Codes P0171 and P0174

[The Radium King]

check the boot that holds the resonance tube in place - it mught be cracked or folded somehow underneath. when you have the resonance tube off check the secondary air injection system - it has a couple of vacuum connections in that area.

[Jamesp]

Originally Posted by The Radium King

check the boot that holds the resonance tube in place - it mught be cracked or folded somehow underneath. when you have the resonance tube off check the secondary air injection system - it has a couple of vacuum connections in that area.

Done. Everything looked good. Tried to blow through the spagetti tubing and all the valves must be closed because there was no airflow. Is it common for the air injection cut off valve or the vacuum reservoir to leak? Could that be the source of the vacuum leak?

[JFP in PA]

Originally Posted by Jamesp

Done. Everything looked good. Tried to blow through the spagetti tubing and all the valves must be closed because there was no airflow. Is it common for the air injection cut off valve or the vacuum reservoir to leak? Could that be the source of the vacuum leak?

Definitely, the vacuum reservoir and its lines are common problems. If you have a hand vacuum pump, you can disconnect the reservoir and pump it down to test it.

[Jager]

I like the "Jamesp Extreme Super Smoker" that's a great idea.

[Jamesp]

Pumped down everything south of the vacuum check valve by connecting a vacuum source (the Extreme Super Smoker in reverse - turning out to be handy) to the check valve itself and pulling a vacuum. pulled the check valve off after about 30 seconds and there was plenty of vacuum. Checked the actuator for the butterfly valve in the resonance tube and it's tight. Can the air injection cut off valve have a constant leak that shows up in a smoke test??? I blew into the tube and that valve is closed at present. Can the butterfly valve stem have a leak?

[JFP in PA]

Originally Posted by Jamesp

Pumped down everything south of the vacuum check valve by connecting a vacuum source (the Extreme Super Smoker in reverse - turning out to be handy) to the check valve itself and pulling a vacuum. pulled the check valve off after about 30 seconds and there was plenty of vacuum. Checked the actuator for the butterfly valve in the resonance tube and it's tight. Can the air injection cut off valve have a constant leak that shows up in a smoke test??? I blew into the tube and that valve is closed at present. Can the butterfly valve stem have a leak?

Yes to both questions.

Rather than pull a vacuum and then listen to see if any is left, you need to be testing with a unit that allows you to pull a known level of vacuum and watch for any changes:



Sometimes the vacuum leaks that cause these codes are slow but continuous ones.....

[Jamesp]

Thanks for your reply JFP. I used time instead of a gauge. If the system holds a low vacuum for a full 30 seconds my sense is any leak is less than a pinhole. I think I'll go check it for a full minute though. I did listen for a hiss as well and did not hear one. I bought a plastic vacuum pump similar to the one you show to bleed the clutch as it was marketed for use in brake jobs. It would have been a better tool if it was compatible with brake fluid.

[petee_c]

Originally Posted by Jager

I like the "Jamesp Extreme Super Smoker" that's a great idea.

I like it too. I've got that I think Harbour freight transfer pump?

Sent from my SGH-I747M using Tapatalk

[Jamesp]

Originally Posted by petee_c

I like it too. I've got that I think Harbour freight transfer pump?

Sent from my SGH-I747M using Tapatalk

That is exactly what that is. It is also a vacuum pump to check the integrity of the vacuum reserve.