I failed emissions for NOX, and my mechanic tells me that while my EGR valve works, the problem is the solenoid that operates it.
The problem is, I'm searching for a replacement KA and don't want to put money into my current one. At the same time, I'm running out of time as I only have until Sept 9th to pass emissions.
So on to my question... assuming a solenoid is just a switch, can I just set the EGR valve to open or closed, which ever it's supposed to be for emissions and sweak through my test ?
I would really appreciate any input you can provide.
Can the EGR valve be operated manually ?
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Kinesthesia
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Kinesthesia
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I pulled this from another forum and I think the answer is in here somewhere...
Changes in the exhaust backpressure affect the BPT which controls the EGR and thus emmisions. Headers, Free flow CAT exhuast will cause problems. The exact reason is stated below:
The BPT controls the amount of vacuum the EGR sees and hence the amount of Exhaust Gas recirculation. The BPT is between the EGR and the vacuum source.
The EGR operates from 8" HG vacuum to 2" HG vacuum (medium throttle). At high vacuum (closed throttle) the EGR solenoid shuts of the vacuum to the BPT and thus the EGR.
The BPT controls the amount of vacuum the EGR sees and thus the amount of exhuast gas recirculation. It does this by having a calibrated leak in line with the EGR vacuum line. The BPT utilizes Exhaust Manifold Pressure to actuate a diaphram, which opens or closes the air leak, variing the amount of vacuum the EGR sees. Low exhaust back pressure (deccelerating, closed throttle)OPENS the air leak and drops the vacuum to the EGR thus closing the EGR and limiting the exhaust recirculation. High back pressure CLOSES the air leak and increases the vacuum the EGR sees allowing more exhaust recirculation.
Basically the BPT controls the EGR so that the proper amount of Exhaust is recirculated as per engine RPM and throttle position.
The problem with the BPT is it is a CALIBRATED System. It is calibrated to the exhaust back pressure produced by the stopck CAT, Exhuast and Headers. Change any of these and you effectively lower back pressure (free flowing exhaust = less backpressure) This causes the BPT to close the air leak less than normal and thus the EGR does not see the correct amount of vacuuum. Since the EGR sees lower vacuum than it should for engine RPM and Throttle Postion, less EGR is recirculated than should be.
This leads to failed emmissions tests simply because not enough EGR is being recirculated. The BPT is not calibrated for the lower back pressure. CAT Back systems should be fine, but replacing the headers will usually lead to a problem with the e-test.
The BPT needs a weaker spring to accomodate the lower back pressure. Or you can restrict the air leak, by restricting the filter on the BPT valve. Restrict the air leak until you encounter drivabilties issues then back off the restriction slightly (duct tape the filter)
Posted by:Mike92 LE COUPE
Changes in the exhaust backpressure affect the BPT which controls the EGR and thus emmisions. Headers, Free flow CAT exhuast will cause problems. The exact reason is stated below:
The BPT controls the amount of vacuum the EGR sees and hence the amount of Exhaust Gas recirculation. The BPT is between the EGR and the vacuum source.
The EGR operates from 8" HG vacuum to 2" HG vacuum (medium throttle). At high vacuum (closed throttle) the EGR solenoid shuts of the vacuum to the BPT and thus the EGR.
The BPT controls the amount of vacuum the EGR sees and thus the amount of exhuast gas recirculation. It does this by having a calibrated leak in line with the EGR vacuum line. The BPT utilizes Exhaust Manifold Pressure to actuate a diaphram, which opens or closes the air leak, variing the amount of vacuum the EGR sees. Low exhaust back pressure (deccelerating, closed throttle)OPENS the air leak and drops the vacuum to the EGR thus closing the EGR and limiting the exhaust recirculation. High back pressure CLOSES the air leak and increases the vacuum the EGR sees allowing more exhaust recirculation.
Basically the BPT controls the EGR so that the proper amount of Exhaust is recirculated as per engine RPM and throttle position.
The problem with the BPT is it is a CALIBRATED System. It is calibrated to the exhaust back pressure produced by the stopck CAT, Exhuast and Headers. Change any of these and you effectively lower back pressure (free flowing exhaust = less backpressure) This causes the BPT to close the air leak less than normal and thus the EGR does not see the correct amount of vacuuum. Since the EGR sees lower vacuum than it should for engine RPM and Throttle Postion, less EGR is recirculated than should be.
This leads to failed emmissions tests simply because not enough EGR is being recirculated. The BPT is not calibrated for the lower back pressure. CAT Back systems should be fine, but replacing the headers will usually lead to a problem with the e-test.
The BPT needs a weaker spring to accomodate the lower back pressure. Or you can restrict the air leak, by restricting the filter on the BPT valve. Restrict the air leak until you encounter drivabilties issues then back off the restriction slightly (duct tape the filter)
Posted by:Mike92 LE COUPE
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sleepyRPS13
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so where you're at they test your car by testing the obdII? i guess i'm lucky here in tn they test my car with a sniffer. my car failed its test twice before passing. on that lucky day i had the timing retarded, lower idle and a new cat. the aiv and egr are both removed on this car. a new cat can go a long way.
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Kinesthesia
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Thanks Eddiec, that's good to know.
My car is OBDI and failed the sniffer test.
I have a tankful of 87 octane with CRC's "Guaranteed to Pass" in it. Sometime this week, I'm going to Seafoam my motor directly than replace the O2 sensor and plugs, refill with 87 octane and roll the dice again. I may retard the timing as well.
How can you lower the idle ? Although here I don't think it matters, they run the car at various speeds.
I'm about a week away from ordering a BRM exhaust and cat, but I'm running out of time to pass so I probably won't have it in time.
My car is OBDI and failed the sniffer test.
I have a tankful of 87 octane with CRC's "Guaranteed to Pass" in it. Sometime this week, I'm going to Seafoam my motor directly than replace the O2 sensor and plugs, refill with 87 octane and roll the dice again. I may retard the timing as well.
How can you lower the idle ? Although here I don't think it matters, they run the car at various speeds.
I'm about a week away from ordering a BRM exhaust and cat, but I'm running out of time to pass so I probably won't have it in time.
check with the testing place. here they give a 30 day grace if you fail. i tried some of that gauranteed to pass stuff and failed with it.
the idle was turned down to ~600. you may be aware but get the car/cat really warmed up before testing. the cat works best when thoroughly warmed. my idle was set back to 18.
the idle was turned down to ~600. you may be aware but get the car/cat really warmed up before testing. the cat works best when thoroughly warmed. my idle was set back to 18.