CardShark

I'm having knocking problems after swapping the stock MDP sensor for a AEM 3.5 Bar MAP in my '06 Evo IX.

I've searched but can't find the answer....what exactly does the MDP sensor in a US Evo IX do? Does removing/replacing it make the EGR do anything funny?

I read multiple accounts of people swapping the MDP sensor out to a JDM, Omni, or AEM MAP, without any mention of ill effects so perhaps it is just coincidence

The only thing that has changed from no knock (1 count) to lots of knock (2-9) is:

1. Re-torqued ARP head studs and cam caps (obviously this is not the problem but maybe something I removed/re-installed in the process?)

2. Cut MDP wiring and installed AEM 3.5 bar map sensor

Nothing seems to have changed in my AF ratios or load, and the timing is actually lower in the logs where I'm knocking since it is being pulled. I'm really puzzled.

gkania

iTrader: (6)

You can't just cut out sensors and swap in whatever you want. The ECU uses it for a reason. Now your AFR is all screwed up and its causing knock. Put the sensor back or get the car pro tuned by an Evo specialist.

CardShark

While I appreciate the post...this is entirely false. There is plenty of sensors in this car and in every car that you can just be wholesale eliminated without any ill effects....mostly related to emissions crap. Coming from the DSM world, the MDP sensor in a 2G can be removed without any ill effects since all it does is monitor EGR Function. The rear O2 sensor is also completely useless from a performance standpoint since all it does is monitor catalytic converter function.

In addition, there is nothing wrong with my AF ratio (or atleast is not the cause of the new knock). It is perfectly stable, going from a 11.8 slowly tapering to about 11.3 at redline. This has remained unchanged from no knock to knock.

R18eclipse

gkania: Swapping out the sensor incorrectly isnt going to screw up his AFR's

I think what is happening here is the the EGR function is all over the place and the valve is possibly opening under WOT. If so, that could cause hot Exhaust gases to enter into the intake path. i do not think California 91 octane would like that very much and would **** it off???

Just a guess....

Ron