Hi folks,
I've got a very strange issue with an M57 I've swapped into a Jaguar XJ40. It's driven spot on for 20,000 miles but picked up this issue a couple of thousand miles ago.
The idle picks up to around 1400rpm and won't drop any lower. The revs are also slow to drop down to this level (basically the same symptoms as having your idle screw too far out on a carb car). It's rock steady at this idle, not rough.
It happens intermittently, though has been getting worse over time. Sometimes the idle is higher (2000rpm) or lower (1100rpm). Sometimes something seems to snap back into place and it drives spot on again for a while.
The symptoms above don't fit with leaky injectors, unless they're all leaky to exactly the same degree, and keep un-leaking themselves every now and again, all at the same time.
Fuel economy takes a hit each time this happens so it's clearly overfuelling.
I've replaced the temp sensor in the head in case it was thinking it was colder than it actually is, but no change.
I've changed the vacuum actuator solenoid for the turbo, but no change (and pulling the vacuum hose off of it doesn't change the idle.
No codes on the ECU.
Any clever ideas?
I've got a very strange issue with an M57 I've swapped into a Jaguar XJ40. It's driven spot on for 20,000 miles but picked up this issue a couple of thousand miles ago.
The idle picks up to around 1400rpm and won't drop any lower. The revs are also slow to drop down to this level (basically the same symptoms as having your idle screw too far out on a carb car). It's rock steady at this idle, not rough.
It happens intermittently, though has been getting worse over time. Sometimes the idle is higher (2000rpm) or lower (1100rpm). Sometimes something seems to snap back into place and it drives spot on again for a while.
The symptoms above don't fit with leaky injectors, unless they're all leaky to exactly the same degree, and keep un-leaking themselves every now and again, all at the same time.
Fuel economy takes a hit each time this happens so it's clearly overfuelling.
I've replaced the temp sensor in the head in case it was thinking it was colder than it actually is, but no change.
I've changed the vacuum actuator solenoid for the turbo, but no change (and pulling the vacuum hose off of it doesn't change the idle.
No codes on the ECU.
Any clever ideas?
