Hi all,

Got a 2001 X-Type 2.5L with some pretty depressing engine issues. The car drives like it's got about half the power it used to have, and when I place my foot flat to the floor there's just no power and I'm just struggling to beat average cars. Somewhat embarrassing.

The car also died one morning directly after starting it up, it died straight away after running for about 3 seconds. I could turn it over, but it didn't start again. I did some research and figured it was the crank case breather hose which was still the original. I ordered a new one (the revised patterned type) along with the valve and replaced them. The car started after some coercion and got better, but not for long.

I then had issues where on certain low RPMs with I suppose a higher load than normal (high gear/low speed/uphill) the car would feel like it's misfiring and hesitate. Then it would go away on higher RPMs. It's more repeatable when the engine is cold, but still does it when warm.

So thinking it was a vacuum problem I took off the intake manifolds, replaced the upper and lower gaskets, the throttle body gasket, (also did the spark plugs while I had it off) and put it all back together and still nothing. I then replaced the Intake Manifold Tuning (IMT) seals with no difference either.

So thinking it's not a vacuum problem I used an app called Torque which can read fault codes. It came up with P0037, P0057 & P1647 which I looked up to be oxygen sensors. With the symptoms I described above, would they be typical of malfunctioning oxygen sensors? Or do I have some other issue?

BTW if you're in ACT give me a shout

Cheers!

 

What is Mileage of car?
What you need is some live data particularly, fuel trims.

Once you have those it will help others in diagnosing, It could be O2 sensors but why both post cat heaters would go down together begs further investigation.

 

You likely have a faulty O2 sensor:

"P1647 Fault description - ECM Ho2 sensor control malfunction - bank 2 upstream (2/1)

Possible causes
- Ho2 sensor heater failure
- Ho2 sensor 2/1 sensing circuit: short circuit to ground, short circuit to high voltage, open circuit
- ECM failure"

It would cause rough running and intermitent faults because with a faulty sensor the engine would overcompensate (run rich).
I would replace the sensor and test from there.

 

Cheers for the advice, I will run some live logs driving around town to get some fuel trim stats and I'll report back. I think my problem is most likely a faulty oxygen sensor but with three to replace it becomes expensive very quickly. So I just want to make sure it's not something else.

 

P1647 says which ONE is suspect.

 

Okay went for a drive for 20 mins and 24km to check the fuel trims and none of them moved past 0. Some didn't display any data at all. The car has 166,000km on it, mostly highway driving.

I logged the intake manifold pressure and it ranges from 2.32-13.78PSI. With a mass air flow rate of 2.79-80.74g/s. Also have a fuel flow rate of 3.47-491.79cc/min. Not sure if that helps in the diagnosis.

With the P1647 code, unfortunately the Torque app doesn't say which specific sensor has the fault. Is there a specific reader which will tell me?

 

Dude the clue is in what I posted:
"P1647 Fault description - ECM Ho2 sensor control malfunction - bank 2 upstream (2/1)

That's all you need to find which one...

 

The O2 sensor reading faulty is the one mounted on the exhaust manifold prior to the catalytic convertor on the side of the engine closest to the radiator.
First locate the sensor and trace the wires back to the gray plug. Check the wires for any damage (breaks, melted insulation). Next check fuse 42 in the fuse box located in the interior of the car beneath the dash on the left hand side of the car.
If the wiring is good and the fuse is good then it is time to replace the sensor.
The removal/installation requires a special O2 sensor socket. Since it is in the exhaust you will need to apply ample penetrating oil to help loosen it. Prior to installing the new one apply some Anti-Sieze lubricant to the threads.

 

omgsh Revere, I'm sorry I must of skipped over your reply.

I know you can check the resistance of the two black wires from the plug. But I'm not overly technical on exactly how to measure resistance on the plug. Do I simply stick in the meter plugs into the ports for the black wires and set the meter to resistance?

 

Upstream sensors are indeed for fuel trim, but I doubt it would be responsible for such massive power loss.
I'd rather expect worse fuel economy.
I had bad upstream oxygen sensor too, jag disabled fuel trims (on both banks short time fuel trims were constantly zero) but was running rather normally.
Moreover, with full acceleration, oxygen sensor readings are not used. AFAIK too rich mixture is best then.

 

If the oxygen sensors are not responsible for the power loss, could it be I still have a vacuum problem even after replacing all the common vacuum leak issues with the X-Type? Is there anyway to test for vacuum loss?

 

Vacuum leak affects mostly idle operation.

And it causes high fuel trims. Faults P0171 and P0174 "too lean" will show up on idle after long time fuel trims get past 20%.
The simplest test for vacuum leak is observing fuel trims on idle.

I don't think is is vacuum leak either...

Maybe your catalytic converters are clogged? But I don't see such faults in your posts (low cat efficiency and misfires)

 

You know what, after looking into catalytic converter failures and their symptoms, they appear very similar to what I'm experiencing. When I try to accelerate, I in turn create more pressure to go through a blocked cat which gets backed up and trapped. The car stops sucking in air because there's no more flow going through the car and it stalls/misfires/hesitates. My fuel economy is also bad in addition to the low performance.

This is pretty concerning because in the right conditions this makes the cat very very hot and if the sensors are also malfunctioning the car might try to run rich and unburnt fuel might go directly into the cat which could ignite, melt the cat, and cause a fire.

 

Clogged cats are quite common on X-Types.
I had this problem too on one bank.

Car ran pretty well on low revs, with steam visible from both exhaust pipes when cold.
But once it got past 4k rpm it suddenly was losing power and misfires started to happen.

I thought "whoa, my Rover K-Series 1.6 engine has more power than this jag...."

Running too rich can definitely destroy cat. Although I don't think it will end up in flames.

 

Okay I checked the wiring and it all looks intact. I checked the 42 fuse which is actually in the engine bay (for my car anyway) and that's not a problem either.

I suppose my next option is to replace the oxygen sensor and hope it all works after that. I really hope it's not a cat problem otherwise that's gonna be an expensive fix....

 

Yeah, and there's two cats - one for each bank, along with two O2 sensors in each cat.

 

Okay so got the new oxygen sensor this morning, installed it and took the car for a test drive. Amazing! The car no longer hesitates or feels like its misfiring/jerking. I can actually go up hills like normal now. Although the performance is a lot better, it's still lacking a little bit from a few years ago. I cleared the fault codes, refreshed them and the P1647 code is gone, but I still have the P0037 & P0057 which references other oxygen sensors.

I'm going to drive the car around a bit more and see if it gets any better. If not, then I'll just have to buy the new oxygen sensors later down the track since two of them would set me back almost AUD500.

 

Buy over the net so much cheaper?

 

Well, I haven't bought the other two oxygen sensors for codes P0037 and P0057 yet. I'm thinking of doing them at a later stage.

However today I was driving normally and just above 3000RPM the car went into a kind of limp home mode, I lost a lot of power. I put the clutch in and the throttle wouldn't respond past 3000RPM, then eventually after a few pushes of the pedal it revved normally. I put the car back into gear and about 100m down the road it happened again. I cleared it again, and drove gently back home.

Before the car was off I had a look at any codes and I got P0333 which is knock sensor circuit high input.

I'm just wondering if those other oxygen sensors could be causing the engine to produce the incorrect mixture and produce a ping/knock?

I started the car up again about an hour after this ordeal and it worked as normal, and the code was gone.

 

3000RPM cutoff is normal with detected problems with fuel trims (and probably other serious problems too).
There should be "CRUISE NOT AVAILABLE" message on trip computer too and check engine light.

Oxygen sensors are responsible for adjusting fuel trims (and correct mixture).