eastz28

1991 Z28 EGR Location / Repair / Diagnostic


I have a 1991 z28 Camaro TPI 305

My engine looks exactly like this. Can someone identify the yellow circle? Is that my heater core?
Also is my EGR valve located under the plenum..... a brass piece connected to the intake...flying saucer (cant see it because the runners are in the way ....pink arrow). I have the EGR diagram under my hood that Vader often post.....The yellow circled item in my opinion is not on the diagram under my hood. Can someone circle (using the picture I provided) what is meant by a bad EGR........the flying saucer thing.... the box or what? I titled my thread as such...... to help others using the search menu. Please fill free to provided pictures/diagrams of this model/ year engine to help others in the future. Thank you all in advance.
My questions:

Can someone identify the yellow circle?

Is the flying saucer the EGR (cant see it because the runners are in the way ....pink arrow?

How many separate 3/16 hoses are connected to the EGR?

When you replace the EGR vacuum hose do you need 2 ft of hose or what?

This is what I learned about the EGR valve from thirdgen.org in a more laymen's term approach:

1) A small crack in the vacuum hose/accidentally disconnected or bad/dirty EGR valve.... can cause your healthy engine to:
a.) act as if compression is low
b.) engine to stall when breaking hard
C.) service engine light to come on and present Code 32 or exhaust related Code 44 (O2 sensor etc)


Please feel free to correct me or add other technical information. Please present facts for debates really take up reading time and creates a larger than necessary thread.

Thank you http://www.soundsolutionsaudio.com/z28forsale.html because I used a picture from your site thats a Hot!! car you have for sale! Hot meaning nice not stolen you will find SSAudio fix up restore camaros and sell

eastz28

Moderator do you believe the best time of the week for someone to answer my question.... (that actually knows the answer to my question) is on Friday or Saturday? Can you move my question to a different category if you believe it belongs in a different category? If you want to delete it please feel free, thus I can re-post on the day you suggest. Thank you for your time.

jamesbob02

Ok I can answer some of your questions.

1) Your picture is difficult to see, but I know enough to verify that the yellow circle contains the heater control valve (or diverter valve). It should have a vacuum line attached to it that goes to the firewall, I believe. When you turn on the heater, I believe the valve opens and sends hot coolant to your heater coil to produce the hot air. NOTE: Do not confuse this with the A.I.R. system valve, which looks similar and is in the same area.

2) Yes, the flying saucer is the EGR.

3) I believe only one vacuum line goes to it, and goes to the EGR solenoid which should be located below your coil.

4) You should need much less than 2 feet of hose to hook up the EGR to the solenoid. It's like less than a foot. If you need to hook up the lines that go to the solenoid, though, you may need quite a few feet to get them where they need to go. I'm pretty sure one goes to the vacuum canister underneath the driver fender, but I dont know where the other one goes. Mine was never hooked up correctly anyway, and none of the diagrams floating around helped much.

5) As for symptoms, I couldn't tell you really. I disabled mine and haven't looked back. In addition to the list, it sometimes will cause a loss of efficiency (economy), and may not prevent engine knock like it usually would.

And YES, that car is HOT, if only it had a 350 in it, it would be perfect!

eastz28

Thank you, I did not want to clog the post with a large picture....he's selling the car for $6,700 in the classified section now .......check it out.......was $12,000


Thanks again for your time

Coqpit

Here's a great pic origanally posted by vader to help diagnose the egr system...

Steve89GTA

Awesome. How do I check if the diaphragm is moving when I vary rpm from idle to 2,000rpm. Can I simply feel undernearth the EGR valve and will I notice the diaphragm moving quite easily.

I have a stumble off idle till about 1900rpm when my egr valve is connected to the solenoid (I believe it's activating when it shouldn't since the stumble is eliminated when I disconnect the egr valve from the solenoid).

Is the P/N switch the park/neutral switch? What does this have to do with the EGR circuit?? Also, I have a 5speed and my car does NOT start if I don't have the clutch pressed. I'm guessing this means my p/n switch is operating normally.

ERICCAMARO

Im haveing this same problem wondering if you ever found the solution???

Speedgraphic

I had the same problem. A bit of stumble on acceleration. I had not seen the great diagnostic at the time but I had read somewhere - probably Chevy High Performance - that changing out the EGR on an older car would improve performance.

I changed it out - not that expensive, and not that hard to do...

MAN! It felt like my car had picked up ten HP and learned manners all at the same time!

If you have the original EGR valve installed it's most likely way past time to replace it!

Let us know what happens... Oh yeah Autozone offers a direct fit EGR that is considerably less expensive than from GM!