Smog experts

[sam 15]

I need some sure answers on this. If I cant get this smogable for cheap I may just have to 86 (sell/trade combo of both) it for something more streetable. The guy I bought it from said this engine did not require an 02 sensor behind the cat.


I bought a 97 tj with a 97 chevy 5.7 cmpi vortec (AZ) from a truck that I would like to make California smog legal. I have only two 02 sensors befor the cat. I can't get anyone so far to tell me if I need one behind the cat. The guy at the smog station said some chevy trucks didn't have on behind the cat but couldn't tell me if mine was one of them. He recommended that I have it inspected by a ref. I called them to make an appointment but they said their new policy vehicle has to fail at smog station before I can get an appointment. I don't see a third (or fouth) 02 sensor plug coming from the wiring harness (howell). I e-mailed howell and asked them about a rear sensor. Their answer was unclear. They said they make a harness with three and four sensors, but didn't answer my question if I needed the rear sensor for my engine. Has anyone gotten a california smog legal cert for a 5.7 vortec with only the two 02 sensors before the cat?

[peteyg]

The question is, did the donor engine come from a Federal Emissions or California Emissions vehicle? When doing an engine swap, it is CRITICAL to get the Vehicle Emissions sticker from under the hood of the donor vehicle to bring with you to the ref. That is the only sure way to know what exactly is required.

In California, the engine swap laws state that the emissions from the donor engine must be exactly the same when put into the new vehicle. That also means that, for example, the O2 sensors must be within 3" of the original location.

You CAN get a ref appointment if you tell them it is to certify an engine swap. You have to make sure you're specific on that. They can't turn it back, because it is required by California law that all engine swaps must be inspected and certified by a BAR Ref before it can be registered.

Good luck.

[sam 15]

Thanks for the quick reply, From my other research it looks like smoging this vehicle is going to be more than I'm willing to do for the purpose I want it to serve, which was to have second vehicle available when wife has the car and to drive to and from trails. I wasn't looking for a daily driver. Too bad as it has pretty much everything I wanted in a built jeep. I can't afford a tow vehicle and trailer so this may come up for sale or trade real quick here.

[JJsKJ]

Why not swap a 4.0L back in? Sell the existing drivetrain and find a wrecked 97 drivetrain to go back in?

[Guest]

Thanks for the quick reply, From my other research it looks like smoging this vehicle is going to be more than I'm willing to do for the purpose I want it to serve, which was to have second vehicle available when wife has the car and to drive to and from trails. I wasn't looking for a daily driver. Too bad as it has pretty much everything I wanted in a built jeep. I can't afford a tow vehicle and trailer so this may come up for sale or trade real quick here.

You can green sticker it, but then it's only good off road. But, it's a thought as well.

[sam 15]

You CAN get a ref appointment if you tell them it is to certify an engine swap. You have to make sure you're specific on that. They can't turn it back, because it is required by California law that all engine swaps must be inspected and certified by a BAR Ref before it can be registered.

Good luck.

When I tried to make the appointment I didn't mention that it was for an engine change. I will try to make another appointment this week seeing how it has to be inspected by a ref anyway.

[dirtman13]

You are going to need more then two O2 sensors to pass smog/inspection. The two on either side of the engine are for fuel trim. They feed the computer with information so it runs right. The others go behind the cat and measure its performance. If the engine originally came with two cats you will need 4 sensors.

You will need the VIN number for the referee. He uses the VIN number to find out what the original vehicle was equipped with.

California is very strict on engine swaps. When I did mine the referee made me re-route my exhaust exactly as is was on the original vehicle.

[sam 15]

You are going to need more then two O2 sensors to pass smog/inspection. The two on either side of the engine are for fuel trim. They feed the computer with information so it runs right. The others go behind the cat and measure its performance. If the engine originally came with two cats you will need 4 sensors.

You will need the VIN number for the referee. He uses the VIN number to find out what the original vehicle was equipped with.

California is very strict on engine swaps. When I did mine the referee made me re-route my exhaust exactly as is was on the original vehicle.

I won't have the vin from the donor vehicle. i'm told the ref will be able to get whatever info he/she needs from the engine block to make his/her decision. Maybe I should go to the wrecking yard, get a vin from a Chevy truck before I get the appointment. I've been told both ways regarding the 02 sensors....three or four...I guess I'll let the ref decide and go from there. Again my biggest issue is with the wiring harness....I won't mess with it....when I touch two wires together I usually get smoke...ha ha..two things I won't mess with, electricial is one of them.

[chris142]

I am sure someone has thought up something Leave your car hooked and another on the tail pipe.

Naw that don't work either.

When they hook up the computer to Sacramento the Chevy computer will tell them that they are smogging a Chevy pickup but the VIN # that they scan on the registration tells them it's a Jeep.

Hooking up to the Jeep computer will show a non running engine with missing sensors but the tail pipe will show emissions so the thing will abort the smog test.

[dirtman13]

I won't have the vin from the donor vehicle. i'm told the ref will be able to get whatever info he/she needs from the engine block to make his/her decision. Maybe I should go to the wrecking yard, get a vin from a Chevy truck before I get the appointment. I've been told both ways regarding the 02 sensors....three or four...I guess I'll let the ref decide and go from there. Again my biggest issue is with the wiring harness....I won't mess with it....when I touch two wires together I usually get smoke...ha ha..two things I won't mess with, electricial is one of them.

The VIN number is in the ECM (computer). That's what the referee will be looking at. If your running the stock ECM it's not that hard to add the other sensor. The only thing is it would be my guess the PO had the sensor removed from the ECM programming. Wiring it is the easy part.

By the way. That is a sweet Jeep.