sensors on exhaust really needed?

[thebeastjuggalo]

i have had my '95 jimmy 4dr 4x4 for about 6months now, and when i look at the exhaust i see absolutly no sensors on it anywhere and do not even see lines for the sensors coming down anywhere, is this bad? i have no check engine soon lights come on or anything. and could someone also post a pic of what the sensors look like and about where they would go on the exhaust so i have a better idea of what to look for?

thx.

[Chris Stewart]

Have you got under the car and looked? The easiest one is just upstream from the catalytic converter...on the exhaust pipe/under the car, almost directly under the passenger seat. Looks like a spark plug.

[mansvoice]

Actually, unless altered, you will have two O2 sensors. one is directly in front of the catalitic converter and the 2nd is directly behind the catalitic converter.

[MT-2500]

Originally Posted by thebeastjuggalo

i have had my '95 jimmy 4dr 4x4 for about 6months now, and when i look at the exhaust i see absolutly no sensors on it anywhere and do not even see lines for the sensors coming down anywhere, is this bad? i have no check engine soon lights come on or anything. and could someone also post a pic of what the sensors look like and about where they would go on the exhaust so i have a better idea of what to look for?

thx.

Unless the little green man ate them it should have some.
Like 3 or 4 more or less.
As said get under there and look around for something like a spark plug with wires out the end of it sticking out the exhaust pipe and rear exhaust manifolds.
What engine code Z or W and what computer VCM or PCM.
If the sensors are on there ad working they should show up on a good engine capable scanner.

Any mods on the pcm/vcm?
I have saw some that have dummie 02 sensors on them.

[old_master]

MT is correct; it depends if the vehicle is equipped with OBDI or OBDII, (early '95 was OBDI, late '95 was OBDII). OBDI has 4 sensors, OBDII has 3 sensors.

[blazes9395]

'92ish-94 (vin W) will have one heated sensor (TBI(vin Z) switched over to heated sensors somewhere around '93)

'95OBDI will also have one heated sensor, upstream(before cat)

'95 OBDII will have two sensors, one upstream(before cat), one downstream(right after cat)

'96 to around '98 will have three sensors, two upstream(before cat, one on each down pipe), one downstream(after cat).

'99 was changed again with four sensors

Hope this helps.

[thebeastjuggalo]

yes i have been under there and looked, just put in new piece of straight pipe where whoever had it before my put in flex pipe that wouldnt stay in. i see absolutly no wires or even holes in any part of the exhaust where these sensors could go. i have looked all the way from where they exhaust joins into one pipe to the end of the exhaust system...the vin is W and i dont no if its vcm or pcm.

[MT-2500]

Originally Posted by thebeastjuggalo

yes i have been under there and looked, just put in new piece of straight pipe where whoever had it before my put in flex pipe that wouldnt stay in. i see absolutly no wires or even holes in any part of the exhaust where these sensors could go. i have looked all the way from where they exhaust joins into one pipe to the end of the exhaust system...the vin is W and i dont no if its vcm or pcm.

Also check the rear of exhaust manifolds.
Some front sensors are in the rear of them.
On a PCM the computer will be behind glove box area.
A VCM computer will be under the rad overflow tank on right fender.

Does it still have a cat or cats on it?

I would get it on a engine capable scanner and see if it has any 02 sensor readings in scanner.
And check for codes and other engine running data.
If it has no 02 sensors and no check engine light some one has moded it.
To be legal you need cats and 02 sensors.