newbie needs maf help

spanky · 08-19-2008, 05:01 PM

hi everyone. i am new to the mr2, in fact i do not own one, i am just trying to get one running for a customer. the car runs very good on heavy acceleration but stumbles and misfires on cruise. it will immediately pop code 31 for the mass air flow sensor. the original sensor was out of spec when tested, the replacement tests good. my concern is the connections at the maf sensor. according to the wiring diagrams i have available to me the wires are in the incorrect position. i was hoping that someone might be able to take a picture of the connector and post it for me or possibly just list the color code and position of the wiring. the manufacture date is 1987, according to the color code of the wiring at the maf, it matches the 1988 wiring diagram. i am unsure of the history of the wiring in the engine compartment.

any help would be really appreciated

thanks for the time.

steve

87mr2aw11 · 08-20-2008, 02:37 PM

it should just plug in do not unscrew the connector from the afm if you do that it is junk after that. there is a clip that holds the connector on

mr2tim · 08-21-2008, 04:12 PM

Hey Steve,

I suspect the spring inside the AFM may be damaged or hanging up due to rust or some other de-generative (electrical) crap.

The rubber plug atop the AFM can be (carefully) cut loose from the body to check for these obvious problems.
Hint: Trace the E-2 terminal inside as this is the low speed setting, then vb, then vc
(I would suggest waterproof "goop" to re-fasten the lid.)

If you see nothing "poopy" in there you'll need to go to the attached resistance measurement and inspection criteria.(see attached photos)

I will assume if your a profesional you've already checked the manual movement of the measuring/compensation plate?

How's your Sarasota weather bro? (We got 8 inches of rain in Ft Laud)

Tim
mr2tim

Please let us know how this works out as some Club members may use this information in the future on their cars!

spanky · 08-27-2008, 02:08 PM

thank you for the info and the wiring diagrams. i have checked the operation of the plate, everything feels smooth, i dont feel anything hinky. i am also a little hesitant to pull the cover off due to warranty issues on an expensive part. all of the resistance values check out good which is what has me wondering if someone has pulled pins out of the connector to the maf sensor and then put them back in in the wrong positions. sooooo. to ask an almost complete stranger a favor, could you possibly take down the sequence of the wiring to the mass air and give me a color code of the wiring i would be forever thankful.

thanks again, steve

mr2tim · 09-04-2008, 11:34 AM

Ok Steve,

This from Page FL-94 BGB and Electrical Manual.

Left to right N/A fc e1 e2 vb vc vs tha
" " " S/C " " " vc e2 " "

Fc=green/red striped
e1=brown (goes to "e" ground)
e2=brown
vb=black
vc=lite blue/red striped
vs=yellow/blue
THA=yellow

Hope this gets you some where.

I understand your hesidensity in not opening the AFM, although, as long as the top is replaced with adequate sealant you have no future problems.

Remember this equipment is 20+ years old, even aluminum will turn to white powder in the right conditions.

Hope this helps,

Tim
Hurricane Central

08-19-2008, 05:01 PM	#1 (permalink)
spanky No Skills Join Date: Aug 2008 Posts: 2 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	newbie needs maf help hi everyone. i am new to the mr2, in fact i do not own one, i am just trying to get one running for a customer. the car runs very good on heavy acceleration but stumbles and misfires on cruise. it will immediately pop code 31 for the mass air flow sensor. the original sensor was out of spec when tested, the replacement tests good. my concern is the connections at the maf sensor. according to the wiring diagrams i have available to me the wires are in the incorrect position. i was hoping that someone might be able to take a picture of the connector and post it for me or possibly just list the color code and position of the wiring. the manufacture date is 1987, according to the color code of the wiring at the maf, it matches the 1988 wiring diagram. i am unsure of the history of the wiring in the engine compartment. any help would be really appreciated thanks for the time. steve

08-21-2008, 04:12 PM	#3 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 690 Thanks: 2 Thanked 41 Times in 38 Posts My Google Map iTrader Rating: (2/100% )	Hey Steve, I suspect the spring inside the AFM may be damaged or hanging up due to rust or some other de-generative (electrical) crap. The rubber plug atop the AFM can be (carefully) cut loose from the body to check for these obvious problems. Hint: Trace the E-2 terminal inside as this is the low speed setting, then vb, then vc (I would suggest waterproof "goop" to re-fasten the lid.) If you see nothing "poopy" in there you'll need to go to the attached resistance measurement and inspection criteria.(see attached photos) I will assume if your a profesional you've already checked the manual movement of the measuring/compensation plate? How's your Sarasota weather bro? (We got 8 inches of rain in Ft Laud) Tim mr2tim Please let us know how this works out as some Club members may use this information in the future on their cars! Last edited by mr2tim; 10-27-2008 at 02:23 PM.

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08-20-2008, 02:37 PM	#2 (permalink)
87mr2aw11 ACE Join Date: Jul 2007 Location: sarasota, florida Posts: 22 Thanks: 4 Thanked 0 Times in 0 Posts My Google Map iTrader Rating: (0/0% )	it should just plug in do not unscrew the connector from the afm if you do that it is junk after that. there is a clip that holds the connector on

08-27-2008, 02:08 PM	#4 (permalink)
spanky No Skills Join Date: Aug 2008 Posts: 2 Thanks: 1 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	thank you for the info and the wiring diagrams. i have checked the operation of the plate, everything feels smooth, i dont feel anything hinky. i am also a little hesitant to pull the cover off due to warranty issues on an expensive part. all of the resistance values check out good which is what has me wondering if someone has pulled pins out of the connector to the maf sensor and then put them back in in the wrong positions. sooooo. to ask an almost complete stranger a favor, could you possibly take down the sequence of the wiring to the mass air and give me a color code of the wiring i would be forever thankful. thanks again, steve

09-04-2008, 11:34 AM	#5 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 690 Thanks: 2 Thanked 41 Times in 38 Posts My Google Map iTrader Rating: (2/100% )	Ok Steve, This from Page FL-94 BGB and Electrical Manual. Left to right N/A fc e1 e2 vb vc vs tha " " " S/C " " " vc e2 " " Fc=green/red striped e1=brown (goes to "e" ground) e2=brown vb=black vc=lite blue/red striped vs=yellow/blue THA=yellow Hope this gets you some where. I understand your hesidensity in not opening the AFM, although, as long as the top is replaced with adequate sealant you have no future problems. Remember this equipment is 20+ years old, even aluminum will turn to white powder in the right conditions. Hope this helps, Tim Hurricane Central