I just installed a cold air kit on my 2008 H3. I also cleaned the throttle body with CRC throttle body cleaner and gave the Mass Air Flow sensor a good cleaning with the CRC MAS cleaning product. The H3 idles and runs great but the check engine light came on. I disconnected the battery for an hour, restarted the car and the check engine light was off. Then I drove it to work and on the way, the freeking check engine light came back on. After looking everything over, could the cause be the one hose from the evap can that is not going back into the air intake? I did some searching for old posts concerning this issue but I did not find anything. Any ideas, fixes or suggestions would be a great help. I was wondering if I should cut into the cold air system piping and route that hose from the evap can into the intake system.

 

You need to tell us what code the OBDII is throwing. If you don't have a code reader go to your local auto parts store and have them read the code and give you the # of the code. Can't help ya without a code.

 

If you didn't connect the small black rubber hose at rear upper bout of engine you're gonna get a error.

 

i follow 2 jeep forums and here. 90 % of problems come when going from perfect stock stuff to new and improved mods,,,with very few improvements,,,just saying. my stock stuff is trbl free.

 

I am getting a P0171 error code. "Bank one system too lean". Any suggestions? Will the computer eventually adjust to the improved air flow?

 

I suspect that the issue might be related to the evap fuel canister hose which is not connected to the intake anymore. I am wondering if I should mod the intake piping on the cold air system and connect the hose from the evap canister past the mass air sensor (closer to the intake). Perhaps that is tripping the error code.

 

OK, no suggestions? I just put the stock system back on. Hopefully the check engine light will not return.

 

You bought the wrong intake for your truck.

An aftermarket air intake will cause a CEL when there is a leak downstream from the MAF, and on the 2008+ they were designed with the EVAP system tapped into the Air Filter box. When you remove the Air Filter Box and open up the EVAP connection, that can also lead to your issue.

If you were to use a closed performance intake system, instead of an open K&N type system, no CELs.

 

it seems that the computer would maintain the air/fuel ratio of the mixture to be the same as it was when it left the factory regardless of mods.

 

OK Doc Olds, here is a photo of the installation. You will notice that the hose from the evap can is not routed to anything. I suspect that is what is triggering the CEL. The other hose from the manifold that connects to the underside of the stock box (marked Vortex) is properly connected. I am wondering if I run a new hose from the evap can to a fitting I would install in the black Vortex box, if that would suck whatever from the evap can and not cause the check engine light to come on (and the P0171 code). What do you think about that as a work-around?