it goes back down to 13-15afr. I could try adjusting my Openloopthresholds to match 50% throttle rather than 69%(i put it at 69 for LTFT Hi tuning which i was about to do until this) or what do you proclaim would be best? i just cant think of any idea why its acting so weird, it almost seems like there is a big BL which i doubt there is since i just was BL free about 4 days ago.

 

[turboglenn]

I will have to look and see what it's called in DSM link but there's a common issue of all engines that they go lean when you make sudden throttle openings and there's "accelerator pumps" in carbs and similar functions in EFI to accomodate for this,maybe those settings are too low on your setup.. i'll see if i can find it ifit'sthere

 

[DeadlyScone]

I found this on DSMtalk

Re: Lean on the 1st dip into the throttle
Well, I would definetly check that out first. If that isnt it I would check the vac to the FPR. If you share that vac line with the BOV or boost gauge you might be damping the vac signal too much and causing a hesitation in the signal.

I usually sit anywhere's from 11-14psi during vacuum. Maybe this is why the afpr was set a bit higher and that is why i am leaning out?

 

[turboglenn]

I think the accelerator pumpi'm talking about is called BaseTipinTPS Adjust in DSMlink, i'm gonna compare your values to those of others who's logs i've looked at and saved recently

 

[DeadlyScone]

I think the accelerator pumpi'm talking about is called BaseTipinTPS Adjust in DSMlink, i'm gonna compare your values to those of others who's logs i've looked at and saved recently

alright, i will also look at what the BaseTipinTPS is.


EDIT:

I adjusted all of BaseTipinTPSAdj cells up 5 and adjusted the maf comp some more and re adjusted my BISS to 30(for some reason it keeps getting itself up to 40-45) it seems a bit better but I still get weird readings. here is a snippet before the BISS adjustment and after all the other stuff.

 

[DeadlyScone]

When i log TPSdelta it doesn't seem to do anything, and when it does it only goes to 1 and that's very rare. It also caused it to run pretty rich when i stepped on the gas. Here is the most up to date log.