Egr Solenoid Rebuilding? (Page 6/10)
Kitskaboodle SEP 20, 09:03 PM
Ok, here is the “report card” for my 85 GT.
Asian FYI I forgot to mention that I replaced the ECM (with one from another 85 Fiero V6) but it did not help.
Also, I made sure both of my egr solenoid brass filters were clear. (they were)

On another note, I really need a few V6 folks to test their egr vacuum hg at full operating temperature.
Kit
Mickey_Moose SEP 22, 02:00 PM
Electrical side:
You should be able to activate the solenoid by applying 12v to the 2 pins, so no need to rev the engine (get a spare connector from the junk yard to make it easy). This will eliminate any issues with the wiring in the car. If the system now "works", then you know there is a problem with the wiring. IIRC you said you have 12v on the connector, so there could be a problem with the wire going to the ECM.

Vacuum side:
What is your vacuum reading at the input to the solenoid?
You have stated you only get 2.5 hg at EGR, but what do you get at the output of the solenoid (when it is suppose to be open)?


This is my thinking with regards to vacuum test (power applied so valve is open):

If bad at input = something wrong with this line (blocked, leak).

If good at input and bad at output = something wrong with solenoid as it is not opening. This could be electrical or mechanical. Maybe coil is weak, piston not moving, etc.

If good at input, good at output, bad at EGR = something wrong with line going to EGR (blocked, leaking?)


edit:
As an added thought, if you are not getting in codes, this makes me think that you are getting proper vacuum at the output of the solenoid as this is where the sensor is that would cause a code to be thrown (unless the 1 port of the "T" that goes to the EGR is blocked).

[This message has been edited by Mickey_Moose (edited 09-22-2022).]

Kitskaboodle SEP 22, 09:23 PM
I have never had a check engine light.
Thanks for all the advice / questions!
I will get back with you on them
Kit
Kitskaboodle SEP 24, 09:41 PM
Ok, here is what I did this afternoon:

I found a way to verify that the egr solenoid is getting 12 volts to the lower two pins (that command’s the egr solenoid to open) at the proper time. I unplugged the 4 pin connector, put my ohmmeter test leads on the bottom two pin connectors, then read the meter for voltage as i increased rpm’s. At idle the voltage was all over the place on the meter but as I revved the engine over maybe 1800 rpm or higher, the meter would then begin to show 12+ volts. This confirms that the ECM is triggering the egr solenoid properly to open.

For the next test, I then plugged the 4 pin connector back on the egr solenoid, then I took off just the hose/line that goes out from the solenoid “T” junction nipple, (and goes to the egr valve) hooked up a separate vacuum hose to this nipple and ran the other end to my MightyVac gauge, revved the engine to about 1800-2000 rpm but got almost no vacuum.
This leads me to believe that the egr solenoid is not opening or there would be vacuum at this connection (that goes to the egr valve) if 12 volts is getting to the solenoid.

Test #3
I tried the same tests with my other egr solenoid (from my 86 GT) but the results were the same.
As I mentioned before, my 86 GT passed smog recently so I don’t know why both egr solenoids appear to be not opening.

Your thoughts?
Kit

[This message has been edited by Kitskaboodle (edited 09-24-2022).]

Patrick SEP 24, 10:26 PM

quote
Originally posted by Kitskaboodle:

I took off just the hose/line that goes out from the solenoid “T” junction nipple, (and goes to the egr valve) hooked up a separate vacuum hose to this nipple and ran the other end to my MightyVac gauge, revved the engine to about 1800-2000 rpm but got almost no vacuum.



Kit, you've probably already reported this, but there are a lot of posts to re-read, so...

To take the EGR solenoid out of the equation for a moment, what is the vacuum reading at 1800-2000 rpm at the end of the hose that goes into the solenoid from the throttle body? (...the red hose in the diagram below and/or the lower tube in the bottom image.)



[This message has been edited by Patrick (edited 09-24-2022).]

Notorio SEP 24, 11:45 PM
Kit, thank you for posting your test results. I should have time Sunday to compare to my last three tests. Also, my vac tester finally arrived so now I have no (good) excuse to continue avoiding this issue.

[This message has been edited by Notorio (edited 09-24-2022).]

Kitskaboodle SEP 25, 12:49 AM

quote
Originally posted by Patrick:

Kit, you've probably already reported this, but there are a lot of posts to re-read, so...

To take the EGR solenoid out of the equation for a moment, what is the vacuum reading at 1800-2000 rpm at the end of the hose that goes into the solenoid from the throttle body? (...the red hose in the diagram below and/or the lower tube in the bottom image.)







I forgot to mention that I did the very test you are asking me to do but I didn’t post the results. Yes, I checked vacuum on the line that goes from the underside of the throttle body to the egr solenoid. (I tested it on the egr solenoid end) As a curious note, when the throttle body is completely closed, there is pretty much no vacuum but when you start to open the throttle butterfly, I start to get a good 8-10 hg of vacuum with only moderate rpm. So then, my egr solenoid is getting plenty of vacuum.

Seems to me the solenoid is NOT opening.
Is there another test / way to confirm my egr solenoid is not opening? Maybe I need to do a different test…
Kit
skywurz SEP 25, 12:41 PM
Cap the breather on the EGR Solenoid (the single vent tube that is pointing to the front of the car)
Then start and rev to 2k rpm and see if your EGR actuates. If it does not check the vacuum on it. If its still low or not actuating the EGR then your brass filters are probably plugged. Its also possible there is a burr or corrosion on the end of the tube inside the solenoid that the disk is suppose to seal against. If it cant seal pull flat and seal then even if its working it will never work.
Kitskaboodle SEP 26, 01:29 PM
Skywurz, thanks for the advice.
I think I am FINALLY making some progress!
As you instructed, I capped off (plugged) the filter end of the egr solenoid, (that takes in fresh air from the air cleaner) then I connected / teed in my vacuum gauge to the line just before the egr valve, warmed up the engine for about 3-4 minutes, then read the vacuum gauge at idle (zero) but then after increasing the rpm to about 1900-2000 rpm or more the vacuum gauge started to show 5-7 hg! 😀
It looks like we are getting close…..
Ar this point, I’m a little confused as to what is going on here. Yes, I now have sufficient vacuum at the egr valve but why did capping the fresh air coming in port solve the issue?? Maybe I should leave it capped at this point? Do I need this fresh air from the air cleaner?
By the way, because you also mentioned checking this, I did check the vacuum line coming in from the air cleaner (while revving the engine to 2K or so) and I got zero vacuum. I can see getting strong vacuum from the throttle body but how much vacuum are you supposed to get from a line that simply goes into the air cleaner canister?

Thanks, Kit

.
skywurz SEP 26, 01:48 PM
Kits

Capping the end that goes to the air cleaner bypasses the solenoids function. This has basically set the car up as the old school vac from the intake directly to the EGR. This test allows you to verify that the vacuum is all good with the system meaning the issue is with the solenoid its self. I had mentioned prior that perhaps your other GT has an obstruction in the air cleaner line and that's why that solenoid is also not working in this car. Capping the line can probably get you through smog as it will open the EGR under the test RPMs and you probably wont throw codes during the test. but you probably should not cap it where its easily seen. Basically you will probably suck more exhaust into the intake than typical this will reduce your NO but it wont be right. I suspect that either the flat plate is not sealing well against the air intake line or the magnet is too weak to pull it well. You could also have some sort of electrical or computer problem that just is not firing the solenoid.

[This message has been edited by skywurz (edited 09-26-2022).]