Car Running lean during idle and cruise under 2k

[Joel_SS]

My car seems to be running very lean at idle and cruising while under 2k rpms. What paramaeters would I modify to increse the fuel under those conditions?

[GMPX]

We need a bit more info on the engine combo, what Operating System (GM or Custom EFILive), MAF or Speed Density?

Cheers,
Ross

[Joel_SS]

We need a bit more info on the engine combo, what Operating System (GM or Custom EFILive), MAF or Speed Density?

Cheers,
Ross

347 LS1 226/234 112 cam. And I am running an 2002 GM OS with the MAF. :cheers:

[ringram]

Are you running stock exhaust?

You might have an exhaust leak. Have you done any tuning or just logging so far?

[TAQuickness]

any chance you are running a FAST intake manifold?

[ringram]

TAQuickness likes FAST intakes :bash:

[joecar]

TAQuickness likes FAST intakes :bash: Ringram--> :bash: <--TAQuickness
FAST--> :bash: <--TAQuickness
TAQuickness--> :bash: <--FAST

Edit: I'm only allowed 4 emotiglyphs, I can't say more...

[jfpilla]

What is the AFR that you consider lean?

[Joel_SS]

No FAST intake. I thought I had an intake leak and replaced the intake and all seals.. I do not have a WB 02 but my ltft are +15 +20 during those ranges. The seem to be fine at the higher RPM though.. I can provide some logs if anyone is intrested.

[TAQuickness]

have you tried spraying starter or carb cleaning fluid around the intake? What you are describing sounds very similar to the leaky manifold problems I am having. I to have replaced every gasket several times and cannot seem to get it to seal up. Just a thought.

[Joel_SS]

have you tried spraying starter or carb cleaning fluid around the intake? What you are describing sounds very similar to the leaky manifold problems I am having. I to have replaced every gasket several times and cannot seem to get it to seal up. Just a thought.


No I have not done that yet. I guess that is my next step. I just put a new stock LS1 intake on and new intake gaskets. (Third time to pull the intake double check it and make sure it is seated.) I used new ARP intake bolts, and torqued them down in sequnce first to 44 inch pounds and then final pass to 88 inch pounds. TB gasket was not changed but it looked like it was in good shape. And I was having this same issue with the old intake, and I did not re-use the TB gasket from the oginal intake. Here are some logs and my current tune. Does this unlock any clues? I am at my wits end tracking down this problem. Thanks for any help!! :cheers:

[BowlingSS]

No I have not done that yet. I guess that is my next step. I just put a new stock LS1 intake on and new intake gaskets. (Third time to pull the intake double check it and make sure it is seated.) I used new ARP intake bolts, and torqued them down in sequnce first to 44 inch pounds and then final pass to 88 inch pounds. TB gasket was not changed but it looked like it was in good shape. And I was having this same issue with the old intake, and I did not re-use the TB gasket from the oginal intake. Here are some logs and my current tune. Does this unlock any clues? I am at my wits end tracking down this problem. Thanks for any help!! :cheers:

File does not seem to be any good.

Bill
:beer: :nixweiss:

[Joel_SS]

Try this file..

Native Scan Tool format
http://members.torquecentral.com/joel/efi/logs.efi

CSV Format
http://members.torquecentral.com/joel/efi/log.csv

Current Tune
http://members.torquecentral.com/joel/efi/tune.tun

[Treurentner]

Hi,

after I took a look into your logs I found that you are lean all over the range. If you observe your LTFT maps you will find pos. trimming fom 12 to 25 %, the more the longer the engine runs.
No signs for some intake or exhaust leaks, But your fuelpressure could be to low. I´d check this first and adjust it 5 PSI above the current value. After that log again and you should be in the 0 to + 10 % trimming range.
An other thought is - Did you port your stock maf? or
Did you setup your backup VE table due to the more airflow with the new cam and you are still running the maf?

