code 31 boost leak or AFM

[slowsupra89]

i recently added a large spearco replica intercooler and 2.5 hard pipes, rerouted throught the headlight hole instead of the fender, and car ran like crap for the first few miles then after about 150 miles i now have code 31 can it be boost leaks or can code 31 only mean the afm is bad.

my other mods are 3 inch elbow, dp exhuast and k&n filter, only happened after my intercooler change, i just dont know why its doing it it was running fine, i also have compresoor surge at 4psi and up with the new pipes and stock bov is can there now be too much volume for the stock bov.

 

[gaboonviper85]

Sounds like oil from the k&n filter fucked your afm...and possible boost leaks

 

[black91turbo]

Your car will run like crap as long as you have a code 31 (unless you go speed density) Try another AFM....

 

[black91turbo]

Your car will run like crap as long as you have a code 31 (unless you go speed density) Try another AFM....

Try running an aftermarket BOV and reroute back into the intake pipe.....although the stock BPV should be able to handle stock boost without problem....

 

[grimreaper]

You can test the afm KS signal very easily.

 

[blk92suprat]

process of emilination...

Check afm signal
Check all couplers for leaks
aftermarket bov for added safety/peace of mind

 

[slowsupra89]

i dont know anyone else with a mk3 so i have to test the afm and i dont have a multimeter right now. just to make sure though will a boost leak trip a code 31?

 

[slowsupra89]

i think the afm is bad, its weired though the cel only comes on when decellereating if im cruising at highway speeds or accelerating the light wont come on and the car drives good but once i let the rpms drop or come to a stop the light is back on, anyone have a afm for sale?

 

[Wills7MGTE]

I had same problem a while back, afm was fucked from K&N oil, I have a new AFM now and the K&N isn't as oily now so it should be fine I have had the new AFM for a year no issues. At the same time I had a boost leak which I resolved by replacing couplers with silicon ones on my custom hardpipe setup we did. I also run an HKS SSQV on my auto if you have a stick you'd need to recirculate it, the venting doesn't bother my auto much LOL

 

[SupraKingz]

my valve cover is leaking really bad when i do boost leak test could this possibly be causing my code 31 on my 1jz because i'm pretty sure they dont have afm's.

 

[grimreaper]

how are you pressurizing the crank case (and head) from a boost leak test?. im guessing you left the pcv hose attached to the intake and stuck the tester on.

 

[SupraKingz]

I removed the air filter stuck the pressurizing kit on it and pumped it up and it started to leak really bad from the valve cover and two of the I/C piping couplers. And there is a hose attached cirectly to the valve covers from the intake piping so that how it also got pressured.

 

[SupraKingz]

pic of the intake hose attached to valve cover

 

[grimreaper]

Take that hose off next time. Your going to push your seals out.

other then that i cant see how a vac leak would cause that code. I would ask the 1J guys.