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Subject:
Re: EGR Valve on L98
From: Eugene Blanchard <blanchae(at)telus.net>
Subject: Re: EGR Valve on L98
Lines: 45
Date: Sun, 09 Sep 2007 05:13:20 GMT
NNTP-Posting-Host: 205.206.115.90
Bytes: 2784
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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?
gjt wrote:
> `90 L98 Vert. Service Engine Light would come on after about 15 minutes of
> driving. Any time I would turn off the engine, it would reset. Comes
> right
> back on when it warms up. Took it to local Firestone. They said my EGR
> valve was badly stuck. Said if I continue to drive as is, the Cats would
> eventually load up with Carbon. They want $450!!! I think this is a bit
> excessive. Is there something about an L98 that makes this a difficult
> job? From doing some searches, looks like the going rate for the valve is
> around $70.
>
> Thanks for your input.
> gjt
--
Eugene Blanchard
http://www.cadvision.com/blanchas
Home of the DIY Hot Rod Kustom website
From: "gjt" <gjtooley(at)bellsouth.net>
Subject: Re: EGR Valve on L98
Lines: 95
Date: Sun, 9 Sep 2007 07:15:30 -0500
Bytes: 5571
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Excellent info. Thank you!!!!!!!!!
"Joe" <Joe(at)yahoo.com> wrote in message news:fbvmp6$nij$1(at)aioe.org...
> gjt wrote:
>> Thanks guys......
>>
>>
>> "Dad" <knockers(at)fisher.net> wrote in message
>> news:hpCdnZUoR-6Cu37bnZ2dnUVZ_r2nnZ2d(at)bright.net...
>>> "Bob I" <birelan1(at)yahoo.com> wrote in message
>>> news:x2EEi.567$ZU7.7(at)newsfe04.lga...
>>>> Dunno about space issues on a `90, but I did the one on our `95 in
>>>> about a half hour and that included waiting for the flat black paint to
>>>> dry, because the replacement was cadmium plated and the original was
>>>> flat black. I believe I gave about $65 for the valve at NAPA, so $70 is
>>>> about right. Firestone will charge you dealer retail for the valve, so
>>>> figure they will get what, maybe $140 for the valve, plus all the
>>>> "nickle and dime" stuff like handy wipes and environmental disposal,
>>>> and what ever other charges they can pad the bottom line with. Just
>>>> make sure you get a clean gasket surface before you bolt it up.
>>>>
>>>> gjt wrote:
>>>>> `90 L98 Vert. Service Engine Light would come on after about 15
>>>>> minutes of driving. Any time I would turn off the engine, it would
>>>>> reset. Comes right back on when it warms up. Took it to local
>>>>> Firestone. They said my EGR valve was badly stuck. Said if I continue
>>>>> to drive as is, the Cats would eventually load up with Carbon. They
>>>>> want $450!!! I think this is a bit excessive. Is there something
>>>>> about an L98 that makes this a difficult job? From doing some
>>>>> searches, looks like the going rate for the valve is around $70.
>>>>>
>>>>> Thanks for your input.
>>>>> gjt
>>> Bob`s right on the money on this exercise ACDelco is the cheapest valve
>>> at $60/$65 and they have 2 numbers 2145535 and 2141429 (plastic vacuum
>>> fitting). Airtex is $70 and a metal fitting but shows no gasket with it
>>> so check before you get back to work and there is none, FEL-PRO gasket
>>> part # 70954, and ACDELCO part # 10077547. Wouldn`t be a bad idea to
>>> remove the valve to take it with you, but before you do that clean it
>>> and the manifold up and see if the diaphragm will hold a vacuum and work
>>> the plunger, if so put it back with the new gasket. The $450 repair just
>>> became a $2 job.
>>>
>>> --
>>> Dad
>>> 05 C6 Silver/Red 6spd Z51
>>> 72 Shark Black/Black/4spd
>>> 64 Red/red/white top/4spd
>>>
>>
>>
>
> Take a close look. My `89, and I think all of `85 - `91 had the EGR under
> the plenum --
> not out in the open as in the LT1.
>
> If this is the case, you`ll need a set of Torx bits and a flare wrench to
> remove the plenun and the vacuum lines. It`s tight but you can get the
> EGR out without pulling the runners.
>
> As Bob says, get the little gasket for the EGR. Shop around and get a
> partial intake gasket kit...one with just the gaskets between the runners
> and the plenum. New throttle body gasket is also a good idea.
>
> If the `90 has a MAF, remove it but leave the throttle body hanging.
> Disconnect the vacuum hoses to the plenum and check for an electrical lead
> to a MAT sensor on the bottom of the plenum ...might not be one on the
> `90. Gently tap the plenum to break it loose from the runners and lift it
> out, vertically so as to not scratch the mating surfaces or drop broken
> gasket material down the runners.
>
> Should be about two hours coming apart, 30 minutes to swap the EGR and
> clean up the intake mating surfaces and a couple of hours putting stuff
> together again. If the car has over 80K miles it might be good to clean
> the inside of the plenum
>
> Looks like you`re making about $ 85 an hour and have some "free" tools for
> the next job.
> Six-pack isn`t included in this pricing. (8-O
>
> Suggestion: Not that I don`t trust the highly qualified Corvette
> specialists at Firestone... however, before you leap into this, dump the
> codes and make sure you`re dealing with an EGR issue.
>
> The Haynes C4 manual has some tests that can be run on the EGR. Making
> sure there`s vacuum to the EGR is a good idea-- a vacuum leak would
> prevent the valve from working.
>
> HTH
> --
> pj
> `89 auto / `02 6-spd
From: Bob I <birelan1(at)yahoo.com>
Subject: Re: EGR Valve on L98
Lines: 58
Date: Sun, 09 Sep 2007 09:02:27 -0500
NNTP-Posting-Host: 66.188.214.61
Bytes: 3914
________________________________________________
At least on the `95, the ECU command to the EGR control valve and if it
doesn`t "see" the expected manifold pressure change, sets the check
engine light. As for "blocking" it off, well the purpose is to reduce
the amount of "excess o2" and reduce combustion chamber temperatures to
preclude the formation of NOX, during specific operating conditions
(primarily LOW output levels, meaning cruise and small throttle
openings) Visualize not very much fuel being injected to need available
oxygen. So they replace some of the pumped volume with a gas that has
the oxygen removed. Cooling the intake charge is good for maximizing the
amount of oxygen available for WOT conditions, but please tell me how
much time you spend there!!! If blocking off the recirculation resulted
a 20% increase, I would surmise there was a lot more "broken" and not
functioning on that Ford than just the EGR valve controls. Given CAFE
fines, I doubt the manufacturer is going to "give up" 20% gas mileage to
reduce NOX emission with an EGR valve.
Eugene Blanchard wrote:
> 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?
>
> gjt wrote:
>
>> `90 L98 Vert. Service Engine Light would come on after about 15 minutes of
>> driving. Any time I would turn off the engine, it would reset. Comes
>> right
>> back on when it warms up. Took it to local Firestone. They said my EGR
>> valve was badly stuck. Said if I continue to drive as is, the Cats would
>> eventually load up with Carbon. They want $450!!! I think this is a bit
>> excessive. Is there something about an L98 that makes this a difficult
>> job? From doing some searches, looks like the going rate for the valve is
>> around $70.
>>
>> Thanks for your input.
>> gjt
>
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