symptons of a bad AFM?

From Tune Ups to Oil Changes, maintenance related

Moderator: toayoztan

symptons of a bad AFM?

Postby yamayuki98 » Sat Aug 05, 2006 6:46 pm

what are some of the symptons of a bad AFM? Does it always throw a code when the AFM goes bad. Reason i'm asking is a few months back my fuel pump died on me, and i replaced it with a Walbro 255, also replaced the Fuel Pump Relay...car won't start unless i bridge the fp/+b terminals...but when it does, it bogs a lot when cold and then dies when warmed...i thought that maybe the Walbro was pushing out to much fuel for my stock FPR, but then i just recently purchase a SARD adj. FPR and tried to adjust it...the car still acts the same...the car never acted like this before just incase anyone was wondering...if revved it keeps up rpm, but if set to idle it will die...all suggestions and advice are welcome...

PS: i'm not assuming that the AFM is the culprit at this point, its just something for me to think about...
Members don't see the above ad. Register now - it's free!
91' platinum silver celica alltrac
CA
yamayuki98
Club Member
 
Posts: 231
Joined: Wed Aug 11, 2004 10:11 pm
Location: Fresno, CA

Postby m_haiser » Sat Aug 05, 2006 9:06 pm

mine was doing kind of the same thing. make sure the afm is fully plugged in.
m_haiser
Club Member
 
Posts: 54
Joined: Mon May 22, 2006 2:25 am
Location: Washington

Postby RedCelicaTRD » Sat Aug 05, 2006 9:39 pm

The stock pump has a high voltage mode and a low voltage mode. The walbaro will only run in the high mode setting. Remove the fuel pump relay and bridge the correct terminals. You can find out which ones in the tuning section of the main page and then I think its under easy mods.

On a side note, you do have an st185 right?
Wayne
1990 All Trac
2017 SRT Challenger Hellcat
Grumpy Moderator
RedCelicaTRD
GTFour God
 
Posts: 3947
Joined: Sun Aug 08, 2004 6:58 pm
Location: Syracuse, UT

Postby Gary » Sun Aug 06, 2006 1:45 am

To answer the original question, here are some symptoms of bad AFM from my own experience with few different used damaged AFMs.
- Car starts, runs for a few seconds and and shut down, code 24, 31, 32 (check AFM plug)
- Car starts, run sluggish, code 31 (check AFM using ohmmeter)
- Car does not start, no engine light when key in "ON" position (check AFM using ohmmeter)
- AFM resistance are not in spec.
93 ST185
Image
Gary
GTFour God
 
Posts: 6430
Joined: Sun Aug 08, 2004 1:03 pm
Location: Carolina

Postby m_haiser » Sun Aug 06, 2006 2:04 am

Gary wrote:To answer the original question, here are some symptoms of bad AFM from my own experience with few different used damaged AFMs.
- Car starts, runs for a few seconds and and shut down, code 24, 31, 32 (check AFM plug)
- Car starts, run sluggish, code 31 (check AFM using ohmmeter)
- Car does not start, no engine light when key in "ON" position (check AFM using ohmmeter)
- AFM resistance are not in spec.


thats what mine was doing when the plug wasnt fully connected.
m_haiser
Club Member
 
Posts: 54
Joined: Mon May 22, 2006 2:25 am
Location: Washington

Postby yamayuki98 » Sun Aug 06, 2006 7:04 pm

just to let you guys know the walbro was actually running for about three weeks after my pump died, it wasn't until then that the relay gave out...replacing it did not help, so as of right now the AFM is out of the quesiton, i'm going to try and bridge the relay terminal...only one problem though, the fuel pump mod is not there anymore...it only show the fuel up mod...can someone who has done this mod tell me the correct color wire to bridge and the gauge size...thanks everyone for your help, i'll keep everyone updated
91' platinum silver celica alltrac
CA
yamayuki98
Club Member
 
Posts: 231
Joined: Wed Aug 11, 2004 10:11 pm
Location: Fresno, CA

Postby RedCelicaTRD » Sun Aug 06, 2006 9:27 pm

Use 10 gauge wire and bridge the bottom left and upper right terminals (if i remember correctly).
Wayne
1990 All Trac
2017 SRT Challenger Hellcat
Grumpy Moderator
RedCelicaTRD
GTFour God
 
