EGR: leave plugged or clean it out ??
04-06-2004, 09:29 AM
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EGR: leave plugged or clean it out ??
EGR: leave plugged or clean it out ??
97 maxima se:
Took my car to the dealership last week. (97 Maxima) they said the egr is completly plugged with carbon deposits. I also have a service engine light on addressing the egr hi/low flow.
they said i should leave it plugged because if it was cleaned out i would lose HP.
after reading the article below, i wonder if i should try cleaning it out: i race the car for fun and have a upgraded ecu which does cause some pinging. i also plan to mix some 100 octane unleaded gas next time at the track.
looking for other opinions and experience with this -
Online Article:
Most people like to disable the EGR because they claim that hurts performance. In actuality, disabling the EGR can hurt performance. Here is why. As we already know, at certain throttle positions and RPMs, the ECM will command EGR operation. This is to cool combustion chamber temps under load. Well, with cooler combustion chamber temps, we can further fuel economy by advancing the timing. We know that to much timing will cause "pinging". But when we keep the combustion temps down, the timing can be advanced without the "pinging" effect. At highway speeds, the ECM commands EGR operation and will advance timing accordingly. With a blocked of EGR, the computer thinks it is flowing when it is not and will advance timing. Now that the combustion chamber temps are much hotter, the advanced timing is no longer a good idea and detonation occurs. Since detonation can severely damage an engine, knock sensors are used. When the knock sensor detects detonation, it will retard timing. It takes more to stop detonation that it does to cause it and this is where it hurts performance. For example, at highway speeds, your total advance may be, lets say 30° BTDC. If the computer advances it one more degree to 31° and it detects detonation, it can't just go back to 30° to stop it, it must retard timing to like 25° to try and stop it, and if it still occurs it will further retard timing. If the EGR was working properly, the temps would have stayed cool enough to operate at 31° with no problems.
thanks for the help not sure what to do ?
97 maxima se:
Took my car to the dealership last week. (97 Maxima) they said the egr is completly plugged with carbon deposits. I also have a service engine light on addressing the egr hi/low flow.
they said i should leave it plugged because if it was cleaned out i would lose HP.
after reading the article below, i wonder if i should try cleaning it out: i race the car for fun and have a upgraded ecu which does cause some pinging. i also plan to mix some 100 octane unleaded gas next time at the track.
looking for other opinions and experience with this -
Online Article:
Most people like to disable the EGR because they claim that hurts performance. In actuality, disabling the EGR can hurt performance. Here is why. As we already know, at certain throttle positions and RPMs, the ECM will command EGR operation. This is to cool combustion chamber temps under load. Well, with cooler combustion chamber temps, we can further fuel economy by advancing the timing. We know that to much timing will cause "pinging". But when we keep the combustion temps down, the timing can be advanced without the "pinging" effect. At highway speeds, the ECM commands EGR operation and will advance timing accordingly. With a blocked of EGR, the computer thinks it is flowing when it is not and will advance timing. Now that the combustion chamber temps are much hotter, the advanced timing is no longer a good idea and detonation occurs. Since detonation can severely damage an engine, knock sensors are used. When the knock sensor detects detonation, it will retard timing. It takes more to stop detonation that it does to cause it and this is where it hurts performance. For example, at highway speeds, your total advance may be, lets say 30° BTDC. If the computer advances it one more degree to 31° and it detects detonation, it can't just go back to 30° to stop it, it must retard timing to like 25° to try and stop it, and if it still occurs it will further retard timing. If the EGR was working properly, the temps would have stayed cool enough to operate at 31° with no problems.
thanks for the help not sure what to do ?
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