VE BLM tuning via Dave’s spreadsheet

[dave w]

23 Jan VE1 chart.jpg23 Jan VE1.jpg
I think you are correct that it’s running out of fuel at the top end. I do not know what the fuel pressure is. What a PIA it is to get the fuel pressure on a 1990 K1500 350 TBI!
I bought an adapter that goes between the high pressure line and the TBI inlet. It has a 1/8 pipe thread for a pressure gauge but have not it installed yet. I need to replace the fuel line anyhow, so I guess it’s a good time to do it.
When you say set BPW do you mean to the Hack (00AB00AC or do you mean “Base Pulse Width (135.00)??
BTW I think the chart and the 3d are different.
Thanks, MarkJ

I think Mark was talking about BPW 135. Looking at your VE table, I would increase the BPW from 135 to 137 to help get the higher KPA numbers into the upper 120's. Not everyone tunes the same way, so there will be other opinions on how to get the higher KPA numbers into the upper 120's.

dave w

[EagleMark]

We are talking the Paremater BPW. It should be 135 stock.

Darn good looking fuel table!

Daves being polite! We have been back and forth with the BPW, I keep testing his theory of raising it to boost some fuel at top end and since the last time we discussed this I've found it does work accuratly only about 10 over what was stock or what was calculated. After that it turns into a fueling curve instead of a straight line. Dave can still tune it!

You could try and add 10 to BPW with the same tune and re data log. See where the whole BLM table goes? It should go down across the board.

But look at your Main VE table. Where you are going into 135 BLMs your VE table is already mid 90%, your already at the limit and even beyond in cells further up to 96%. Your on the edge or more accuratly past the edge and if going any higher RPM it's only going to get worse! Your log is only showing to 2400 RPM, even a stock motor is capable of much more!

You need more fuel!
Whether it's filter time or and old pump or when you get a fuel pressure reading and it's under 13psi?
You need more fuel!

Post a data log! If you have installed the BPW hack we can watch BPW in ms and the injector duty cycle. BPW value in ADX file needs to have your injector bias correct in conversion.

[majacoby]

Attached are my out come after setting BPW to 145. This isafter making the adjustments to the VE1 from the spreadsheet with Historyaverage.
I think I’m running out of fuel up in the 2400 area. I knowwhat I have to do next. Fuel filter and adjust pressure.
Am I going in the right direction?
MarkJ

24 Jan VE1 BPW 145.jpg24 Jan hist Avg 3d bpw 145.jpg

[dave w]

Attached are my out come after setting BPW to 145. This isafter making the adjustments to the VE1 from the spreadsheet with Historyaverage.
I think I’m running out of fuel up in the 2400 area. I knowwhat I have to do next. Fuel filter and adjust pressure.
Am I going in the right direction?
MarkJ

24 Jan VE1 BPW 145.jpg24 Jan hist Avg 3d bpw 145.jpg

It appears BPW of 145 lowered the BLM's into the 120's for KPA's 80 ~ 100 range below 2400. The downside to BPW 145 is the KPA's 30 ~ 60 range are mostly below 120 which is too rich. I think I would go back to the first VE table and try BPW 140. What I think is likely to happen is the low RPM's / low KPA's will be slightly rich, so the high RPM's / High KPA's will have enough fuel.

I really wish GM would have used a vacuum referenced fuel pressure regulator on the TBI. I've seen the TBI VE table Tug-O-War several times ... add fuel pressure to get good BLM's at high RPM's / high KPA's but end up with to much fuel at low RPM's / low KPA's. With a vacuum referenced fuel pressure regulator, the fuel pressure is increased (goes up in pressure) at the high RPM's / high KPA's yet for low RPM's / low KPA's the fuel pressure is lowered (goes down in pressure) to get good BLM's.

dave w

[RobertISaar]

I really wish GM would have used a vacuum referenced fuel pressure regulator on the TBI.

TBI injectors fire into atmospheric pressure air, correct?

[dave w]

TBI injectors fire into atmospheric pressure air, correct?

Yes.

I was thinking about the vacuum referenced fuel pressure regulator Turbo City used to sell.

dave w

[RobertISaar]

that would be why. gm uses a vacuum referenced FPR to keep the injector flowrate consistent when injecting into a vacuum. it also keeps the injector characteristics predictable.

[EagleMark]

Here's my take on the VRFPR on TBI.

As fuel pressure rises from stock the Injector Bias needs to be adjusted as well, but most guys don't? I just take the % of fuel pressure raise and add it to bias. If your adding 50% pressure from 12 PSI to 18 PSI then Injector bias changes from .396 to .594 is a lot of fuel! But the real purpose is as pressure increases it takes longer for injector to open...

If you work with the injector bias as you raise pressure it all works well to about 20 PSI, after that idle fueling starts to suffer, you may need Open Loop Idle. There; also a Idle AFR bias and Idle OR correction error...

After 22 PSI the VRFPR works really well! Idle is a PIA here, but then doing VE in the small resolution $42 table sucks! This is where you really need VE1 and VE2 so add 20% to VE2 and you have to get Dave to fix the spreadsheet cause I hate doing math cell by cell!

You know how I set BPW...

When you need this much pressure there's obviously something done to motor! Many other things need to be adjusted for it before you can work VE fuel. Things like INT delay has to be fixed for headers. Proportional gains has to be fixed for cams, fixed anyways in a lot of bins.... BLM learn tables need to be adjusted so idle and low RPM are not in same cells. Spark advance table needs a more performance oriented attitude before you start all these, then work on VE fueling.

[majacoby]

OK guys, I finally got time to adjust my fuel pressure. I modified the regulator and rebuilt the TBI.
If the stock one was running at 12 psi and I raise the adjustable to 14 psi, do I need to change any thing to run and start data logging again? I know it's always safer to go rich instead of lean.
MarkJ

[dave w]

OK guys, I finally got time to adjust my fuel pressure. I modified the regulator and rebuilt the TBI.
If the stock one was running at 12 psi and I raise the adjustable to 14 psi, do I need to change any thing to run and start data logging again? I know it's always safer to go rich instead of lean.
MarkJ

I would set the adjustable pressure regulator to 14 psi and then go data logging test drive.

The data log will help figuring out where the BLM's are Rich / Lean, then we can make adjustments as needed.

dave w

[majacoby]

I finally got around making the adjustable TBI pressure regulator. The original regulator was just over 9 PSI. The adjustable is now set at 11 PSI fuel pressure.
I also checked for updates on TurnerPro RT and download the latest 5.00.8202.00 and installed it. What a mistake! It wiped out my default bin, adx and xdf.

What I have found and loaded is $42-1227747-V5.1.xdf and $42-1227747-V4.1.adx.
Are these the latest and/or the best to use at this time?

I want to get back to tuning.

I did do a record data session with $42-2011.xdf loaded while dragging a 3 fertilizer spreader cart around tonight. Can I still use this data in Dave's spreadsheet and get good results or should I start over?

[EagleMark]

The latest realesed versions are always here:
http://www.gearhead-efi.com/Fuel-Inj...Information-42

Dave's spreadsheet will work with all versions. Having a load on while data logging is a good thing, no reason to start over.

[ony]

I cannot see this post after page 1, don't no why its the only post that is this way that I have been looking at ? never mind I posted and it all showed up,i don't no why.