Code thrown but not for my year/MAP issue

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SquareRoot

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Yes that's right. Excuse my rubbernecking!
It never fails that we will come upon a wreck and my wife somehow captures all the minute details with her eyes and then turns to me and asks "What happened" to which I reply, "How the hell do I know, I was with you the whole time!"
 

bucket

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After threatening the burb with the parts cannon I whimpered at the idea of spending money when I didn't need to so I went out and started fiddling with stuff. As I was wiggling some things and checking to see if anything changed I decided to pull the vacuum line off of my EGR. Well that did it. I blocked off the lines and took it for a spin. Besides the little puff of blue smoke for the first 15 seconds of driving it ran like it was supposed to. So the next thing on my list is trying to figure out why my EGR is opening when I just crack the throttle. The old EGR solenoid tested bad so it got replaced along with the vacuum lines recently.

It's not everyone's cup of tea, but anytime I have any trouble at all with an EGR system on one of my vehicles, I either disable it or remove it completely.
 

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After threatening the burb with the parts cannon I whimpered at the idea of spending money when I didn't need to so I went out and started fiddling with stuff. As I was wiggling some things and checking to see if anything changed I decided to pull the vacuum line off of my EGR. Well that did it. I blocked off the lines and took it for a spin. Besides the little puff of blue smoke for the first 15 seconds of driving it ran like it was supposed to. So the next thing on my list is trying to figure out why my EGR is opening when I just crack the throttle. The old EGR solenoid tested bad so it got replaced along with the vacuum lines recently.
I bet you have the wrong EGR. There are positive and negative backpressure EGRs. Only get an AC Delco. I had a thread on this somewhere with the part number...search it up. I replaced mine and had an off idle stumble. Parts house said it was right. But it was not. Replaced with the proper part and all good.
 

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Sounds kinda similar to what im trying to find. I'm really starting to think that the electrical egr valve on the 99 vortec 350 is bad. Because I have an inconsistent but most of the time stumble off idle when starting out. A couple months ago I redid intake gaskets and the spring tension on egr valve felt weak. I'm really wondering if that's my issue? Sorry to hijack.
 

Jawzjeep

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It's not everyone's cup of tea, but anytime I have any trouble at all with an EGR system on one of my vehicles, I either disable it or remove it completely.

Hey if its not gonna cause a problem I'm fine with it. I found its a very common opinion. And right now its working.

I bet you have the wrong EGR. There are positive and negative backpressure EGRs. Only get an AC Delco. I had a thread on this somewhere with the part number...search it up. I replaced mine and had an off idle stumble. Parts house said it was right. But it was not. Replaced with the proper part and all good.

I read about that here and in some other places. Positive, negative and pulse or something like that. There may really be something to this because the previous owner put in a new distributor and EGR valve. He didn't seem too savvy.

Sounds kinda similar to what im trying to find. I'm really starting to think that the electrical egr valve on the 99 vortec 350 is bad. Because I have an inconsistent but most of the time stumble off idle when starting out. A couple months ago I redid intake gaskets and the spring tension on egr valve felt weak. I'm really wondering if that's my issue? Sorry to hijack.

No hijack.
In my best psychiatrist voice.....
This is a place for sharing! Lol

I was able to test my EGR solenoid to see if it was bad and it was. I have no idea if it's the same procedure but yours has to have one too. Im still looking for why I need to unplug it. I've found mention of clogged exhaust system being a possible culprit as well. It was said that it could cause the EGR to open early. Idk
 

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here is the proper EGR part number AC Delco 214-5073.

if you have no more off idle stumble with the EGR hose plugged, I'd suspect the likely culprit to be the wrong type of EGR if the EGR solenoid is operating properly. the valve and the solenoid components are tested separately.
 

Jawzjeep

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here is the proper EGR part number AC Delco 214-5073.

if you have no more off idle stumble with the EGR hose plugged, I'd suspect the likely culprit to be the wrong type of EGR if the EGR solenoid is operating properly. the valve and the solenoid components are tested separately.
Thanks for the part number!

Yes, all the stumbling and stuttering stopped when I unplugged and blocked the hose between the EGR solenoid and the EGR.

Previously I tested the EGR with vacuum and it killed the engine when I applied vacuum, and held vacuum fine when testing while not running. I did test the EGR solenoid independently and it tested bad and was replaced earlier.

I'll replace the EGR with the correct one if it is indeed wrong. It's pissing again here in the Great Northwet so it'll be a little bit. EGR seems to be told to open way too early so I need to dig to find out why. I found mention of the computer reading the CTS, TPS, P/N switch and the RPM signal from the distributor to regulate the solenoid so I'll start there. Something's not happy.
 

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here are photos comparing the old one (correct part, but old) and the new one (incorrect part) from when I had issues. the correct new one I acquired later looked exactly like the old one, just clean
 

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gmbellew

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last pic because you can only attach 5. I'd pop yours off and compare to these pics to make sure it looks exactly like the old one in these photos
 

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Jawzjeep

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last pic because you can only attach 5. I'd pop yours off and compare to these pics to make sure it looks exactly like the old one in these photos
Will do thanks!
 

Jawzjeep

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@gmbellew the number on the EGR in my burb says 17087194 and I got excited. So looking at my local parts store options they have an AC Delco with the part number you gave me but the number on my burb is listed as the same.
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I'm still gonna pull it out to compare and look though when I won't be dodging raindrops
 

Jawzjeep

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So I have a couple around town trips done with the EGR disconnected and lines plugged. No highway at all. It runs fine perfect. No check engine lights, nothing. At this point I'm so glad to just be able to drive it that I'm not messing with anything right now. When I yank it out I'll post it.
 

bucket

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So I have a couple around town trips done with the EGR disconnected and lines plugged. No highway at all. It runs fine perfect. No check engine lights, nothing. At this point I'm so glad to just be able to drive it that I'm not messing with anything right now. When I yank it out I'll post it.

If you drive at speeds of 55+ for a little bit and then coast down to a slower speed (like an off-ramp for example) it should pop the light on and store a code for lack of EGR flow. It will still run fine, just turn the SES light on. If that bugs you, you can blip the throttle a couple times while coasting down to avoid it.
 

Jawzjeep

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@bucket good to know, thank you. As long as that's why the light is on I'm fine with it. At least now I can anticipate it. Feels fantastic just to be able to drive it.
 

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The ECM operates a solenoid to control the exhaust gas recirculation (EGR) valve. This solenoid is normally closed. By providing a ground path, the ECM energizes the solenoid which then allows vacuum to pass to the EGR valve. The ECM monitors EGR effectiveness by de-energizing the EGR control solenoid thereby shutting off vacuum to the EGR valve diaphragm. With the EGR valve closed, and O2 sensor fluctuating normally, fuel integrator counts will be greater than they were during normal EGR operation. If the change is not within the calibrated window, a Code 32 will be set. The ECM will check EGR operation when: • Vehicle speed is above 50 mph. • Engine vacuum is between 15 and 55 kPa. • No change in throttle position while test is being run.
 

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