Marco

[Joel_SS]

Hi,

after I took a look into your logs I found that you are lean all over the range. If you observe your LTFT maps you will find pos. trimming fom 12 to 25 %, the more the longer the engine runs.
No signs for some intake or exhaust leaks, But your fuelpressure could be to low. I&#180;d check this first and adjust it 5 PSI above the current value. After that log again and you should be in the 0 to + 10 % trimming range.
An other thought is - Did you port your stock maf? or
Did you setup your backup VE table due to the more airflow with the new cam and you are still running the maf?

Marco

Maf is not ported, it is 100% stock. I just put a new motor in.. below are the specs

LME 347 LS1
Weiseco 3.905 pistons
CA Dura Moly Rings
Stock Rods and Crank
ARP rod bolts
Fedral Mogul Main Bearings
Clevite rod bearings
Dura Bond cam bearings
Balanced and blueprinted
Patriot Stage 3 heads 2.055/1.57 59CC (11.3:1 compression)

Before my motor swap my fuel pressure was right at 61 PS1 @ idle. I messed up my sending unti for the fuel pressure when I put the new motor in so I can only assume it is still in that range. I bumped up may MAF freq by 20% across the board and it seemed to bring my trims back down. But I want to make sure that this is not a band aid fix covering the real problem.

[Treurentner]

Hi,

I´d tune the ve table first by unplugging the maf.
So you can ensure that your new engine setup is properly calibrated.
Don´t do only a fix at the MAF because the this influences the mainspark or trannytables which are load sensitive.
If you multiplicate the Maf tables by 20% the engine load rises equivalent and so your timing will be less advanced and you are loosing power.
If the Maf is stock and you put the fitting (original) tables in the calibration your trimming MUST be nearly close to the optimum +-5% (belonging on altitude, airpressure, ambient temperatures etc.)
You should believe only the maf readings because they are factory calibrated. Adding of an linear factor to an exponential function is not the right way to get the things work.

Marco

[Joel_SS]

Hi,

I´d tune the ve table first by unplugging the maf.
So you can ensure that your new engine setup is properly calibrated.
Don´t do only a fix at the MAF because the this influences the mainspark or trannytables which are load sensitive.
If you multiplicate the Maf tables by 20% the engine load rises equivalent and so your timing will be less advanced and you are loosing power.
If the Maf is stock and you put the fitting (original) tables in the calibration your trimming MUST be nearly close to the optimum +-5% (belonging on altitude, airpressure, ambient temperatures etc.)
You should believe only the maf readings because they are factory calibrated. Adding of an linear factor to an exponential function is not the right way to get the things work.

Marco

Can I use the Autotune with my NB 02 to get the VE tuned for part throttle?

[SSpdDmon]

Nope...kinda need to set some stuff up in Excel to use the NBO2's.

If you want to try and tune it the easy (all be it wrong) way, you can log manifold vacuum vs. LTFT's and make corrections directly to the injector flow rate table. That's how it was done years ago and worked even though it's not the PC way of doing things in the tuning world. Once you start increasing the MAF over ~18%, you loose frequency at the top of the MAF scale since the max is locked at 512 grams/sec. I usually get the majority of cruise lined up in the MAF (to about 7500Hz) and add any additional fuel in the IFR table. Makes tuning on the dyno a hell of a lot faster. Same goes for the street. I used to think like a lot of people as far as going with the whole VE tune, then recal the MAF, etc. But all that does is drive me (and others) nuts. I've been messing with my car for over a year and it made me realize how anal I was about tuning. I should be done futzing with mine by now. A FREAKIN' YEAR! Now, my attitude is get it close one way or the other and if you have -5% here and -1% there - IT'S OK. Just make sure you set the WOT right/safe when you get there.

Either way, your MAF is calculating your current fueling. You need to increase the values in the MAF table (since they're still set for the stock cam) or reduce the values in your IFR table to add more fuel.

[Joel_SS]

Nope...kinda need to set some stuff up in Excel to use the NBO2's.

