The Much Awaited #230 (L99) Update.

[radz28]

Thanks for all the info' Scott and trying to educate us. Hopefully, many members who are concerned will be able to hold out until it's determined what the problem(s) has been.

Thanks again

[redjewel]

Originally Posted by Scott@Bjorn3D

Ok guys do not go running to your dealers saying you have a slow car. Several things have to happen. First they have alot of data to study on my car. Second they have to see if they can simulate what my car did with one of their cars. In talking to them my ECM could of just been real slow at learning or we could have even a gas issue in Eufaula . Meaning how often is the 93 octane getting refilled. If iit gets filled only once a month since allot of cars do not use it then the octane levels could lower.

Once again, there is no reason to go running to your dealers. GM is aware of the issue with my car and need to see if they can make their cars have the issue. There is nothing the dealer can do unless GM comes out with a fix.

The issue is also alot of L99's are running great. So DO NOT GO RUNNING to the dealer. There is no fix at the moment. If and when there is one GM will let us know. Also how do you know you car running slow? Been beat by cars that should not beat you?

Guys by telling you this info and keeping you informed I do not want to open a can of worms. We have to be smart and play this out. My car was for sure slow and I only know of 2 others that have been proven slow that got beat badly buy cars they should not of.

Lets wait and see what GM comes up with.

I will wait and see what GM comes up with. I am even considering it just might be the heat and humidity down here in Houston.

I received my car on almost empty. I filled up at a Shell station using 93 octane as I could not find a Chevron close enough. I have only used Chevron 93 since that first fill up so I don't know if gas is a problem but I don't think it is.

On a side note and I am going to open a new thread with it. I went to LMR today and had the CAI installed. When leaving the shop I actually spun the tires a little for the first time. The sound difference is definatley noticable and I feel like there is more power. 0-60 is still 6+ seconds.

[wullger]

Thanks for the updates, Scott!

Are you getting to enjoy the car now?

[fdjizm]

Wow scott I know you have been through hell with this car i cant believe it was just that simple problem, so they reset the ECU so it can see that you are just running 93 octane?, i'm glad it worked out for you bro! i'm sure the difference is night and day.

[djpheer]

For those having this same issue, maybe try adding some octane booster to your tank for a tank or two to bump the ECU back into 93+ octane tune more quickly. Just a thought.

[SK360]

HPTuners.... copy High octane table, paste into Low octane table.

Homebrew "fix"

[PQ]

Originally Posted by Supermans

Anyways, glad top see at least Scott with a faster Camaro L99. PQ, you're next

I sure hope so.

Originally Posted by Scott@Bjorn3D

Ok guys do not go running to your dealers saying you have a slow car.

....there is no reason to go running to your dealers.

There is nothing the dealer can do unless GM comes out with a fix.

So DO NOT GO RUNNING to the dealer.

Lets wait and see what GM comes up with.

Uhh? Wait..... I took a lot of crap in the other thread to get my car to the dealer. Should I not now?

Originally Posted by BackinBlackSS/RS

That's a lot in my book.

Ya, I agree, but some on this site were telling me it could lose me a half second to a full second. NO WAY. Two tenths is what I was willing to concede. It's nice to finally know for sure.

[fdjizm]

Originally Posted by irpq11

I sure hope so.



Attachment 45297 Uhh? Wait..... I took a lot of crap in the other thread to get my car to the dealer. Should I not now?

Ya, I agree, but some on this site were telling me it could lose me a half second to a full second. NO WAY. Two tenths is what I was willing to concede. It's nice to finally know for sure.

He didn't say anything about WALKING to the dealer

[ElAntonius]

Originally Posted by irpq11

Ya, I agree, but some on this site were telling me it could lose me a half second to a full second. NO WAY. Two tenths is what I was willing to concede. It's nice to finally know for sure.

Wait, 4.6 (reviewed)-4.7 (advertised) time, 5.1-5.2, with 5.3-5.4 on the tester, sounds to me like losing .5 sec to 1 sec 0-60 in the weather is realistic.

Or am I missing some part of this conversation? If I am, I'll shut up.

I mean, given my experience 5.2 seems to be what my car will usually run in the Florida summer...I'd expect not that different where you guys are at.

[UCF w00t]

FWIW, the fastest I've managed with the LS3 is 5.2 (but that's with a program I wrote for my phone so may not be 100% accurate). Usually I'm in the 5.5 range. Haven't gotten the launching down pat yet.

[Capstone]

Thanks very much for the long post. It was informative.

[PQ]

Originally Posted by ElAntonius

Wait, 4.6 (reviewed)-4.7 (advertised) time, 5.1-5.2, with 5.3-5.4 on the tester, sounds to me like losing .5 sec to 1 sec 0-60 in the weather is realistic.

