Trouble passing emissions HELP NEEDED!!

[twinsnakes23]

I have a '97 GT and I took it to get inspected. Now the Check Engine light has been on ever since I've had it for like 2 years now. It runs fine with the exception that it sometimes stalls when I'm slowing and engaging the clutch. The emissions guy told me that the problem was the o2 sensors, bank 1 sensor 2 and bank 2 sensor 2, so I switched the 2 sensor after the cats. After all that the check engine light is still on and it's reading the same problem. What do I do now.

Also my speedometer and reverse lights don't work. I changed the speed sensor but no luck. I also checked my fuses and all are good. I haven't change the reverse sensor on the transmission yet, but that still leaves the speedometer.

This is the first time I'm trying to pass emissions legally and I'm having to many problems, can anyone plese help.

 

[bdcardinal]

do you have a K&N? could be the oil from the filter has glopped onto your MAF.

 

[twinsnakes23]

don't have a K&N whole car is completely stock

 

[bdcardinal]

sorry. missed it was the rear o2s. could be your cats are blown out, or else there is a wiring issue.

 

[tomustang]

get a multimeter and check the lines going to the O2 sensors

 

[hognutz]

have you went and got the codes pulled?

now is the light just on or were you failing emissions? I mean did they put you on the sniffer or did you just fail the odbII test.

if you car is actually failing emissions it is proably your front 02's that are bad. if it is just an odbII proablem it could be your rears. rear 02's are diagnostic only. so if your car is actaully failing the sniffer they are not the problem at all.

 

[Mike97gt]

have you went and got the codes pulled?

now is the light just on or were you failing emissions? I mean did they put you on the sniffer or did you just fail the odbII test.

if you car is actually failing emissions it is proably your front 02's that are bad. if it is just an odbII proablem it could be your rears. rear 02's are diagnostic only. so if your car is actaully failing the sniffer they are not the problem at all.

most states will not sniff a car where it already failed the OBD2 test. I would say his problem is in the cats/rear 02's

Now the way I would fix this is either get a tuner and have the cat monitors shut off or go and get some MIL elims. the tuner works better.

the OBD2 on board diagnositics is a lot more senistive than the state tests, so it's possible that you can have cats that are on there way out and failt he on board tests but if you get the light turned off they will pass the state tests.

 

[twinsnakes23]

I got codes PO141 and PO161.

I also found out that harness that connects to the rear 02 sensors also connects to the speed sensor and reverse light sensor, which my speedometer and reverse light are not working. I pulled out the harness and checked all the connections and they are all good. So now what do I do?

 

[twinsnakes23]

A mechanic friend of mine checked the harness and told me the harness was fine and the problem is that the computer is reading wrong. Do computers even need to be replaced? And if I need to get a new one where can I get one?

 

[Mike97gt]

ok you have circuit faults for both rear 02's also check fuse 1 15 amp in the interior fuse panel, not the panel under the hood.


and with the speedo and reverse lights out that means ALL things on that harness that runs along the trans is inop. that harness is the problem, look up near the trans bellhousing and make sure it's not pinched, your going to have to remove the plastic tubing that surrounds the harness and check fior broken wires.

I bet with that many circuits out if you follow that harness up to the eninge compartment you will find damage to it that you can see without cutting the tubing off.

I would take a good look at that harness first

 

[twinsnakes23]

That's what I thought, my mechanic friend pulled out the harness and checked every connection with a multimeter. All the connections were good. The harness did have some burned marks, but the wires inside were fine it didn't get past the plastic covering. Is it possible that the harness connections can appear to be good when testing current, but be bad when connected to the car sensors?

Also I did check the fuse it's fine.

 

[Mike97gt]

That's what I thought, my mechanic friend pulled out the harness and checked every connection with a multimeter. All the connections were good. The harness did have some burned marks, but the wires inside were fine it didn't get past the plastic covering. Is it possible that the harness connections can appear to be good when testing current, but be bad when connected to the car sensors?

Also I did check the fuse it's fine.

well I assume he did a voltage test to see if any power is going to the 02's without a breakout box this is about the only tests you can do and does not give you the full story. make sure that harness is good before you go and replace the PCM. it might be the pcm but I find it funny that all the stuff that is wired from that harness has gone bad. I would say thats a good indicator of a bad harness.

 

[twinsnakes23]

Is there anywhere I can get a new harness or do I have to get one from the junkyard or ebay?

 

[bdcardinal]

dealership.

 

[Mike97gt]

I doubt you have to replace the whole harness. if you did that you would have to replace the whole engine harness. you need to find the breaks int he wirring and repair them.