so i just bought an evo, and the guy i bought it off of put in a apexi s-afc2 controller... me being stupid i dinked around with the settings the moment i bought it... car ran like crap ever since! ... at one point i had all the settings in good by messing with it... check engine light came off by itself and everything was good until today where it just came on again for no reason... so i unplugged the s-afc... and the car is running crappy CEL is still on... idles at 1600.... took it to auto parts store pulled the codes got two codes (technically i got 4 but it pulled 2 of each).... i forgot what the codes were but one was for the Mass Air Flow sensor and the other one said something about O2 Heating?... i pulled the codes after i hooked the safc back on thinking i could mess with the settings and maybe get it running decently.... ahhhhhhhhhh.... its driving me nuts! any suggestions?... do i just go buy a new MAF? i dont wanna be throwing away money for a part i might not need....

 

Bump For Help

 

I don't think your MAF is at fault likely though the wire for the MAF is tapped into by the controller's harness. Its been awhile since I looked at the wiring diagram for a S-AFC but i'm positive that there is a way to bypass it with a plug of some sort.

One thing is for sure you should dig into the wiring harness and wire the car back up to stock and see if she runs right.

 

well i disconnected the SAFC completely... i guess the guy had it done right and had a plug basically where u could disconnect it.. so shouldnt that have set it back to stock? since the wires werent going anywhere even if they were tapped into?

 

So you have the plug then?

Yeah that should have fixed it but without checking the wiring you can't be sure.

 

where would i check the wiring? sorry total newb when it comes to stuff like this... (last car i messed with was a 00 civic si.. and you can take that whole car apart with a screw driver and a 10mm socket wrench.. lol no joke).. and if the wiring does check out.. is there any way i can check if the MAF is good? just by taking it out and looking it over or... either way thanks for your help!!! greatly appreciated!!!!!

 

check your fuel pump there is one rubber seal which is put wrong

 

Well the wiring its tapped into is the ECU harness which is under and behind the glovebox. To check if the maf is really good the easiest way would be to plug it into another evo if you can't do that I could probably ohm out the pins for you on my car.

Good luck.

 

oh yeah sorry! i do have the plug!

 

speaking of that i should have mentioned that!... i did take the ecu out... spliced wires.. and i was thinking it was from the turbo timer.. there was one wire that did consern me since it wasnt hooked into anything and it was just kinda sitting there.. i thought it was really strange!...

 

Find a shop that tunes EVO's and get it tuned properly, that should solve your problem.

 

Well looks like you need to bust out the ole wiring diagram and figure out what it really is.

http://www.roadraceengineering.com/e...-ecuwiring.htm

I think they label it volume airflow sensor so pin 90

 

ill have to look into that when i get home.. at work right now doubt im even supposed to be looking at any non work related sites but oh well... thanks for all your help ill let you know how it goes.. thanks again!

-as for taking it to a shop... closest one is 3 hours away.. and i rather just get the stock settings back.. (i hope thats possible without a tune??)..

 

Check your MAF plug, and reset your ECU by disconnecting battery or removing fuse (ENGINE LOGO, underhood fuse panel in front of battery, it's the 20amp closest to the front of the car). Anytime you disconnect the MAF the ECU needs to recalibrate the MAF.

After resetting the ECU, start the car and let it idle for 5 minutes and then drive it easy for a few miles.

Get rid of the SAFC and get a ECU Flash tune. Why is it on the car in the first place (what mods does the car have)?

 

why do you think that?