I finally got my very own code 32 problem! Probably just bumped it wrong when I was replacing my heater core hoses.

I think I get the +s and -s of removing EGR (both political and mechanical), but I'm curious what everybody else thinks. If you're me, do you pull the EGR (and ignore the occasional SES light or burn a new PROM) or fix it?

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Joel Geerling
Red 91 Formula, 305 TBI
Edelbrock 14x3 open element
TBI 1/2" spacer
Hypertech street chip
Crank/Alt Pulleys
*
Exhaust is next!

 

Fix it. If you let the ses light come on you won't be happy and neither will your ecm. If you trick it into thinking it's working when it isn't. The fuel and spark will be changed so that you'll probably end up getting knock.

 

Pull it. I've ran mine without it for a long-*** time (just pulled the SES bulb 'till I fixed the chip). You should adjust the chip so the light doesn't come on, if you've got the stuff to do it.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

You do understand that EGR alows the engine to run with more spark and less fuel right? So if you don't have EGR working your combustion chamber temps are going to be high (because of the amount of oxygen). With a high combustion chamber you can't run much spark or you'll get knock.
The only right way is to either disable EGR by turning the on temp in the eprom really high, or fix the EGR. Since you probably don't feel like spending $$$ for a fastchip with just EGR disabled, I would recommend fixing the EGR because it's the cheapest mod and it doesn't hurt performance.

 

I didn't have any problem with knock after I got rid of mine. I only run the 93 octane in my car, if that makes a difference. It was alot easier to get rid of it than fix it is why I got rid of mine. Now that I've got L98 heads and a Torker II intake EGR is out of the question anyway.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

I would keep it. I can't tell you that your wrong if take it off, because I HAD to remove mine for the time being (EGR to IAC clearance).

I program my own chips so I just set it not come on. If I could I'd be using it 'cause it keep combustion chamber temps down.

The old hot-rodder thing of taking it off to get more performance is crap. The EGR valve never comes on when your running it hard anyway, so I don't think it's worth the trouble its gonna cause you.

I have a 2 week old ACD EGR valve that I can't use anymore b/c the intake I have takes a different kind. E-mail if you are interested.

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'92 Astro, GM crate 350, Holley Pro-Jection Intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's, Polished & Bored TBI, Custom EPROM in progress

[This message has been edited by V8Astro Captain (edited November 17, 2001).]

 

i havent had egr on my car in two years. since i took it out i have had no codes for it. before i took it out i used to get the good old 32 once in a while. go figure...

i have had no problems without it as far as the computer goes. just my $.02.

-brian

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1991 Camaro RS
GMPP 350 HO crate engine - 454 TBI, MSD ignition, SLP exhaust, everything is new
700R4 - 2,400 stall converter, vette servo, shift kit
My car's webpage - z28boy.cz28.com
President - Central New York F-Body Association
Email - z28boy@twcny.rr.com
AIM - "Z28 Boy"

 

Relocate to EGR valve to the nearest trash can. It has no business on a performance car. Plain and simple. Do you see top fuel dragsters with EGR?
NO EGR is not a performance option. I will agree with everyone on the blahbalha less fuel less knock kinda stuff, and on a daily driver beater car that you did not care about it would be a good thing.
As far as I am concerned it is cluttering up my engine bay, and looks plain ugly.
and as soon as you guys see an EGR valve on a dragster let me know and I will remove my block off plate and stick one in there and reprogram my 7747 to use it.

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69 Chevelle 2dr hardtop blue, bench seats, 12 bolt w/3.73's muncie 4 speed. TBI w/custom harness and prom best 14.5@90

 

 

EGR doesn't hurt performance so.....that's all I have to say.

 

Um... let me put my two cents in. I would have to say the EGR DOES hurt performance. We all know what EGR stands for, but for those who don't, it's Exhaust Gas Recirculation). When an EGR valve opens, it is allowing the exhaust (or better put) SOME exhuast in the the intake manifold where it then goes in the clynder.

