So I hate to say this but I've been doing a little research on how to dele- I mean 'misplace' my EGR and AIR system on my 1987 L98.

I've been hearing that the dreaded code 32 will pop and you'll have a hell of a time, but no pinging or knocking, which is fantastic. However, I've heard people with my exact same car (stock and with misplaced catalytic converters) never have an issue. I had my EGR temp switch (the one that sits inside the crossover pipe from exhaust to intake chamber) disconnected for the longest time, about a year, without a single code coming up. I also had my EGR solenoid switch disconnected for some time, without any codes or pings or knock knock who's there oh hello mr rod.

What I'm wanting to do for this little project is free up some space if I can misplace my EGR and AIR system. I am going to either buy new shortie headers, or use tin snips to cut off the existing small pipes from the AIR system and make them nice and pretty maybe some nice copper caps. I am going to gut the AIR pump so it's lighter and can be used as a free weight pulley. Block off the EGR and the crossover pipe. want to remove all AIR system piping, shove the pigtails elsewhere and call it a day.

I'm curious if this is at all possible on a stock engine without computer tuning. And who knows, now that I'm this far I'll go with speed density

 

AIR should not be an issue. EGR, probably and ECM tuning will fix. IIRC, we blocked off the EGR hole on my 91 F-body and it did come up.

 

I also blocked off the AIR and EGR on my 91 Z28 305 but had no codes. So that's why I'm asking, I'm sure I'll get different responses which make it a coin toss. I'll check and see if my local corvette specialist can tune my computer to not check. I appreciate the response! I'm just wondering what others ran into and if a code even showed its ugly face.

 

Hi

The EGR code only came on when on the highway at a steady speed when my car was fairly standard, I used tuner pro with an ostrich emulator to remove the EGR check.

Perhaps your car has had this done already?

 

AIR pushes air into the manifold when the O2 sensor isn't active so nothing happens. After which, air is pushed into the cat so again, nothing happens.

If you are interested, get someone to dyno tune the car and remove code 32

 

Deleted AIR and EGR on my 86, when it was stock. No issues and never set a code for EGR.

 

That's interesting. Mine comes on when I have done a certain amount of cruising. So maybe nothing for 5 minutes but it could come in minute 6, etc.

 

Let me search through my electrical diagrams and find out what the entire EGR system looks like. The fact that the temp sender and EGR solenoid have been disconnected without codes tells me the computer may have been messed with already. I'll see what I can find

 

My EGR fell off. Before it did, I noticed it won't trip the light every day but only when certain conditions are met. Maybe he didn't meet those conditions?

 

I dont see any sensor that measures the amount of exh gas recirculated. I think what triggers an EGR code is a open or ground in the solenoid circuit. Once the EGR solenoid is energized (by the ECM) it grounds the circuit through the ECM to make circuit power flow. If your EGR is disconnected w/o codes then i suspect someone has disabled this before u or your CEL is inoperative. Can scan for codes and see if there is one there? Can u real time scan to watch the EGR cyle? I can see my EGR cycle at low cruise speeds when i blip the throttle.

As for removing the AIR its not going to gain u any HP. The pre-electric powered units did add parasitic drag to the motor but the air injected does no harm to power - plumbing just looks ugly.

The EGR doesnt harm power at WOT either. I know it looks like a parasite but that vac signal drops to near zero at WOT and the EGR vlv cant open. Large overlap cams provide enough exh gas recirc they dont need EGR - take note as the LT4 had no EGR connection and a pretty mild cam too.

I guess what im saying theres not much emissions equipment worth removing for street performance as even todays Cat Converters flow pretty darn well also. Getting a good tune is way more inportant.

 

http://tech.corvettecentral.com/2012...egr-diagnosis/ does go into a lengthy explaination. Bottom line is I am not sure what happens when the temp sensor is disconnected. What does infinite resistance signify to the ECM? IDK.

It makes it hard to work on with another bunch of garbage in it. You are right that the power gains are so slight it isn't worth it from that standpoint unless you are full out racing but the access it grants is very good.

When you have to reach in and get cut or move the AIR stuff out of the way, it gets old pretty quick so cutting it off gives more clearance. Tried that with just capping off the pipes and found it was nicer without the 4 small pipes sticking up joining into 1 bigger pipe.

 

That's exactly what I'm going for Aklim, SPACE. I have a stock L98, I'm not looking to race anything or put it on the track. It's a daily driver. I do my own work to the car so why wouldn't I make it just slightly less painful on myself by removing all this cluttered piping when most of it has rusted away as it is.

Tomorrow I'll test by disconnected both sensors for the EGR and hit the highway to see if they codes will pop. If I do get a SES light I'll drop by my local corvette specialist to see what they can do, I wouldn't think it would be an expensive thing to do, right?

 

Not cool. I would be afraid that air could get into the rust holes and mess up the O2 sensor reading. Of course there is the argument that exhaust is under pressure but if the exhaust gas is going one way, could it create a Venturi effect and pull air? IDK. I'd remove it or at least seal it up.

I don't know what the conditions are for it to trigger so IDK. My Code 32 with the Accel Superram and Accel Tri-Y headers only popped up once in a while. Not sure how difficult to remove the code in the ECM program. You'd have to copy the program, UV light the EPROM, reprogram it WITHOUT code 32 or reset the conditions it appears. Not sure how much they will charge for all that. If it were me, I'd get a dyno tune and have them do it at the same time.

 

That article has a ton of incorrect information in it. The small holes in the intake runners are for the cold start injector and have NOTHING to do with EGR. The EGR gasses go through the small round pipe on the passenger side from the intake manifold to the plenum and then to the two small holes behind the throttle plates, like so:



I have heard of people deleting their EGR system and NOT getting a code 32. Some people DO get a code 32, so it's sort of random. Note that the SES light will go out if you stop and restart.

These are the conditions to get an SES light and error code 32 (I call it the "cruising down the road" error):

Error code 32: EGR temperature switch not grounded when EGR is commanded
Coolant temperature > 194°F (89.8°C)
EGR duty cycle commanded by ECM > 51.9%
TPS > 5.8%
TPS < 30%
Error codes 21, 22, 33 and 34 not present
EGR switch input on pin C15 not grounded after EGR commanded
All conditions must be met for > 256 seconds (4.27 minutes)

Note the TPS constraints. You must be cruising down the road at a pretty steady speed to meet the required conditions. The 4.27 minutes pretty much means you'll have to be on the highway to get this error.

 

I haven't spent any time with the EGR system since mine fell off the car. So according to the article, the determination in 90-96 is via the O2 sensor after some tests and pre 90 it was temp switch. IDK. Again, never checked since I don't have one or intend to put one. So how does it diagnose a problem? Is there a temp sensor in the OP's year? If you disconnect that, will it throw a code? IDK.

 

I have long tubes without EGR or AIR provisions. I get a code 32 every once in a while if i
have cruise control set but never without. This is NOT to say the cruise control affects the
EGR, but that my driving style doesn't seem to meet the parameters to enable EGR much.
Try it on your car and see. The tests you've already done point to this not being much of
an issue.

 

If the parameters stated by Cliff Harris are met, it will throw the code. One important thing is that all those conditions are met for 256 seconds. With cruise control, sure. Without, you might be hitting throttle and relaxing it so it might start the 256 second clock all over again.