robertbartsch

Last year my H/C car failed inspection so I bought LS1Edit and reduced the values in the High Octane table by 5%; it passed by a whisker after I added several bottles of dry gas (alcohal) to the tank for the test.

This year with no additional performance mods the car failed once again. In preparation for the re-exam I have done the following:

1. Replaced O2 sensors - front
2. New plugs/wires
3. New PVC valve
4. Run a tank of gas with $10 fuel injector cleaner
5. Cleaned air filter
6. Reduced the values in the High Octane table by an ADDITIONAL 7%

Although I have not done an Ltrims test, I smell a tad bit of raw fuel at idle. Above idle I don't smell any raw fuel from the exhuast.

Is there any Edit tune to fix this?

ArKay99

iTrader: (1)

Go to the Main VE table and multiply 400 by 85%, 800 by 90%, and 1200 by 95%. For cold idle you can go to FuelAir Multiplier table and select the whole column from -10C to 50C and multiply that by 95%. See how that gets you. Remember if you go too lean you will raise NO emmissions.

robertbartsch

Thanks....

I'll have to find these tables - I assume they are in the engine calabration section somewhere, right....?

ArKay99

iTrader: (1)

Engine Cal, Fuel tab.
Also, I would try putting the spark tables back to stock. I have read here that you can add some denatured alcohol to the tank or some of the Pass Inspection additive... That will help your HC's

robertbartsch

OK; thanks your help is really appreciated.

I did add the dry gas (alcohal-based) to the tank last year and it worked - so I will repeat this exercise again for the re-exam.

You suggest changing the spark table back to stock which is confusing. Last year I reduced the values in the high octane table by 5%. This year I reduced the values in the high octane table another 7%.

Do the values in the high octane table control both timing advance (spark) and fuel rate flow or just timing and not fuel or just fuel and not timing?

I'm clicking my heels three times and wishing for a comprehensive written manual that guides dopes like me through the tuning maze of confusion. If someone really understands this stuff they could make a bunch of money writting and selling this guidance. I've looked at the Holman manual mentioned in the post at the top of this topic but it is Greek to me.

I was thinking more of a hands-on type manual. For example, it would have a section describing exactly how Edit is used to reduce or add timing. The Carputing manual is pure junk IMO. I thought they would be forced to address this significant short comming in their produce when a competing product (HP Tuner??) hit the market. Apparently, they have not got the message. I don't understand how you could sell a $600 piece of software with no useful instruction manual.

...basically a rip-off if you ask me.

Thanks again for your help!

ArKay99

iTrader: (1)

If I am understanding your timing you have pulled 12 degrees timing total from the high octance fuel table. I'm not sure this will help improve your emissions because GM has put a lot of timing into the tables to help keep emissions down. The values in the timing tables only control when the spark occurs at a calculated rpm and load factor. They don't deal with fueling directly. The tables in the fuel tab are what handles that.

The Main VE table contains values that the PCM uses to control the amount of fuel delivered at a given rpm and load. It is one of several components and tables though. And it is used differently depending on what mode the engine is currently operating under. There are many posts and articles around that can give you more specific information than I can regarding LS1 pcm controlled timing and fueling, but here is a couple of things I've learned that may help you.

I've told you about the VE table. The higher the value, the more fuel will be delivered for that cell. The 400 and 800 rpm cells at the lowest MAP will have control over idle fueling.
The MAF also has input to this and it also has some control over timing, but I wouldn't make any changes there.

The Fuel Air Multiplier table is kind of like a software choke. It is used to control the mixture at idle when the engine is in open loop, or cold.

In the Idle + Limiters tab the Idle Air table will control AFR by opening or closing the throttle blade slightly to meet the values in the cells at a given coolant temperature.

That is about as much as I understand on the topic and I may not be correct in my assumptions, but I have found these tables to control these items. There may be better ways to do it, but it's tough on LS1Edit. Like you said, the documentation is far from adequate. I have found a lot of help on this forum and I have been trying to correct a problem and I have been playing with a lot of tables and values. One last thing regarding LS1Edit is it is very basic. The other programs have more tables and better ways to visualize the data. LS1Edit was the first to come up with pcm editing for the GEN III motor and they have paved the path for what is to come, but it may be that their days are numbered unless they put on a BIG push to build a package as comprehensive as HP Tuners or the new EFILive stuff.

robertbartsch

OK thanks.

I put 5% back into the high octane table so cumulatively for the last two years, I assume I have only pulled about 6 degrees of timing out Vs. stock.

I also reduced VE table by the 400, 600, 800 you suggested and the rest of the table I multiplied by 93% so I assume this has leaned out the fuel air mixture a tad.

It runs more like stock now.

I just hope the sucker passes inspection.

Is there a chance I will run too lean with this tune and burn up valves, pistons and such?

Question: I saw a stoch mixture which was set at 14 to 1 fuel to air. Can this be used to reduce or add fuel?

Thanks again...

ArKay99

iTrader: (1)

I would try putting your timing back to the stock table. I don't think retarded timing is not going to help you run leaner.

You should have multiplied the 400rpm column by 85%, the 800rpm column by 90% and the 1200rom column by 95%. And not touched the rest of the table. So I would put the whole table back to stock and just do the changes to those three columns.

If you want to lean out the motor across the board a better way would be to multiply the IFR table by 100% + the amount you want to lean it out. 110% would give you 10% leaner. 13:1 will go to 14.3:1. I wouldn't make changes to the AFR without knowing what is happening via AutoTap, or some other scanner first. If you go too lean you will burn stuff up, get excessive KR etc.

