Is my QX finally broken?

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Wed 15 Jun 2005 22:59
Is my QX finally broken? - Gazza
Everytime I used the car in the last two week, it has stalled at least once per journey. Everytime the car is fully warmed up and the car "shiver" for a second and the engine just stopped. (If I catch it in time before stalling, I can keep it going with throttle and Left-Foot-Braking, though I don't want to practice this all the time especially in traffic or in a bend.) Then engine would just crank over but not start. Eventually, it would start after 2-3 minutes with a BIG cloud of blue smoke.

Furthermore, if the car requires prolong cranking to start, it would also start with a BIG cloud of blue smoke which I can only assume is burnt engine oil.

The car is a Nissan QX 3.0 Auto with 145k on the clock. I pulled the fault code from the car and only the knock sensor is noted by the ECU to be faulty.

Any suggestion? Many thanks, Gazza
Reply | Report as offensive | Link
Wed 15 Jun 2005 23:42
Is my QX finally broken? - frostbite
That big cloud of blue smoke rings bells with me.

Have you got some sort of vacuum operated device on there?

I don't really know what I'm talking about here and I'm not familiar with your motor, but I had an Audi which did this once - turned out a diaphragm had corpsed and the engine was sucking in large quantities of auto fluid on the overrun.
Reply | Report as offensive | Link
Thu 16 Jun 2005 01:33
Is my QX finally broken? - Aprilia
I would start out with a good clean of the throttle body (use some carb cleaner and a toothbrush). If you're feeling keen then clean the idle air valve too. Don't fiddle with the idle speed adjusters though.
Your PCV valve (positive crankcase ventilation) is probably clogged up. You're actually supposed to periodically replace it - but no one does. They are only a few £'s from the dealer. Replace the PCV and clean out the vent hoses. Wouldn't be surprised if that doesn't fix it.
Reply | Report as offensive | Link
Thu 16 Jun 2005 14:17
Is my QX finally broken? - frostbite
"Wouldn't be surprised if that doesn't fix it."

Lack of confidence, or unintentional double negative?
Reply | Report as offensive | Link
Thu 16 Jun 2005 19:04
Is my QX finally broken? - Aprilia
The latter......
Reply | Report as offensive | Link
Thu 16 Jun 2005 21:24
Is my QX finally broken? - Gazza
Many thanks, I shall clean up the whole lot in the weekend after this. As Aprilia mentioned to me in the past, I cleaned the throttle body and sprayed carb cleaner inside the Idle Control Valve last summer. This improved the idling so I am surprised if it suddenly got clogged up this quickly in the past two weeks.

I have also called Nissan for replacement PCV valve, only 19 pounds + VAT so if the cleaning do not work, I'll change this part.

For the last three weeks, I was on an away job in Germany and at least 50% of the time the car was in full-throttled, maximum speed driving, often full-throttled for 30-45 minutes at each journey and lifting only momentarily for traffic. Maybe a coincident but would a lot of high-speed run affect the idling/throttle body/PCV?
Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide

From which small car to buy at which price point to the best UK-built cars, our Top 10s have the lot. Click now for your shortlist.

Unsure of what to buy? Our Top 10s are here to help you....