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DAMNED EGR!!! Can I run the car without it and still pass emisions?!?
This will be a bit of a rant, so I'll apologize to readers now...
I decided to take the Corvette to work today, since it was a nice day (for late October here in Ontario, Canada) and the forecast calls for bad weather over the next couple of days. I haven't driven the car in a couple of weeks so I figure it's a good time to do so before putting it away for the winter.
I started it up, ran great, but - my luck - the SES light comes on! Great. I shut the engine off, disconnect the battery for a few seconds to clear the code (in case it was just an anomaly) and restart the car. Sure enough, the SES light comes on again!!! F@$K!!! Not having time to play with it this morning, I put the car back into the garage and take my DD.
After getting home this evening, I ran a quick diagnostic on the car and find it's showing code 32 - EGR Circuit. Now, I haven't conducted a full diagnostic to figure out what's actually wrong (it could just be something simple like a vacuum leak) but I replaced the EGR valve less than two years ago, so this is really upsetting!
Now that I've ranted, my question is this: is there any way I can run the car without an EGR and still pass emissions?!? I realize that a custom chip would be required to compensate for the missing EGR, but would that allow the car to pass emissions?
Sorry for the rant guys. It seems this week is just dragging on .
My understanding is (boy does this sound like a lawyer) maybe. It depends on your state and the kind of emissions test and checks they perform. I note that you are Canadian, so... In Pennsylvania, the answer would be, out of the Pittsburgh or Philly area, yes it would pass.
BTW, did your car perform worse, the same, etc.? Perhaps all you have is a loose wire to the solinoid. I would try fixing it before elimination. That way you will not have possible issues of detonation.
Last edited by KeyWestJack; 10-25-2007 at 11:57 PM.
The way I read it, the computer looks for a change in mixture after calling for an egr signal. From personal experience it can be hard to pass emmisions without the egr (fails NOx) depending upon your mixture Leaner/hotter = NOx. Unplugging it would just cause it to set 32 codes, rather than elliminating them. Check your vacuem to the egr through the solinoid
If you have the egr temp switch on the cross over feed tube over the valve cover,it might be going bad.They sort of twist out over time and the white ceramic looking coating comes apart.
I had this happened twice on my former 86 years ago,the switch failed and threw a code and light,but no driveability problems.The wire going into the switch,the metal part where its white,was very loose and wouldnt stay put.I had 2 failures and replaced it twice in a 9 year span.
The egr temp switch plugs into a wire down behind the distributor.Looks very much like another 02 sensor plug in.Unless you have small hands,or can remove and replace the distributor with ease,its hard to fit back there and plug in a new one.
If the switch is failing,a new switch will fix it easy.Trying to unplug the old wire and plug the new one in is hard with the distributor in the way.Thats why some of the egr temp replacement switch kits tell you to cut the old egr temp wire near the distributor and splice the new one in to get it done in a few minutes.
The EGR only opens when certain conditions are met. Such as when you car gets up to a particular speed, (35??), the valve will open allowing exhaust gases to mix with intake.
When the car goes back to idle or sitting still, the valve is closed to improve engine idling.
The way I see it, most places that inspect cars don't actually drive them. They idle them in a service bay while they stuff a sniffer up the tailpipe. While the EGR does improve emmissions overall I don't think it has an effect on inspection.
It's amazing... folks don't even understand what the EGR REALLY does.
It does TWO things -
1. It lowers NOx by introducing a small amt of exhaust gas back into the intake. This effectively lowers the temp of the combustion chamber...
2. ... which directly results in lowering NOx and REDUCING detonation!
Ain't that neat? I thought so.
I know what the EGR does, and I understand how it functions. I was asking if there was anyway to run the car without it (assuming I get some type of custom tune) and still pass emissions. There's lots of people running Mini-Rams that don't have an EGR, so I can only assume that it's possible. I just want to know for sure.
Originally Posted by bogus
Leave the EGR. If you are having a glitch, the switch is bad. BFD.
If I can't pass emissions without the EGR and a tune, then I'll have to leave it on... at least for one more year. The car goes in for it's last e-test in '08 (cars older than 20 years are exempt from being e-tested in Ontario).
And I'm not yet certain it's the switch. If it is, then it's no big deal - called a dealer today and they said it was only $26. Unfortunately, they also informed me the EGR solenoid (another potential cause of the code) has been discontinued. With luck, it won't be the problem.
You're probably right - the EGR circuit is pretty simple. It's just upsetting that this happened out of nowhere... especially since I replaced the EGR valve just over a year ago (because the car failed emissions due to high NOx).
Originally Posted by CorvetteMike2004
Do they do a visual check on smog tests where you live? I live in California and we have **** smog checks here.
Not really... at least, not as stringent as what you guys live with out there. If the car's emissions readings are fine (CO, NOx, etc...) and the gas cap holds pressure, then it gets a pass.
The SES light came on as soon as I started the car while I was in the garage, so I didn't drive anywere (I had no idea why the code was thrown at the time). The car idled fine, and rev'd OK, but I don't know if it would have performed OK had I started driving. My guess is that it wouldn't have been any worse/better to peceive, but that's just a guess.
Originally Posted by KeyWestJack
Perhaps all you have is a loose wire to the solinoid. I would try fixing it before elimination. That way you will not have possible issues of detonation.
I checked the wire going to the EGR temp switch and it was on tight as was the harness connector. I did a quick scan of the vacuum hoses and they were all securely attached too.
According to the FSM (thanks Agent 86!), baring a grounding problem, it could be one of five culprets: the EGR temp switch (which is cheap and easy to replace), the EGR solenoid (which has been discontinued), the EGR valve itself (which is only a year old on my car!), a faulty ECM (of which I have a back-up), or a vacuum leak (which probably wouldn't have caused the code anyway). None of these are difficult issues to resolve... it's just a PITA!
Last edited by TheCorvetteKid; 10-26-2007 at 11:23 AM.
My 87 started throwing a 32 code right after buying it, drove it 2100 miles to get it home, got about 29mpg on the trip and replaced a broken EGR part (EGR Valve Temp switch) for about 25 bucks when I got home.....
Mine passes MD inspection with no EGR (no provision for it on my current setup, so even visually it looks OK). It also passed with a stock tune (ie, still expecting EGR) on a more radical setup, after I fixed my issue with the AIR system.