Egr Solenoid Rebuilding? (Page 5/10)
Notorio SEP 01, 12:42 AM
Kit,

You have enough observations and test results now that it's getting hard for me to keep it all straight. It's not clear to me if you have shown that the:

1 - solenoid works on its own, by applying power directly to the terminals, and
2 - the wires/connector for the solenoid are delivering the proper signal at the proper time.

Yes? Since both solenoids produce the same result (2.5 Hg) and your lines hold a vacuum, this suggests that the signal going to the solenoid isn't working correctly.
armos SEP 02, 06:29 PM

quote
Originally posted by Patrick:

Is this info from a 2011 datalog of any help? I believe it was taken from my '86 GT, and it should be with a stock PROM, although I can't swear to it.



Based on earlier posts it sounds like kitskaboodle is trying to test EGR by revving at 2500rpm while stopped. This looks like a driving log where you stopped at some lights, but I don't see any revving except while actually driving.


I was curious so I found my stock chip and tried it. It does work, at least on my car. In fact, looks like EGR will start to open somewhere just below 2000rpm, and is definitely open at 2500rpm in Park. Once open, it wanted to stay open until RPM got much lower.

This is with the 'AATC' chip - 1986 V6 automatic 3.33 California.
The Y-axis is showing RPM, the numbers would be different for the EGRDC sensor but you can see EGRDC coming up when it revs high enough. The "Speed" and "Park/Neutral" graphs don't show well but I promise it was sitting in Park the whole time.
Caveat: my EGR solenoid doesn't actually work, but no code 32 was detected yet so I don't think this influenced the ECM at all.


@Kitska - 1985 uses a different ECM and I don't know if yours is auto or stick, so it's always possible your EGR is programmed to behave differently, but good chance it's the same.
So I agree now, it probably *should* be activating EGR when you rev at 2500rpm.
If you can, it would help narrow down the problem if you can test whether it actually is commanding EGR. WinALDL can do that (look at the EGRDC value), or there's probably a signal wire that can be probed with a multimeter (I haven't looked into the wiring scheme). Even better if you can check both - if WinALDL and the signal wire don't agree then that presents some different possibilities.

If you can confirm that the solenoid is being signaled to open EGR, but at the same time that there is no vacuum during that command, then you'll have a better pinpoint on the issue.


quote
Kitskaboodle
Test #1 / Tested continuity at vacuum sensor (top two pins) and it registered a flat 0.0 ohms (i.e. OPEN)


I don't know if this is a simple mistype or if it changes the test interpretation - but just in case I should point out that 0.0ohms is a dead SHORT - not open. An open would show as "OL" which is near infinite ohms.

[This message has been edited by armos (edited 09-02-2022).]

Kitskaboodle SEP 02, 09:11 PM
Here is pic of the test you are questioning.
Meter is reading 0.L If you are correct than mine is reading infinite ohms. (for this test)
So far, it looks like it is doing what it should according to the buddycraig thread. However, I’m a little confused about the last step where he applies 12 volts to the solenoid pins while putting his finger on the brass block off plate. Also, maybe me is all put back together as you can see in my pic.
Kit

[This message has been edited by Kitskaboodle (edited 09-02-2022).]

Patrick SEP 02, 09:20 PM

quote
Originally posted by armos:

This looks like a driving log where you stopped at some lights, but I don't see any revving except while actually driving.



It's been a long time since I was an adolescent.
Kitskaboodle SEP 02, 10:49 PM
I forgot to answer your question.
My 85 GT is an auto.
Kit
Kitskaboodle SEP 17, 07:47 PM
Update:
Because I’m at a loss as to why my egr is not being “commanded” to open, I decided to take a gamble and bought another ECM from an 85 SE. I was hoping it was a computer issue. So, I swapped ECM’s this morning and then checked vacuum at the egr valve after being fully warm. Unfortunately there is no change. ( h.g. Is still only 2.5 at about 2K rpm but book says it should be 5.0hg minimum.
I’m about ready to give up.
I’m totally at a loss as to what is wrong.
Kit
Kitskaboodle SEP 18, 10:17 PM
It was mentioned above that it is possible that the ECM only triggers the egr solenoid to open while in Drive. I’m thinking this is not correct but since I’m at a standstill anyways and making no progress, I decided to do a little experiment. I don’t have a scan tool / Winadl, etc so I’m going to tee in to the vacuum line going to the egr valve, run the vacuum line outside onto the decklid / rear window area, hook it up to my mighty Mite vacuum gauge, tape it down to the decklid, then drive down the road at speed, warm it up abs see what the vacuum is then. (at 2500 rpm in Park it would only register 2.5 hg)
My bet is there will be no difference.
Stay tuned…….,,,
Kit
Kitskaboodle SEP 19, 11:50 PM
As promised, I ran a real road test this afternoon and as suspected, there is still no difference in egr vacuum whether sitting in Park or driving down the road. (2.5 hg at the egr valve)

I did a few more tests as well to double check my previous findings. I tried both egr solenoids from both my Fiero’s and had no change in egr vacuum. I checked both plastic hard lines that go from the egr solenoid to the egr valve and the other line that goes to the underside of the throttle body. (I plugged one end and applied vacuum at the other end to see if they would hold a steady vacuum. (they did)

Question:
What would happen if I re-routed the egr valve line directly to the throttle body or intake? This would make the egr stay open all the time.
Kit
Notorio SEP 20, 12:32 AM

quote
Originally posted by Kitskaboodle:

I did a test on my 85 GT today. I put a vacuum gauge in-line with the hose that goes to the egr valve, warmed up the engine, revved it to 2500-3000 rpm and the vacuum gauge barely read 2.5 hg. I heard the minimum is at least 5 hg. Despite no codes, I think my egr solenoid is not allowing vacuum to get to the egr valve. And my Nox is way too high.
Kit



Kit, would you mind posting your numbers from the smog test? I found a vac leak on my GT, fixed it, and re-set the timing, and failed again for high NOx. All other numbers look good and the car runs great except a little popity-pop from the exhaust during shifts. I'm going to buy a mityvac and run your tests and start a post dedicated to that.
Kitskaboodle SEP 20, 09:01 PM
Ok, here is the “report card” for my 85 GT.
As an 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

[This message has been edited by Kitskaboodle (edited 09-20-2022).]