Please help with LS1 rich condition

[dhoagland]

That decel might be it, I got my PLX wideband display working today and it shows decel really rich no matter what the speed is. I don't have it hooked to HPT and looks like it will never be.

What PLX do you have?
Do you have pro features set with the Pro-Link? I have a PLX EGT and it logs VIA anaolog output

[Finnish Fireball]

To me it is odd that if decel is the problem, why it doesn't set the codes in MAFONLY mode, cutoff DFCO we have not touched so it should work similar. If my memory serves in some old Mafonly instructions they disabled DFCO and LTFTs, I have no understanding why but those were written 15 years ago for older versions.

I think we are on a right path, car works flawlessy so maybe we need just to keep going editing air/Hz and fuel? The trims are looking better!
Also some older forum comments say to drive at least 50minutes or so for the LTFTs to do their thing. I see no point if we reset them anyways before next log?

Compare first and last log

first.jpglast.jpg

[Finnish Fireball]

What PLX do you have?
Do you have pro features set with the Pro-Link? I have a PLX EGT and it logs VIA anaolog output

It's old version with Bosch 4.2 sensor, and most of the time display goes crazy, common issue. I have no pro features and when I searched for PLX to HPT instructions all I could find were like 6 years ago and reguiring NASA level education both sw and electricals to get working, and even after that ppl were debating of the calibration. So maybe it is not worth the hassle?

[dhoagland]

To me it is odd that if decel is the problem, why it doesn't set the codes in MAFONLY mode, cutoff DFCO we have not touched so it should work similar. If my memory serves in some old Mafonly instructions they disabled DFCO and LTFTs, I have no understanding why but those were written 15 years ago for older versions.

I think we are on a right path, car works flawlessy so maybe we need just to keep going editing air/Hz and fuel? The trims are looking better!
Also some older forum comments say to drive at least 50minutes or so for the LTFTs to do their thing. I see no point if we reset them anyways before next log?

Compare first and last log

first.jpglast.jpg

Are you still MAF only?
If so only work with the MAF calibration table

See if you can download this layout, then we can be looking at the same graphs

[Finnish Fireball]

Yes I'm on MAFonly. This laptop refuses to open that file, on monday latest I will solve that with my work computer. Is that excel?
BTW if the issue is decel, after 30 years of drag racing I have an brilliant idea (as usual), NEVER LIFT
Also I would like to learn this, many guys are running SD only, whats the difference between that and MAF only?
What if I never return back but instead keep this MAFonly since it is working without codes?

[dhoagland]

You download the file to your HP Tuners Layout folder. Then you can load it into your scanner. Maybe a better way but this seems to work for me.


Never let up works LOL
I'm not an authority on MAF only or SD... In brief I'm told MAF only is for people who don'y know how or don't want to spend the time calibrating the VE table.
As for SD, it is supposed to be better for Superchargers and stuff with fast transients where the MAF is weak or possibly the airflow is out of MAF range. But I believe thats pretty much take care of with 2bar OS and other stuff...

For you I would dial MAF using the filters for Decal (and really after you confirm no mechanical issues).
Then fail the MAF and Calibrate your VE
There are ways to do both at once but I haven't ever done it and I believe going through each seperately is best to learn and better understand the process

[horsepowerguru427]

A lot of people do MAF only because its easy and doesnt take very long. On a stock or moderately modded vehicle it works well. Theres only one row to recalibrate vs having a whole table like VE. MAFs are suseptible to air reversion if the cam is big enough, so air goes back and forth during periods of overlap. Meaning the MAF reads it 2x, then doubles fueling based on the air that was read 2x. MAFs are extremely accurate at STEADY STATE but not during transients. During transients the VE table is usually referenced to veryify MAF sanity. This is why blended air is used under 4000rpm for transients that occur before and after pedal movements. This is also why dynamic air is usually set to 4000rpm from the factory. Past that point youre usually at WOT or at least not moving the pedal around, so youre more than likely in steady state and the MAF gives very accurate air density readings. Also, there is the issue of maximum g/s a MAF can read, hence going SD with a blower or turbo. Its kinda like tuning OLSD or CL fuel trims or any mix in between. Its kinda preference and results you end up with. Theres no WRONG choice when it comes to MAF only or SD or blended, but there are better options for some vehicles....

Just some pros and cons off the top of the head...

