Error Code: 31

[suprflyusmc1]

So I bought a 1990 Turbo Supra w/ 180k miles on it.

When I bought it, I was getting 2 different codes.

The first was a knock sensor code. I fixed it.

The second was a code for the water temperature sensor. I fixed that as well.

Now with the car together, I am getting an error code 31.

I have done the diagnostic test on the AFM (http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=96) and it passes w/ about 2700 at 70 degrees Fahrenheit. I'm pretty sure my vacuum system is good to go, as i've referenced it multiple times and done tracing.

What happens is this: The engine idles like crap, and it runs very rich. Soot is shooting out the back of the car mixed w/ condensation. If the AFM passes the diagnostic test, what else could it be?

is it possible that the engine is poorly timed causing the the code to come up because the engine can't adjust the timing properly? (Say one of the cams was put in improperly?)

I've read a few articles about 31 and I don't feel any of them are like this.

Thanks,

Martin

 

[BoostedFloto]

if there is a code 31...the afm is the problem. PERIOD. replace with knowing working one or make sure its plugged in

 

[suprflyusmc1]

if there is a code 31...the afm is the problem. PERIOD. replace with knowing working one or make sure its plugged in

Ok, well the problem is according to the diagnostic test on my first post, it is a properly functioning AFM. Yes I made sure it was plugged, as well as checking that the plug that plugs into the AFM is in good condition. I'll have to find/order one.

 

[plaaya69]

Check the wiring harness that runs on top of the valve covers behind the timming cover infront of the coil cover. You may have a burnt wire. That is what I had on my old motor. I just replacd the harness on that motor.

 

[suprflyusmc1]

Check the wiring harness that runs on top of the valve covers behind the timming cover infront of the coil cover. You may have a burnt wire. That is what I had on my old motor. I just replacd the harness on that motor.

Good call I'll check that out tommorow.

 

[BoostedFloto]

Ok, well the problem is according to the diagnostic test on my first post, it is a properly functioning AFM. Yes I made sure it was plugged, as well as checking that the plug that plugs into the AFM is in good condition. I'll have to find/order one.

that test doesnt test the afm...it tests the iat sensor inside the afm...

again its the afm... change it out and done with it.