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ECMlink SDRatio VE Adjust tool with MAF installed

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rabenne

15+ Year Contributor
1,803
836
Apr 21, 2006
Racine, Wisconsin
Hello all, noob question for you. First time playing with SD.
I have been reading the wiki on how to get some base VE values from the maf sensor before setting the base maf type to SD. I cant seem to figure out if I need to have the GM IAT wired in while trying to do this.

The wiki says "...you must have the intake air temp sensor installed and connected to the intake air temp input of the ECU..."

But then in the notes section, it talks about not being able to use the IAT signal as a GM IAT (post turbo).That makes sense, because the maf is seeing fresh air and the GM iat is seeing compressed air and the temp will be very different.

The notes also describe zero-ing out the sliders in the SDTempWeighting table so that the SDRatio calculations arent using bad data.

so help me out:

1) does that mean the GM IAT should be installed and the maf should be hooked up (minus the two IAT wires) and then zero out the table, collect data, and run the tool?


OR

2) does that mean I run the maf hooked up (all wires including stock IAT) and then zero out the table, collect data, and run the tool?


I am sorry if this is obvious. I believe it is probably option 1 - purely on my own (likely flawed) logic, but when I tried this, my VE suggestions were mostly in the 120-130 ranges...

Thanks for your help!!
 
I am getting ready to log some data with the SDTempWeighting table zero'd out and the maf (including stock IAT) connected. I will post a datalog and resulting suggested "corrections".
 
I had the exact same question back when I did this last year.........ended up just giving up on getting some base VE values from the maf sensor. never did get an answer. I saw the same contradictions as you with no explanation in the wiki.

just did it on my own instead. wasnt a big deal. looking back it was so easy that all the searching i did to get this question answered was a laughable waste.

dont sweat it too much
 
Im not up on this but from memory i believe you can take a log that uses your maf and somewhere is Ecmlink upload it a d your vakues are adjusted for SD (i might be chatting crap here) but i do remember something abkut being able to use the maf as a base line and its infact better to do this then starting fresh from SD.

I am about to buy SD aswel ready for the future and free up space so if you do find out log it here anyway so i can save the findings please. Cheers
 
I think you are on the right track Bobby, but I can't tell you since I just jumped right to SD without any playing with the MAF.
 
I think you are on the right track Bobby, but I can't tell you since I just jumped right to SD without any playing with the MAF.
Im glad i remember something haha, i actually think it was a video i watch on this and it may have even been ecmlink themselfs or maybe another member on youtube who walked through this swap. I know i need to find it again as i will have to do this myself when i get my SD setup in
 
I posted the link to the wiki on ecmlink forums. You seem to have it right, Bobby. My specific question was which iat sensor should be wired in when you zero the SDTempWeighting table and collect the data. GM IAT or stock IAT built into MAF.

After reading the wiki a few more times, I am 99% sure you leave the maf alone (iat specifically) until after you have collected the data and ran the tool. The confusion stems from the wiki which says "you must have the intake air temp sensor installed and connected to the intake air temp input of the ECU".
The notes then go on to say you zero out the SDTempWeighting table so the ecu doesnt "...try to treat the factory MAF sensor's air temperature reading as a GM IAT sensor located in the upper IC (or intake manifold). The results will be an inaccurate calculation of the SDRatio value and inaccurate adjustments to your SD VE table." - This would suggest the factory MAF sensor is what is providing the "reading" to the IAT input at the ECU.
 
I think you are on the right track Bobby, but I can't tell you since I just jumped right to SD without any playing with the MAF.

That is probably the direction I will be going, but I wish I had some type of tool or calculator that could speed up the process of doing it manually!

edit: removed attachment that was not supposed to be there.
 
Last edited:
Heck, I'm retuning mine today because I got into some overrun on my VE table. You shouldn't use anything over 100 and I had a few boxes over, one at 125 so I am retuning with less Global adjustment, making it richer to start with. 2150s on gas because my E85 supplier is out currently or I would be tuning E first.
 
I made a few long trips yesterday to try to get more data for making sure my maf cal is on point. It was not. I made some adjustments last night and drove the car to work today, so I have a couple more logs to review the effects of my changes.

When I am confident I can't make the maf calibration any better, I will try using the tool the way I understand the instructions. No replies on link forums and [email protected] hasnt gotten back to me.

If I switch over and its not in the ball park, I will try doing it manually (if it will idle).

On a side note, by looking into the "odd" data that the tool was generating, and where in the VE map they fell, I think I may have been getting odd values because of down-shifting/coast down in gear. My DD has "generative engine braking" for the hybrid system, so I have 2 solid years of habitual downshifting and coasting down in RPM/speed. I also have tried to put the car into 6th gear twice since putting the new trans in (3k miles). Damn Honda, damn my habits!
 
Your worries are understandable but believe me, I swapped, learned the VE table and timing needs along with global and deadtime adjustments. Even both of my sons can get a car running on SD and then get it to idle with the right fuel trims. Its just new so you are tipping your toes in instead of jumping in feet first. Its scary but it shouldn't be made out to be. Its gonna work out for you just fine. :thumb:
 
Anytime. Its not as hard as one would think once you are used to using the tools that Link gives you like tracking your SD table and timing table live and making the adjustments that are needed THEN not later when trying to look at a log. I use SDAdjust to some extent but to get what I want I have to still manually make some adjustments so the car is happy.
 
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