L98 EGR System
Thread Starter
Burning Brakes
Joined: Nov 2003
Posts: 1,234
Likes: 5
From: Herriman UT
L98 EGR System & Pinging
I've read the function of the EGR system is to introduce exhaust gassess into the intake under light throttle conditions. This lowers combustion temperatures which reduces NOx emissions and also reduces the tendency to ping.
I've noticed increased pinging lately under moderate / heavy throttle along with intermittant Code 32. Question; Would a malfunctioning EGR system cause pinging at moderate to heavy throttle conditions?
I've noticed increased pinging lately under moderate / heavy throttle along with intermittant Code 32. Question; Would a malfunctioning EGR system cause pinging at moderate to heavy throttle conditions?
Last edited by geezel; Aug 13, 2004 at 06:26 PM.
Instructor
Joined: Jun 2004
Posts: 249
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From: clinton ut
What I think I know is NOX forms fast above 2500 degrees F. EGR introduces 6% to 10% exhaust gas as an inert medium that does not burn so fuel charge is less than it would be without EGR. That cools the combustion chamber below 2500 degrees. EGR systems work mainly at cruise speed and acceleration between 30 and 70 mph. Slight timing retard also reduces NOX somewhat. NOW, would it cause pinging? Well I suppose if it was not working the temperature would reach 2500 or greater and detonation could be a problem. I think so but others need to help out since I pulled most of this from a book!!!
Advanced
Joined: Feb 2004
Posts: 51
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From: Mission Viejo CA
Depending on the mileage and condition of your car, there could be many reasons for the pinging under moderate and heavy throttle applications. However, since you are getting an intermittent code 32, I would address that as well as making sure that timing is set correctly and that you're using gasoline with the required octane rating. (I don't know what year your Vette is). If you have a L98, you'll need to remove the plenum; not difficult, just time consuming. Make sure that the vacuum signal to the EGR valve is working correctly. There may also be an obstruction in the passage between the EGR valve and intake manifold. This is where the Helm's manuals come in real handy.
Time to roll up your sleeves.... Good luck....
Just noticed your Sig....did this just start to happen? What is different now? You can see where I'm going with this, right? Time for systematic troubleshooting...
Time to roll up your sleeves.... Good luck....
Just noticed your Sig....did this just start to happen? What is different now? You can see where I'm going with this, right? Time for systematic troubleshooting...
Last edited by mvmechanic; Aug 13, 2004 at 06:44 PM.
