Ive always wondered ever since i got my Max what this thing does for the car. Even before i changed the intake, i always noticed this sensor attached to the side of the ram labeled "hitachi boost sensor." I know the Japan spec model maximas have a sport mode but i doubt that relates to this "boost sensor". Any ideas what this is or does?

 

It's more common name is MAP (Manifold Absolute Pressure) sensor. On the Maxi it is used to sense ambient pressure and is used by the ECM to determine basically the altitude of the car and the ECM uses this (along with coolant temp) primarily to adjust/determine the start mixture. Located on the '00s on the stock intake as noted, and under the instrument panel fairly close to the ECM on '01 and later cars. MAP or manifold pressure (the pressure in the intake downstream of the throttle) was used primarily before the common use of the MAF as the main parameter or driver used by the ECM to determine fuel delivery. My '92 Beretta was an example and from a maintenance point of view the MAP was bullet proof and of course it did not have any of the issues that we all know about with MAFs. You could use a K&N filter with no worries at all. The MAF system was actually used by at least some manufacturers before the MAP system but the MAF was a PITA (too delicate) at that time and for a period afterwards they used MAP. MAF systems came back and I believe have become standard because the system can determine more accurately the amount of oxygen that is in the intake air, which makes it better for controlling emissions.

 

Currently I have a pop charger w/ an adapter plate (& MAF). Its funny you mentioned K&N because i was planning on getting a K&N cone filter this week because im tired of the one i have now..what are the benefits to K&N as opposed to any other filter? Also is it detrimental to the cars performance not having that sensor operational? Are there any risks?

 

This is a required sensor for the reason that I stated, so you cannot remove/disable it. If you want to relocate it fine, but it has to be operational or the ECM will set a code and put on the SES light. Any oil type filter (particularly an "over oiled" one) such as the K&N can contaminate the MAF and cause engine performance issues.

 

how would i go about relocating it? right now its just connected like it was on the ram but not connected to the side of the ram itself.

 

It's installed on the stock intake but it could be located anywhere within the reach of the electrical harness. The pressure sense hose originates at the intake ducting between the air filter housing and the intake flex duct section. I think it tees into that hose that is also shared with the VIAS control solenoid. I believe it may have been located up high so there is no chance of water (from condensation in the hose?) from ever being able to reach it. Keep that in mind.