1991 Chev K1500, How many oxy sensors?

[otis24]

1991 Chevrolet K1500, 4.3 V6, does this just have the one oxygen sensor? Vehicle stalls at idle and hesitates on acceleration. I just changed the fuel filter (it looked ancient). No "check engine" light on, so no codes.Will probably do plugs, rotor and cap as well later this summer.j

 

[joegreen]

It's a tbi engine. I believe it has just one non heated o2 somewhere by the exhaust manifold.

 

[Kira]

If it's like my friend's 1989 K1500 it has one O2 sensor in one manifold. It is the most common sensor ever built. The application printout was 64 pages long.

He had hellacious fuel richness problems which caused the engine to stutter and shake. The bottom line was that the battery cable has a tap off for the nascent computer system and the lead swag was all full of lead oxide. A new cable fixed us up.

Does this truck of yours have the large (5" X 6") black plastic controller mounted atop the engine forward and to the right of the TBI?
The '89 also had its computer mounted ahead of the glove box. It bulged into the engine compartment through the firewall.

Check the vacuum hose (big 1/2" hose) in the intake manifold. His was old and crispy.

Does your rig have the air injection? Those connections were heavily rusted and worthy of inspection.

 

[otis24]

It looks like it either had an air pump a one time, it doesn't now, or that the engines came with the bracket so that it could be added per order/demand. This is the TBI engine. I only see one oxygen sensoe and will replace it. It is displaying th symptoms of a bad oxygen sensor.

 

[The_Eric]

Yep, just the one. Some engines came with an air pump, some didn't, but the provisions were there even if it didn't have one.

 

[joegreen]

Just don't get a Bosch o2 sensor. For some weird reason people have had issues with them in tbi applications.

 

[JTK]

I remember my Dad's 1990 4.3L, 5spd 1500 W/T having a single O2 sensor and an air pump.

In regards to the idle issue, maybe something is amiss with the idle air control? I don't recall what they used for this on this particular TBI. Been years since we had them in the family!

 

[mjoekingz28]

What is an air pump?

Was it some poor attempt at emissions?


Is the forefather to the rat's nest we have now? Although I admit in my Chevy with DBW it is nice having some problematic sensors disappear.

 

[artificialist]

Originally Posted By: mjoekingz28
What is an air pump?

Was it some poor attempt at emissions?


Is the forefather to the rat's nest we have now? Although I admit in my Chevy with DBW it is nice having some problematic sensors disappear.

The air pump was a very early smog device, however, some cars still use them. In the past pumps were operated by belt, but modern cars use an electric motor.

The air pump exists so that when excess fuel is in the exhaust, the added oxygen combined with the heat in the exhaust system would ignite the excess fuel.

This is also good at reducing smog when the engine is too cold to light off the catalytic converter.