Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
MAF
Author Message
jasonporter181 Offline
Member
***

Posts: 18
Joined: Apr 2008
Reputation: 0
Post: #1
MAF
I have a question about my MAF if anyone can help.

According to my Hayes manuel, I have a MAF sensor w/ a heated wire that changes resistance as air flows across it. It has 3 wires; B+, signal+ and signal-.

How should I hook up my resistor to the sensor? And also, I would like to put a pot on instead of a resistor to adjust on the fly.

Thanks
05-19-2008 11:21 AM
Find all posts by this user Quote this message in a reply
colchiro Offline
Moderator
*****

Posts: 3,265
Joined: Feb 2008
Reputation: 11
Post: #2
RE: MAF
Jason, have you read Tuning for Mileage?

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
05-19-2008 03:02 PM
Find all posts by this user Quote this message in a reply
jasonporter181 Offline
Member
***

Posts: 18
Joined: Apr 2008
Reputation: 0
Post: #3
RE: MAF
Yes I read tuning for mileage. I just wanted a little clarity. I installed 25ohm pot in seires with the signal - and when I barely turn the pot, the car starts to idle very rough. I disconnected the pot and tried a 10ohm resistor instead of the pot, to see if it had to do with the pot, and the car would barely run.

I wanted to make sure I am installing this correctly and I need way less resistance or/and that I am correct in assuming I have a frequency based MAF. Or am I missing somthing all together? Thanks
05-19-2008 07:56 PM
Find all posts by this user Quote this message in a reply
colchiro Offline
Moderator
*****

Posts: 3,265
Joined: Feb 2008
Reputation: 11
Post: #4
RE: MAF
Jason, I had similar results with my Toyota's MAF. A resistor in series with the ground doesn't work for me, even a 7 ohm.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
05-20-2008 02:36 PM
Find all posts by this user Quote this message in a reply
Atfab Offline
Member
***

Posts: 124
Joined: May 2008
Reputation: 0
Post: #5
RE: MAF
Try a 5K or 10K pot, you may be drawing off too much current.

atfab

Atfab
99 S-10 Pickup 2.2L auto, Std cab, Short bed, Alum cap
Stock, Ave. 25.5 MPH
05-21-2008 06:57 AM
Find all posts by this user Quote this message in a reply
jasonporter181 Offline
Member
***

Posts: 18
Joined: Apr 2008
Reputation: 0
Post: #6
RE: MAF
Atfab, I put the 25ohm pot in series. 5k would be alot more resistance. Should I try to drain some off to ground off the signal- or should I put a pot in paralell between signal +&-?
05-21-2008 08:37 AM
Find all posts by this user Quote this message in a reply
jasonporter181 Offline
Member
***

Posts: 18
Joined: Apr 2008
Reputation: 0
Post: #7
RE: MAF
I have got everything else hooked up except the MAF on my vehicle and want to do some extensive testing. Can somone please help me out with this MAF adjustment problem so I can proceed with my tests. thanks
05-22-2008 06:39 AM
Find all posts by this user Quote this message in a reply
hhosurfer Offline
Member
***

Posts: 30
Joined: Apr 2008
Reputation: 0
Post: #8
RE: MAF
You need to see a voltage meter on hte signal wire and find out what it is doing. Then you can see why the idle goes ruff.

Put the resistor in line on hte ground wire will increase the volts on the signal wire.

You should only need to increase the signal by millivolts. I have mine with 5ohms yes ohms not K ohms.

When you cut the ground wire you should see the signal wire increase to 12v.

You only need a little for it to work.
05-22-2008 11:24 AM
Find all posts by this user Quote this message in a reply
jasonporter181 Offline
Member
***

Posts: 18
Joined: Apr 2008
Reputation: 0
Post: #9
RE: MAF
ok, thanks, I'll try that and let you know the outcome.
05-22-2008 02:02 PM
Find all posts by this user Quote this message in a reply
Atfab Offline
Member
***

Posts: 124
Joined: May 2008
Reputation: 0
Post: #10
RE: MAF
hhosurfer Wrote:You need to see a voltage meter on hte signal wire and find out what it is doing. Then you can see why the idle goes ruff.

Put the resistor in line on hte ground wire will increase the volts on the signal wire.

You should only need to increase the signal by millivolts. I have mine with 5ohms yes ohms not K ohms.

When you cut the ground wire you should see the signal wire increase to 12v.

You only need a little for it to work.

Gee, I must be stupid, Tuning for milege says you want to lower the output. (with a note that some Fords might need to raise it)

Yes K ohms is not recomended, my bad, I seldom have need for low ohm pots in my work. A 50 ohm pot would be ok.

Hook it up back to normal, run the car and measure the voltage on the OUTPUT wire to the ground. Connect your pot in series on the ground wire, use only the center and ONE outside terminal and turn the pot so it measures as close to zero ohms as possible. Start the car, hook your meter back up as before , slowly turn the pot, by very small amounts to lower the output voltage by no more than needed to make it just start to stumble(take your time, the computer may not respond quickly, read the output volts. Set the pot back to half the voltage between normal and stumble. Shut the car off, see if it will restart, if so drive it a while, check mileage (at least 1/2 a tank).
Fine tune from there.

If it won't start, turn the pot for 1/2 the volts from where it is now towards normal volts, retry. Some cars will require another approach if you can't get it to start at all.

atfab

Atfab
99 S-10 Pickup 2.2L auto, Std cab, Short bed, Alum cap
Stock, Ave. 25.5 MPH
(This post was last modified: 05-24-2008 04:29 AM by Atfab.)
05-24-2008 04:20 AM
Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)