quote Originally posted by sabotage: Should I replace the MAP sensor?

If you have a mity vac hand pump you can suck on the MAP sensor and compare vacuum gauge reading to WINALDL reading. I'm still not clear what the MAP data in your log file is. Is it raw data or has WINALDL converted it to kilopascals?

1 bar = 100 kilopascals absolute pressure - or about 1 atmosphere
0 bar = 29.5 inches Hg vacuum

so 40 kilopascals is about 17.7 " vacuum.

It's strange on the data log that engine starts idling with MAP about 40 and then after it runs awhile it's idling at about 50.

quote Originally posted by Dodgerunner: What I do is pull my AC fuse and turn on the ac which runs the fan and keeps the temp at the 195 level without running the ac. Have not bothered to wire a switch for the fan since I rarely have to do this.

Rory, doesn't pulling that fuse also disable the blower in the heater/defogger so that you can't even have (cooler) air from outside being blown into the cab?

No the AC fuse only disables the compressor. At least it does on my 88 and 85. The heat/ac controls have their own ground that connects to the fan relay control line so does not care about the fuse.

Ok. I'm heading to the part store to return the IAC. I was thinking about getting a new map sensor to see if that helps.

quote Originally posted by Dodgerunner: No the AC fuse only disables the compressor. At least it does on my 88 and 85. The heat/ac controls have their own ground that connects to the fan relay control line so does not care about the fuse.

Rory, which fuse exactly did you pull to disable the A/C compressor?

I'll double-check, but it seemed I couldn't kill the A/C without also disabling the heater/defogger blower on my '86 GT.




[EDIT] Found the following in another thread. Maybe this explains what's going on.

Rory, is it just the high speed setting on your blower that works when you pull the A/C fuse?

quote ...and your a/c concern is or could be the a/c comp clutch,if it only blows with a/c on. also on that circuit is blower fan and fan resistor except when blower is on high.

[This message has been edited by Patrick (edited 05-16-2009).]

quote Originally posted by Patrick:

If my A/C is nonfunctional, I leave the clutch unplugged. Then you can turn the A/C on and start the radiator fan

[This message has been edited by sanderson (edited 05-16-2009).]

quote Originally posted by sanderson: If my A/C is nonfunctional, I leave the clutch unplugged.

Where's that, at the compressor?

quote Originally posted by Patrick: Where's that, at the compressor?

Yes

Sounds like it's worthwhile checking out. Thanks!