im wonder if this could be related to a sticky ebpv

 

Couple things. First check that the EBPV butterfly valve is opening and closing freely and not sticking. You may need to rebuild your EBPV pedestal. If it seems to move freely you can then check the connector and circuit for the EBPV solenoid using the pinpoint testing below.

You should have two wires going into the EBPV pedistal connector for the EBPV valve solenoid. One should be GY/R (Gray/Red) and the other wire should be BK/W (Black/White). The BK/W wire is pin A in the connector. Measure the resistance between Pin A and Gnd, you should see less than 5 ohms. If you see more than 5 Ohms resistance then the wiring harness, specifically this wire is open.

You can also disconnect the PCM harness and measure voltage across the power circuit. You would measure Voltage at Pin B and Gnd. You should see NO voltage, If you get any VPWR (Vehicle Power) here you have a short to power in the GY/R circuit.

Lastly you can measure resistance at Pin B and Gnd. Here resistance should come in below 10k Ohms. If not you have a short to Gnd in the GY/R circuit.

To summarize. The above pinpoint testing will either confirm or eliminate the EBPV solenoid as the problem. It is not uncommon to find the butterfly valve sticking and or the oil fed actuator sticking or leaking oil.

If you decide like many others here to go without the EBPV, then you can by a terminator for the EBPV Harness/connector that will stop the SES codes and allow you to disconnect the EBPV and your done. Some people worry that in cold weather they will need the EBPV, but you will not. I am in snow and cold all winter in Lake Tahoe and have been w/o the EBPV pedistal for 4 years.

BTW, if you decide to go w/o the EBPV do some searching on how to remove the EBPV. They sell non-EBPV pedistals for about $125.00 and you will also need to disable or remove the Turbine outlet valve for the EBPV.

Good luck and let us know.

 

Awesome stuff NorCalDiesel. Thank you. I will try the steps to see. I would love to remove the EBPV. I did on my 97, it was stuck closed, I just unhooked the rod and tied the valve open.

 

I gutted my EBPV about 7 years ago and live north of Seattle. Haven't really needed it. I never did the terminator mod, but I never get an SES light from it. The code is there though. I clear it every so often, but it comes back.

 

Oil pressure closes the exhaust back pressure valve. If it is letting oil leak by it will cause the valve to close while running.