Possibly a map sensor problem?
 

I wasn't sure whether I should put this here or in E.M. but here will probably get the most responses.
I've been having alot of low rpm part throttle issues, bad bogging effect that won't go away no matter what I do (I've changed everything on the dizzy, set and reset the tps way too many times, even tried redoing my map in BRE). Could I possibly have a map sensor issue? I have a vafc hooked up (more as a light show these days :P) that shows a max of 12.5 inches of vacuum on a decel, and around 10" at idle, where as when I hook up a vacuum gauge I get at least 26" on decel and closer to 18" at idle. The map sensor line's coming off the proper spot, but it's an old pm5 sensor (but my pm6 one does this as well). My old z6 setup that had the map into the TB used to show alot more vacuum on that vafc than what it says now (or the last 2 b-series motors for that fact). Any insight as to why?

Re: Possibly a map sensor problem?
 

do you have a mech gauge to check vac with? 12 is way less than you should have.

Re: Possibly a map sensor problem?
 

wouldnt your ctr cams mess with vac at idle?? my cams only show me about 10-11 lbs of vac. at idle

Re: Possibly a map sensor problem?
 

These are only the SiRII cams not the ctr's...mechanical guage will show 18" at first start up. I also just checked the sensor voltage according to the afc, won't drop below 1.125v at idle.

Re: Possibly a map sensor problem?
 

my afc is never super accurate. have you checked voltage with a meter?? posibly to advanced or reatarded timing would cause vac. problems too.

Re: Possibly a map sensor problem?
 

I just swapped in a d15b and started driving last night and I had the same issues as you. I unplugged the throttle mounted MAP sensor and plugged in the MAP on my firewall(that was there from the old engine) and it runs like a champ.

Re: Possibly a map sensor problem?
 

Well it worked fine on the TB mounted map, but since I went to the firewall mounted one it's been really weird. I switched to another spare firewall one I had laying around and it didn't really make a difference in drivability, but I was able to see the afc hit 13.3" on a highway speed decel. It just doesn't make sense that a product intended to screw with your map signal wouldn't be accurate enough to properly interpret the map voltage signal. Only other thing I can think of is the map wiring might be backwards, as right now I think my arrow for the map signal on the afc's sensor input is pointing down.

Re: Possibly a map sensor problem?
 

Nevermind on that arrow setting, late night stupidity ownz me. :1 (forgot that was for throttle ;D)

Re: Possibly a map sensor problem?
 

see how the little ---- fucks you over.. thats why i call you all the time because i overlook little ---- and go straight for the major!! ;D