98 gtp 3.4 pulley with supporting mods 2.9 KR @ WOT

[850Morrison]

Background of Vehicle
I have a 98 GTP 195,000 miles, my current mods are 3.4 pulley w/ gator back belt, headers (wrapped), 3'' down pipe, 3'' pipes to dual dynamax mufflers, al104 plugs gaped @.060 , 160 tstat, FWI-CAI, P&P TB, P&P LIM, P&P Eaton M90 SC, intense standard 1.0 pcm. Running 93 Octane

I just purchased the HP Tuners MPVI Standard and did a scan on the car and i am getting some knock at wot runs. Im just starting to learn the tuning aspect of these cars, and reading all the different threads. So far i have only adjusted idle and shift points, too scared to adjust the other stuff untill i have studied this stuff more. All this stuff seems overwhelming, i'm looking for a place to start to squeeze a little more power out of the car. Any help / advice is appreciated

Is this a good area to start? http://www.grandprixforums.net/start...ers-43997.html

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[GeoJB]

Welcome.
I have a tune guide Just for our 3.8's.
PM me & I'll sent it to you via E-mail.
Or, Go to RegalGS.org. in their DIY section is the same tune guide.

Either way.

I haven't looked at your scans (yet) I will say, get your scanner configurations in order.

[GeoJB]

You need a scan congfig for you MAF. Before you can dial in your car.

From what I have seen your running on the rich side. (According to your VE table).
I still scratch my head on quite a bit of stuff. I'll be more than glad to help where I can.
What part of town you in? Perhaps some one local to you could help with a little one on one.

[850Morrison]

ok i set the main table with maf htz and configured a histogram to map maf htz vs ltft. i also set another to save maf htz vs maf lbs/min. then i (THINK) i copy the results over to the maf calibration in the editer and smooth the difference out. Am i understanding this correctly? I will post a scan log here in a few hours.

Oh yeah, i live in Fort Walton Beach, FL

[850Morrison]

thanks GEOJB,
i used your config file and did a scan then copied over the maf vs ltft over the the maf calibration with special paste % half then smoothed. i did this twice and the car seems to have a little better light throttle acceleration. here is the log and tune for tuning the maf twice. I think i am supposed to keep doing this untill all my ltft are within 5% of 0. also am i referring to the histogram 8maf vs ltft ( is this what i am trying to get within 5% of 0 on?) If so then i guess i have to keep repeating untill they are all in range. i have power enrichment off so i havent been going wot, i havent seen any kr, so should i go a little harder acceleration or just keep going as i have been.

heres my last tune and scan
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Am i headed in the right direction?

[GeoJB]

Your on the right track.
E-mail replied.
My boost config is messed up, haven't got around to fixing it after the Beta up-grade.

[GeoJB]

BTW, you don't have to copy the whole thing.
If wanted you can copy & paste special lets say between, 3000 & 5000. make only adjustments to those particular cells. and then smooth or manually go in grab (lt click & hold) the line and adjust it.

[850Morrison]

ok i got my ltft dialed in, it took 6 scans and tunes to get like it is now. i noticed my fuel mileage went up too im getting 30mpg just casual driving around town. My throttle response feels good, it breaks the tires free from a 15mph roll at 30% throttle. so now im gonna set power enrichment back on and do some wot scans and try to get the naroband 02's in range of 930 and 940. Let me know what you think on what ive done so far.

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[GeoJB]

Wait....
Now you need to dial in the VE, the same way you did the MAF.
Some will argue it's not needed.
It is there for a reason! GM put it there for reference for the MAF. I don't thinks it is known how many times the PCM refers to it. But it does. I believe your car will like it. Mine does. If the MAF ever fails, the VE is what is used to run the car.
It's like shinning one shoe before you go out....

Read the tune guide I gave you.
What I do is disconnect the maf. If the trouble light bugs you turn that off.

Your on the right track..... keep going.

[850Morrison]

i had the last tune i posted on my car today, i did it at night when it was 77f outside. hoped in the car this morning 93f and was scanning it on my way to work and my ltft were off again. up to -17. I think i might have an intermittent vacuum leak, thats messing with my head/tune. normally engine warm, idle, in park at 950rpm on my boost gauge is -22psi. Now its reading -18 to -20. Would a small vac leak cause my ltft to go out of whack. Also i just got done fighting a low oil pressure light in the dash. Hp tuners was saying that my oil pressure was -15. i got pretty scared because i just replaced the pressure sensor 3 months ago and figured it was still good, so i was sure i had a serious problem. Yanked the sensor out and taped a manual gauge in and mounted it in the engine bay and my oil pressure is at 60psi cold idle. (THANK GOD) So i havent had the time to mess with the scanning or tuning today. im gonna over look all my vac lines tomorrow and use some carb cleaner and try to find the small leak. Im using all new silicone vac lines, but i think some of the adapters might not be sealed 100% so until i am certain i have no leaks, i will not be doing any more adjustments to the tune. Sorry for the long post.