If you want to try and tune it the easy (all be it wrong) way, you can log manifold vacuum vs. LTFT's and make corrections directly to the injector flow rate table. That's how it was done years ago and worked even though it's not the PC way of doing things in the tuning world. .

Could you ellobarate a little more on this method, and using the excel spreadsheet for the NB 02 Autotune? At this point I need the car to run safely and not squeeze every ounce of HP out of it. It is my DD and needs to be reliable. Once it is retired from DD duty I can work on more precise tunning. But like I said for now it just needs to run in safe operating parameters. If I am giving up 10 or 20 hp because of it, that is fine with me as long is my new motor is safe.

Also thanks to everyone who has given me input! I would be dead in the water without this board! :cheers:

[joecar]

You could try this...

enable CL, disable MAF, disable PE, disable COT...
create a calculated PID for 1 + (LTFT1 + LTFT2) / 200,
create a map (MAP vs RPM) using this PID,
log data into this map which you then multiply to your VE table
(i.e. same as if you were doing Auto VE Tune, but using LTFT's instead);
you'll know it's working if your LTFT's goto zero.

* But before you do anything, make sure you have no intake/exhaust leaks *

[TAQuickness]

Joel - Get with Chad, Black02SS, for a WBO2. The time and headache you save with a WB and AutoVE vs NB's and Excel is well worth it. If you are dead set on tuning with NB's, I believe you can find the spread sheets on ls1tech

[TAQuickness]

You could try this...

enable CL, disable MAF, disable PE, disable COT...
create a calculated PID for 1 + (LTFT1 + LTFT2) / 200,
create a map (MAP vs RPM) using this PID,
log data into this map which you then multiply to your VE table
(i.e. same as if you were doing Auto VE Tune, but using LTFT's instead);
you'll know it's working if your LTFT's goto zero.

* But before you do anything, make sure you have no intake/exhaust leaks *



And double check your fuel pressure

[SSpdDmon]

Could you ellobarate a little more on this method, and using the excel spreadsheet for the NB 02 Autotune? At this point I need the car to run safely and not squeeze every ounce of HP out of it. It is my DD and needs to be reliable. Once it is retired from DD duty I can work on more precise tunning. But like I said for now it just needs to run in safe operating parameters. If I am giving up 10 or 20 hp because of it, that is fine with me as long is my new motor is safe.

Also thanks to everyone who has given me input! I would be dead in the water without this board! :cheers:

Look at the Injector Flow Rate table. You can quickly create a map that looks like this in the scanner. You'll need GM.MANVAC, SAE.RPM, and SAE.LONGFT1. Plot manifold vacuum in the rows as seen in the tuning software, plot RPM in a single column (8000RPM to capture all), and plot LTFT% in the data section. This will give you an idea of where your fuel trims are. Log a bit of driving (try to avoid WOT as this needs a wideband) and see what the avg LTFT's come back as in the map. If you see +8~+14% LTFT's, I'd start with -11% from the IFR table (across the board). Remember, reducing the IFR table adds fuel. Flash and log again to see where the new trims line up. After you put some miles on the car and give it a chance to learn the new trims, log again and make your changes. It shouldn't take more than 2 or 3 tries to get it close. Then, when you get your wideband and have time, set the IFR back to stock and do the VE/MAF tune if that's how you want to do it.

As for the Excel part, I can email you my sheet when I get home and explain it if you want.

[Joel_SS]

Look at the Injector Flow Rate table. You can quickly create a map that looks like this in the scanner. You'll need GM.MANVAC, SAE.RPM, and SAE.LONGFT1. Plot manifold vacuum in the rows as seen in the tuning software, plot RPM in a single column (8000RPM to capture all), and plot LTFT% in the data section. This will give you an idea of where your fuel trims are. Log a bit of driving (try to avoid WOT as this needs a wideband) and see what the avg LTFT's come back as in the map. If you see +8~+14% LTFT's, I'd start with -11% from the IFR table (across the board). Remember, reducing the IFR table adds fuel. Flash and log again to see where the new trims line up. After you put some miles on the car and give it a chance to learn the new trims, log again and make your changes. It shouldn't take more than 2 or 3 tries to get it close. Then, when you get your wideband and have time, set the IFR back to stock and do the VE/MAF tune if that's how you want to do it.

