Okay just installed my new in dash vacuum guage. for some reason only pulling around 6 hg's. at idle? around 850rpm's. I know I have a pretty big cam but that seems kinda low. I have a bigger guage that I hook to the intake and it always reads 10-11 hg's. would I lose some pressure running about 8 ft. of vacuum hose going to the guage inside the car... I can't seem to find my big guage right now to verify it, plus I already mounted the smaller guage in the car. I know I don't have a intake leak, because I fixed it about 3 months ago and not leaking a drop. and I can't find any vacuum leaks.

also Im getting a high map code on my autoxray. it is fluctuating from 2.84-2.95 at idle, is that right? Im thinking so from the bigger cam, I have 3 map sensors here, I tried all 3 and they read the same, one is even brand new. if that's not normal any ideas? I think my map gasket is wore out, fit's really loose.. could that be the problem?

and last but not least, my left blm's sit mostly at 108 and climbs to 116 every now and then. the right blm's sit pretty much at 128's. my left and right integrators fluctuate from 116-136 but sit around 128's the most. any ideas on the left side... I have new 02's ac delco's. they are reading fine.. so at a loss...
thanks for any help. I would really appreciate it...

 

2.84-2.95V on the MAP sensor indicates a MAP of about 65kPa. It generally take a reading of 68kPa to set the high MAP code. 65kPa corresponds to (assuming you are at sea level) about a 38kPa vacuum, or about 11.0"Hg. So it would seem to confirm your "large" vacuum gauge reading, and throw into question your new gauge. The vacuum reading will not be affected by a long line leading to it, at least not under static conditions, like at idle. When vacuum is changing rapidly, the longer the line, the more "delay" there is in the reading reaching the mechanical gauge, in effect dampening the movement of the gauge.

I would think the 306 might produce MAP readings in the 60-65kPa range, but it may be possible to pull them a little lower with a bit of tuning, lower idle rpm, or adjusting the spark advance at idle.

Your BLM is changing because you are moving through the range of 18 different "cells", based on the specific combination of MAP and RPM. Each cell has a stored BLM for the left and right bank. You need to get the BLM for as many cells as possible to try and pin down the cause. At idle, with a large cam, and a 58mm throttle body, "split" BLM's aren't unusual. The question is, does the "split" continue to exist at higher RPM/MAP cells, where it would indicate a source other that a cam/TB induced split.

 

thanks Injuneer... I notice when driving down the highway or upper rpm's. that the blm's get alot closer to each other, within 5 blm's of each other.. so maybe it is because of the 58mm t.b. and the cam... thanks. I will also check the vacuum line going to the new guage, maybe it got pinched alittle causing the low reading, if not then I'll have to live with it, darn autometer guage..