[GeoJB]

Oh hell ya... a vac leak will mess with you.....

That -22psi, not sure about the grand prix and how things are read.
If thats reading LFT's a -22% lft's are an indication that Evap system is acting up.
If so
http://www.hptuners.com/forum/showthread.php?t=39743
Also
http://www.regalgs.org/topic/52807-f..._fromsearch__1

[850Morrison]

Good info, When i purchased the car back in 1-1-12 it would not run and i spent alot of time and money chasing all kinds of problems. i got them all fixed and then started doing aftermarket mods in the past few months. I was having a problem of the p0446 ses code at random times and i would delete it and it would come back in a week or so. But the last time i have seen that code was 2 months ago. I must have deleted it 50 times and thaught i finally fixed it. but maybe its still there, i will try unplugging the connector and and the hose and leaving the vac line on and taking it for a drive/scan. Here is a thread of me fixing the car and what i have replaced. HERE

I will post an update soon

[850Morrison]

Dbl post

[850Morrison]

Thanks GEOJB, You were dead on. I did some tests and came up with some good results. (You nailed it) I rechecked all the vac lines and was certain i had no leaks. LTFT were still in the -20 ranges. I unplugged the evap purge solinoid (4 months old) and all ltft looked good. Did 2 scans and never had a ltft reading - of 0. plugged the solinoid back up and rescanned and ltft were back at -20. Here are the 3 scans i did, they are short scans but shows the results. Refer to histogram 3 & 8 for reference between the 3

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These were morning scans when it was 81F outside all 3 were done at the same temp when motor was warm back to back.

Also i never had a SES light come on.... Is this good or bad. Should i get the part replaced under warranty or just delete it? Is there any benefit or downfall to removing it completely?

Thanks again for all your help GEOJB!!!

[Mobile Chassis Dyno]

3800's will use the V/E table if it believes the maf is failing. It does not work the same as a LS1 where the tables are used at the same time for fuel calculations.

Some OS's will resort to the V/E if there is a big enough difference between the two. Most of the OS's that I have used will ignore the VE table until the pcm thinks the maf is failing.


Looking at bins with Tiny Tuner will tell you more of what the pcm is wanting to do with a failed maf.

[850Morrison]

Ok good info i will defiantly do the VE tables after the MAF tables are within 5. Quick question: do i adjust the MAF calibration tables the same way i was doing it before when the numbers are positive(LEAN) without the - in front of them indicating that it is running rich.

Example: Scan log is MAF 2500HTZ with LTFT at -17 (RICH) then I copy and paste special multiply % half under 2500HTZ MAF calibration tune file.

I have been doing this and now all the trims are running lean not rich.

Do I use the same special paste multiply % half when the log is reading MAF 2500htz with LTFT at 8.2 (LEAN)? Or do i use another special paste function?
Im close to getting the ltft within 5 but a few are still outside that range. Also Does it help if i get them as close to 0 as i can, and do i want them lean or rich?

[GeoJB]

All + numbers indicate a LEAN condition
All - numbers indicate a RICH condition.
The desired LTFT cell values of "0", indicating that the car is running well, not rich, not lean.

Taken from the tune guide I sent you.

I believe that a little on rich side ( - numbers) the car runs a little happier.
Also, the bit of extra fuel adds a touch of cooling to the engine.
At least that has been my experience.

@ Mobile dyno.
A real question.
When I left the VE table alone, Vs, dialing in the VE similar to the MAF.
My MPG got a bit better with VE table in line.
Do you know how often the ECU refers to the VE Vs. the MAF?

And yes I do know the MAF is the main sens used to fuel the car.

[850Morrison]

Yeah i read that guide that you sent me, but it dosent say if you use the same special paste (multiply % half) for lean and rich ltft's when adjusting the maf htz. So i assume its the same special paste?

Oh and i put my car in SD mode to do the VE tuning, and it does not like it. It took 10 minutes just to get the car to stay at idle finally did a 1 hour scan and the numbers in the table are way lean getting 15 to 20 in most of the cells. Car felt restricted on acceleration. Im adjsting the tables tonight and will flash/scan tomorrow and post the results. My MAF is within 8 now but on the lean side.

[850Morrison]

OK i got my LTFT's dialed in tell me what you think....

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[GeoJB]

Ok, now your on the lean side.
IMHO, you need to be a little on negative side of the numbers.

Car running Leaner means more heat in the engine. Heat is not always good thing.
(If you want longevity)

I stand with my previous post.

Hope someone else chyme in to add any more advice than I can give.
BTW, I don't have a wideband, so can't help you when you get to that point.