VE tuning with HPT Wideband and Narrowband how to

[softy91]

Guys,

I am getting ready to do a SD tune and I can't thank everyone enough that has posted here.

You all in some fashion have answered questions that I have had that have been holding me back from "Doing the Tune".

Also regarding the "Boosted Truck", I can't fault the logic of being normally aspirated for part throttle tuning.

Keep it up guys, this is Good Sh@t!
and
Warp 10 Always!

[Confused1]

Sorry mines a 2002 TA.

I'm going to recheck in the morning and see if I get the same results when the MAF is plugged back in.

[WS6snake-eater]

Hey guys, sorry I haven't been around the last couple of days. I broke a valvespring yesterday and have been dealing with that. I'm not too sure what the p0068 is....? I have never thrown that code in any of my tunes. Does it give a description of what the code is? For those of you having this problem; does your MAFs have the IAT built in? I bet it has something to do with that. How did you disconnect the MAF but still assure that the IAT is plugged in? Most people have been cutting the wire, but if you cut the wrong one, I'm sure that could send some sort of IAT code. Is the P0068 an IAT code? It is not in my drop down box in HPT's DTC section so I must assume that it is a code that is only relevent to people using the Vette' and/or truck MAF's with the built in IAT.

Matt

[Screamn03]

Dude, I can't find a P0068 on alldata or when I searched google/yahoo. Are we sure it's a "P" code? I'm thinking it's a "C" code which has to do with the EBCM (Electronic Brake Control Module) or maybe something else. I'll see what I can dig up.

[corpsvette]

Hey Scream,

Don't know if it is a P or a C but here is the description for 068:

MAF/MAP Throttle Position Correlation

It lists with the 0102 under the DTC errors when I fire it up. I may try to SES light off. I know the 3 - no error reported did not stop it from occuring.

THanks,

Jim k

[WS6snake-eater]

Hey Scream,

Don't know if it is a P or a C but here is the description for 068:

MAF/MAP Throttle Position Correlation

It lists with the 0102 under the DTC errors when I fire it up. I may try to SES light off. I know the 3 - no error reported did not stop it from occuring.

THanks,

Jim k

Hey Jim you don't want to use the 3 - no error button. Just set the light SES off. That should do the trick. I'm still curious as to what the code is for. Do you have a cam? If so how big?

[corpsvette]

Hey Matt,

Stock Cam. Also, I don't actually get an SES light for this error. I get the "Service Vehicle Soon" message on the driver information center which I then reset with buttons on the Corvette cluster. The only reason I am worried about it is because no one else seems to get this message and I figure it is a new 2004 thing with the car since mine has some minor tweaks from the previous models. It is no biggie, the car runs, thats good right ;D. Off to wash my nasty filthy truck and then make some runs in the car before she gets her bath.

Jim K.

[rattle]

DTC P0068
Circuit Description
The powertrain control module (PCM) uses the throttle position (TP), barometric pressure (BARO), intake air temperature (IAT), and engine RPM in order to calculate the predicted mass airflow rate. The PCM compares the predicted mass air flow (MAF) value to the actual mass airflow value and the speed density calculation in order to verify the proper throttle operation. If the PCM detects that the difference between the actual air flow (MAF) and the speed density calculated air flow is greater than expected, DTC P0068 sets.

Conditions for Running the DTC
DTCs P0601, P0602, P0604, P0606, P1516, P2101, P2108, U0107 are not set.
DTCs P0120, P0220, and P2135 are not set at the same time or DTCs P0120 and P0220 are not set at the same time.
The engine operates longer than 1 second.
The engine speed is more than 500 RPM.
Conditions for Setting the DTC
The PCM detects that the difference between the actual airflow (MAF) and the speed density calculated airflow is greater than expected.
The above condition is met for less than 1 second.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
A message center or an indicator displays Reduced Engine Power.
Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Inspect the throttle blade for being broken, bent, or missing.
Inspect the TP sensor for proper installation. A sensor that is mis-aligned could set this DTC.
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
Physically and visually inspect the throttle body assembly, and correct any problems that you observe. Manually move the throttle blade from closed to wide open throttle (WOT). You should not need to use excessive force. The throttle blade should move smoothly through the full range and should return to a slightly open position on its own.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
For an intermittent condition, refer to Intermittent Conditions .

[Chris@HPTuners]

This is the same as the older P1514. It's an ETC check, basically cos you are modding your VE the calculated airmass (g/cyl) is reading higher than expected in the P1514 table.

Check the help file under the Engine Diagnostics, General section.

[corpsvette]

So what is the recommendation on this Chris. Do I leave it alone and deal with the Service Engine Soon or should I mod this table to prevent it (and how the heck do I do that) I am guessing just leave it along until I am done SD tuning. Thanks,

Jim

[JimMueller]

Chris: Which units does this table use? Suggestions on how to locate which cells are now inaccurate as a result of VE tuning?

