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Corvette Forum Archive (38 950 posts)

Subject:
Re: EGR Valve on L98

From: "gjt" <gjtooley(at)bellsouth.net>

Subject: Re: EGR Valve on L98

Lines: 62

Date: Sun, 9 Sep 2007 09:46:55 -0500

Bytes: 3808

________________________________________________

Yep, that`s what the guy at Firestone told me. If left alone and not

corrected, the long term effect is loading up the CATs with carbon. He said

the CATS on an L98 are not cheap.

"Butcher" <butcher57(at)swbell.net> wrote in message

news:cuTEi.2105$ZA5.770(at)nlpi068.nbdc.sbc.com...

>

> "Eugene Blanchard" <blanchae(at)telus.net> wrote in message

> news:QhLEi.26498$Pd4.10951(at)edtnps82...

>> My answer is a little bit off topic but it concerns the egr valve. Don`t

>> know where you live but if you don`t have yearly smog tests to pass. I

>> suggest you block off the egr valve.

>>

>> Now I don`t have a 90s Vette but bear with me. On my 92 Ford Ranger, the

>> computer controls the EGR valve position using vacuum, then there`s an

>> EGR

>> position sensor to verify that its working. So disconnecting anything

>> brings up the Check Engine light and a trouble code.

>>

>> To get around the computer, I made a metal plate which matched the

>> outline

>> of the EGR valve gasket and installed it with the gasket. The EGR

>> position

>> sensor reports that the EGR is working and no error codes!

>>

>> Why block off the EGR? It recirculates the exhaust gas back into the

>> intake

>> manifold to reduce NOx emissions. Ideally, you want the coolest air in

>> the

>> intake, the EGR adds extremely HOT exhaust gas in. And it screws up your

>> fuel/air mixture - rather than clean outside air, you have hot CO gas

>> coming back in. The result is less power and poorer gas mileage.

>>

>> Blocking off my EGR valve increased my overall hp (every little bit

>> counts

>> on a 2.3l ford) and increased my gas mileage by 20% around town.

>>

>> http://www.cadvision.com/blanchas/Ranger/egr.html

>>

>> Comments?

>>

>

> Since my LT-4 doesn`t have an EGR valve because of additional cam overlap

> I`m assuming the valve is supposed to close when rpm/throttle increases

> (vacuum decreases, or should I say manifold pressure goes up), so it`s

> `active` only with little or no throttle. And since the ECU controls the

> mixture thinking the EGR is working I`m wondering if the mixture will be

> richer because of the blockoff (instead of just a cooler charge) --

> enriching mixture is usually a good thing for power and throttle off/on

> transition with these newer cars that run so lean, and more power means

> less throttle at any given power setting so mileage would go up a little

> maybe. But what about carbonizing the cat. over time because of the richer

> mixture? Maybe the fix will cause an expensive repair later on if the

> cats. are left in place and block up?

>

> Just a thought...

>

> Butcher

> `96 LT-4 CE

From: "Fixitman" <fixitman333(at)yahoo.com>

Subject: Re: EGR Valve on L98

Lines: 91

Date: Sun, 09 Sep 2007 17:34:21 GMT

Bytes: 4714

________________________________________________

Hmmm.... "badly stuck" can have two very different meanings:

The 1990 Vette has a basic negative backpressure EGR valve. It doesen`t have

an electrical connection, so the ECU cannot directly determine if it is

functioning. The ECU calculates EGR functionality based on changes in sensor

output (knock and O2) when it "expects" the EGR to turn on/off. If it

doesen`t see the change it expects, it will set a code 32 (EGR circuit). If

the EGR is stuck open, it will most likely set a code 45 (Rich exhaust). A

stuck-open EGR will reduce oxygen content in the combustion chamber at all

times though, resulting in poor performance (especially at idle).

basically...

Stuck open = runs bad, code 45 present, CAT damage possible

Stuck closed = runs well, no code 45, CAT damage doubtful

Fixitman

"gjt" <gjtooley(at)bellsouth.net> wrote in message

news:qHTEi.38647$wN3.27074(at)bignews2.bellsouth.net...

> Yep, that`s what the guy at Firestone told me. If left alone and not

> corrected, the long term effect is loading up the CATs with carbon. He

said

> the CATS on an L98 are not cheap.

>

>

> "Butcher" <butcher57(at)swbell.net> wrote in message

> news:cuTEi.2105$ZA5.770(at)nlpi068.nbdc.sbc.com...

> >

> > "Eugene Blanchard" <blanchae(at)telus.net> wrote in message

> > news:QhLEi.26498$Pd4.10951(at)edtnps82...

> >> My answer is a little bit off topic but it concerns the egr valve.

Don`t

> >> know where you live but if you don`t have yearly smog tests to pass. I

> >> suggest you block off the egr valve.

> >>

> >> Now I don`t have a 90s Vette but bear with me. On my 92 Ford Ranger,

the

> >> computer controls the EGR valve position using vacuum, then there`s an

> >> EGR

> >> position sensor to verify that its working. So disconnecting anything

> >> brings up the Check Engine light and a trouble code.

> >>

> >> To get around the computer, I made a metal plate which matched the

> >> outline

> >> of the EGR valve gasket and installed it with the gasket. The EGR

> >> position

> >> sensor reports that the EGR is working and no error codes!

> >>

> >> Why block off the EGR? It recirculates the exhaust gas back into the

> >> intake

> >> manifold to reduce NOx emissions. Ideally, you want the coolest air in

> >> the

> >> intake, the EGR adds extremely HOT exhaust gas in. And it screws up

your

> >> fuel/air mixture - rather than clean outside air, you have hot CO gas

> >> coming back in. The result is less power and poorer gas mileage.