The Stoich Ratio value you saw is the calibration value for the O2 sensors. I wouldn't change that because it will throw the O2 sensor calibration off and you will have a whole new set of problems to deal with. Actually it should be 14.7xx. Mine says 14.737.

LS1Edit is a good tool to make changes to the running condition of an LS1-LS6, but without a scaning tool to monitor what you are changing you have no idea that the changes you've made are helping you or hurting you. The last thing that should be kept in mind is when making changes, make them one at a time and in small amounts, then scan to observe what you've done or undone.

robertbartsch

OK; thanks. I will start modifying an earlier file and only change the two tables you suggested. I think I will start from the LS!Edit file I used for the first time I tuned (October 2003). The Ltrims were normal back then. I've since changed the O2s but no other mods have been made.



So if a multiply the IFR values by 110% that will reduce the fuel ratio by 10%?

I also have a scanner tool (OBD2) but it would not connect to my Camaro last night. I think it either does not like the separate (different) OBD2 software that I loaded for the wife's BMW or it has something to do with the fact my hard drive crashed since the last time I used the Camaro version of OBD2.

SSpeedracer

iTrader: (8)

Is your car in open loop during the emissions test? If its in closed loop, then IFR will not change A/F ratio. Fuel trims will compensate to match 14.7 AFR. Most of the forum is specific to WOT/closed loop tuning.

I'm having similar emissions with a TR220 114. If your test is measuring HC PPM then determine the highest RPM that your car can be tested at (ie 1200 idle or 3000 on dyno) and run it there. HC PPM (raw fuel in your case) will go down as RPM increases. Retarding spark will increase HC (incomplete burn) and is not likely something to look at in your case. Keep stock spark table, perhaps advance if you know KR isnt comming up, and run 93 octane. If you run higher octane, the wave front propagates slower and increases unburned HC for a given spark setting.

Also, confirm you dont have excesive oil in the intake ala PCV and change the oil 10w-30.

The risk of increased NOx occurs at lean and hot conditions. Increased thermal energy allows the chemical action for NO to occur.

If I am mistaken about above, please post up.

robertbartsch

SS:
OK; I'm a novice at tuning so you need to be more specific.

I thought the open loop tuning occurs before the engine fully warms. After the engine reaches full operating temperature the PCM switches to closed loop; right?

Anyway, I specifically asked the shop to let the engine fully warm before they do the test; they indicated they did, and that they sniff tested the car several times; so I can only assume that the test is being done during the closed loop. (These guys are real dump, however, they changed the engine oil in my wife's BMW and used 5 instead of 8 quarts of oil, etc.)

Is the sniff test conducted while the engine is in idle; I'm certian the sniff is on a vehicle lift in a garage with no load on the engine? I'm just not shure if they were testing during idle or at a higher RPM.

The shop owner asked me about the mods and he said that I should use the LS1Edit software to (i) reduce fuel air ratio, and (ii) reduce the timing based on the results.

These are the test results that failed NYS:

HC = 1.36gpm (allowed = .60)
CO = 13.35gpm (allowed = 10.0)
Nox = .82 (allowed = 1.50)

So my current tune is:
1. Close to stock for timing (high octane table).
2.The VIE table is 400 x 85%, 800 x 90%, 1200 x 95%, VS, stock and the rest of the table is 100% stock.
3. The entire IFR table has been MULTIPLIED by 110% (fuel reduced by 10% over stock???????)

My OBD2 monitoring software is not operable at the moment so - should I go for the second NYS test now or wait (a week or so) until I get it running so I can do an Ltrim test and confirm it is running in tune?

Thanks a bunch again!

robertbartsch

P.S. I raised the idle last year with LS1Edit so, when warm it currently idles about 850-900?

Can I go higher then this; how is idle speed raised with LS1Edit?

as always...THANKS!

SSpeedracer

iTrader: (8)

1 is ok
2 is probably fine
3 wont do anything unless you peg out STFT and LTFT, in which case a SES code will light.

I am new to tuning and use HPT software, so cant tell you what menu to get at for A/F during closed loop.

If you passed before, there is no reason why you shouldnt pass this time assuming that the max levels are still the same.

Retarding the timing may increase your HC count. You can adjust AFR slightly by altering rich/lean O2 set points. I used 150mV and it worked great. Adding the dry gas may have had a similar effect last time. The steps you have taken to increase AF ratio will not accomplish your goal. While in closed loop, the engine is trying to get ~500mV on the O2 sensors. This is a perfect 14.7 AFR.

Add the dry gas, get the car real hot, and then test. You may want to try blocking off the intake slightly, raising the idle to 1krpm, and droping the O2 switch points. I think the 112 LBA is your biggest concern. Good luck.

robertbartsch

Ok - Thanks...

LS1derfull

Robert, based on these readings you are running rich(hi CO readings) meaning you could clean up emissions by leaning it out at idle. I also agree about raising idle rpm to state required max. rpm. This will do the most to clean up emissions.

robertbartsch

Well. I'm totally stumped now.

After the latest Edit tune recommended above I took it back for re-inspection. The car got a lot worse than the first time it failed.

Is it posible that the new o2 sensors screwed the tune up; I think I will return the PCM to the tune that I used last year and which barely passed. I did add a 10 small bottles of alcohal (dry gas) to 1/4 tank of fuel which is the other variable that may have impacted the test.

wait4me

iTrader: (10)

just put it back to stock, dissable misfire detection, set the fans to turn on at 235 and off at 230 , set idle to the max aloud for state, and add a couple degrees of timing, and make sure the stoch ratio is set to 14.9 and do the ve table mod, it will pass..