94 Voyager code 21

[tempfixit]

94 Voyager 3.3 engine.

The engine acts like it is starving for fuel, changed fuel filter. I can hear a loud air sound or vacuum sound by the battery area when put it in reverse and sometime stalls, but starts right back up. I am getting code 21. I am thinking it has sometihing to do with the EGR system but that is my opinion.

Thanks for any and all advice.

[jpb53]

The sound you are hearing could be from the IAC. You might pull the air tube off the throttle body. Could be you sucking noise will be much louder.

[tempfixit]

thanks jpb53, I cleaned the throttle body and IAC today, it was built up with carbon. I also disconnected the negative battery cable to reset the computor. It didn't stall in reverse or drive and did not spit and sputter when driving. She is going to drive it and see what happens. Hopefully that did the trick.

thanks again

[RIP]

If it starts again, a code 21 means one of two O2 sensor circuits has a problem.

[tempfixit]

I have been told that it is doing the sputtering again while driving, I will check the 02 sensors circuit for problems. SHouldn't the ECM go into preset mode if oxygen sensors are not working?? Last time it did the sputtering it would also backfire like it was starving for gas. I will also have to check the fuel pressure but it starts just fine.

thanks

[RIP]

Originally Posted by tempfixit

SHouldn't the ECM go into preset mode if oxygen sensors are not working??

Yes, but what is the preset mode for? To get you home or to a repair facility to get it fixed. It may run but efficiency and driveability will suffer. Another point is MIL code 21 is only telling you that you have an O2 sensor circuit problem. It's not specifying the exact problem or which of the two circuits has the problem. I would bet the "preset mode" would depend on the fail mode. Only a scanner can tell you which circuit (upstream/downstream) and the fail mode (heater/functionality). Unfortunately, your van is equipped with the old OBDI diagnostic system so unless you can find an OBDI scanner, you're out of luck. You'll have to get a meter out or just change a sensor and pray. I've got a hunch you know the upstream sensor is the more likely cause.

FYI - I've been reading more and more automotive articles in magazines and automotive websites where experts are recommending O2 sensors be treated as scheduled maintenance. If I remember correctly on your van they recommend changing them every 80K miles. Not sure I would go that far but, it's food for thought.

[jpb53]

This is OBD1 and does not have a downstream O2 sensor.