Ford Focus problems

marksandsparx

Fords are a bit of a pain to be honest, diagnostic wise.. I am absolutely certain that you need to replace to cat, had it on 4 focus' and ka's in two weeks!

adriandilly

marksandsparx wrote: »

Fords are a bit of a pain to be honest, diagnostic wise.. I am absolutely certain that you need to replace to cat, had it on 4 focus' and ka's in two weeks!

The cat would be my guess, as it has been from the start, it makes the most sense.. however, I can't ignore the other possibilities, I need to get round to hooking up a scope to try and monitor the O2 signals, or get a better OBD bluetooth adaptor, then I can know for sure.
I want to say it's the Cat now, save all the hassle, but all the garages I've talked to say sensors, even though I think that is wrong. I wanna prove to myself the sensors work, I am an electrical test engineer and even though our industry isn't cars, we need to fault find before ordering expensive replacement parts

marksandsparx

I understand what you mean, I am the same, but it's highly unlikely that a sensor would fail to a degree where it would give a false reading within its tolerance. Normally they fail open or closed and usually its the heater circuit that fails on the sensors. What the code is saying is " the sensor readings before the cat and after the cat are plausable, but the post cat reading should be lower than what would be expected with a correctly operating cat" (if that makes sense!)

atrixblue.-MFR-.

adriandilly wrote: »

I've found some new information by doing a few checks on my car today

I disconnected the top sensor (Green connector), turned on engine and got code P0135 within about 2 mins
Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)

I reconnected the green one, cleared the code and then disconnected the blue connector (accessed from underneath the car) turned on engine and got code P0141 also within a couple of minutes
Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

From this I assume that both sensors are at least working to some degree

I plugged in a code reader and got the following information in menu 3 (I/M)
MIL OFF, MISFIRE READY, FUEL READY, CCM READY, CAT NOT RDY, HCM N/A, EVAP N/A, 2AIR N/A, A/C N/A, O2S NOT RDY, HO2S NOT RDY, EGR N/A

Why would CAT, O2S and HO2S not be ready?
Am I homing in on the problem or would they all come up as not ready because I've just disconnected and reconnected them?

Thanks

this is normal readings when your car is in the I/M status menu. because basic code readers cant read with the engine running, so will show O2nt rdy OR INC because theres no way for the reader to monitor them their not fitted with correct software to enable them to do so their just a quick hand held to give you an idea as to what causes the code and erase them. the only time youll get OK is when youve taken car for 30 min run and the ecu stores the readings for the reader to obtain.

i guess from the codes you got you didnt enter freeze frame for the detailed info before you erased the code on your handheld.

adriandilly

marksandsparx wrote: »

I understand what you mean, I am the same, but it's highly unlikely that a sensor would fail to a degree where it would give a false reading within its tolerance. Normally they fail open or closed and usually its the heater circuit that fails on the sensors. What the code is saying is " the sensor readings before the cat and after the cat are plausable, but the post cat reading should be lower than what would be expected with a correctly operating cat" (if that makes sense!)

Or, the second sensor reading is too similar to the first, so what's in the middle isn't doing its job

adriandilly

atrixblue.-MFR-. wrote: »

i guess from the codes you got you didnt enter freeze frame for the detailed info before you erased the code on your handheld.

There's nothing 'detailed' about my code reader!

marksandsparx

adriandilly wrote: »

Or, the second sensor reading is too similar to the first, so what's in the middle isn't doing its job

Yeah much easier explaination!

atrixblue.-MFR-.

go to motor factors, get a cat and cat fitting kit. rule the big one out then replace the pi$$y bits later if not the cat

adriandilly

Just had a quick check of the pre cat o2 with a multimeter. One pin is at 14V, two are almost at chassis potential (175mV and 48mV) and the other pin *appears* to be switching at 600mV (its hard to tell with an autoscaling meter). I'll check the post cat later

adriandilly

I'm now suspecting the head gasket.
Today I checked the voltage of the post cat sensor and it's oscillating between 0.1 to 0.8V quicker than the multimeter can keep up. So I guess the cat converter is shot. I'm also getting water dripping from the tail pipe and chuffs of white smoke when its revved. I also saw bubbles enter the coolant tank with the engine running.
Should I suspect the worse or just get the cat changed?