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Old 02-09-2019, 03:17 PM
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EGR mystery

As i continue to try to make sense of what my 3VZE runners PO has done to this truck, I noticed the EGR valve is missing a connector. I discovered it is the egr temperature sensor. At first I thought they might have tried to do some hack job Egr delete but it’s still on the vehicle (just missing the sensor connector).

Question is this some sort of egr mod that you’ve seen before? Or do I need to reconnect a temp sensor wire? I am imagine this could cause performance issues.

Last edited by gilesitis; 02-09-2019 at 04:31 PM.
Old 02-09-2019, 06:02 PM
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You don't say what year your truck is and whether it is federal or cali spec. Not all emissions regimes used an egr temp sensor.

Don't think the temp sensor actually exerts any control, but only lights check engine light and sets code if low temp indication shows that there is no egr flow when the ECM says that there should be flow.

You got a wiring harness plug and no sensor on the egr, or you got a sensor on egr and no harness plug???
Old 02-09-2019, 06:07 PM
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Originally Posted by millball
You don't say what year your truck is and whether it is federal or cali spec. Not all emissions regimes used an egr temp sensor.

Don't think the temp sensor actually exerts any control, but only lights check engine light and sets code if low temp indication shows that there is no egr flow when the ECM says that there should be flow.

You got a wiring harness plug and no sensor on the egr, or you got a sensor on egr and no harness plug???
1988 model and I don’t believe it’s Cali specific. It has been in the southeast since the dealership.

i don’t have the sensor on the egr and I could not find a vacant harness plug
Old 02-09-2019, 06:21 PM
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I don't think your '88 truck ever had an egr temp sensor.

I've got a '92 FED/CANADA spec 3vz that has NO egr temp sensor and I have a '95 FED/CANADA spec 3vz that DOES have the temp sensor. Both are 4Runners.
Old 02-09-2019, 06:23 PM
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Originally Posted by millball
I don't think your '88 truck ever had an egr temp sensor.

I've got a '92 FED/CANADA spec 3vz that has NO egr temp sensor and I have a '95 FED/CANADA spec 3vz that DOES have the temp sensor. Both are 4Runners.
I think this mystery is solved, thank you. I also just read something that supports the temp sensor is only for Cali spec.

Do you you know how I could check to see if the egr valve is stuck?
Old 02-09-2019, 06:31 PM
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With the engine idling, apply vacuum to the egr valve diaphragm and the engine should run very rough, or even stall.

This proves egr function. A valve stuck partially open often causes rough idle,

Last edited by millball; 02-09-2019 at 06:32 PM.
Old 02-09-2019, 06:33 PM
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Originally Posted by millball
With the engine idling, apply vacuum to the egr valve diaphragm and the engine should run very rough, or even stall.

This proves egr function. A valve stuck partially open often causes rough idle,
Thanks, not sure how to do that, but I’ll keep researching it.
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