Or am I missing some part of this conversation? If I am, I'll shut up.

I mean, given my experience 5.2 seems to be what my car will usually run in the Florida summer...I'd expect not that different where you guys are at.

Ya, you missed a part. We're talking about the time lossed from the 21" wheels as opposed to the stock 20s.

[CamaroSpike23]

Originally Posted by irpq11

Can't remember what gas my dealer put in it. But why would it take so many fill ups and still be lagging? And shouldn't this have been reset by the battery reset?

because depending on if you run the tank nearly completely empty before filling up, you will still have some 87 in the tank, which mixes with the 93. also, depending on how long the battery is pulled to reset the computer. I've had numerous times where you would pull the battery, let the car sit for ~20 minutes, and it would still be showing faults etc. but letting it sit for over 30 minutes let it fully reset. im wondering if he didnt leave it disconnected long enough.

Originally Posted by irpq11

I've been getting a consistant 6.1 to 6.2 0-60, in ALL modes. Even with TC on. EVEN in 'D'. There has been no difference.

driver mod

Originally Posted by faninc

so if you have an RS running 87 octane and 900 miles on it and switch to 93 octane will it relearn and produce some faster results and more HP?

thanks
J

ideally, running higher octane allows for more spark advance. however, these computers are finicky. once they see knock, they pull timing and very slowly advance it.

Originally Posted by Scott@Bjorn3D

They said if the car runs low octane gas it will right away reduce the timing to keep from knocking. Then they said if you start running high octane it will slow take away the timing retardation and the car will get more HP.

The big question is why did my car not learn? I have been using several different stations incase it was bad gas and car has still thought it had low octane gas. That may be something that needs to researched by GM.

that might have contributed to it. depending on the fuel you were getting from the individual stations, it might have not been the quality that was advertised. just something to think about.

Originally Posted by RipGear

Scott -

So how does anyone else get thier slow L99 fixed?
reset the computer, fill up with premium.


What happens if you are unable to find 93 octane? Will the computer let your motor knock like crazy?
No, the computer will pull timing if it gets detonation.

Did you press the brake pedal with the battery disconnected? I've read and been told to do this when trying to reset an ECU, but it may just be a myth.
myth

This sounds like putting a band-aid on a gunshot wound. I hope the GM engineers will figure out why the computer is not "learning" the octane being used and issue an actual fix. I'm still trying to hold out on making the purchase until this issue is properly addressed, but it is very hard.

it might be learning, but learning slowly. its not a gunshot wound by any stretch of the imagination. it is a very small and isolated group of cars that are having this issue and a lot of them are in the southern part of the US in this blazing heat and humidity

Originally Posted by GMRULZ

I beleive their explanation to be true. If the computer senses knock it will change to the low octane tables in the ECM. These run much less timing and hurt performance. To be on the safe side I`m sure GM makes the computer take a long learning curve to get back to the higher octane tables once good high octane gas has been restored, just to be sure.

To give you an example, I just dynoed my car, put down 319rwhp, run 2
319rwhp, pulled the ecm fuse to clear the memory waited about 5 minutes put it back in run 3 327rwhp....Gained 8rwhp by reseting the Long Term Fuel Trims and possibly moving back to the high octane table from a lower one, I`ve only had 2 tanks of gas in it. So this computer is very, very conservative, if it senses anything it doesn`t like it will take drastic steps to fix minor issues.

did you do another run after that? just wondering cus the time you waited to reset the computer might have given you a cool down period as well for the computer to push timing a little more

If a tuner can turn this learning curve off or at least desensitize it it will help greatly.

Irpq11,

I think your huge dip in air fuel was cat over temp protection, it sensed an overheat of the catalytic converter and dumped a bunch of fuel in to save the cat. Other than that I can`t explain your a/f dip.

Originally Posted by irpq11

Sounds like they adjusted only the part that was the problem. Resetting the whole commputer didn't do my car any favors. On my Dyno, they unplugged the battery for anout 5-10 minutes and it didn't really change anything. The next pull was 2 extra HP. Whatever they did, it gained Scott about half a second or more.

shoulda left it unplugged longer.

Originally Posted by djpheer

For those having this same issue, maybe try adding some octane booster to your tank for a tank or two to bump the ECU back into 93+ octane tune more quickly. Just a thought.

octane booster is a waste of money. it doesnt just add points directly to the fuel. it only adds to the RON of the fuel, not the overall rating. so while it markets a 2 point upgrade, you might only see .5 points

[GMRULZ]

To answer your question it was only about 5 minutes between the 2nd and 3rd run w/ the fuses pulled, being the last pull it was heatsoaked, so it was the clearing of the L Trims that saw the 8rwhp jump.