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Bad EGR Valve: What Symptoms (3vze)?

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Old May 22, 2010 | 06:54 PM
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Bad EGR Valve: What Symptoms (3vze)?

I know what the factory manual says, but I wanted to hear from someone who's experienced it. If it was stuck open so that it was letting exhaust gas into the intake manifold all the time how would the engine run? -- Matt
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Old May 22, 2010 | 07:02 PM
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If you have a bad EGR Valve, you will have "High NOX" and not pass emissions, at least in California.

It's a cheap part and easy to replace yourself.

http://www.aa1car.com/library/egr.htm




.
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Old May 22, 2010 | 07:41 PM
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In the factory manual it says that it will cause low power when the engine is cold. An open EGR is in effect a vacuum leak. I've got terrible low power when cold that improves a lot when the engine is thoroughly warmed up. And idle vac is a little low at 15 ". Sound familiar to anybody? -- Matt
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Old May 22, 2010 | 08:15 PM
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Uh I'm pretty sure you can plug the egr vacuum lines and if the performance improves, then you found your problem. I would research that a bit more before trying it.
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Old May 22, 2010 | 08:37 PM
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I disabled the vac line to the EGR valve, it didn't change anything. If the main exhaust passage of the EGR is stuck open vacuum lines won't change anything. -- Matt
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Old May 23, 2010 | 05:32 AM
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I plugged my egr vac lines and it runs like a champ now and dont have a regret in the world about doing it. lol
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Old May 23, 2010 | 08:11 PM
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There's a lot to the EGR system. There's the Valve itself, the modulator, a vacuum switching valve, and some interaction with the ECU and the throttle body. I can see why a person might want to pass on trying to figure it out and fix it right.

In any case I pulled the valve off today and found that it is not stuck in the open position. While it was off I plugged the EGR port on the intake manifold. The result was that eliminating the EGR valve made no difference for my problem. I'm starting to think that the valve timing is off by one tooth on the timing belt.

The last owner had a head gasket repair done right before he sold the vehicle to me. He was an Army recruiter. Part of his job involved hanging out at the area high schools. He ended up letting the vo-tech automotive class do the job. I'm starting to think they didn't get the timing belt on right. That ought to be easy enough to determine. -- Matt
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Old May 24, 2010 | 01:24 PM
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Hmm, I have bad/low power/surging/struggling issues when the engine is cold but they pretty much go away once its fully warmed up.
Might look at the EGR valve also
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Old May 24, 2010 | 03:39 PM
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EGR keeps combustion temps down. Given that high temps in cyl 6 already causes a lot of head gasket failures on that motor, it would probably be a good idea to make sure it's working correctly. EGR does not operate at full throttle, so it doesn't impact power. It actually improves gas mileage by a small amount. In keeping combustion temps down it not only protects the head gaskets from blowing and valves from burning, it also fights pinging which can cause the ecu to retard timing (which decreases power). And nitrogen oxides are the nastiest components of smog - they're the ones that burn your eyes.
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Old May 24, 2010 | 04:03 PM
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Originally Posted by sb5walker
EGR keeps combustion temps down. Given that high temps in cyl 6 already causes a lot of head gasket failures on that motor, it would probably be a good idea to make sure it's working correctly. EGR does not operate at full throttle, so it doesn't impact power. It actually improves gas mileage by a small amount. In keeping combustion temps down it not only protects the head gaskets from blowing and valves from burning, it also fights pinging which can cause the ecu to retard timing (which decreases power). And nitrogen oxides are the nastiest components of smog - they're the ones that burn your eyes.
I knew Toyota thought it was a good idea for some reason! Well said.
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Old Sep 19, 2010 | 06:51 PM
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And I was just going to pull mine since it failed tonight. Anyone have a working/reconditioned assembly full components for sale?

Thanks,
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