service engine soon light

[eirc58]

Hi all, My service engine soon light keeps coming on so I checked the ECM via the ALCL and it came back as a code 64. I checked the manual and code 64 reads "Right bank oxygen sensor circuit lean exhaust indicated". Now I hate to sound un-educated here but I looking for some help in locating the sensor. Is it the one just below the catalytic converter on the exhaust pipes? Does the 93 LT1 have 2 oxygen sensors? (Some of the parts sites stated "two required". I could really use some good info here. Any help is greatly appreciated.

Thanks, Sven

[manicmechanix]

I think it's the O2 sensor in the exhuast manifold near the engine on the passenger side. If it's a '93 it shouldn't have an O2 sensor downstream of the cat. That's why the parts site was saying 2 O2 sensors, one for the left bank and one for the right.

[eirc58]

Thanks Manic. That's what the code book said, right bank sensor, mixture to lean. Hopefully changing the sensor will do the trick.

Sven

[discnik]

The "Lean" condition is not due to the sensor malfunctioning. You probably have a vacuum leak on the right bank of either the intake manifold, exhaust manifold or some source that will allow unmetered air into the right bank.

[eirc58]

Thanks discnik
Short of bringing it to the shop, can you (or anybody) provide some help on how to find a vaccuum leak?

sven

[Schrade]

Originally Posted by eirc58

Thanks discnik
Short of bringing it to the shop, can you (or anybody) provide some help on how to find a vaccuum leak?

sven

'94 has 2 O2's on the passenger side, one on the driver's side. '93 MIGHT be the same way. '94 has NO code for 3rd sensor. If '93 is like '94, either front or rear O2 will light up passenger side fault.

Vacuum leak on the exhaust? Or on the intake side? Intake leak is an easy find. Exhaust is a little tougher...