MAF test...

[Nixon1]

I've got this feeling I have a faulty MAF. See my signature.. My car has all sorts of intake upgrades, such as a cam with higher lift, 1.6 rockers on top of that...high flowing cylinder heads...a Cobra intake...so it should be running lean if anything. YET, my car runs VERY rich right now. Practically all of my sensors are new... New O2 sensors, new TPS, new IAC, new CTS....what is NOT new is the MAF. The only explanation I can think of is a faulty MAF.

Only symptoms besides running rich are occasionally if I put the car into neutral it'll either stall abruptly or the idle will drop to around 500, try to stall, and then either it bounces repeatedly between 500 and 900 until it stalls, or it will not sustain an idle without me giving it gas.

Is there a way to test the MAF for proper operation, like with a voltmeter? I figure it's a continuously varying signal and all so it'd probably be either impossible or a pain... I know about unplugging it and seeing how the car runs without it but most of the time the car runs fine so it'd be hard to tell.

Thanks! This is starting to tick me off a little!

[Nixon1]

Any takers?

[lx mike]

How do you know it's running rich?? do it blows black smoke or can you smell it when you stand in back??

as for the stalling thats the dreaded idle surge from the cam. sometime resetting you computer and then reset your idle will help but most people say you need to clean your 10 pin connectors, there behind your intake. have to seperate then and open up male end a lil more so it make good contact.

which maf do you have??

[Nixon1]

I can smell it. It's not running nearly as rich as it was though..I discovered my EGR valve was bad and stuck in the closed position. But I still want to know how to test the MAF, for reference. If it IS testable, which I kind of doubt. The MAF is the factory piece of junk.

10 pin connectors...you mean the 2 white, funky looking things with the plastic bracket on the backside of the intake, behind the throttle body?? What do those control? I figured EVERYTHING, with how many wires there are going to them!

And about the idle...I lowered it about 50, so it idles right about 700 now. I dropped the idle so that it lopes like crazy, even in gear. Sounds more impressive. I just have to watch out for my brakes. At that idle speed I only pull about 10 HG's of vacuum.

[canukracer]

i know a bad maf sensor will cause a surgeing, like your running out of fuel,try tappin the maf meter with a screwdriver handle, not real hard, if it's bad it will stall or run better or worse,i have also used a heat gun or hairdryer to find a problem/// sounds like yours is constant rich if so your o2 should set a code? u can also test the maf with a frequency meter and the ford spec for it.

[Nixon1]

Originally posted by canukracer
sounds like yours is constant rich if so your o2 should set a code

Operative word in this sentence is SHOULD. My computer is crazy..it does what it wants when it wants to. Ran rich for weeks..never threw a rich operation code. My EGR valve has been dead for months now. Frozen shut...completely non-operational. It was fully connected to the computer and all. The computer never threw a single code to alert me of this...it just decided it'd try to choke me with gas fumes until I figured to check it and see it was busted. And yes, the Check Engine light DOES work...the computer just decides to never alert me of any problems.

My car surges sometimes..usually on startup, or if the rpms drop suddenly like from taking the car out of gear. Usually stalls during that though, but if it manages to stay running, it dips to about 500 rpms, then bounces between 500 and 800 until it finally finds an idle speed it likes of about 650-700.

[Katmandu]

Did you try cleaning the tiny wires inside the MAF yet ???

Try cleaning out the IAC as well.

Also, with those mods, you "should" have an Aftermarket Chip burned to take full advatange over your upgrades.

Get with www.FordChip.com They are the BEST out there concerning Chips for Fords.

[Nixon1]

In the MAF, are you referring to the single small wire in the little inlet in the top of the thing? I don't see anything else in that MAF besides the single wire. The MAF screen is clean and the inside of the MAF looks clean too.

The IAC valve is brand new as of maybe 3-5 months ago.

And I'd get an aftermarket chip if I had the spare cash...but right now I'm barely getting by. Hell, I have a TCI Street Fighter tranny and $400 stall converter to order in the next week or two...so that blows any thought of a chip out of the water unfortunately!

[Katmandu]

Yea, that single wire inside MUST be CLEAN. It's actually a tiny heating element, that when cooled by incoming air, gives a voltage change reading through the sensor.

I would also be searching for Vacuum leaks around the intake, TB areas as well.

[Nixon1]

Vacuum-At an idle speed of about 700 rpms I pulled 10-12 HG's of vacuum. If I had brought my idle up to about 900-1000, which most people do for my cam, I would pull 15. I can't hear any vacuum leaks and all the hoses are intact and connected. The car doesn't surge or act strangely, except every once in a while when the cam tries to do its own thing.

Oh and this style MAF uses the heating element-type wire? Never cared much for that kind....I always preferred the type that vibrates with the incoming air. Wonder which is more accurate.....