Questions and Answers

Nissan 200SX EGR Q. Hello, My name is Chris, and I own a 1987 Nissan 200SX with the V-6 in it. I have solved many of the problems that I had, but the only one left is dealing with the EGR solenoid. When I took the car to Nissan earlier, they claimed that the EGR valve was stuck open.

On my own, I found that it is functioning properly. I then found that the EGR solenoid that controls the vacuum suction is getting the wrong signal. I tested this signal with the engine running at idle speed, and it was below battery level. Then, when I raced the engine, the signal did not change. I ran power from the battery directly to the solenoid at idle speed, and to my surprise, it clicked and cut off the vacuum.

The chiltons book written for my car only said to check wires, and at first glance, they seem correctly run and not cracked. What do you suggest I do next?

Thank you,
Chris

A. I would check the EGR Back Pressure Transducer (BPT) and make sure it is working properly. The BPT monitors exhaust pressures to activate the diaphragm. The valve controls vacuum applied to the EGR control valve. This allows the operation of the EGR control valve to be controlled by engine operating conditions. A common failure is the plastic nipple on the bottom of the BPT breaks off.

To test it:

1. Connect vacuum pump to two uppermost ports one at a time and check them for leakage.
2. When vacuum is applied to uppermost port and port immediately below that is open to atmosphere, uppermost port should open at 2.36 inches Hg.
3. When vacuum is applied to top two ports, they should both open at 19.69 inches Hg.
4. When two uppermost ports are open to atmosphere, valve should be closed.
5. If valve does not operate as described above, it should be replaced.

Additional Information provided courtesy of ALLDATA