MAP sensor or PCV valve buzzing whining

[jem270]

My stock 97 GP 3.8 has been making a buzzing and whining sound lately. The whining sound only starts after it has been driven a few miles. I used the old broomstick in the ear trick and narrowed both noises down to the MAP sensor/PCV valve area. Does this make any sense? I tried to take the MAP sensor off but I have not figured it out yet. I don't want to break it. I read that it is mounted directly over the PCV valve. Any thoughts?

[BNaylor]

Originally Posted by jem270

My stock 97 GP 3.8 has been making a buzzing and whining sound lately. The whining sound only starts after it has been driven a few miles. I used the old broomstick in the ear trick and narrowed both noises down to the MAP sensor/PCV valve area. Does this make any sense? I tried to take the MAP sensor off but I have not figured it out yet. I don't want to break it. I read that it is mounted directly over the PCV valve. Any thoughts?

If the noise is definitely coming from the left side (passenger) of UIM here's a pic of things to check and how to get at the PCV valve in a GT or Series II NA 3800:

http://macgp.clubgp.com/howto/engine/pcv/gt/pcv.html

I left the big red seal off one time changing the PCV and I got a buzzing sound like a vacuum leak.







Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[richtazz]

there is a pcv repair kit gm#89017274 that includes all the pieces to eliminate the rattle you have. It includes the pcv valve, spring, 2 o-rings, and the plastic cover that the MAP sensor clips in. Dealer retail is $19.29. You may be able to get it cheaper at a Delco distributor if you have one in your area. I sell it for $11.05, but S/H may make it cost prohibitive to get it from me.

[jem270]

Great instructions!

Just one question. When you toss the PCV valve in the trash is it done with an underhand toss or a wrist flip? Just kidding. Great work.

bnaylor3400:
Thanks for the link. It shows pulling the MAP sensor off. It has a couple of snap looking things on each side. When I pull those outward, does the sensor just pull straight up?

richtazz:
Thanks for the info. I will look close at it and replace with the repair kit you suggested if needed.

[BNaylor]

Originally Posted by jem270

Great instructions!

Just one question. When you toss the PCV valve in the trash is it done with an underhand toss or a wrist flip? Just kidding. Great work.

bnaylor3400:
Thanks for the link. It shows pulling the MAP sensor off. It has a couple of snap looking things on each side. When I pull those outward, does the sensor just pull straight up?

I use the slam dunk method.

On the two snaps on each side, you push them in and then pull the MAP sensor up. Good luck and you're welcome.







Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[richtazz]

Be careful putting the MAP sensor back on, as the nipple is off center and you'll break the little plastic clips that hold it down if you put it in wrong.

[jem270]

I did notice in the instructional link that it looked like one of the plastic clips were broken off each side.

Thanks again!

[jem270]

Thanks for the help everyone!

My car started missing real bad when accelerating up a hill. I suspected either a vacuum leak or bad spark plugs.

I went to the dealer and bought a map sensor ($40.00)(mine had broken in two pieces and had oil in it), iridium spark plugs ($48.00) , spark plug wires ($65.00), and the PCV valve kit you suggested ($19.00).

I went ahead and did the engine rotation trick (took out bolts and pulled it forward by hand (wound up being REAL easy). Plug replacement was a breeze. Hardest one was the back right one that was behind the O2 sensor. I used a universal joint with it. I decided not to put the plug wires in after I test drove it. The origional ones look fine and I did not have time to route the new ones like the origional. I will do it another time.

I also put in the PCV kit and it no longer buzzes!

It runs great again! Once again thanks to bnaylor3400 and richtazz for their help and also to others on the site that posted info about sparkplug removal. THANKS !