3.0 GU TD problem.

Submitted: Saturday, Nov 22, 2003 at 21:13

ThreadID: 8687 Views:2418 Replies:9 FollowUps:7

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Member - Andrew (Bris)

What a day I had yesterday. 8.30am and the 3.0 GU is blocking traffic in the centre of Brisbane. Driving through the city I firstly lost power, appears the 'computer' put the vehicle in 'limp-home' mode. Thirty seconds later while trying to move over and let the other traffic past the smoke started. Awesome cloud of black smoke everywhere. I wasn't able to move, so simply parked in the middle of the road, in peak-hour, and waited for a tow. I was amazed at the number of drivers who called out very unfriendly remarks to me while I sat there watching traffic back up. No way I was going to get out and push 3 tonne of vehicle through the traffic on my own, and there was no-one around offering help.

Nissan Service and the RACQ to the rescue.

I was towed out of the way 'to a safe location' and then had to wait for a breakdown person to come and tell me that I would need to be towed again.

Finally towed into a Nissan dealership at 1.00pm to be told by the 'friendly' service person that they were booked out yesterday and Monday, but would look at the patrol 'when they got time'. I wasn't very happy, and I think they got the idea.

After a 'nice' conversation with every 'manager' I could find at the dealership, at 4.00pm they were finally able to tell me that there was a problem with the EGR valve, but it would not be until late Monday before they knew exactly what was wrong with it, or what to do to fix it. This didn't make me any happier.

Now I'm at home with a lovely 15yr old ute that the dealer so graciously lent me for the weekend, and in exchange he has my $60000 piece of steel called the Patrol. Interestingly the ute they have provided has a speedo that doesn't work, a tacho that doesn't work, is missing at least one stud off each wheel, but the air conditioning works.

Has anyone else had a problem with the EGR valve on a Patrol? Yesterday was the first time I'd heard of an EGR valve. I pay mechanics to work on my vehicle and have never had an interest in getting grease on my hands.

I don't need to know about anyone's third cousins neighbours problems, but if you have had a similar problem with the patrol please let me know.

Does anyone know of other items I should insist Nissan check while they are working on the car?

Are there any future consequences of a problem with the EGR valve?

I'm still a bit peeved, but when I calm down, I'm sure I'll go back to loving the Patrol. Despite having no radio for four weeks while it was away being repaired, and spending four weeks waiting for a leaking seal in the automatic transmission to be replaced, (all under warranty), it hasn't been a bad vehicle.

What's really upset me is that in the last two weeks I've put new tyres, shocks and springs into it, and was looking forward to spending this weekend giving it a bit of a bash.

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Reply By: Member - Bob - Saturday, Nov 22, 2003 at 21:22

Reply By: Member - jaksun - Saturday, Nov 22, 2003 at 22:38

Reply By: joshinthecity - Saturday, Nov 22, 2003 at 23:10

Reply By: Truckster (Vic) - Saturday, Nov 22, 2003 at 23:47

Reply By: Member - Errol (WA) - Saturday, Nov 22, 2003 at 23:52

Reply By: Member - Hugh (WA) - Sunday, Nov 23, 2003 at 02:50

Sunday, Nov 23, 2003 at 02:50

Hi Andrew,

Sorry to here of your troubles. I hope this gives you some background to EGR valve.

EGR stands for exhaust gas recirculation. EGR is used under part load conditions to introduce exhaust gas (inert) into the inlet manifold to dilute the charge and fill the combustion chamber with only enough air (oxygen) to support combustion. Because part load only requires a small amount of fuel, if there was no EGR the excess air (oxygen) would lead to excessive NOx formation which is bad for emissions control. Also, the EGR reduces inlet manifold pressure, which then reduces the engine's pumping work and hence allows for improved fuel economy.

The use of EGR has been around for quite a while (gasoline and diesel engines), however modern direct injected diesel engines run stratified lean combustion at part load and can tolerate much higher amounts of EGR, with associated emissions and fuel economy advantage. As EGR flow increases, larger valves are required to control the flow of gas. These valves are typically stepper motor devices controlled via the engine ECU. There is a map in the ECU that works out how much to open the valve based on engine speed and pedal position inputs. Bigger valve area and hotter exhaust gas are a designers nightmare. Typical failure modes are sticking valve (carbon) or stepper motor failure (heat). If the EGR valve is truly at fault then it requires replacement.

I'm not familiar with Patrol EGR failures, however I have seen enough prototype EGR valves fail to know they do fail. I am surprised that an EGR valve failure would bring things to a halt though. To prevent such issues, the control strategy (onboard diagnostics within the ECU) is set up that the valve drives closed if a problem is detected (usually before complete valve failure). In this way the engine still functions fine, albeit with increased fuel consumption and worse emissions (engine fault light would come on). How many kms have you done on the GU?

Now I also have a GU Patrol and have experienced first hand the crap service from dealers, most of whom I've found do not have a good understanding of modern engine technology, let alone latest common rail direct injection diesel technology and associated EMS. These guys would have run a diagnostics check and it would have spat out EGR valve as a likely cause. I'd be getting them to explain exactly what was wrong with the valve. Wouldn't surprise me if there was another fault. Early 3L DIs have had ECU problems.

None of the above probably helps too much when your vehicle , however I hope you have a better understanding of EGR and why it's used.

Regards,
Hugh

AnswerID: 38150

Follow Up By: Member - Andrew (Bris) - Sunday, Nov 23, 2003 at 09:32

Sunday, Nov 23, 2003 at 09:32

The vehicles 12 months old and done 47000km.

No lights came on the dash to say anything was wrong.

I couldn't drive it because it was going crazy. Revs were going up and down like a yoyo. It wasn't stopping completely, but alternating from roaring down to almost stopping.

FollowupID: 27688

Follow Up By: Member - Cocka - Sunday, Nov 23, 2003 at 11:36

Sunday, Nov 23, 2003 at 11:36

That's a worthwhile and informative explanation Hugh, not that I have a problem, but we are a little wiser about the workings, thanks.
What you say raises another Q though. ie who can we rely on for competent servicing ?
Many of us do wonder about dealer servicing competency, particularly on TD's. Whilst I read about injector specialists, boost specialists, turbo specialists etc etc. is there really a mechanic about these days who understands the modern electronic diesel and who can balance and tune an engine, or have all these tradesmen been replaced by the introduction of the computer mechanic nerd. Years ago I used to deal with a bloke who would take the vehicle for drive down the street and back then know exactly what the problem was, and he could fix (repair) it.
Unfortunately many of these DIY options are disappearing. My first car was a '29 A Model and over the years I rebuilt that car. My Dad and I had a wonderful workshop which I eventually inherited and I still have a garage full of beautiful tools, but today all of the tuning work requires a computer, so what can I do ?
Where do we take our mobile 4WD comuters. Are ARB, TJM, your mates down the road qualified enough ? Who is a qualified mechanic these days, where do you find him/her ??

FollowupID: 27693

Follow Up By: Member -BJ (Sydney) - Sunday, Nov 23, 2003 at 18:15

Sunday, Nov 23, 2003 at 18:15

My truck mech looks after mine & as he's a 4wdriver himself he knows his stuff. i'm tyring to get him to advertise here so thoe's is Sydney will know of him.Regards Bob
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