Topic: Code 31, what can cause it?

[Zoomschwortz]

I changed out AFM's on my 89 because it wouldn't turn on my fuel pump.

I installed a re manufactured AFM yesterday and the fuel pump now works, but, it runs like  and kicked out a code 31.

I don't have my manual with me right now, but it said something about shorted circuits in the AFM.

I have never had this code before. What are the odds that I received a bad AFM?

Is there a chance that something else is wrong and if so, what?

Thanks
Ken

[fordh8r]

could it be that the old AFM caused the code and now the light is on since it runs now? Had you cleared codes since changing the AFM? 

[*FFC*]

Had you cleared codes since changing the AFM? 

Good point!

Oh check yer PM's Zoom

[Zoomschwortz [OP]]

could it be that the old AFM caused the code and now the light is on since it runs now? Had you cleared codes since changing the AFM? 

I had the battery out of the truck for 2 months while I was rebuilding my engine, so the memory was clear. When the fuel pump wouldn't work unless I jumpered it, I checked for codes and there were none. After going through the wiring diagrams in the Toyota service manual, I came to the conclusion that the problem was coming from the AFM or ECU, so I bought an AFM. When I installed the new AFM, the fuel pump started working, but, it now ran like c**p so I checked for codes and got the 31. I cleared it, restarted the engine and got the same problem and same code.

After reading the diagnostic codes in the service manual, (which is at home right now and I'm at work) it talked about a shorted circuit and listed the different posts on the AFM.

I at first thought that it has to be a short in the new AFM, but, the more I get thinking about it, it could possibly mean a short in the wiring too, couldn't it?

I never got this code before and luckily, Shucks is replacing it, no questons asked, but it won't be here until tomorrow afternoon and now I'm wondering what I will do if I have the same problem again. I would hate to have it turn out that there is a problem with the truck that is damaging the AFM.

Thank you for the input.
Ken

[fordh8r]

I at first thought that it has to be a short in the new AFM, but, the more I get thinking about it, it could possibly mean a short in the wiring too, couldn't it?

  very possible. check all possible areas for damage. I.E. pinched, burned, chafed and the like. If no visible signs of damage are evident then maybe err on the safe side and do a pin check at the AFM connector for proper voltages and grounds before you connect the new AFM. Hopefully something is noticeable to repair or you'll just cringe with hope that the new AFM will fix it only to be sure by firing it up. What have you got to lose? Hope you find it. 

[*FFC*]

Not sure if it'll help, but you got an email

[jimbo74]

my friend had a code 31.... we couldnt figure it out, his truck would run fine, then run like crap, then would be unpredictable and fine again.....

he ended up taking his truck to a specialist, and hte specialist found that somehow, a harness got cut/frayed (was wierd since it sat in his driveway all the time) we did do some work on the truck while sitting, but nothing that would have caused the problem) so anyways, the specialist soldered the lines back together, and his truck ran perfect again..... it was the harness that went to his afm that made the truck run bad....

[Zoomschwortz [OP]]

my friend had a code 31.... we couldnt figure it out, his truck would run fine, then run like crap, then would be unpredictable and fine again.....

he ended up taking his truck to a specialist, and hte specialist found that somehow, a harness got cut/frayed (was wierd since it sat in his driveway all the time) we did do some work on the truck while sitting, but nothing that would have caused the problem) so anyways, the specialist soldered the lines back together, and his truck ran perfect again..... it was the harness that went to his afm that made the truck run bad....

Thank you for the information.

I'm going to do some tests before I plug the new AFM in tonight using the information that FordFreakChik sent me.

Thanks again everyone.
Ken

[*FFC*]

Thank you for the information.

I'm going to do some tests before I plug the new AFM in tonight using the information that FordFreakChik sent me.

Thanks again everyone.
Ken

Keep us posted, I wanna know if it works for yah!

[Zoomschwortz [OP]]

I got the new AFM last night and checked it with an ohm meter before installing it. It checked out alright and after installing it, it runs great.

Took it out for a drive in the hills around here and now have a total of 60 miles on the engine. Life is good

Thanks for your help.
Ken

[fordh8r]

Awesome!  So it turned to be just the AFM? No wirng probs? Still, it's good feeling when something finally turns out right.     Especially after all the worry of "WHAT IF...?".      

[Zoomschwortz [OP]]

Awesome!  So it turned to be just the AFM? No wirng probs? Still, it's good feeling when something finally turns out right.     Especially after all the worry of "WHAT IF...?".      

Your right, but, I still have one more what if, and only time will tell.

When I fired up the engine to break in the cam, the person that was watching the gauges inside of the truck got a little lax after 15 or 20 minutes and didn't notice the temperature rising and I didn't know that the fuse for the electric fan had blown.

To make a long story short, it started blowing water into the overflow, so I'm concerned about possible HG and warpage problems, but so far no milkshakes, oil slicks, or waterfall coming out of the tail pipe.

Thanks again and take care.
Ken

[fordh8r]

the person that was watching the gauges inside of the truck got a little lax after 15 or 20 minutes and didn't notice the temperature rising and I didn't know that the fuse for the electric fan had blown.

First,  then  and then  bust mostly  . I hope for the best for ya!