My friend is experiencing a weird problem with his 4th gen, the SES light comes on intermediately. I checked it today NO codes while the SES light was illuminated, he had it checked at autozone two weeks ago, and he was told that an 02 sensor/clogged cat. converter can cause whatever code he had... I test drove it today, and it does have a huge lose of power, and he's been complaining about horrible gas mileage. I'm just lost whereas to go with the diagnosis. What usually triggers an SES light, but no codes? Do these symptoms fit a clogged cat? I figure that's causing the o2 to throw inaccurate reading sometimes causing a on/off SES light. Help appreciated.

 

Throw some chevron techron in the tank. That should help to clean some things up.

 

An easy way to detect a clogged cat is to listen to the exhaust. You should be able to hear or feel slight pulsations come from the tail pipe at idle. If you have a very smooth hush feel/sound with no pulsations chances are the cat is clogged. They tend to get very hot when they clog up too. Some glow red hot after the car is driven a bit. A loss of power, especially after the car is at operating temp is another clue.

If the CEL is on, there should definitely be a code stored. Make sure your not clearing them by accident before you get the system to dump them. I assume your checking codes with the ecu screw?

 

Autozone I'm guessing?



No I have a little mac scanner, and no i didnt clear then scan, the light was on but scan tool read no codes, so THEN I cleared the light and ever since the light has not come back on. I did check for hushness at the tailpipe was indeed quite. I forgot to mention it is a 5spd, and while driving the gear box makes this funny noise, i'm starting to think that's where the loss of power is.

 

yea u can get it from autozone.

Have u ever replaced tranny fluid? Still, tranny issues shouldnt cause a loss of power. Thats all engine issues. Or a bad clutch.

From the description of the problem u provided, i still say throw some chevron techron in the tank. Might need 2 bottles if the cat really clogged.

 

Its my friends car, i dont think he's ever changed fluid..... well tranny issues can cause lost of power just in it's own way, I'll tell him to try that stuff though.

 

dude needs to get the codes for the SES as well. That will help provide direction as to what to fix. He should still run the techron

 

Another symptom of a clogged cat is a similar smell to rotten eggs. The exhaust smell isn't the typical scent.

 

That's the problem no codes were stored although the light was on, that's why I said I don't know where to really start the diagnosis.

 

Techron may help clean fuel injectors and intake valve deposits, but it will not do anything for a catalytic converter. Does Chevron make such a claim?

 

Well I'm back...... his SES light came back on, I retrieved an P1148 a.k.a. 0307, BANK 1 closed loop control. I checked the wiring for the o2 it's all good, so I'm going to go ahead and replace it, then see what happens from there.

 

Naw they dont make the claim. But chevron particles burned in combustion hopefully will be enough to purify exhaust and unclog cat. Yup, I believe in the stuff that much! .

Hell for $10/bottle at least give it a try before lookin at buying a new cat. Whats he got to lose

Dude should run 93 with a bottle of chevron. i bet his SES goes off

 

I think Techron is good too, but can't imagine it reviving a catalytic converter. On the other hand, I certainly would not jump to replace an OEM catalytic converter. It is the aftermarket cats that are poor quality. Looks like he's investigating the oxygen sensors, a good place to start before blaming the cat.

 

I just did the transmission pan, the screen and the gasket... the fluid is at right levels. I also have the p0141 o2 sensor code. i always ran 87 octane and after the car sat a month during repairs i put 93 in it hoping to make it run better but im having a exhaust sound ... i have an exhaust thats very quiet but it sounds like theres a hole... im not sure if its a clogged cat or a hole in the exhaust. and if the o2 sensor code is because of the exhaust in one way or another? any suggestions help is appreciated. - 99 maxima gle automatic