3.0 TDI with erratic loss of boost

[Kagiso II]

Chipompi - I believe you have just touched the REAL culprit of the ZD30 engines going chitty-chitty-bang-bang,,,
Hight above see level ... MOSt [if not all] pf the ZD 30 engines giving way happened on the "high" ground and in temp of 30 ++ cels.

The only answer I could ever derive from a Nissan "person" was that the computer for the ZD30 Nissans were set as default for european situation - [lekker koel daar, en amper seevlak .....] - So, hier in Afrika en daar onner in OZ - dis waar hulle breek.
Groot hartseer dat Nissan nie hulle flop erken en die enjins vervang asook die komputers [hulle het wel 'n paar "faulty" ECU's vervang - maar net 'n fraksie wat werklik die skade aangerig het. [ten minste doen Toyota 're-call' van miljoen en meer karre, iets van "ethics" wat Nissan gerus kan leer..

Ek het altwee my ZD30 enjins ge -"Chip" .. en konserwatief laat stel .. en sover hou dit... - mag dit so bly

[JoshJ]

HI,

This was a very interesting read. My Trol has not even had its first service yet. Only 13400k's done thus far and i am experiencing the same loss of power when costing at 100-110km/h. When i want to overtake I can put foot but there is no response. Also found that playing with the throttle helps, but only for a while. Thank for clearifying this Tony. It has helped me tremendously. Thought its just my Troll thats pap.

Xcuse the spelling. Ingalish not to hot at 3 in the morning

Maybe a spell check is a good adition to the toolbar

[Stefan]

Spell checker is standard functionality in Google Chrome.

[Tinus lotz]

I need that spell checker thingy magodi....big time..lol

[IanT]

Not a Patrol I know but I had the same thing happen on my Disco 3 (Land Rover took 3 months and could not find the problem!!) took it to a private LR Mackie and he sorted it out in 30 mins!! Driving normally there was no problem it only happened when I was on the highway and put my foot down to overtake, I would lose most of the power and have to pull back into the slow lane and then power would come back??? It turned out to be the diesel filter on the LR they are supposed to last 70K but I must have put some bad diesel in and the junk was half blocking the filter, normal driving was fine but when I asked the motor for more power it was not able to get enough diesel through the filter and the computers kicked in and dropped the power. The other times it has lost power it was a problem with the solenoid on the turbo

[ricster]

Not too clued up on the 3.0 diesel, but there is a good chance that either the main diesel filter is blocked, or the small metal filter on the diesel pump where the banjo fitting is on the diesel inlet to the diesel pump. If the main filter was changed recently, then this other filter, that not many know about needs to be cleaned out and refitted. I believe it in a quick simple operation.

[gupster]

Mine had exactly the same symptoms. Right in the beginning of this post, Koos Best mentioned the adjustment to the VNT screw for the turbo. After I turned mine down, the problem went away. I found that at the coast however, higher atmospheric pressure, the symptom happened again occasionally, so i turned it down a little further until it went away completely.

[JoshJ]

I live in the highveld 1570 above see level. Ands its ugly flat here, so coasting is the norm

I replaced the filters. Both of them. This solved the dying proplem i talked about a while ago. Those filters that the car came with since new had cotton as well as silicone like pieces in them. Stealers say it can be from standing at the factory or harbours to long. The only filter not checked is that metal inline one you owes are reffering to. I will have the stealers check it on its service along with the boost sensor.

Gupster, i'm itching to djust the VNT screw, but the Trol is under warrenty. So i'll have to wait my turn for these things. In the meantime i am learning from you guys on the forum. And in return teaching the stealers.

[Tony]

Since all the work I have done on my troll, I have experienced a strange one - I find only some times that when cruising along at a steady speed (can be highway driving at 80 or 100, or at 60 in town) and I accelerate, nothing happens! If I lift off and re apply pressure I can feel her boosting - alternatively, if I keep my foot down she slowly starts boosting but it takes quite a while, and in the meantime my EGT's climb like crazy. Also when driving on open roads I am finding that my EGT's climb far too high on uphills unless I put foot well before the incline and then EGT temp settles as the speed slowly decreases but way up at between 550 and 600 deg. I find also that if I approach a hill at an easy pace (80 - 90km/h) and ease my foot down, I pick up speed, but once again EGT's climb like crazy and she runs out of steam, and accelerating more acheives nothing more than higher EGT temps. This never used to happen before, boost was always instant, and 550 deg for EGT was never reached, now, just climbing the hill at the new road offramp in Midrand had the beeper going at 650 deg and I was only doing 100 km/h. I have replaced the boost sensor close to the radiator just under the MAF with the 3 little vacuum pipes attached to it - I never new that there was another one at the intercooler - could it be the culprit. Also, I screwed the VNT skroeffie in (clockwise) a little, would that influence the boost when she runs out of steam if I accelerate at the bottom of a hill - did I maybe turn it in a little too much??

[gupster]

Hi Tony. I found that when doing the few mods to my 3.0, I had to do them piecemeal because when something odd happened, I was not sure which one caused the problem. Do you have a boost gauge? Can you turn the VIN screw back to its original position and check again? I have attached, I hope, some info from Au forum that might help. I used it successively to determine that my MAF was kaput. I tested the voltages and had bad readings on mine.
I think that the little unit under the MAF is only used to control vacuum to the variable turbo from the the ECU and that the (over) boost sensor is on the intercooler. Interestingly, JG Shields found that this sensor to be at the root of his problem. The trouble with the 3.0 is that it has so many sensors feeding information to the ECU, if one of them sends faulty data, the ECU could easily over oil and when a diesel runs rich it over heats, unlike a petrol engine.
Its a good thing you have that EGT set up. I once removed my MAF just after switching off my engine and found quite a lot of oil mist in there. So perhaps, unless you have already done so, cleaning the MAF would be a good place to start. On the older engines, I guess the catch can mod would be very preventative of an oiled MAF.