> >>

> >> Blocking off my EGR valve increased my overall hp (every little bit

> >> counts

> >> on a 2.3l ford) and increased my gas mileage by 20% around town.

> >>

> >> http://www.cadvision.com/blanchas/Ranger/egr.html

> >>

> >> Comments?

> >>

> >

> > Since my LT-4 doesn`t have an EGR valve because of additional cam

overlap

> > I`m assuming the valve is supposed to close when rpm/throttle increases

> > (vacuum decreases, or should I say manifold pressure goes up), so it`s

> > `active` only with little or no throttle. And since the ECU controls

the

> > mixture thinking the EGR is working I`m wondering if the mixture will be

> > richer because of the blockoff (instead of just a cooler charge) --

> > enriching mixture is usually a good thing for power and throttle off/on

> > transition with these newer cars that run so lean, and more power means

> > less throttle at any given power setting so mileage would go up a little

> > maybe. But what about carbonizing the cat. over time because of the

richer

> > mixture? Maybe the fix will cause an expensive repair later on if the

> > cats. are left in place and block up?

> >

> > Just a thought...

> >

> > Butcher

> > `96 LT-4 CE

>

>

From: Eugene Blanchard <blanchae(at)telus.net>

Subject: Re: EGR Valve on L98

Lines: 57

Date: Mon, 10 Sep 2007 04:33:21 GMT

NNTP-Posting-Host: 205.206.115.90

Bytes: 3438

________________________________________________

Butcher wrote:

>

> "Eugene Blanchard" <blanchae(at)telus.net> wrote in message

> news:QhLEi.26498$Pd4.10951(at)edtnps82...

>> My answer is a little bit off topic but it concerns the egr valve. Don`t

>> know where you live but if you don`t have yearly smog tests to pass. I

>> suggest you block off the egr valve.

>>

>> Now I don`t have a 90s Vette but bear with me. On my 92 Ford Ranger, the

>> computer controls the EGR valve position using vacuum, then there`s an

>> EGR position sensor to verify that its working. So disconnecting anything

>> brings up the Check Engine light and a trouble code.

>>

>> To get around the computer, I made a metal plate which matched the

>> outline of the EGR valve gasket and installed it with the gasket. The EGR

>> position sensor reports that the EGR is working and no error codes!

>>

>> Why block off the EGR? It recirculates the exhaust gas back into the

>> intake

>> manifold to reduce NOx emissions. Ideally, you want the coolest air in

>> the intake, the EGR adds extremely HOT exhaust gas in. And it screws up

>> your fuel/air mixture - rather than clean outside air, you have hot CO

>> gas coming back in. The result is less power and poorer gas mileage.

>>

>> Blocking off my EGR valve increased my overall hp (every little bit

>> counts on a 2.3l ford) and increased my gas mileage by 20% around town.

>>

>> http://www.cadvision.com/blanchas/Ranger/egr.html

>>

>> Comments?

>>

>

> Since my LT-4 doesn`t have an EGR valve because of additional cam overlap

> I`m assuming the valve is supposed to close when rpm/throttle increases

> (vacuum decreases, or should I say manifold pressure goes up), so it`s

> `active` only with little or no throttle. And since the ECU controls the

> mixture thinking the EGR is working I`m wondering if the mixture will be

> richer because of the blockoff (instead of just a cooler charge) --

> enriching mixture is usually a good thing for power and throttle off/on

> transition with these newer cars that run so lean, and more power means

> less throttle at any given power setting so mileage would go up a little

> maybe. But what about carbonizing the cat. over time because of the richer

> mixture? Maybe the fix will cause an expensive repair later on if the

> cats. are left in place and block up?

>

> Just a thought...

>

> Butcher

> `96 LT-4 CE

You might of guessed it by now, but the cat is long gone...

--

Eugene Blanchard

http://www.cadvision.com/blanchas

Home of the DIY Hot Rod Kustom website

Last "Cars" Post on Wordpress:

Title: Volkswagen Golf R
Date: Fri, 25 Sep 2009 11:36:24 +0000
Author: symo

Primo: bisogna trovare una vera erede mk6 della sempreverde R32. Secondo: non è possibile che la Ford Focus RS sia sempre cosi avanti anni luce da tutte le altre (o quasi), bisogna trovare un modo di avvicinarsi alla concorrenza. Probabilmente questa può essere la volta buona, in Volkswagen sembra abbiano pensato davvero a tutto nella creazione di questa Gof R.

Dal punto di vista meccanico la R è mossa dall’ormai famoso TSI 2.0 litri 4 cilindri che abbiamo già visto su Audi S3, TTS o Scirocco R. Questo motore permette di erogare la bellezza di 270 CV a 6 mila giri/min e una coppia massima di 350 Nm in un range di 2500 giri/min (da 2500 a 5000 per la precisione).

Le prestazioni sono di assoluto rilievo: la massima è limitata a 250 km/h e l’accelerazione 0-100 varia di 2 decimi di secondo in base all’adozione del cambio manuale (5,7 secondi) o automatico DSG (5,5 secondi).

More on: http://wrongpassword.wordpress.com/2009/09/25/volkswagen-golf-r/

____________________________________________

Title: Porsche Carrera GT tuned by Konigseder
Date: Fri, 25 Sep 2009 14:58:00 +0000
Author: Safirutza

This Porsche Carrera GT has a new body kit released by Konigseder featuring alloy wheels, a new front and rear bumper and side skirts to give the car a more aggressive look, extra air vents, a larger air diffuser and a large fixed rear wing.

It has the factory 5.7 litre V10 engine that produces 612 hp and 590 Nm of torque.

More on: http://safirutza.com/2009/09/25/porsche-carrera-gt-tuned-by-konigseder/