fuel trim

[anchew02]

so ive been driving my car for a couple days now after chip and 650 injector install. my lt fuel trims have been decreasing slowly and as of now it is 87.5%.
question is does this mean im running really rich?

 

[NOSLO2PT0]

Yes. I assume the chip is programmed for 650's? You verify the injectors are in fact 650cc injectors?

 

[anchew02]

yea they are, found out chip is set for 37 psi fp and i was running 43, set that back to 37, and did the lower maf hack(backed out screw and removed lower honey combs.

 

[NOSLO2PT0]

Running 43psi via AFPR? The lower MAF hack will give you a little more room for airflow metering purposes before you run out, and a result will be to run slightly leaner. Hopefully, this will bring your LT trims back up to normal.

 

[MY1GDSM]

Your low trim isnt dropping because your fuel pressure more then likely your injectors just require a bit less deadtime then the norm. Or the 20 year old crappy maf is not reading right they really are a pos....

As I said before to you should only be needing to make fp adjadjustments base off you high fuel trim which was perfect from my understanding when you Pm,d me
. An haking your maf is only gonna throw thing off more since no changes where made in the maf comp. For the chip...

 

[anchew02]

Ii think its time to upgrade to a second gen maf.I think its breaking up on the top end

 

[donniekak]

Ii think its time to upgrade to a second gen maf.I think its breaking up on the top end

The 1g maf is maxxed at around 30 lbs/min. When you over run it, the wideband goes crazy with lean spikes, which can destroy stock pistons rather quickly.

 

[MY1GDSM]

The 1g maf is maxxed at around 30 lbs/min. When you over run it, the wideband goes crazy with lean spikes, which can destroy stock pistons rather quickly.

Yes this is very true...

Here's a good example of just how early the air flow signal can go to shit

http://www.dsmtuners.com/forums/152575367-post6.html yes that really is less then 1200hz that it starts to get skewed