How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22908
Experience:  BEng hons Mech engineering, in auto industry 22 years
Type Your Jaguar Question Here...
Matt is online now


This answer was rated:

We purchased this car 2 days ago. When viewing it, the engine was running. Test drove it and all was well. collected car Friday and drove 40 miles home without any problem (the car was again running when I went to collect it). Yesterday, the car started normally and I filled up with diesel then took it out for a drive to get used to it. After a short distance the engine started to misfire. No warning lights came on, and continued to misfire on an off for the next few miles. i was driving at fairly low revs. On pressing the accelerator after the over-run I experienced hesitation, but on pressing further the engine would take off and run perfectly well. I returned home with the car still misfiring in the same way.
This morning I put the key in the ignition, it started reluctantly and I put my foot on the accelerator to try and catch it (like I would have done with a petrol engine) but quickly realised this was a mistake and took my foot off, turned the engine off and started it again in the correct manner as per the manual. Both times on starting there were billows of white smoke from the exhaust, and the engine chugged badly. There were still no warning lights on the dashboard. I set off along the road, hoping it would clear itself,but the engine was misfiring very badly and smoking from the exhaust so I returned back home immediately.
The car is 2004, 155,000 miles, has some service history and generally very good condition.
Could you give me an idea of what the issues are and what to do with it.

if there's a lot of white smoke

1st check if the car is using coolant as if its is then this could be a head gasket problem

if the coolant level doesn't drop then its more likely to be excess fuel and I'd first check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost.

a burst or loose pipe will result in over fuelling

If both of these are OK then also check the connections to the EGR valve, if either the vacuum pipe of electrical connection are damaged / corroded then the EGR can be on all time which certainly will hurt performance. Its also possible that its a fault with the EGR valve so its worth removing the valve and cleaning it out with brake cleaner, if it looks particularly clogged then replace it.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues and its best to have the boost pressure measured actually measured with a boost gauge to check that the turbo is healthy and that the sensor is reading correctly

If its a variable vane turbo (they’ll be an actuator on the turbo body - but not a wastegate) then check its vacuum pipework as above and check the connections to the diaphragm / solenoid valve

Matt and other Jaguar Specialists are ready to help you