[Finnish Fireball]

Thanks for the explanation horsepowerguru!

And hats off to DH for that layout, I loaded it and will log a good drive or two tomorrow the latest. Today seems a bit busy with other errands. Looks like we are doing right moves calibrating MAF. I found stock 1997 corvette tune, and the airvolumes are a good bunch lower compared to mine. So they should due to my mods, but where did the current airflow amounts come from. Are they questimates or was it properly tuned in a dyno, street, who knows.

[Finnish Fireball]

Here's the log per DH's layout and my tune in use. Couple observations:

- Watching WB that DECEL is rich on lower speeds, above 60 mph when I lifted my WB was screaming for LEAN everything red.
Tried that three times
- First time the DTC codes popped up using Mafonly tune, now it was just P0172 and P0175 "System too rich" for both banks, also some
knock warning due to those lean situations I believe. No high voltage error.
- LTST + STFT table is a lot worse than yesterday even nothing was changed and the weather is the same, odd.

Can @dhoagland modify this tune based on that log with your layout?

Tero tune 3.2MAFONLY07202025.hpl
Tero tune 3.2MAFONLY.hpt

[edcmat-l1]

MAF only never works well on GEN 3 stuff. On the GEN 4 stuff you can get away with it but in these it never really is in "MAF only" mode.

Having the VE and MAF too far apart causes its own issues.

[Finnish Fireball]

Makes sense edcmat, thank you from that info.

[dhoagland]

I'm looking at it right now

[edcmat-l1]

Youse guys are overlooking the obvious. At idle, the injectors are "bottomed out". They flat line at 2.3 ms. See the attached screen shot.

Not only are they flatlined, the trims are pulling close to 20% and the narrowbands are still over 800mv.

This is always due to the injector data being incorrect or incomplete. In the case of this vehicle, it looks like both the minimum pulse width and default need to be lowered. I'd start at .3 and see what that looks like. You should see a much lower injector pulse width at idle and the trims shouldn't have to work as hard trying to get it to stoich.

Tuner tip: Injector pulse width should never stop moving completely. If they do, something is wrong. Usually it's caused by this same scenario.



injector on time.jpg

[Finnish Fireball]

Oh, bummer. The new injector data was put in by very reputable tuner but maybe there is a fault like edcmat found out. My understanding is not enough, and my bad english doesn't help any. @edcmat do you mean with "I'd start at .3 and see what that looks like" to lower the number 1.277 that is now in both minimum and default injector pulse to 0.977 or what?

I will try contacting him to doublecheck the data source.

pulse width.jpg

[dhoagland]

Youse guys are overlooking the obvious. At idle, the injectors are "bottomed out". They flat line at 2.3 ms. See the attached screen shot.

Not only are they flatlined, the trims are pulling close to 20% and the narrowbands are still over 800mv.

This is always due to the injector data being incorrect or incomplete. In the case of this vehicle, it looks like both the minimum pulse width and default need to be lowered. I'd start at .3 and see what that looks like. You should see a much lower injector pulse width at idle and the trims shouldn't have to work as hard trying to get it to stoich.

Tuner tip: Injector pulse width should never stop moving completely. If they do, something is wrong. Usually it's caused by this same scenario.



injector on time.jpg

Thank You

[edcmat-l1]

Oh, bummer. The new injector data was put in by very reputable tuner but maybe there is a fault like edcmat found out. My understanding is not enough, and my bad english doesn't help any. @edcmat do you mean with "I'd start at .3 and see what that looks like" to lower the number 1.277 that is now in both minimum and default injector pulse to 0.977 or what?

I will try contacting him to doublecheck the data source.

pulse width.jpg

If he didn't know those tables need to be changed for 60 lbs. injectors there's no use contacting him for anything.

No matter what, the injectors are bottomed out at 2.3 ms. That's your primary problem. Change what I suggest, and I'd bet they start acting right.

[Finnish Fireball]

Ok so .997 across both tables is what you mean?

[dhoagland]

Ok so .997 across both tables is what you mean?

Yes, He said both tables.

[Finnish Fireball]

Consider it done, thanks for pointing that out edcmat! DH can you change that already to next version?

[dhoagland]

Consider it done, thanks for pointing that out edcmat! DH can you change that already to next version?

Here is the last tune you posted with the 2 tables set to .998
Table says minimum of .996, but it kept defaulting to .998, which should make the difference Ed referenced