06 LS2 with SC - Runs Great but Rich at IDLE

I've got an 06 Vette with a Supercharger that was tuned by the shop that did the work. Runs incredible and had no problem for about the first 1000 miles but lately it's running a little rich at idle and even threw a code for Rich bank 1 and Bank 2 (Forget it right now but will get it).

I'm reading through but in an effort to shortcut this issue was looking for some tips on where to adjust first. Want to do it myself. Assuming Part and WOT throttle are fine, to tweak IDLE A/F start with Base Running Airflow or somewhere else?

I do have a Wideband I can use but even with the WB wanted to know where to start.

Thanks!

Tune the MAF table. A scan should show that you're too rich in the lower MAF area. That is assuming everything else checks out. Don't assume that since the shop did the tune that its golden. If you have it post it.

First, put the car in open loop and turn off fuel trim learn. See what kind of AFR you're getting at idle. If it's stoich (or close to it), then your O2 sensors may have bit the dust.

Thanks. I will post the tune when I get home. It is on my other laptop at home. In the meantime one other question. MAF values up = leaner or MAF Values up = richer? Is there any rule of them with regard to what percentage to multiply up or down to start with?

:worship:

More than likely you don't have the proper injector calibration within the calibration. You have to start there, then work the MAF and/or VE.

60lb Siemens.

57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 57.64081 59.06403 60.17044 61.11990 62.30575 62.54312 62.54312 62.54312 62.54312 62.69813 62.69813 62.69813 62.69813 62.69813 62.69813 62.69813

I've attached the actual tune. Again, car runs great but welcome suggestions on how to thin out the bottom end or other recommended changes.

Thanks

ps: MAF - Low vs High Frequency Tuning. Where to start?

Well, sorry to burst your bubble, but those are the incorrect values for those injectors, PLUS you can NOT just change the IFR table. You have to account for ALL of the injector parameters with injectors that are NOT stock.

You need the correct data for those injectors. Greg Banish (goes by the name of "eficalibrator" on these forums, and many others) has those, and you can purchase his tuning training DVD, and you'll have all the proper values, PLUS it'll show you how to tune properly everywhere else for your vehicle. Trust me, it will be the GREATEST investment you'll ever make.

Buy his DVD from here:

http://www.summitracing.com/parts/SME-DVD-1/

Ignore the "estimated" ship date that's listed. They should be shipping now or any day now.

No bubble burst here. I am not going to name names but this was tuned by what is probably one of the biggest supplier/tuner of Supercharged Corvettes in the country. Does that make it right, no. Does it run good, yes. Is it optimum, perhaps not.

I ordered the DVD. Thanks for the tip. Not cheap but hopefully well worth it. I want to learn how to make the best of it without asking a ton of dumb-azz questions. In the meantime though would like to get the rich idle sorted out so still open to suggestions.

Thanks

That's awesome you ordered it! Greg also goes over airflow scaling in that DVD, as you're going to run into a 63.5# limit on your IFR table, so he explains the exact workaround for it (those Siemens Deka 60s actually flow approx. 73.x on a 4-bar GM [58 psi]). It's pretty easy, tho slightly time consuming, but once you "understand" the process it'll go pretty quick. Doing this basically doubles the airflow estimation of the pcm, such as double the MAF transfer, double the IFR, double the airflow axis range on the spark tables, etc.

Also, yes, you're right, just because they sell a ton of kits doesn't mean they know how to properly tune (I know exactly who it is you're talking about, too). I promise that you'll feel a drastic difference in overal drivability and power delivery once you get the proper injector specs in there, and then get all the fueling and spark dialed in.

Quote:

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Originally Posted by RWTD

Greg also goes over airflow scaling in that DVD, as you're going to run into a 63.5# limit on your IFR table, so he explains the exact workaround for it (those Siemens Deka 60s actually flow approx. 73.x on a 4-bar GM [58 psi]). It's pretty easy, tho slightly time consuming, but once you "understand" the process it'll go pretty quick.

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James,

I did not see any injector scaling in the DVD, just working in the tables. Thankfully, I have Ford modular FI experience, so that was easily accomplished once I found everything that needed to be scaled with your help.

Mike

Quote:

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Originally Posted by RWTD

That's awesome you ordered it! Greg also goes over airflow scaling in that DVD, as you're going to run into a 63.5# limit on your IFR table, so he explains the exact workaround for it (those Siemens Deka 60s actually flow approx. 73.x on a 4-bar GM [58 psi]). It's pretty easy, tho slightly time consuming, but once you "understand" the process it'll go pretty quick. Doing this basically doubles the airflow estimation of the pcm, such as double the MAF transfer, double the IFR, double the airflow axis range on the spark tables, etc.

Also, yes, you're right, just because they sell a ton of kits doesn't mean they know how to properly tune (I know exactly who it is you're talking about, too). I promise that you'll feel a drastic difference in overal drivability and power delivery once you get the proper injector specs in there, and then get all the fueling and spark dialed in.

