p0240 code

So the only thing I have changed is the fuel pressure regulator. Man after I did that my cars been running super, even has some added pick me up on acceleration! :)

So today my check engine light comes on and I get this code????

p0240... :( :disappoin

I think you have the wrong code.....sure it is not P0204? That has to do with the injector #4 circuit.....could be a bad injector, or the wiring harness to it.....see mice get under the upper plenum and eat the insulation on the injector harness......

I think you have the wrong code.....sure it is not P0204? That has to do with the injector #4 circuit.....could be a bad injector, or the wiring harness to it.....see mice get under the upper plenum and eat the insulation on the injector harness......

I'll have to wait till the check engine comes back on, I cleared it and am not sure now... sorry :eek7:

I'll have to wait till the check engine comes back on, I cleared it and am not sure now... sorry :eek7:

Okay, the code came back on today. P0420 looks like catalytic converter.

So, O'reillys or special order?

Okay, the code came back on today. P0420 looks like catalytic converter.

So, O'reillys or special order?
I would go online and order one. How's the rest of the exhaust? If it is old, you can order the whole shabang for a couple hundred. It easier to replace than trying to splice in a new Cat to an old system.

I would go online and order one. How's the rest of the exhaust? If it is old, you can order the whole shabang for a couple hundred. It easier to replace than trying to splice in a new Cat to an old system.

I'll get underneath it this weekend and see, and start looking online!

Well I bought a infrared temp gun at Home Depot yesterday for $32. I checked the front end of the Cat at 288F and the back at 450F! So I'm guessing the Cat is doing pretty good.

No leaks that I can see, so I'll wager it's the O2 sensor. :)

I was waiting till payday to get a Cat... well not no more it looks like. :)

Well I bought a infrared temp gun at Home Depot yesterday for $32. I checked the front end of the Cat at 288F and the back at 450F! So I'm guessing the Cat is doing pretty good.

Not necessarily....that front temp is kind of low.....usually 350 or more....rule of thumb is 150F difference, front to rear.....however you can have an efficient running engine, and it can be less than 100F.....



No leaks that I can see, so I'll wager it's the O2 sensor.

Before I would think about that, I would do one of two things.....get a scan tool that can plot data, or get a scan tool and read before and after cat data.....

If you plot the data, and the image of the rear "mirrors" the image of the front, you have a bad cat......or look at the data of both sensors....the pre sensor should be rapidly changing low to hi and back, from 100mv to 800mv.....the data from the rear O2 sensor, should change very slow....if it changes rapidly like the pre, bad cat.....



I was waiting till payday to get a Cat... well not no more it looks like.

Still could be cat......rich running engine could create a temp difference, and cat will not be running efficiently....