Just thought I would mention this for brief discussion. See what some of you guys thought. Now, I installed the JDM Map sensor quite some time ago. Using the commonly available instructions for it. (96940011)

Immediately after installing it & flashing the car with the new tables etc... I noticed a bit of a change in the way the car drives. Almost like an increase in engine braking when off throttle. Acceleration seemed less touchy, smoother - but at the same time this is all transient stuff probably the same as going from one evo to another.

Now, I just installed a new clutch. So while I was in there, everything that didn't NEED to be on the car - well left. Like the entire mess of vacuum lines and misc emissions crap and all the brackets associated with them. I stumbled over to the pile of DSM parts while I was doing it and decided to block the EGR while I was at it.

Car drives / feels 100x better. Its not even close. Part throttle, full throttle... everything is smoother / cleaner. I wonder if some how the values for the EGR associated with the JDM map install are fudged, causing it to open when its not supposed to. Or maybe mine were? I have also seen a significant drop in knock all over. ( I'm running pretty close to the edge of reason - close enough a sharp change in weather can make it knock a bit.)

I know alot of this is a matter of interpretation; but just thought I'd open it for discussion. See what you guys thought. I would attribute a driveability change mostly to an EGR problem. I can't see the evap making a significant enough change even if malfunctioning that you would notice.

I know I just changed the clutch, but I changed it previous to melting it down. So I wasn't having terrible trouble with it making this a harsh contrast to how the car was / versus now. Don't get me wrong, the changes in clutch feel, etc are noted and great.

 

Any chance you had a big boost leak from the EGR or related equipment? Just a thought?

 

I would agree its possible - it is unlikely as none of those lines came off in any friendly kind of manner. Everything I pulled seemed awfully sealed.

I am also speed density - so boost leaks don't really effect me in the way they do a stock MAF evo.

But the change to the JDM map / and tables was an instant change. Something I noticed the second I flashed it and drove it. It never seemed right since then. I got used to it. Put the MAFT Pro on speed density... tuned the car to its limit. Probably put a few thousand miles on it - and just assumed it was going to be that way from that point forward.

Took the emissions stuff off / blocked the EGR - and its better than it was previous to the change.

All the solenoids are still plugged in with no lines attatched. I have no CEL either.

I have boost leak tested the car previous to; and after that change with no leaks.
I've blown off the bov line and at a T fitting once or twice. But nothing since.

Just looking for a few thoughts. Nothing huge.

 

I've said it many times before in other threads... the MAP sensor does not in any way control the EGR system. With regard to the EGR system, the only purpose of the MAP sensor is to determine whether the EGR system is working so that the car can pass US emissions. The way it works is that the ECU reads the MAP sensor before and after the EGR valve is opened. When the EGR valve is open, the manifold vacuum will be slightly lower because there is effectively an air leak into manifold when the EGR valve is open. This is all plain as is possible in the ROM code.