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Speed density tuning


TurbochargedBerserker

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I've found a very easy way to complete VE tuning for those using HPT (only slightly more difficult for Edit - but maybe just as simple). I found this on HPT / LS1Tech, so for those of you who are bi-site, you probably know this :)

 

1) put in the stock maf table, and stock VE table

2) set PE to come on late (you won't be a wot anyway) or disable open loop altogehter

3) unplug the MAF (ignore the SES light for now -- you will lose IAT logging as well)

4) use the LTFT histogram and add the difference in what you see and what you want to the VE table in that cell

 

(e.g. if you want a -2 and the LTFT is -5, add -3 to that cell, conversely if you want a -2 and see a +5, add 7)

 

5) rinse and repeat, and drive with the MAF unplugged until stable

6) decide if you like SD too much to go back to mass air, and if not, plug the MAF back in (which will set your LTFTs off)

7) adjust the MAF table until your LTFTs are back in line

 

Be aware that LTFTs are +/- 4!!

 

Make sure you reset your LTFTs after each VE table change. Make sure you warm up the truck -- "warming up the truck" in my experience is more than just letting the temp gauge get to your normal operating temp. It takes about 15 minutes for my LTFTs to wake up after a reset -- and log at least 15 minutes after that, trying to hit all the cells in the LTFT histogram (I run in 2nd gear and massage the throttle and brakes to get as many cells as possible).

 

If you are not going to convert to speed density (i.e. delete your MAF), you can ignore everything over 4000 rpm in the VE table (because with the MAF plugged in, the VE table is not used over 4000 rpm unless there is a catastrophic failure of the MAF itself).

 

!! WATCH YOUR KR !! You will be getting some. You can minimize this be going to an extremely conservative low octane timing table (the truck will be in that table most of the time with the MAF unplugged -- regardless of octane). Also, make every throttle transition as smooth as you can.

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:D Heheh... Standard internet based tuning stuff... The necessary info is slowly trickling out.

 

Seems like Keith@HPT forgot to mention that you absolutely have to have the IAT sensor hooked up. I'd thought based on the first post from them that you could just change the Closed loop enable, but now they are saying without the IAT your LTFTs wil act crazy (much like mine are..)

 

So to do this, you need to jumper the tan and purple wires (edit: on my truck they are tan and black -- if you pull off the maf and match up the plug to the IAT, its easy to see which ones you need) in the MAF harness to the MAF receiver plug. :dunno: Who knew?

 

Another update soon.

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