Good afternoon everyone hope all is well. 2014 Jeep Grand Cherokee Laredo with the V6 cheers to over 200,600 miles and still counting. It was Tuesday I installed a throttle body spacer along with an 80mm throttle body at which I noticed after installation I let it idle for a few minutes and came back to see the check engine light was off. I've travelled over 100 miles as that's usually when the check engine light would come back on for evap codes but surprisingly still hasn't come back on and its been five days. What was it about installation of the two parts it killed the evap codes for good? I find it quite interesting honestly.
@imperator It was throwing Code P0440, P0442, P0455, P0456
ok what is their meaning?
@imperator P0440 code is an OBD-II code that indicates a malfunction in a vehicle's evaporative emission control system, P0442 is a diagnostic trouble code that indicates a small leak in the evaporative emission control system, P0455 indicates a large leak in the EVAP system, and P0456 indicates a small leak in a vehicle's evaporative emissions system
The EVAP system uses vacuum from your engine intake to extract and burn gasoline vapors.
It's possible that when you worked on your throttle body, you re-seated a vacuum line that was loose before. Time will tell.
What is this spacer supposed to do?
@imperator Perhaps I did I'm just having a hard time remembering lolz. and the spacer increases space between the throttle body and the intake manifold which allows more air to flow into the engine.
how does it allow more air?
@imperator lengthens the intake
well that's probably going to increase throttle delay and reduce manifold vacuum (which could be affecting the evap system). The engine was tuned and engineered to run a certain way. Best not to mess with it if you don't know what you're doing. Cars with tuned intakes are able to adapt intake length to the load, so your spacer might actually be hurting you more than helping.
if you do a bit of research and look at dyno test results, spacers are pretty much snake oil. It might have made a difference back when we had carburetted engines.
@imperator sorry for the late response but makes sense.
Obviously whatever you did reduced or eliminated evap system leakage. (Presumably you dealt with evap hoses when installing that junk.) Have you checked to see if there are pending codes?
@chucktobias I did
@chucktobias I did, there were none
Obviously you changed something that affected the evap system, even if inadvertently. There really is no other possibility since we're not dealing with some kind of magic here. Hopefully that aftermarket crap won't cause you more serious problems down the road. You also have not said anything about whether there are pending codes.
@chucktobias No pending codes