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That's all nice and all but still doesn't help me in the meantime. I appreciate the sales pitch for someones DVD, especially if you have no vested interest in the sale, but while waiting for it I joined the foum and provided info in the hopes that besides a sales pitch I can get some tips from forum members on how to best attack this. I don't mind taking the time to learn, but first hand experience from other users would be helpful as well.

So if the IFR's are off, I'd be curious why and how and how to go about getting them right. I previously had an IFR calculator when tuning with older PCM's (LS1 and 6's). If these calulcators still apply then I can come up with the rates. But then having done that, what's the best way to back into the correct MAF values?

That's the type of tips I really could use while waiting for the DVD and time to sit down, go through it, and absorb it.


Thanks

Those Siemens Deka injectors you have flow a minimum of 73.x on a 4-bar system (58 psi), and that's the approx. value for the 0 kPa cell on the IFR table, therefore the 80 kPa cell is going to be even higher! Furthermore, as I mentioned to you before, there's more than just IFR values.

You can't even begin to start properly tuning the MAF until:

1: You account for ALL the injector parameters.
2: You "scale" all the parameters back that reference airflow and torque calculations (more on that in a few), since you have an IFR limit of 63.5 #/hr and a MAF limit of 512 g/sec (or 67.7 #/min).
3: You disable VE, whether temporarily or permanent, so as not to skew your MAF tuning (more on that in a few).

- In regards to #1, you absolutely *must* tune the following parameters when using the non-factory injectors for your vehicle:

Offset vs. Volts vs. VAC
Flow Rate vs. KPA
Short Pulse Limit
Short Pulse Adder
Min Injector Pulse

- In regards to #2, so how do you get around the IFR table limitation? Please read these threads here:

IFR Value Limit Workaround - Parameters to scale?

Ratioing down the airflow values. HELP !!!

It is recommended you scale everything back by 50%. This will give you double the IFR range, double the MAF range (1024 g/sec, aka 135.4 #/min), and double the airflow estimation (i.e. your Y-Axis "Cylinder Airmass (g/cyl) will double, which is important to keep from running out of spark table headroom for forced induction vehicles).

- In regards to #3, you can NOT properly tune the MAF and/or VE with both of them enabled at the same time. You must independently tune each of them. You can force the vehicle to use one of the other at all times, so the goal is to disable the VE and tune in the MAF, then disable the MAF, re-enable and tune in the VE. Of course, you can run pure MAF mode at all times (nothing is wrong with this), without having to worry about the VE. Once you feel more comfortable in the entire tuning process, and get everything dialed in on pure MAF mode, then I suggest you work to tackle the VE.

In your particular case, you do not have the standard VE tables of yesteryore, but instead your system using a highly complex logic. At this time, the ONLY way that allows for you tune in your VE is by using the "EQ <> VE" program by bluecats and ktoonsez:

http://www.hptuners.com/forum/showthread.php?t=20539


Aside from all that above, I will say this, if you're using the stock MAF sensor, you will more than likely peg the factory frequency range of 12.2k. However, you can call Andy at A&A (I believe this is who's SC kit you're running), and get his C6 Z06 MAF housing, which is physically larger, and buy the LS7/LS3 slot style sensor and pigtail (for plug-n-play to the factory harness) from a GM dealer. The larger housing coupled with the LS7/LS3 slot-style sensor, will lower the frequency range enough to keep you from pegging the MAF table.

With that being said, there is one other option for you: HPT's 2.5 bar OS upgrade. However, your calibration may or may not be supported yet. Please see here:

http://www.hptuners.com/forum/showthread.php?t=14800
(read the ENTIRE thread)

Regardless, there is STILL the IFR table limitation on the 2.5bar upgrade, as Chris was not able to address that. You do get double the MAF airflow range, BUT you also get more frequency range on the MAF table (instead of 12.2k you get 15k), which would prevent you from having to get the aftermarket MAF housing and LS7/LS3 sensor (tho this is a better, more accurate sensor than the one you're using), and on top of this, you get ole skool original style VE tables to tune with (you still don't have to use them if you'd rather run in pure MAF mode - again, perfectly fine to do this, as many of us do).

Now, is this good enough of an effort for you so that I don't have to get assessed as potentially giving you a sales pitch? ;) Seriously tho, all kidding aside, I hope this helps in your endeavors.

Sincerely,

James

Quote:

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Originally Posted by RWTD

Now, is this good enough of an effort for you so that I don't have to get assessed as potentially giving you a sales pitch? ;) Seriously tho, all kidding aside, I hope this helps in your endeavors.

Sincerely,

James

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That is all extremely helpful, thank you. Obviously I need to digest it as best I can and obviously I need to come up with the right values for the injectors first.

I do appreciate the help but also find it a little dissappointing that others on the forum, and I am sure there are many with the knowledge and experiance as yourself, don't jump in and help others out. I'd be happy to assist others if I had the know-how but am not up to par to do so.

Anyway, thank you. And I am looking forward to both getting into the DVD and researching the best way to go about doing a decent tune.

Not to worry, there are a TON of individuals here that will help you. My guess is that it's the weekend, so you should start hearing from others come early next week.

must be a long weekend!!