EGR questions.

[QuickTop]

Ive got a lot of questions about getting rid of this EGR along with my new header install.. I plan on getting some pacesetter LT's. and i figured while im working in that department ill ditch the EGR/A.I.R regulators. but ive heard stories about OBII cars that will not start after a EGR delete. so bascially to make this as short as possible im wondering is it possible to tune my PCM (say with SB's street tune) to get rid of the error codes an EGR delete will cause before the EGR is deleted. the car is my DD so i would like to have it out of action for a weekend at most.. Thanks guys.

[Fox Slaughter]

Once again another reason to switch to OBD1 .

EGR is Exhaust Gas Recirculation. Basically what it does is, it takes exhaust gases, injects them back into the intake manifold to make another trip through the cylinder to attempt to burn off everything in the exhaust.

It also only does this under certain conditions.

As far as OBD2, hell I pulled it off my Saturn to clean it, you start the car up and it will idle high, vacuum leak. Never had a problem starting at all.

[QuickTop]

didnt justin just have huge issues with his EGR and it not starting..?

[Fox Slaughter]

I don't know who Justin is

According to a 95 stock tune,

EGR acctives at
36.2kpa on the MAP
Min RPM of 900
Max RPM of 2100
Min Coolant temp of 50c (high start IAT)
Min Coolant temp of 82c (low start IAT)

So by the sounds of it, and the nature of the EGR. It is not operating during the start procedure.

[Sic96]

didnt justin just have huge issues with his EGR and it not starting..?

Yes.. yes he did. If you remove the EGR, as I did for the new headers as well, get it deleted from the PCM. PCMFORLESS did mine in a couple days. you can either send them your PCM, or they'll send you one until yours is done in case it's your dd. It only took three days though from the day i shipped it, they're located in Stow, OH. But yes, have them delete the EGR, AIR, and whatever else. they'll calibrate your tire sizes, cooling fan times based on thermostat (like a 160), and anything else you need for $190.00. It's super easy and well worth the money, and just the tune alone will net you some decent hp increases! As SMAN stated, some cars don't really react to having the EGR removed, but mine did! And from what i've been told, most will and should on OBD2 cars. I cant really vouch for SB tunes, but no matter who does it, as long as they are reputable, you should be fine. HowellEFI.com will do it also, located just north of Detroit. check them out also.

[QuickTop]

I just realized i should just call Steve himself and ask him this question. lmao hindsight

[Fox Slaughter]

"EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle. The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions)."

"In most modern engines, a faulty or disabled EGR system will cause the computer to display a check engine light and the vehicle to fail an emissions test."

As far as Justin, what were the mods done and what did you have tuned?

I highly doubt a EGR would cause the car not to start. A EGR will get clogged with carbon and not function, the car will still run just fine. Its only an Emission device.

[Sic96]

"EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle. The EGR valve also cools the exhaust valves and makes them last far longer (a very important benefit under light cruise conditions)."

"In most modern engines, a faulty or disabled EGR system will cause the computer to display a check engine light and the vehicle to fail an emissions test."

As far as Justin, what were the mods done and what did you have tuned?

I highly doubt a EGR would cause the car not to start. A EGR will get clogged with carbon and not function, the car will still run just fine. Its only an Emission device.

I tuned it out and it ran great.. before that it would not run for shit. pcmforless told me it wouldnt run on 96/97 cars without being tuned out. You are right though, the egr does not affect the start-up, or high acceleration situations. My car always started and idled, but the second i put it in gear and touched the gas, it fell on its face. My neighbor also confirmed this, and he's been building LT1's a looong time. SO idk.. I took some people's advice and it worked like a charm. the only thing that was different on the car than before was the EGR. Nothing else changed. The car was running great, I blocked the egr, and it never ran again until the tune, simple as that. I tuned it for LT headers and what not, but they aren't even on the car yet.
As far as EGR just being an emissions deal, so are the cats. Yet, when they clog and aren't functional, it can drastically change the way the car performs, if it allows it to run at all. I know they are two totally different scenarios, but still the same concept applies. And either way, why not just tune it out and remove the light anyway, regardless if it affects the performance or not. Let us know what SB tuning says, I'm curious if he will give the same info as what i was told.

[00firebird]

I can't say about the older cars but I deleted mine off a 00 3.8 and there was literally no difference. I did it because I broke the tube while taking my upper/lower intakes off and it wasn't worth buying a new egr tube especially after I just acid washed the black gunk out of my upper. I got the block off plates from ZZP and all is well. The top plate required a little modification for my car, I put some sand paper on an orbital buffer and trimmed an edge down so it fit better.
The SES light stays on until you get the code deleted but it doesn't make the car drive any different. YMMV.

after modifying:


before modifying:
IF you have this problem with the bottom plate, flip it upside down and rethread the bolt. because one side will not line up since the bottom plate is threaded. I guess you could also get two plates that are unthreaded.

[meissen]

Yikes, lots of opinions and debates on the subject going on but at the end of the day, if you're going to have it tuned by Steve anyway, I'm positive he could tune out the EGR for you before you delete the EGR. That would be the best and safest way to do it.