firechicken_98

iTrader: (8)

I'm obviously a n00b at this.

I got my VE's tuned finally (+/- 3). That stickied write up needs to be edited for 98 tuning, but anyways. According to the same stickied tuning process it states that I should now tune my PE table. The question I have may be a dumb one. Now that I'm done with my LTFT's, do I plug the MAF back in and set the fail frequency back to stock before proceeding on?

After PE tuning, where do I go? Timing? MAF? I've already got the trans tuned.

Any help would be appreciated. Thanks.

brad8266

iTrader: (23)

I am assuming you mean you got the VE table dialed in, so now plug the MAF in and set the fail freq back to stock and do more driving/logging and watch LTFT's again. After enough logging you will have to adjust the MAF table to get your trims dialed in again with the MAF in system. Once you get the MAF table dialed in with good LTFT's then go ahead and do your WOT/PE tune. You will want a wideband 02 sensor for the pe tune.

firechicken_98

iTrader: (8)

Yeah, VE's are what I meant.

So I plug the MAF back in, set the fail freq. to stock, and log some more. Will I also have to adjust my VE's again or just the MAF?

transam02

just the maf

firechicken_98

iTrader: (8)

Thanks.

crewchef

iTrader: (6)

firechicken_98, not to get off topic but... Wondering what you saw in the stickies that you would change for the 98. I'm working with the same model and just wondered what you might have come across that maybe I overlooked.

firechicken_98

iTrader: (8)

Well, I followed the stickied write-up trying to tune my VE's. I adjusted it exactly like it stated and was getting nowhere. I spent all day doing this. It was like going in circles. I would log, make changes, and log some more. Nothing was getting better. I finally said to h#ll with it and went back to the stock VE.

Later that night I did some research and found out that on 98's and early 99's you need to also adjust the secondary VE table as well as the primary; otherwise, you will get nowhere. You just basically copy and past the row from the primary to the corresponding row on the secondary(the primary rows are in mulitples of 5 and the secondary is in multiple of 10, you go 10-10, 20-20, etc...). Don't do this until after you correct the primary.

I also found a better way to adjust the VE table. Instead of taking the VE table and +/- for the LTFT in the log you use this equation, which came from the HP tuners website in the help section (LTFT + STFT)/2 = VE table adjustment.

I did those 2 things and on my first attempt I got my LTFT's +/- 5. I then did the smoothing trick from the write-up and my LTFT's went to +/- 3.

I hope this will save you some time.

ninobrn99

iTrader: (8)

im pretty sure that its in the writeups. The one I read had that in there.

firechicken_98

iTrader: (8)

I'm sure it may be in one of them, but not the one I used. Which one were you looking at?

I'm not trying to knock, bash, or flame the write-ups by any means. I hope nobody thinks that. There's a lot of great info in there and I've learned a lot from them. I'm just conveying my experience from the one I read. It was actually a good learning experience.

crewchef

iTrader: (6)

firechicken, thanks for the response. I assumed the secondary table was what you were talking about but thought it worth asking. I see it mentioned in some write ups but not others. I've seen a lot of guys ask the question "why aren't my LTFTs changing after I update my VE table" knowing they probably have a secondary table.

Now that you've got your VE close you can work the MAF over and get things dialed in good. There's a recent post on HPT forum that details setting up a histogram that will match the MAF frequency to the associated LTFT cell. I set it up and it gave me another point of reference to dial in the MAF besides the standard MAFTune (#8).

98Z28CobraKiller

iTrader: (17)

Yeah, I had the same problem and did not see it mentioned on the HPTuners or one here on LS1tech. I ran into it on redhardsupra's bloge site. (Secondary VE for 98).

firechicken_98

iTrader: (8)

Anyone have a good write-up on how to dial in your MAF? Or can someone tell me how to do it?

Most of the ones I've found are very technical and complicated and doesn't really tell you how to adjust it. I'm not an engineer or a scientist, so maybe one that's simplified.

brad8266

iTrader: (23)

Pretty easy. You can do it the easy way and lets say your LTFT's are 4 then you could just scale the entire MAF table by 104% which is an addition of 4% more hence richining up a little. You can then also dial it in more by looking at the specific MAF frequencies in a spreadsheet and what the fuel trims are at each frequency and then adjust the corrosponding frequency in the MAF table. MAF adjustment is fairly easy though for me and I am using old LS1 edit/scan so i would guess its easier in hpt or efi. Much easier than VE table.

firechicken_98

iTrader: (8)

Are you talking about the Engine>Airflow MAF Calibration - Frequency vs. Airflow table?

crewchef

iTrader: (6)

Firechicken, search the posts on HPT forum. Reference my earlier post, there's a description (and screen shot) of how to set up a new histogram. With this set up it's just like tuning your VE using LTFT/STFTs. It logs the LTFTs in the individual frequency ranges so you can accurately adjust each cell on your MAF table. I would also check #8 histogram to make sure your new numbers are close to what it's logging. Mine were about 3/4% higher than the #8 logged.

crewchef

iTrader: (6)

Here's the post on HPT

http://www.hptuners.com/forum/showthread.php?t=5369

firechicken_98

iTrader: (8)

Thanks...crewchef. That really helps. I was wondering how to set-up the histograms.

Runn

Thanks i´ve been looking for that