Exhuast is previously BURNED air/fuel mixture. Sure, there are SOME fumes still in the exhaust that can be burned, but part-for-part not a whole heck of a lot.

What is going to give more power when burned? 100% fresh air/fuel mixture or a smaller percentage of fresh air/fuel mixture with pre-burned air/fule mixture (a/k/a Exhaust)? Personally, I'm going for the 100%!!! But for street, and to be able to pass a year state inspection, I'll deal with the EGR.

Also, (and I'm asking this question as I don't understand it) I see a few posts that stated with the EGR functional, it keeps the combustion temps down. How is that when the exhaust is 600+ degrees and the fresh air/fuel coming into the cylinder is far less cooler?

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89 T-Top Firebird 305 TBI Project Car (with approval from my wife!)

[This message has been edited by Nitroburn (edited November 19, 2001).]

 

Nitroburn,

I have wondered that myself... the explanation I've always heard is that, since the exhaust gas is basically inert (like you said, already burned), most of it doesn't combust (x,000 degrees F?) with the rest of the air/fuel mixture in the cylinder... but, compare that with the fact (like you said) that you just skyrocketed the temperature of the incoming air/fuel mixture from roughly air temperature to 100s of degrees, is this "cooling" effect really that significant? My first impression was that the exhaust would heat up the mix so much that you could have combustion before the spark, but I guess I'm wrong b/c I've never seen that happen with EGR...

How bout it? Any thermodynamic physicists or chemists out there want to clear this up?

 

You guys are forgetting one thing: EGR is off when you go WOT or whenever the ecm is in PE (power enrichment) mode.
So I will say it again, "EGR doesn't hurt performance." It only increases gas milage and adds a few extra pounds to the front end.
Everybody understand this? Yes EGR lets in exhaust gas, this gas should have very little oxygen in it so basically it's the opposite of N2o. N2o has more oxygen so more fuel and you'll get a hotter flame and more power, less oxygen and less fuel = cooler combustion chamber so you can run less fuel (gas milage) and more timing.
EGR turns off instantly when you mash the pedal.

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, Jon (350 TBI!)
91 Red My website

 

Jon,

I was glad to see you reply with the EGR not being in use at WOT. I was wondering how long it would take........

 

*Sigh*

Now how in the world is EGR going to hurt performance. In the 7747 ECM, it's only on when the TPS% is between 1.92 - 3.12!!! And when the manifold pressure is 32.57 - 38 kPa.

OOOO it's gonna hurt your performance AT IDLE, oh no! Those requirements may be meet when you are on the highway at a very light cruise, but when you get more than 3.12% TPS and 38 kPa it turns off.

Basically, when you want power, it TURNS OFF.

Like I said before, only on the old cars when it was connected to a timed vacuum port is when you didn't want it.

As for the combustion temp, yes it cools it down. The flame front in the cylinder is somwhere around 1500*F (?). When you pump in exhaust gas that is 500-600, it doesn't seem like a whole lot. Think of it this way. High octane gas is more dense and therefore is LESS volitile. So you can run more timing without the risk of it going off by itself (detonation). Pump in exhuast gas and make the air/fuel less volitile and run more timing like before, and use some of the unburned gases and reduce the NOx emissions. NOx gases are only formed at very high temps, so they use exhaust gas to keep them from forming. Now don't say that I told you EGR is the same as high octane gas. You are trying to achieve two different things with them.

[This message has been edited by V8Astro Captain (edited November 24, 2001).]

 

I gotta agree with JPrevost on this one only because of a problem I had with my EGR. My EGR was messed, dont know how it happened, but it would not go off at WOT or under hard acceleration. I would end up getting knock and it would throw off the timing and then I had major power loss and bad gas mileage. My mechanic explained it to me and he said unless your car is for strick drag racing and you don't do any daily driving at all it is a good idea to use it on your car. It is fixed and I can tell a big difference, I am glad I have it on my car.

 

Please accept this as a real long story shortened to a practical posting limit.

