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Matt, Engineer
Category: Nissan
Satisfied Customers: 21989
Experience:  BEng hons Mech engineering, worked in auto industry for 22 years on engine, transmission and suspension design
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4.2 turbo diesel 2002 GU wagon

Customer Question

4.2 turbo diesel 2002 GU wagon has been running well but will now not rev above about 2250rpm. engine performs normally below this rpm but splutters with no power above this rpm. Prior to this I have recently changed oil/filters, fuel filter and air filter during normal regular service. Any suggestions please
Submitted: 2 years ago.
Category: Nissan
Expert:  Matt replied 2 years ago.
1st 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
Also worth considering adding a bottle of injector cleaner into the tank as a clogged injector nozzle will reduce power and give poor combustion - the next stage on from this is to remove all the injectors and have them ultrasonically cleaned and flow checked
Also 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.
Customer: replied 2 years ago.
Hello Matt - Thank you for your reply to my question. I am left a little bewildered by your recommended course of action and don't feel that you have helped me much at all.
This 2002 model GU does not have an EGR valve nor does it have an intercooler so that part of your response is pretty wide of the mark and doesn't do much for my confidence level for your organisation not to mention being of no help. I feel that the rest of your response doesn't really amount to much help either.
This is the first time I have used this "service" and this experience doesn't prompt me to use it further.
Consequently would you please arrange to have any monies already debited to my credit card, refunded to my account.
Thanks in anticipation
Regards ***** *****