Tuning Newb question, I'm sure:

When I scan with my MAF unplugged, My LTFT's read generally between 0 and -7. 2 hours later i plugged my MAF back in and my LTFT's now read anywhere between +9 and +22.

Is this normal? If so do I tune with my MAF unplugged first until my LTFT's go between 0 and -4 and THEN replug the MAF and scale it from there?

Any help is appreciated. THX

 

Have you tried scaling the MAF table?

 

I haven't done any real tuning yet I just wanted to make sure it was normal to have neg. LTFT's without a MAF and Positive with a MAF. I kind of figured I needed to scale the MAF table but wanted to check if I should adjust my Primary VE table first.

 

My car behaved the same way. I had to scale the MAF table by nearly 6%.

 

Yeah, my Ltrims jumped by 10% or so when I plugged the MAF back in. Just scale your MAF table to get it back in the ballpark.

 

How do you perform that?

 

You need to log with the MAF out of the equation first, get your VE table spot on, then plug you MAF back in and re enable, look at the differences and this will be how much you need to adjust your MAF.

 

RedHardSupra created a spreadsheet to assist with this scaling, but after using it my MAF table was very spikey. I took the average amount of change suggested by RHS's spreadsheet (6%), and multiplied my entire MAF table by 1.06 to bring the LTFTs back in line, but maintain the same MAF *curve* as the stock table.

 

Clean the MAF thoroughly with an electrical contact
cleaner or some other safe, clean-drying aerosol first;
no point in tuning for spooge. Also, is this or is this
not the stock (virgin?) MAF?

 

Yep, stock MAF with screen.