97 PA PO507 Code

12-28-2006, 12:52 PM
ok, here's my story.

Noticed that I was losing coolant but no visible leaks.

So after reading and re-reading numerous posts about lower and upper plenum problems, I replaced the upper intake plenum (AP Network) and the smaller stovepipe to the lower intake and lower intake gasket(Felpro from Autozone - $59.95). Top of the lower intake manifold was covered with water up to the upper plenum, could not see the 2 hidden bolts. Had to use paper towels to absorb all of the coolant.

Cleaned the throttle body with TB cleaner. Could not believe the amount of carbon (1/16" coating on the inside). At the time I did not clean the IAC.

So here is my problem:
After driving for about 60 miles, I noticed a problem with one of the belt pulleys chirping (whining) while coming to a stop sign or light and whooshing sound coming from the engine after the engine is stopped. Checked the power steering pump and there was hardly any fluid in the pump. Filled the ps pump to full level.

This whooshing sound (lasts about 2-3 seconds)(sounds like the winter wind coming around the corner, if you live in the North), and then stops. And remember the sound only occurs after the engine has stopped and this sound did not happen when the repair to the intake was first made(or at least I did not notice it, maybe it was there but only noticed it after the pulley began to chirp).
The service engine light did not come on at the time of repair, only after driving about 50-60 miles in a 2 day period. Also the chirping pulley did not make the sound either after the repair was made, only after driving the 50-60 miles.

The car runs better than ever but the whooshing sound is not normal (that is what I believe, may it is normal, the Autozone guy said it was normal for the engine to make the sound).

So today I took the IAC off and cleaned it with TB cleaner, but the sound still occurs. Removed the sensor from the air filter rubber boot(to air filter/TB), no change in the whooshing sound and removed the MAP sensor, but the whooshing sound still persists.

Could the IAC be defective(hard movement in the rod)? While cleaning it, I was able to push the rod in about 1/4" but unable to pull it out to the original position.

So I disconnected the wiring connector from the IAC and started the engine idled at 2000 rpms. Turned engine off, reconnected the connector and idle was barely above 1000 rpms (sometimes 1200 but never higher).

After the intake repair was made , the idle speed was normal at 900 rpms, that is what the engine has always idled at before the intake repair. But after driving for 60miles (2day period) the service engine light came on.

Took to Autozone, and the scanner read PO507 -high idle. The code was erased but the 507 code returned the next day and the whooshing sound still persists.

Could the power steering pump be causing a vacuum leak, the power steering pump is quite dirty, grimey, leaks, etc.

Could the MAF be bad?

Took the rubber boot off the TB and started the engine and when the engine is turned off, the whooshing sound was more prevalent. Really loud.

I was going to put the old pvc on but I threw it away(can't find it).

Any help will be appreciated.


Also of note , when I was removing the upper intake the bolts were barely tight(could remove by hand, no tools required on some of them). So if anyone is losing antifreeze, first check and see if the upper intake bolts are tight.

And the original stovepipe came out with the upper intake with no force required. The original stovepipe was just a tube, no collar like I have seen on this site and other websites.

thanks for reading and I will be checking often for suggestions.


ps The Autozone guy said the whooshing sound is normal.
Is it?
Never noticed the sound when the car was new.

12-28-2006, 03:24 PM
First thing to check is for both 'o' rings to be in place under the map sensor where the pcv fits, larger one on top small one on the bottom.

12-28-2006, 05:28 PM
The big black one is new (came with new upper intake) and one on the MAP is old and funky looking. The grooves of the rubber are smashed, not concentric (it is not an o-ring but shaped kind of like a rubber funnel.

I thought the pvc was connected on the side (large rubber hose), next to firewall, of the upper intake, and not on the top.

12-30-2006, 07:33 PM
Hmmm.. you need someone to have the hood open to hear the woosh and identify the source.

It may be the fuel vapor receiver.. or a firing cylinder that is firing into the intake.. Lots of stuff.. Wierd..

Good Luck.

01-01-2007, 12:11 PM
Where is the fuel vapor receiver located?


01-01-2007, 03:50 PM
Are you sure the o ring around the pcv and the one on the upper pcv seat are in place and sealing?

01-01-2007, 09:17 PM
I'll check again but I don't remember there being a smaller o-ring.

Just the rubber funnel shape gasket that goes around the MAP sensor and big o-ring. When I took apart the old pvc assembly and MAP from the old upper intake, the large spring that was in the pvc assembly came flying out. I did not expect the spring, so that was a big surprise.

Does my car have this kind of pvc:

I personally have not installed a new pvc.
If the pvc valve is not inside the new pvc assembly where the MAP connects, then maybe I am driving the car without a pvc.

Do you have a photo of the pvc and proper installation to compare with what I have done?

I have the factory service manual, vol.1 and not the most important volume 2, that pertains to my problems.

I bought a scanner and 507 code continues to come back after being erased.
Also, I heard a "grrrrr" coming from the right rear of the car as the 507 code was being erased. Maybe that was the self leveling system kicking in.

Also, on the scanner the emission light is red indicating something is wrong with the emissions. After erasing the code, and scanning again , the emissions system light on the scanner is yellow.

This wooshing sound and higher idle speed is driving me crazy. Still idles about 200 rpms too high but the car runs great. But I know the higher idle speed and the wooshing sound is abnormal.

I guess I'll have to take it to a GM dealer.

But I'll check the PVC again before doing so.


ps Also I forgot to add that the idle air control sensor o-ring was split, so I used black high temp sealant, as I do not have a proper size o-ring. I am almost sure the IAC is good because when started without the IAC the engine goes to 2000 rpm and does not idle down but when I put the IAC back on it idles at 1000-1200rpm. Do you think that the o-ring and use of the high temp sealant (not sealing enough) could be my problem? I might buy a new IAC, just to be sure since it keeps giving me a idle control system code.

Also, maybe the clear plastic tubing that is in the upper intake has come loose. What do you think about that idea? The sound is definitely coming from the upper intake area.

01-01-2007, 11:08 PM
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01-02-2007, 01:08 PM
Guess what?

Been driving the car without a pcv.

Took old pcv out of old upper intake manifold and the wooshing sound is gone.
The problem was solved in 2 minutes.

Looked like oil was present(wet) when the pcv assembly was removed, is that normal because running without the pcv.
Plastic tubing, that attaches to the underside of the upper intake, was still in place.

maxwedge, thanks for being persistent about the 2 o-rings. I knew that I only saw the big o-ring. thanks again for your assistance. Cleaned old pcv with throttle body cleaner and installed.

Idle is still a little high maybe the computer will learn the new settings.
507 code hasn't come back after 7 starts and stops. Hope that fixes that problem.

The "grrr" sound again was heard this morning while scanning. I have always heard this sound but have never looked into it. I stayed out the car so I believe it is not the self-leveling being implemented.

The emissions light on the scanner is still yellow, so what does that mean?

Probably buy a new pcv and see if the yellow light on the scanner goes green.

thanks again, what a great site this is.

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