Help...Lean pretty much everywhere!

[1972C10_LS]

Finally got truck running after battling burnt plug wires and bringing in the AEM wideband via the AC Pressure sensor input. Seems to idle fine BUT.....Im still a newbie at this but it looks and feels like it is running super lean nearly everywhere except idle? Anything more than gradual throttle (let alone wot or when boost comes on) and it seems to be running out of fuel.

I know these E38's are a pain especially the 07-08 flavors but Im hoping someone can point me in the right direction of the correct way to getting some more fuel added. I've attached the current tune and a log.

Drivetrain specs are GEN IV LY5 5.3 , AC Delco 2bar map sensor, 76MM ON3 Turbo, air2air intercooler, 80lb injectors, PAC 1218 springs, A1000 fuel pump, ZR1 cam, 4l80e trans, 3400 circle d stall.

E38 OS has the 2bar OS applied and the scaled injector data was provided by the vendor Injection Connection. I did the double the stoich value and cut IVT in half trick to match the scaled injector ifr.

Any help would be greatly appreciated.

Thanks!
Eli

[5FDP]

Well, you gotta start tuning the VE and MAF. That is, if you are still going to use the MAF.

Start dialing in the fueling for 0-105 kpa first, get that squared and running around 1.0 lambda, then start working your way into boost. You can use the EQ ratio error to dial in both the VE and MAF for part throttle, then work on WOT. If commanded AFR does not match actual AFR you need to add or remove for the VE or MAF.

So in your case you are lean, you would have to add to the VE/MAF to bring in more fuel. Do a little at a time and carefully watch the logs and your wideband to see if fueling is going the right way. Keep the tables smooth with no large bumps/dips to ensure clean transitions.

You also never adjusted your PE for boost, you are still commanding AFR's around 12.5-12.8. Set it up to run around 11.0-11.5 to make sure you are commanding a proper AFR under boost. You still want to think of the EQ ratio like stock even though you used the double stoich method to scale the injectors.

So instead of 14.68/1.170 = 12.5 you will want it to be 14.68/1.280 = 11.48. Then maybe have it get slighty richer as RPM rise and over 4,500-5,000rpm to 11.0. You can set it up under the normal EQ ratio that way or the Boost enrichment table.


Lower the timing as well once you enter boost, start have it dip down into the mid teens instead of low 20's to keep things safer. Also add injector pulse width and knock retard to your logs.

[1972C10_LS]

On my spark tables, how do I determine exactly what cells represent boost areas? The cyl air mass row values/range seem much lower than I would expect?

[5FDP]

Start ramping it down once you reach around .80, you'll be getting into boost around there and beyond.

[schpenxel]

What formula are you using to convert AC voltage to a wideband value?

Throughout most of the log it's rich. Well, really it's NOT rich.. but the computer is having to subtract 15-20% fuel from to get it back to stoich.

Time to do some tuning 101... I'd put that thing in SD mode and start tuning the VE table. I'd drop the lower end of the table by 20%, increase the top end of the table by 20%, and smooth out the changes from end to end.. Just looking at fuel trims here's how far off it is when in CL.

It's going really lean once you're in PE.. narrowbands are reading like under 10 millivolts.. that's REALLY lean


Fuel trims vs. VE table
FT1.JPG

Boost vs. timing table
Boost vs timing table.JPG

[1972C10_LS]

Thanks for the guidance on this one. I am using the ([7101.10]/.5)+9.3 expression to calculate the AFR coming in the a/c sensor. Before I read your reply I noticed the same thing, rich down low and lean up higher. I've made those nearly exact changes to the tables but havent been able to get back out and log again.

I did however log a little before those changes and of course the fuel is still rich down low and lean up higher but (per 5FDP suggestion) I added knock retard and inj pulse width to the logging parameters and noticed Im getting what I have read to be a pretty good amount of knock retard during boost. Im pretty sure BKR is disabled. I dont here any pinging or knocking so what is this telling me? Attached is the tune that we ran to get the log that is attached,

I also noticed we need to back down the duty cycle on our boost controller, it maxed out our 2 bar MAP sensor at least once which tells me went above the 14-15psi boost we were shooting for..

The custom OS from HPT for our E38 only allowed for a 2bar, what could we do to go to a 3bar sensor on this? Worth it or problematic?

Hopefully we can get some more logging done with the tweaked fueling tables soon.

