I have a Jaguar XF SV8 with a strange issue I can't get to the bottom of.

It goes in to restricted performance mode sometimes after about an hour of driving other times after just 20 minutes, after cooling down for up to an hour it's perfect again for a little while.

When it happens the left bank is running lean and right bank rich. based on my code reader looking at the mixture.

On my code reader I get P0201, P0203, P0205, P0207 so Injector Circuit/Open – Cylinders 1,3,5 and 7 this only comes up very occasionally although restricted performance would be most journeys.

on very rare occasions I can also see 2610 and U0104 for the engine ECU and speed control unit

It has been in with a jaguar specialist this week and they have done multiple short test drives but not got the issue and they have checked everything over and can't see anything that would be causing the issue though they can see the codes on the reader.
While with them it has been for an MOT and passed all of it's emission testing no problems.

it's driving me nuts because when it happens the car is almost unusable it wont push past 3000 pm and slows to about 50mph going up hill, its dangerously slow joining motorways.

I was wondering if anyone had come across something like this in the past?

Thanks

 

Check that the intercooler coolant pump is working, it's on the right of the radiator- there are two identical-looking pumps there, one behind the radiator bulkhead (this is the heater pump) and one in front (the charge cooler pump). If the coolant is not pumped through the intercoolers, the charge temps get too high and cause the restricted performance mode. Lots of threads about this pump and an up-sized Bosch unit that can be installed.

 

thanks @POD XF ,

I actually thought this may be the issue about 6 months ago and managed to get a second hand working pump online at the time, but then I spoke to a Jaguar "expert" at a car show who has a good reputation and he told me he didn't think that would be the cause so I started looking at other causes. I will get the replacement pump fitted and let you know how I get on.

 

The problem with cylinders 1,3,5,7 is interesting as this is a whole bank that has stopped working. On each bank there is a big connector at the back of the engine that links the injectors to wiring harness. The injectors on each bank share a single feed from the engine junction box through this connector to get power, if there was a fault on that circuit it would stop all the injectors on that bank from working (which is what you're seeing). It uses the same wire to the EJB for both banks so a potential fault could be between the where the power for the two banks are spliced together but before the splice (after the connector) that distributes it to the individual injectors (otherwise 0 injectors would work on either bank or only a few on one bank wouldn't work). Could simply be water ingress into the connector causing a poor electrical connection. Try unplugging it and use a contact cleaner to remove any corrosion, make sure its seated properly and its a good water tight seal. The connector is a 6 pin thing near the back of the supercharger intake to the throttle body just where it goes under the windscreen scuttle. It should have the unused pin 6 filled with a rubber grommet to stop water getting in, so check that is still there too. If that doesn't make a difference it seems like there is a fault in the wire somewhere on the violet-grey cable from pin 1 on the connector to the junction box or from the connector to the where it splices out to the injectors, might be temperamental where it only goes wrong when its hot or jiggled in a certain way.

P2610 seems to be a wash up of a load of potential errors, so that's not helpful at all. However interestingly one of the potential faults is with the ECT, if the ECT is faulty, or there is a problem with signal from the ECT to the ECU, the ECU can't be sure what the coolant temperature is and will freak out on you. I suspect it would drop you into restricted performance if it wasn't sure what the engine temp is but I'm only guessing that at this point.



Can you see what the engine temperature and air intake temperatures are when it goes into restricted performance? The intake should be about 15C higher than the ambient temperature (although another possible fault from P2610 is the ambient temp sensor isn't working properly so it doesn't know what that is either). If the temp is high then the charge pump isn't working or it can't circulate coolant properly around the system.