[Chris@HPTuners]

it's just a sanity check on the ETC operation. Many s/c folks have problems with this table cos the MAF is reading way more air than this table is expecting to see. Either way this table needs to be greater than the maximum Cylinder Air (g/cyl) you are seeing.

To disable it just set everything to 1.0 or something big.


Chris...

[tici]

What if my LTFT are all between -4 and -12? Do I first have to adjust the IFR?

I'm using the narrow band system (LTFT + STFT). My LTFT are pretty constant, but the STFT are all over the place (+14 / -14).
Am I really running SD?
I'm working with Edit (and please don't tell me this is the wrong forum): on the codes P0101 / P0102 / P0103 I just set "No MIL Light". THE PCM is still setting as SES.

AM I doing something wrong?

Stefano

[Keith@HPTuners]

Stefano, we have no problem with you using our forums.

While you have LTFT's enabled, STFT's will sway +/- from 0. When they get to far from 0 your LTFT will be bumped toward that direction.

[tici]

Thanks for keeping me

According to your system I have to add LTFT and STFT (maybe also average B1 and B2) and change the VE in accord to it (using % because of Edit).
Situation: constant load, constant LTFT -2, STFT +5 and two seconds later -7.
The % learned is +3 and two seconds later -9.

OK after a time it will be all averaged, but does it have to jump like that?

Other issue: as soon you disconnect the MAF the A4 transmission shifts keeping the TCC locked (at least in my 98 ).
Is there a way to avoit it?

Thanks - Stefano

[corpsvette]

Here is another interesting note concerning a way to enter SD mode without disconnecting the MAF. The full thread is here but the info is
http://www.ls1tech.com/forums/showthread.php?t=247915

you can set your MAF Fail Frequency to 0, will guarantee you're in speed density mode... and still let you see what the MAF's doing

So, instead of actually disconnecting the maf, will this work since sd is forced?

THis post seems to have really slowed down. I have been caught up with work but started tuning again today. IE expect some question from me soon.

[luv2spd]

I have a simple question that I've wondered about. When I did my ve tune, when the ltft was say +6, added like 8 to that cell in the ve. Is this the correct way or should i have multiplied that cell by 108%?

[Magic_Chicken]

Here is another interesting note concerning a way to enter SD mode without disconnecting the MAF. The full thread is here but the info is
http://www.ls1tech.com/forums/showthread.php?t=247915

you can set your MAF Fail Frequency to 0, will guarantee you're in speed density mode... and still let you see what the MAF's doing

So, instead of actually disconnecting the maf, will this work since sd is forced?

THis post seems to have really slowed down. I have been caught up with work but started tuning again today. IE expect some question from me soon.

I'm curious about this as well. I'm trying to tune everything was going well trying to get my AFR around 13 with the MAF unplugged, but then I plugged it back in and set the frequency fail to 0 and now my AFR is back to stoich numbers and that was all I changed was the fail frequency. Although something else might be having an effect is the fact that while my MAF is unplugged, my IAT is also unplugged. Ideas?

[corpsvette]

AAArrrrrggghhhh! More frustration today. Okay, the last two days I went back to tuning via SD since I had a spare few minutes. I had all my cells between 12.8 and 13.2 and was ready to start my PE tuning, again. Had to fill up with gas and started to log only to watch my perfect SD tune drop a whole percent across the AFR table. I thought to myself, self, could you have forgotten to copy high octane to low octane. Nope, wasn't that. Sooooo, I started retuning, again and ran out of time and won't get back to it until after the New Year. I am really starting to question the accuracy of my WB. I have the LM-1 and I calibrate it in free air each day I use it to make sure it is right. So, anyone else have this happen with different gas. My last tank was chevron 91 on my way home from Famoso. This mornings gas was 91 from on base (military) station. Has anyone been able to consistently hold their AFR values from one day to the next. I realize weather and temp each day will change things but this is getting ridiculus. Off to study other things.

Jim K.

[Magic_Chicken]

I'm curious about this as well. I'm trying to tune everything was going well trying to get my AFR around 13 with the MAF unplugged, but then I plugged it back in and set the frequency fail to 0 and now my AFR is back to stoich numbers and that was all I changed was the fail frequency. Although something else might be having an effect is the fact that while my MAF is unplugged, my IAT is also unplugged. Ideas?

I was sitting here thinking about this again tonight and that little light bulb went off above my head. I thought to myself "HP Tuners has Closed Loop controls in the scanner! I can turn Closed Loop off! No need to unplug MAF anymore!" Went and tried it, and of course, HP Tuners rocks. Now I can go back to my regularly scheduled tuning.