Im doing some work for a friend, im doing a knock sensor, fuel filter, pcv valve, some basic stuff, however when i took the tb off i noticed the Butterfly valve does not sit flat, its ALWAYS opened, and i cannot get it to close fully. I was looking at the screws some one was definatly playing with them, the problem is i cant get the butterfly valve to sit flush. Its a little bit better than it was but not a great improvement since i adjusted the screws. Anything i can do, i told my friend to get at a untampered tb at teh junk yard.

 

the tb butterfly doesnt sit flat... if it did the car would not start due to lack of air...thats like someone stuffing your nose and tell you to breath

 

Yea, that whole IACV thing is just there for looks...

Actually it is just like your example above, because you still have a mouth to breathe through...

 

rofl @ pmohr, that was teh funney! To the OP, ya either have to adjust it, or get a junk one if you're uncomfortable with doing that.

The TB being slightly open preobably messes with his shifting too. Not that the TPS is off, but it reads a slightly open throttle @ all times. (that can't be too good)

 

The throttle plate will always be slightly open with the engine cold. This is due to the cold idle feature located underneath the throttle body. It uses engine coolant to move the cam lever on the LH side of the assembly. When the engine is fully warmed up, the plunger will fully extend causing the plate to close more fully, lowering the idle speed.

 

riiiiiiight.....you're talking about the fast idle cam? (that little plunger thingy)

 

Yes, and to position the initial setting on the TPS, the engine should be warm. Otherwise, the fast idle cam will be opening the throttle plate.

 

KOOEL! But in the OPs case, having those screws mess with the position isn't good, right?

 

No, it's not good. That screw isn't normally meant to be adjusted. To do so throws off the entire TPS/cold start setting. It can be re-adjusted if moved however.

 

I honestly dont think its going to be much of an issue unless he is getting really funny cold and hot idle rpms, just find the values for the stock idle rpms and if its in those range it shouldn't be a big deal. Im not sure if the Maxima ECU recalibrates the TPS at all but when i ran custom Injection on my last car moving the idle screw stop barely registered on my tps (maybe a max of 2-3%) and recalibrating the tps after changing the idle stop position really didnt seem to effect my performance or idle. Im not sure about the maxima's fuel system but most systems rely on rpm and MAF for the majority of their fuel mapping so position of idle screw is not necessarily key.

the only negative thing i can see in this situation is that whoever adjusted it, did it to cover up some other problem causing a low idle which could be almost anything fuel/spark/compression related.

just my 2 cents