[Z3PH3R]

Hey guys i just installed a new maf in my 96 mpfi g16b vitara as i was getting poor fuel economy and now I'm getting even worse fuel economy.

my question is, do i need to reset the ecu to relearn the new maf? it is an after market sensor so I'm guessing it could just be poor quality crap?

[Jack]

bad fuel economy can be caused by a bad O2 sensor or a crack/leak in the exhaust manifold

[Gwagensteve]

G16B's don't have very sophisticated EFI or diagnostics. There are acceptable ranges of operation for each sensor and so long as the replacement part is compatible (i.e it's within factory specs) there's nothing you need to do, however, I don't think I'd use an aftermarket MAF as they are quite calibration sensitive.

Firstly, what's "bad fuel economy"
Second, has it changed over time or has it always had bad economy? How bad is it after the sensor was changed?

Don't rule out coincidence, it can be very misleading.

L/100km please.

Are you getting a check engine light?
Do you get a check engine light if you unplug the MAF with the engine running?
Why did you land on the MAF as the cause for the high fuel consumption?

Other possible causes for poor fuel consumption include an internally collapsing engine pipe - the engine pipe between the cast manifold and the cat is a a dual pipe and each pipe is twin wall. the inner pipe can collapse and block the exhaust. Also, these bits can block the cat and/or the cat can internally collapse cause a huge restriction.

Crank keyway wear can retard the timing which will worsen fuel economy.

How is idle quality?