ALL engines (oem 3rd Gen) have some EGR. Period.
Any time both the intake valve and exhaust valve are open, there is some EGR taking place.
On a high performance engine, when you change cams, you increase this self EGR'ing. So you'll want to disable the add on EGRs so that you don't OVER EGR the engine.
The reason you have to run more timing at idle with a bigger cam, is due to the increased self EG'ing.

Top Fuelers have all the EGR they can stand, just thur the cam profiles they run.

EGR for better mileage is a joke in my book, it's an engineers thing. Just falls apart in the real world.

Exhaust back pressure at WOT can OPEN an EGR valve, so yes they do effect WOT preformance. If in doubt, build a little cats whisker movement detector like I did, and find out for sure.

Removing an EGR valve violates Federal law, so is for off highway use only. Same with some cams, and exhaust system can affect the EGRs operation too.

If you eliminate the EGR, recalibrate the timing and fuel to compensate. There can be little gotchas.

The only way to understand what your engine is doing is to fully comment the code, and burn your own chips. Hacs are good but can be inaccurate.

The self EGR of a motor is what controls the ATOMIZATION of fuel as the intake valve opens. Feel free to contact the engineering department at Ford for further details on that. Just you have to to find your own inside guy, as they don't print their R+D on the Net.

Books by Heywood, and Heyt (?) help explain the above.

Nothing is really as easy as it appears

Not to be done without adult supervision
Refrigerate after opening

 

The worst thing about an EGR valve is the carbon it lets get in your engine on the intake side.

 

hahah thank you Grumpy.

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69 Chevelle 2dr hardtop blue, bench seats, 12 bolt w/3.73's muncie 4 speed. TBI w/custom harness and prom best 14.5@90

 

Mines out along with no cat. It runs fine minus the gas mileage problem (which I was having long before removal of EGR).

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Brady
"I see myself as a huge fiery comet, a shooting star. Everyone stops, points up and gasps "Oh look at that!" Then- whoosh, and I'm gone...and they'll never see anything like it ever again... and they won't be able to forget me- ever."~Jim Morrison

 

EXACTAMUNDO!! Your EGR might turn off at WOT, but it doesn't miraculously undo all the carbon buildup in your intake and on the back of your intake valves.



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Romeo Barrera
rbarrera@cfl.rr.com
84 vette 4+3, 24k miles Melbourne, Fl

 

While yes, it allows some Carbon particles back into the intake tract, but the carbon build up on the back of the intakes is a more a function of the additive package of the fuel your tunning then anything else. Normally if it's letting larger particles like from deposits breaking lose, it starts to hang the EGR valve open.
Water Injection is the cure for carbon build up.

 

Actually, it's the cure for EGR too. It performs the same functions as EGR but better. Cools combustion temps, cleans things up, and there's no power loss and possibly a gain with it.



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Romeo Barrera
rbarrera@cfl.rr.com
84 vette 4+3, 24k miles Melbourne, Fl

 

This ones for you JP
http://www.tupics.com/members/Cmartz/EGREvil.jpg

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69 Chevelle 2dr hardtop blue, bench seats, 12 bolt w/3.73's muncie 4 speed. TBI w/custom harness and prom best 14.5@90

 

Cmon Prevost!!!! Look!!

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69 Chevelle 2dr hardtop blue, bench seats, 12 bolt w/3.73's muncie 4 speed. TBI w/custom harness and prom best 14.5@90

 

haha


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90 RS 305 tbi, 4 3/4" cowl Hood, Edelbrock TES headers, Flowmaster exhaust, Crane roller cam, comp roller rockers, vortec heads/intake, ported tbi, w/new injectors, MSD probillet Distributer/ coil, 1 inch tbi spacer, air foil, 14x4 k&n flat base air cleaner, Rebuilt 700r4 w/ B&M shift kit, B&M Megashifter, 3.23 posi, 2 12 RF's with mtx amp, top of line alpine cd player,autometer phantom gauges, soon to have 91-92 gfx, z-28 wing, new paintjob, rims, all new suspension, and new inteior