Only Happens in 4 Low

[siringo]

Thanks for the input Tony, and sorry, I've just got back from the pub and am a bit weary.

When you say FB, I'm assuming you don't mean Facebook!

I need to rest my weary head....

 

[nathand22]

That is proof positive that it's not simply because it's in 4th gear. The initial variations had the fuel rail jumping from 5K psi to 9K - that's an amazing variation - and in 2HI it's probably not scratching the 7500-8500psi mark in variation.

(For the avid reader accustomed to petrol injection fuel pressures of 80 to 200psi, the common rail diesels in these cars have extraordinary fuel pumps that can drive the rail pressure to 30,000psi which is nearly twice the pressure at the bottom of the Mariana Trench, the deepest part of the ocean on the planet).

Much of that variation is going to be the ECM's variations to provide test data for the oxygen sensors in the exhaust.

It looks like in 4LO that the variations are exaggerated. Why? Why in 4th gear, and why only around 2,000rpm?

The ECM knows if you're in gear or not (it has to, because it inhibits the choice of 4LO unless you're in neutral). I don't think there's a variation in the gearbox between 2HI/4HI/4LO - that's all inside the transfer case. Nothing inside the gearbox should change.

And so we come back to a logic problem. Are they using a CAN signal that is incorrectly identifying itself, or is the signal coming from the transfer case sensors cross-linked into the HO2S in the exhaust, or the turbo actuator (vacuum)?

It'd be wonderful if you could manually control the turbocharger vanes, and disconnect the vacuum lines and still have some boost. That would at least discount that.

I wonder if FB could have a squiz at the internal database and see if there are any issues relating to this?

Im not sure if it changes anything or not but the problem is not just in 4th its in all gears from 3rd, 1st and 2nd were fine in my old thai built



-------------------------------------------------------------------------------------

 

[nathand22]

Oh and i think Tony was talking about "Fatboy" not facebook lol

 

[siringo]

Oh and i think Tony was talking about "Fatboy" not facebook lol

I only have this surging problem in low range 4th gear, every other gear is fine.

I'll get in touch with FB and see if he can help us out??

I know 4th low doesn't get used much, but it should work properly, it's part of my 'bullet proofing the Nav' project, to make the truck as useful and reliable as possible.

Thanks again for the help everyone.

 

[user 10312]

it's part of my 'bullet proofing the Nav' project, to make the truck as useful and reliable as possible.

Thanks again for the help everyone.

Once completed you may want to pass on your specs to Nissan

 

[siringo]

Once completed you may want to pass on your specs to Nissan

I might package it and sell it as a performance update kit ;-)

 

[siringo]

Finally got around to booking the ute in for this to be looked at. The dealer said they'd open a 'techline' on it.

Really looking forward to getting this fixed.

 

[siringo]

Dropped the 40 off at Nissan this morning. The mechanic, yep lucky me, I actually got to speak with a mechanic and not a service rep, said it sounded like the 'fuel reg', said it was a common problem with them and will be covered under warranty.

I gave him the print outs of the fuel rail pressure Vs time graphs and all, he seemed impressed and even asked for them.

This is the only significant problem I've had with the 40 up to this point, so if I get it fixed easily I'll be very happy.

 

[Old.Tony]

That's interesting - it's a "common problem" ? I wonder if that's only a KC thing and I wonder if that's been affecting other things like fuel consumption which has been reported by some KC owners as really poor (was it Justdrinkbeer that had one?).

I want to know why the fuel reg is related to the gearbox/transfer case logic too. I guess we'll never find out - let's see how it goes when they rectify it!

Can you let us know if they replace the SCV on the fuel pump?

 

[siringo]

Spoke to the mechanic last night and they're applying to Nissan to get it fixed under warranty as they road tested and agreed that the problem exists.

They also said that there are records of this fault in the Nissan database.

They said Nissan will either send a component or a complete fuel pump, the older mechanic listening in, said they're more likely to send an entire pump, which requires removing the radiator, timing chain and so on.

So I'll get them to check the timing chain and tensioner while they're in there.

 

[longy509]

Keep us posted mine does this aswell

 

[siringo]

Keep us posted mine does this aswell

In what gear longy? 4th low or another?

 

[ourd40]

In what gear longy? 4th low or another?

Mine does the same in 4th low only

 

[user 10312]

Think I may have mentioned before that mine does it to. Only 4th. low but hold it around 2,000 rpm and there is no missing it.

I to will be very interested to see what transpires. A new pump late in the warrantee would be very nice.

My fuel consumption is good but a problem that seems to affect a few King Cab owners.

 

[longy509]

In what gear longy? 4th low or another?

yeh in 4th gear only

 

[siringo]

Just spoke to the service Manager at the local Nissan place.

The official Nissan answer to this problem which is acknowledged by Nissan is that it is normal operation. There is no Nissan fix for the problem

The Service Manager told me it happens with D40's between 2009 - 2011. It can also happen in 3rd and 5th low (which I've never noticed). He also mentioned that over the years, they've tried to fix the issue at the dealers expense by replacing pumps and other bits and pieces but never succeeded.

The service Manager agreed when I said I believed it was a logic problem. He said he had asked Nissan if the ECU (or whatever the computer is known as) could be reprogrammed and Nissan said no.

I have no reason to doubt the Service Manager.

To me it looks like one of those "it only happens to 0.000001% of owners worldwide, it will cost us $9999999999 dollars to fix, we're releasing a new model in X months, it's chepaer to ignore the problem than fix it".

The Service Manager did suggest fitting an EGR blanking plate and looking into fitting a 'chip'.

Nissan said that if I am in 4th low around 2000 - 2500 revs I should be high range. That just tells me that they don't do much off roading.

So to sum it up, Nissan know about the fault, but it's not a fault, it's normal and there is no official Nissan fix.

Over to you guys.

 

[BJJ84]

What a load of shit! To say they computer can't be re-programmed is crap, anything that's programmed can be re-programmed, granted most would have to be done by the manufacture which wouldn't be Nissan, but it could be done.

Very unfortunate that they won't fix the issue!

 

[BravoBrad]

idiots... Yes, I shall select High range for 100m, then reselect low for 50m, than high for 50m than ........arrr f*#k it. hold it flat and ignore the kangaroo hopping d40... they build them like that for australia.

 

[Old.Tony]

"Not reprogrammable" means "No Nissan dealer in Australia knows how to perform the task". There is a mob in the UK that can do it. I used to know a guy about 20km from here that could reprogram anything that had an EEPROM in it but he's long gone.

If it's only happening to a small percentage, it's not "normal operation", it's a screw-up.

I wonder if there's some sensor that's off-spec that's causing it?

 

[siringo]

Yes, I know.
With an electronics background and good dose of mechanical common sense I find it very difficult to understand.

I'm in the process of writing a 2 page letter to Nissan, not inflammatory, but in the hope that it may make someone dig a bit deeper and say "well that just sounds like nonsense, there must be a fix".

If it's a logic problem, then why can't the program used in later models be applied to earlier models? I do understand that many things may have changed, but they must have made a change in something somewhere to get rid of the problem.

The car is still driveable, it's just that I/we shouldn't have to put up with something that doesn't work, it should be fixed.