As for the Excel part, I can email you my sheet when I get home and explain it if you want.

Thanks for the info! I just put my base tune back in place and created a map like you said.. Here are the results.. I am now going to reduce my IFR table by -11% and see what happens.. Again Thanks :cheers: I know tuning by the NB 02 is almost a waste but I really cannot afford a WB after having to drop 3500.00 on a new motor and heads for a car I just bought... :mad:

http://members.torquecentral.com/joel/efi/log2.efi

http://members.torquecentral.com/joel/efi/tune2.tun

http://members.torquecentral.com/joel/efi/before.jpg

[SSpdDmon]

Hold up a second....you need to make the map look like the table you're changing in the tuner (see below). I mentioned only one column for RPM. It changes how your numbers look. The labels for RPM should be "0,8000" to get it all into 1 column. MANVAC - you can use the label creator and go from 0 to 80 in steps of 5. Data's the easy part - LTFT's.

Looking at your numbers, I'd start with a -16% change across the board to the IFR table. Then, see how your fuel trims play out. Ideally, until you get a wideband to see what WOT fueling looks like....you should probably stay out of it. Chances are you're running lean now and you still won't know where your AFR is once you get the trims in line.

I only suggested 11% in my example above because it was halfway between +8 and +14.

Let me know if you have any other questions.

[Joel_SS]

Here is a new map.. But if I set my colums 0 to 80 and steps 5 It only populates a few cells. So I just copied the colum from the tuning tool.. Let me know if I am still doing it wrong or if it is okay to view it like this.. See attached.

[TAQuickness]

Thanks for the info! I just put my base tune back in place and created a map like you said.. Here are the results.. I am now going to reduce my IFR table by -11% and see what happens.. Again Thanks :cheers: I know tuning by the NB 02 is almost a waste but I really cannot afford a WB after having to drop 3500.00 on a new motor and heads for a car I just bought... :mad:

http://members.torquecentral.com/joel/efi/log2.efi

http://members.torquecentral.com/joel/efi/tune2.tun

http://members.torquecentral.com/joel/efi/before.jpg


I would venture to guess your budget is more along the lines of, "Damn - I just spent and ass load of money, I've got to draw the line somewhere and get a handle on this." That's how mine was anyway. So I put off the WB for 6 months. WB = good, NB = not so good

A WB is as important to tuning as oil to the engine.

[SSpdDmon]

Here is a new map.. But if I set my colums 0 to 80 and steps 5 It only populates a few cells. So I just copied the colum from the tuning tool.. Let me know if I am still doing it wrong or if it is okay to view it like this.. See attached.

I still think your missing what I'm saying.

Columns are your up and down where you put RPM. There should be only one column. Labels in the column tab should read:

,8000

Rows are your left and right where you put MANVAC. There should be 17 rows. Labels should read:

,0,5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80

Copy and paste the labels above (including the comma in front of the first number) into your scanner and give it a try. Then it should look right. :) If you still can't get the map to work, change the extension on the attached file to .map (instead of .efi). Move it into your "EFILive\V7\Maps" folder and you should be able to see it when you hit the open new map button.

Did you make any fueling changes already? If so, how much did you take out of the table? One important thing to know about changing your tune is....make sure you have good data before you use it to change anything. You can alter your numbers if you set the table up wrong. Based on what I saw from the log you uploaded earlier, I figured -16% was a good starting point. If you made a different correction, I'd suggest reloading the stock IFR table into the tuning program, take 16% out of it across the board and reflash the car.

