Hi everyone,
my XJR6 was running pretty ok over the last months, with some random hiccups (acceleration juddering).

However now, it is completely stuck: idle is rough and the car stall, when I accelerate (while stopped), the car hesitate drastically (with some back smoke).

I get the following code:
- P0340 (generic) - Camshaft position sensor A circuit Bank 1 or single sensor
- P1193 (jaguar) - Both front HO2S Heater Circuits (High Resistance MAF Sensor Faulty)
- P1178 -(jaguar) - adaptive fuel metering trim too lean

Note that I have replace the coils, plugs (original specs), O2 sensor (bosch/NTK), crankshaft sensor.

Could it be the MAF? TPS? corrosion on ECU (I'm going to check this one after the car is towed). Weirdly, I drove under the rain yesterday and this problem happened today...not sure if there is a link.

Your wise advices are welcomed! Thanks in advance!

 

I would certainly check for corrosion on the ECU pins, but I'm not sure that was ever an issue for the XJR6, still, it's a free and easy check.

It certainly could be the MAF. Have you attempted to (a) clean it using a specific MAF cleaner sold at auto parts stores and (b) adjust the harness connection at the MAF, while running, to see if you get any response? That harness connection, over time, has proven to give some people problems since they may not be making a good connection. A visual check for "crunchy", or brittle wires would be a good idea.

Are you sure you plugged everything back in correctly? Sometimes the two coils closest to the firewall get switched when plugging back in. Are you sure the oxygen sensor wiring wasn't switched as well? You have four plugs.

It could be a dying TPS, and I would also recommend inspecting and adjusting the harness connection while the car was running to see if something is loose, or not making good contact.

What brand coils did you use to replace the previous ones with, and how long ago was that?

Lastly, it is showing a bad camshaft sensor. Maybe it's just that? Easy to replace. I know you replaced the crankshaft sensor, but maybe it's time for the other one?

 

Disconnect MAF (disconnect the connector) and if the car works better the MAF is most likely broken.

 

Hi Vee,
I had cleaned it with MAF cleaner 2 months ago. Will check harness.
I took care to plug the coils properly. It is Eurospare brand.
O2 are plugged properly (I only have two and I check that the wiring color coding was as per the technical book)
I will check the TPS
I might be looking for a spare camshaft as well.

Hi AnttiM,
when I disconnect the MAF, there are no changes at all...

 

Looks like the MAF isn't the primary suspect.

What lead you to swap out the coils and do you have the old ones?

 

When I bought the car, most of the coil were broken...so I change them together with sparks etc...

 

Eurospares aren't known to last very long. It could easily be that.

Unfirtunately the two known good brands, Diamond (OEM) and QYL are difficult, if not impossible to find.

 

Unfortunately, the wiring colours are meaningless for determining how the O2 sensors are connected. It is determined by O2 Sensor Orientation process with Jag Diagnostic system. If you did not check which sensor was connected to which bank before you started and then replicate that with the new sensors then you may have a problem.

Check the STFT on both banks with live data. If you see Max + STFT on one bank and Max - STFT on the other then that is a pretty good sign they are connected incorrectly. Switch them around and try again.

 

Damn, if you just have two of them, switch them up and see if it’s better or worse…

 

Hi guys,
Actually when I got the car, it was not working well, idle was bad...then I realized the O2 sensors were inverted (I only have 2 as it's UK specs). I noticed it based on the cable color coding... then when I inverted, car run very well (especially the idle).
I am trying to get my hand on a VCM1 (I already got IDS 118.5 from our friend on this forum) to do TPS calibration, o2 orientation and other tests, etc...

Beside that, yesterday I took time to clean the ECM and swap it with a spare one (the previous owner had an ECM for XJR but 96' version, US version I think as he throws an EGR code...which is not on the UK model). Anyway, the car run the same however the list of code was more surprisingly more detailed and focusing on random misfire and coil issue on coil #6 (which my original 95' ECM don't throw). I swap it with Coil #1, then idle is still crap but less misfiring when accelerating. The car seems a bit better for now.
I suspect the coils could be the issue (or one of the issue).

On your recommendation, I look for "made in Japan" coils but it's not that easy to find out. I finally got my hand on a set of NGK U5045, slightly cheaper than the jaguar's one (but still pricey...). As i'm in Malaysia, it will take few weeks to reach me but I will keep you updated.

I also have a spare camshaft position sensor on the way...

Hopefully, it works!!

Cheers!