This is the most headway we've made with this thing so far and it is getting back to being fun vs 1 step foraward and 2 back and problem after problem.

Thanks for everyone's help!

[schpenxel]

Custom OS will run a 3 bar sensor no problem and go up to at least 2.5 bar on the VE table, despite the name. Just change the axis headers to whatever you need them to be. I’ll look at the rest later

[1972C10_LS]

I suppose when you change the axis to accomodate the larger range of the 3 bar you lose some resolution? Would it be better to go with 2.5 bar sensor and calibration? We really wanted to keep things safe and arent trying to poke its limits with boost so 20psi and under seemed reasonable? :-)

Thanks schpenxel & 5FDP!

[schpenxel]

Either one is fine. You can run 3 bar sensor and set VE table up with max of 2.5 or whatever, those two things don’t have to match at all. I usually set the max cell of VE table to a few psi over what I’d ever expect to make on that setup then interpolate it down. You will lose a little resolution but not that big a deal IMO

[1972C10_LS]

Got the boost controller duty cycle dialed in to keep us around 15-16psi max. Seeing a lot of knock retard in WOT and boost. Ive taken some timing out of those areas to no avail, is it actually knock? I dont hear anything abnormal. Looks like its still rich down low and lean up top. Attached are the most recent tune and log files. What do you guys suggest/think?

Thanks!
Eli

[gmorris]

Take a bunch of timing out until you get our fuel dialled in and/or sort out your knock issue. You don't want to be knocking it every time you do a pull dialling in fuel. I always assume knock is real until proven otherwise....

[1972C10_LS]

How do you take the AFR ERROR histogram data and apply it to the VE table values? Do you multiply those error values by a certain value or? See screenshot.

Thanks in advance!!

[5FDP]

You can't use AFR error if you did the double stoich method for your injector size. You must use lambda error because you'r stoich reading is 29 and not the factory 14.XX because you had scale the tune for the injector size.

If you pasted that -50% error into your VE it would completely wreck the table.

[1972C10_LS]

With the way I have it setup, I am bringing in my AEM WB AFR in thru the a/c pressure sensor and using the user math area to derive the afr and afr error. I havent come across a how to on setting up this to log lambda and lambda error other than some using mpvi interfaces etc. Do you know how to set this up in the scanner?

Thanks
Eli

[1972C10_LS]

My AEM gauge Lambda range is 0.683-1.365 in volts 0-4.99v. In the screenshot I used the same AC Pressure PID as the AFR. Does this look correct, should the 'unit' be Lambda in this case? Now onto the Lambda Error.....

lambda_math.png

[1972C10_LS]

Im trying to follow along on this guys how to but im stuck on step 2...I would be using the Commanded EQ Ratio PID but it looks like it is already displaying in Lambda in my logs. If I already have a commanded eq/lambda in my pid list, how do I take that and create the Lambda Error pid and chart/graph? The thread below is missing the pictures he refers to...

https://www.hptuners.com/forum/showt...setting+lambda

[schpenxel]

The formula you're going for is essentially:

100 * ([WB LAMBDA] - [COMMANDED LAMBDA]) / [COMMANDED LAMBDA]

You CANNOT reference another math parameter inside a math parameter so the WB Lambda part is going to have to be the full formula for whatever you're using to convert AC voltage to lambda

I'd recommend getting the WB Lambda part working first in a separate math parameter.. make sure it's showing up as lambda and is working right, then work on getting this to work

Also it is NOT LEAN at part throttle. It's very rich. Negative fuel trims means it's subtracting that amount of fuel to make it NOT rich (or adding that much to make it NOT lean).

[1972C10_LS]

Is the pre-existing EQ Ratio Commanded (which is already displayed in Lambda) essentially be the Commanded Lambda PID part I would use in that equation?

According to this it would reporting Lambda in the correct form I need as I am using an E38 ECM.

https://www.hptuners.com/forum/showt...EQ)-Discussion


If this above is true then I should be able to use these math parameters to derive the Lambda and Lambda error??

lambda.pnglambda_err.png

[schpenxel]

50118 is the commanded lambda that you need

Give what you have a try, it's close if not all the way correct. It's saying you aren't logging AC pressure voltage though, so make sure that is in the channels list

[1972C10_LS]

Will I need to setup any other histograms other than the Lambda vs RPM MAP and Lambda Err vs RPM MAP to get the data I need to aid in ve adjustments?