Also, do you understand how this table works? A quick lesson if you don't - 0kPa MANVAC is supposed to equal atmospheric pressure (i.e. the air pressure outside of the car)...no matter what altitude your at. This is because the PCM has its own barometer. It adjusts its reading when you floor it and when you turn the motor on. If there are no obstructions in your intake tract, you will see 0kPa MANVAC at key-on and WOT. Most people see numbers in the 5kPa row when they floor it because of minor restrictions. The further you go down the table, the higher the MANVAC kPa or the lower the MAP kPa. If you live close to sea level, 80kPa MANVAC is roughly 20kPa as read by the MAP sensor. This is usually seen when you're driving on the highway, let off the gas and DFCO kicks in. That said, you should understand what you're looking at in the table. But, what do the values mean? Well, they are how many grams/second of fuel the PCM thinks the injectors can flow given the settings in the other injector tables. If you decrease these values, the PCM thinks it has to keep the injectors open longer in order to feed the motor the right amount of fuel. That's why decreasing them adds fuel and increasing them takes fuel away. Make sense?

Again, fooling the PCM by changing the IFR table is the old way of doing things and is kind of frowned upon by advanced tuners. But, it gets the job done in a time crunch.

Let me know if you have any questions.

[Joel_SS]

I still think your missing what I'm saying.

Columns are your up and down where you put RPM. There should be only one column. Labels in the column tab should read:

,8000

Rows are your left and right where you put MANVAC. There should be 17 rows. Labels should read:

,0,5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80

Copy and paste the labels above (including the comma in front of the first number) into your scanner and give it a try. Then it should look right. :) If you still can't get the map to work, change the extension on the attached file to .map (instead of .efi). Move it into your "EFILive\V7\Maps" folder and you should be able to see it when you hit the open new map button.

Did you make any fueling changes already? If so, how much did you take out of the table? One important thing to know about changing your tune is....make sure you have good data before you use it to change anything. You can alter your numbers if you set the table up wrong. Based on what I saw from the log you uploaded earlier, I figured -16% was a good starting point. If you made a different correction, I'd suggest reloading the stock IFR table into the tuning program, take 16% out of it across the board and reflash the car.

Thanks I got the table to work! See attached. I first started with -11% and it still and the LTFT still seemed a little lean. So the attached is with an addtional -11% taken out of the IFR tables. This seems to gotten back down down relatively safe levels, would you agree?


Also, do you understand how this table works? A quick lesson if you don't - 0kPa MANVAC is supposed to equal atmospheric pressure (i.e. the air pressure outside of the car)...no matter what altitude your at. This is because the PCM has its own barometer. It adjusts its reading when you floor it and when you turn the motor on. If there are no obstructions in your intake tract, you will see 0kPa MANVAC at key-on and WOT. Most people see numbers in the 5kPa row when they floor it because of minor restrictions. The further you go down the table, the higher the MANVAC kPa or the lower the MAP kPa. If you live close to sea level, 80kPa MANVAC is roughly 20kPa as read by the MAP sensor. This is usually seen when you're driving on the highway, let off the gas and DFCO kicks in. That said, you should understand what you're looking at in the table. But, what do the values mean? Well, they are how many grams/second of fuel the PCM thinks the injectors can flow given the settings in the other injector tables. If you decrease these values, the PCM thinks it has to keep the injectors open longer in order to feed the motor the right amount of fuel. That's why decreasing them adds fuel and increasing them takes fuel away. Make sense?

Again, fooling the PCM by changing the IFR table is the old way of doing things and is kind of frowned upon by advanced tuners. But, it gets the job done in a time crunch.

Thanks for the explantion, that really clears things up. I guess to make myself feel better I can say I have a "vintage" tune on my car.. :D


I would venture to guess your budget is more along the lines of, "Damn - I just spent and ass load of money, I've got to draw the line somewhere and get a handle on this."

That is about right, just add "before my wife remove my nutz and cuts me off for good!"

[SSpdDmon]

Glad you were able to get things figured out. :) I'd try maybe another -5% and see where it puts you. It's atleast close for now. :)