jjskibbs

anyone know how to, or can direct me to info on how to rebuild a mass air flow sensor???
mine is bad, went to junkyard and grabbed one, it is bad. i just can't afford a new one right now.

YES - i have done research and searches. i know for sure my maf is bad (the 1st one i de-screened and the car backfired while tuning after i did an injector swap --- not a good thing), i followed diag instructions for code 33 posted here. all my wiring, grounds, relays are good.

so i have 2, count them -- 1, 2 junk bosch mass air flow sensors for '89 305 tpi.

any help???

doc

Look down the MAF tube with a flashlight, do you see any broken filament wires? If any of the fine wires are broken, then the MAF is junk. Furthermore, I do not know how to check the electronics inside the MAF casing.

Also, for a 305, you do not need to descreen the MAF. If & when you buy a new one, just install it as you receive it. The part stores around here want to olf bad MAF as a core return, so dont throw the bad ones away!

jjskibbs

The filaments are still there. i suspect the backfiring damaged the sensor since it worked fine before i did the injector swap and descreened the maf.
i have 2 junk sensors and hoping to find any specs or anything so maybe i could make 1 good one out of the 2.
the new maf will have screens in...
i learnd the hard way and found valuable info afterwards.
the front screen sifts the air to flow evenly over the sensor (removed the sensor may get false readings), the rear screen (closer to the tb) is there as i flame arrestor so when if your engine were to backfire the flame would be suppressed and not damage the sensor.

ibmtech

iTrader: (1)

I found this one at www.autozone.com part number 74-4712

Price
$167.99
Core:
$80.00
Total:
$247.99

You send a core and pay only the $167.99 + Tax comes with warranty

There is a massive theory that you will get more air flow or more directed air flow if you remove the screens.. I see alot of people write that they descreened their MAF's. The air will be disrupted once it hits the center where the wires are anyway. The MAF is designed from the manufactures to use these screens. Once I removed mine, I had nothing but troubles. Unless you are good with Electronics, they are basically considered junk.

Guest

They arent really user servicable. You need to know how to fix electronics, and how to get the thing apart as well.
Check the filament again, its possible and likely one of the wires still looks intact but is no longer connected. IIRC Vader tried to locate the proper wire size and material and was having a difficult time and he's likely the only person here who has enough time and patience to look for stuff like that.
Wrong wire=useless maf without the device to calibrate it.

I suspect you're going to have to save up for a new one, if the ones you have are really defective. Check your wiring, especially by the cooling fan and at the relays. Try replacing the relays. Then get a new one if need be. Getting them at the junkyard, I think you found out what your luck is there.

irocman79

iTrader: (5)

you put a new burn off relay in. Just wondering i had the 33 code on my car and was replacing mafs with used ones and it wasn't taking care of it so i thought i was getting bad mafs. Then i went on here and somebody told me to replace the burnoff relay. As soon as i replaced it the code went away and car runs much better now.

jjskibbs

my relaysare fine. i've gone throught the wiring and tested everything by doing the whole applying 12v to terminal g of aldl, all my wiring and connectors are good and relays work. i know for sure it is my sensor(s). i guess i will have to save up!

pandin

SIA Electronics
730 N. Minnie St.
Tilden, IL 62292
800 737 0915

$68.00 to fix
will check first
Fast turn around.

Change the Maf relays to the fan or AC replacement, It is a heavy duty same price. AZ MR82 $11.99

HCR13

iTrader: (5)

I would recommend getting a new one. I got one from Advanced auto for under $200 with lifetime warranty. It was a Microtech (or something like that). It has the microchip in the path so there is no need for filaments...

pandin

I got one and it makes the ECM run way rich, reports more air than is.
Standard AZ Reman Maf under reports air, makes ECM run Lean.

Same Car, Same prom, Same road, WOT

Maf's
Chip 255 Gr/sec This one goes max LV8 early, resolution is lost, max spark & fuel.
SIA 240 Gr/sec
AZ 183 Gr/sec This one rarely gets to max LV8, power is limited, spark & fuel.

If you tune for one maf then change to the other maf, the tune will then be way off.