Posts: 3947
Joined: Sun Aug 08, 2004 6:58 pm
Location: Syracuse, UT

Postby yamayuki98 » Tue Aug 08, 2006 12:10 am

okay, i tried it, still the same, try the other way still the same...i was over at the mr2 board and there was a topic that mention the open circuit relay..that i could have been burned out....could that cause the car to bogged..?
91' platinum silver celica alltrac
CA
yamayuki98
Club Member
 
Posts: 231
Joined: Wed Aug 11, 2004 10:11 pm
Location: Fresno, CA

Postby theUNYTEDone » Tue Aug 08, 2006 5:25 am

hey gary, how does one check for the resistance? is the the metal flap bit that does the measuring?
Nigel in Hawaii
From Hell and Back
User avatar
theUNYTEDone
GTFour God
 
Posts: 5085
Joined: Sun Jan 22, 2006 10:56 pm
Location: Kamo'ili'ili Town

Postby Conan » Tue Aug 08, 2006 6:56 am

theUNYTEDone wrote:hey gary, how does one check for the resistance? is the the metal flap bit that does the measuring?

:twisted: The resistance is measured in ohm using a special electronic device ;)
When in doubt - increase boost.
User avatar
Conan
Established Member
 
Posts: 2010
Joined: Sat Feb 19, 2005 10:38 am
Location: Lithuania

Postby theUNYTEDone » Tue Aug 08, 2006 8:25 am

...i knew that. :doh:

nah, but...i ALWAYS have a code 24, but wish not to tear into anything..
solveable just by getting another afm?
Nigel in Hawaii
From Hell and Back
User avatar
theUNYTEDone
GTFour God
 
Posts: 5085
Joined: Sun Jan 22, 2006 10:56 pm
Location: Kamo'ili'ili Town

Postby Gary » Tue Aug 08, 2006 12:16 pm

Code 24 is the air temp sensor in the afm.
It's the white plastic thingy in front of the flap.
I'm not sure if you can swap it with another one from another AFM.
You might need a new AFM.

Here is how you check the resistance using ohmmeter.
Make sure you remove the plug first.
Then measure the resistance at the AFM, not the harness.
Image

You can also check the AFM voltage with voltmeter while it is being connected to the harness.
Use the following procedure.
It's easier to do this on the ECU side.
Test is done in three stages,

1. With ignition switch on,
VC-E2 = 4.5-5.5 V
AFM Flap fully closed, VS-E2 = 3.7-4.3 V
AFM Flap fully open, VS-E2 = 0.2-0.5 V

2. At idle,
VS-E2 = 1.6-4.1 V

3. At 3000 rpm
VS-E2 = 1.0-2.0 V

If the voltage readings are not in the range, you might have either bad AFM or ECU
93 ST185
Image
Gary
GTFour God
 
Posts: 6430
Joined: Sun Aug 08, 2004 1:03 pm
Location: Carolina

Postby mison » Fri Aug 11, 2006 7:26 am

Gary:

In a book I have is writen: Perform all voltage measurements with the connectors disconected.

How I may measure some volts if I unplug connectors..?
mison
Club Member
 
Posts: 80
Joined: Mon Jan 16, 2006 11:38 am

Postby Gary » Sat Aug 12, 2006 12:09 am

mison wrote:Gary:

In a book I have is writen: Perform all voltage measurements with the connectors disconected.

How I may measure some volts if I unplug connectors..?


That's weird.
Mine is opposite. :shrug:

Image
93 ST185
Image
Gary
GTFour God
 
Posts: 6430
Joined: Sun Aug 08, 2004 1:03 pm
Location: Carolina

Postby mison » Thu Sep 14, 2006 7:30 am

Image

:D
mison
Club Member
 
Posts: 80
Joined: Mon Jan 16, 2006 11:38 am

Next

Return to General Maintenance and Repair

Who is online

Users browsing this forum: Bing [Bot] and 3 guests