Possible AFM problems?

MK3Brent

MK3Brent

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I just developed a serious problem with the 7M running.
It started yesterday when I removed all the IC pipes to flare the ends.

Since I am so used to taking everything off, I forgot to disconnect the harness to the afm. I noticed this of course when I went to pull the intake away, I felt resistance. (It wasn't hard or anything, just a tug.)

When I came home to install the pipes, the car started and ran fine.
It was after a 10psi pull that I noticed the air fuel ratios beginning to go sporadic.

Check codes : 24 (air temp)
Thinking it might have been the sensor, I replaced it.
Didn't help.

I then pulled back the wiring harness on the AFM and noticed the blue and red wire had broke. I crimped it back together, yet the car still won't drive at a reasonable AFR. 19's or higher :(

No codes are popping up.
What else do you think it could be?
 
G

gixxer750

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MK3Brent said:
I then pulled back the wiring harness on the AFM and noticed the blue and red wire had broke. I crimped it back together, yet the car still won't drive at a reasonable AFR. 19's or higher :(
Click to expand...


There is your problem. Solder FTW...
 
G

gixxer750

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Yes, huge difference. With a signal wire, you never want a crimp. A vibration can cause variations in resistance or just a plain bad connection.
 
MK3Brent

MK3Brent

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Okay,

To test, I just took the wires and wrapped them tightly together and tapped.
I'll be getting the iron in a minute.

But to see if the crimp had any change or not I tried this.

Still no difference... :(
 
G

gixxer750

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thats too high.... I get around 30hz at a 900 RPM idle.... so it's probably running rich at idle I would assume. How do the readings change as load and throttle is applied to the engine?
 
MK3Brent

MK3Brent

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I just came back from driving it. (Note I haven't soldered it yet.)

And it seemed to be driving normally, except for idle. (Idle was rich.) **Maybe one of my IC couplers isn't sealing, I'll check them.)

I'll post back after I solder up the wire. :)

Would a high Hz reading also be because I have a 66mm wheel before the AFM?
 
G

gixxer750

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Check continuity between each AFM wire and the ECU.... Especially the last one toward front of car.... AFM ground... It could also be something else.

You say you have the turbo before the AFM.... like, stock AFM in blowthrough?
 
MK3Brent

MK3Brent

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10:1 idle... then if you slightly press the throttle, it goes to 19:1.

This sure is a fun one.
I think I've narrowed it down to the sensors I have.
One sensor idles like complete crap, and the other seems to idle a lot better but still not the way it should.

Next in order will be a confirmed GOOD sensor to try.
 
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gixxer750

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No, you won't still get contact between AFM and ECU with the safc wired in unless the AFC is turned on. But, I would check all the other wires other than the signal wire. That thing has what.... 5 wires? Check all those, and then check where signal goes into the SAFC. I don't think you have two bad sensors. Are the karman readings going up any when you apply throttle, or staying steady?
 
MK3Brent

MK3Brent

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blackout_89t said:
Stock ecu/afm FTL! :biglaugh:

Time for a real EMS
Click to expand...
I said the same thing.

A good deal came across for a VPC, but I decided if I was going to get anything it would be the maft-pro.

This sucks though, I can't do anything till I get my paws on a multimeter.
 
MK3Brent

MK3Brent

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Aug 1, 2005
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Greensboro and Greenville NC
I've tried that too.

I just did a resistance test with both sensors.
1.62 (on the original sensor)
1.69 (on the second spare sensor)

Which should be about right. :(


*I suppose I should pull a lot of electrical tape and shielding away from the main harness and inspect it all for damage.*
 
Nick M

Nick M

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gixxer750 said:
Yes, huge difference. With a signal wire, you never want a crimp. A vibration can cause variations in resistance or just a plain bad connection.
Click to expand...
Toyota says to crimp the connection, then fill with solder. That doesn't mean a cheap butt connector obviously.

The best way to check the airflow meter is by looking at an 87 and an 89. Off the top of my head, I don't know if there are small differences or not. The plug could be slightly damaged from the light tug. I have seen it before also.
 
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