Fuel consumption for MAF testing is high? - The Unofficial BMW M5 Messageboard (m5board.com)

bugzy · 18th April 2008, 23:04

I'm hitting 160L per hour using the information on this thread, How to test the MAFs yourself and How MAFs work

i assume im running rich since the FAQ says 140L per hour is what should be normal

gsfent · 18th April 2008, 23:18

Quote:

Originally Posted by bugzy

I'm hitting 160L per hour using the information on this thread, How to test the MAFs yourself and How MAFs work

i assume im running rich since the FAQ says 140L per hour is what should be normal

No, that is just considered the minimum acceptable flow. 160 is excellent!
Regards,
Jerry

bugzy · 18th April 2008, 23:24

but im having hesitation issues

and i got check engine light with MAF code and bank 1 and 2 are running rich codes

gsfent · 19th April 2008, 00:16

Quote:

Originally Posted by bugzy

but im having hesitation issues

and i got check engine light with MAF code and bank 1 and 2 are running rich codes

Perhaps there are problems, but based on your flow numbers, it does not point to MAF's. However, they are cheap enough to replace, less than $200 a pair. Worst case is you have a spare set for when you really do need to replace.

MAF failures do not usually cause running rich, usually bad MAF's result in not enough fuel, so if anything, I would expect lean. However, if you have an air leak after the MAF's then you will run rich as all the air the MAF "sees" is not getting to the engine. Check the plumbing from the MAF housings back to the plenum, including the little gasket where the tubes go into the plenum housing.

Regards,
Jerry

badboypolar · 19th April 2008, 01:12

Didn't you just replace your O2 sensors and your cats?

bugzy · 19th April 2008, 02:26

i havent replaced my o2 or cat's yet

badboypolar · 19th April 2008, 03:52

I thought you needed to? That'd be my thought as to why you are running rich. If the O2's or Cat's aren't working correctly then you'd run rich. And if your Cat's are bad then something else went bad that you need to fix as well. Cat's don't go bad for no reason under 500k.

bugzy · 24th April 2008, 03:01

Well got my SES cleared last week, and cars been running beautifully so far

new spark plugs, new MAFS, coolant temp sensor ...

so far so good