Nissan Patrol 4x4 (Africa)

Yesterday on the return leg of our trip to Tembe/Ndumo I noticed that our 4.5E GRX started "pinging" under certain load and engine speed conditions or at least it sounded like the type of pre-ignition that one gets when running fuel of too low an octane.

The vehicle was quite heavily laden and was towing our Conqueror Conquest trailer (also quite heavy).

What was a little weird is that the vehicle did not ping at low engine speeds (say below 2800 rpm), no matter what the load on the engine was (i.e. from light throttle opening to foot flat). As soon as the engine speed increased to more than 3000 rpm, the pinging would start under heavy load. This was quite noticeable while climbing up the Ubombo mountains to Jozini. In my experience pinging is more load related than engine speed related and if anything pinging often decreases as engine speed increases.

I drove in such a manner as to prevent the pinging from occurring as much as possible.

What could be the cause of this? Is it indeed pinging?

There could be a number of contributory factors:
1) I have an exhaust leak at the manifold (I have bought the gasket, but have not repaired it yet). Could this be creating erroneous readings on the lambda sensor which in turn leads to incorrect mixture/timing adjustment by the engine ECU?
2) I refuelled at service stations in Manguzi and Ndumo. Could I have taken on dodgy fuel? I didn't experience the pinging on the way up there, but then again, it was along a different route.

Any opinions and suggestions would be welcomed.

Sit met dieselfde probleem - by Upington was dit die ergste selfs met 95 oktaan.

Dis nou snaaks.

My Ptrl het dit gedoen op een outing, en toe nie weer nie, en toe weer nou die dag, maar toe ons die naweek PTA is, het hy dit nie gedoen nie. . Maar my engine het sos ge-"krrrrrrkrrrrr" teen omtrent 2300 rpm tot 2800rpm, maar net as ek die petrol pedaal 'n sekere diepte trap. Vanmore oppad terug het dit egter nie gebeur nie. Wat kan dit wees? Daar is egter nie verlies aan krag en verrigting nie.

Verskoon my onkunde. Is dit brandstof inspuiting enjins wat almal so maak?

Hi Gerrit
I have found pinking problems on the 4.5 Patrols,not because they are bad enjines but the enjine dont like the lower octane fuel.Like the older moddel VW's.
I tried very hard to fix a 4.5 for a friend of myne,he's also on this forum Hermi Lategan.Hermi has a 4.5 and recentley just bought a 4.8,any way Hermi spend a lot of money and time on his 4.5 just to sort out the pinking nothing else.
It is easy to fix the pinking,just retard the timeing,but that is not the wright way.Less timeing,no pinking,no good consumption and less power.Hermi did not like that and said fix it the wright way.
So I end up openning his enjin,because it did not matter wat I did helped for the pinking.This offcorse after a lot we tried to overcome the pinking.
Ok,enjine open and I found the pistons all 6 where shot,the car pinged for so long and bad it messed up the pistons.Hermi bought 6 new pistons from Nissan and all that we need to close the enjine,bearings gasgets and so on.
We knew about the bad octane and did work on the head,air flow,to make the pinking less.I worked out the kompression ratio off the enjine and we lowered that aswell,it is low std.
Closed up the enjine with new parts and the pinking was gone.Only because Hermi rode the enjine in at a low rpm and light throttle.
When we start to drive it harder the pinking was there but almost gone.Now, when the naked ear can hear a soft ping the enjine or ecu allready know about it,and the ecu will pull the timeing back via the knock sensor.Slower timeing less power and so on.So we knew the car is not perfect an Hermi want's it to be perfect.
Now what now,what else can we do,the enjine is rebuilt and the exhaust is done and the car has a uni-chip.It allready spend hours on a dyno.
The next step was camtimeing,nothing wrong with the factory timeing or me that missed a tooth.
That enjine was designed for high octane fuel,and there is no more, so we did work on the enjine to fix what the pinking broke and better the enjine for pinking.
Ok we decided to go fullhouse,what was left the compression was lowered and so on.We moved the cam timeing and it worked,but the car lost power not mutch but it did.Now we are going to move the timeing half way back,and that is difficuilt.
I must make a vernier sprokket.

Sorry I must go will finish post later
Rdgs
Frans

Hi Guys
Sorry to barge in and highjack an Interesting thread - has anyone ever come across reports or experienced the same symptoms on a 4.8?

If not, why would this problem be unique to the 4.5?
Compression ratios:
4.8 = 9,0:1 (according to various Nissan sources including my owners manual)
4.5 = 8,5:1 (wikipedia, so not confirmed)

So both are relatively low compression engines - what was the fuel specification for the 4.5 engine when it was designed - 97 octane?
The 4.8 uses unleaded and I have not experienced any problem with the unleaded 95 octane at the coast or inland for that matter (Rustenburg area).
What does the 4.5 run on - also unleaded? If so, why would the pinging then be a 4.5 thing?

On the 3.5 V8 Rover (Buick) engine with e CR of 10.5:1, timing and ignition advance curves play a critical role. Would be interesting to establish the root cause of the 4.5 issue.

Re Pinking.
On the 4.5's pinking problem,I am not saying every 4.5 needs to be opend,we opend the enjine to better it.
Herbie the 4.8 has a complete diffirent head,combustion chamber,better.The 4.5 has such a,and I dont want to say it but here go's,bad desighn combustion chamber,the poor thing can't help to ping. Even with that low compression ratio.And the pinking are worse at coast level.
Diffirent head desighn's can better or worse pingking,Audi run a compression ratio of 13.0:1,with pump fuel or 95.Ok they'r injection system help with that also.The 4.5 worked fine with old 97 fuel but it only became a problem with 95 octane.So the world changes and the older enjine must come along or stay behind.97 is not comming back and changes to some enjins must unfortunely happen.Less timeing are a fast cure or use a octane booster for when you work your 4.5 hard.
Rdgs
Frans

hi
manne ek het n 4.2 wat die pinging my mal maak dit is dan maar n nissan ding want ek het ook enjin oor gedoen en n cam laat sny met retarded timing n sak vol geld later en my bloed kook al weer, het begin speel met die timing niks maak nie en die naweek op pad terug teen n lang buld toe is dit weer so ,ruk toe die vacum pyp af blok die gat en siedaar nog nie weer n ping nie so nou sal dit maar ek en die dissy moet wees en houveel drama later sal ek nog moet uitvind

sal laat weet ass reg kry
groete

Stupid question:

Is the pinging a bad thing? Is it signs of engine damage or decay? Will my Patrol blow up and will I die in a blazing inferno? . Or is it just because of a low octane fuel. But then again, why only sometimes? . I must say, with the radio on I don't hear it....

Hello Tjaard,nee jou kar sal nie in vlamme uitbars nie
maar ping is nie goed vir enige enjin nie,ek se altyd,hoe lank kan jy met n bolhammer teen n ruit tik voor hy breek?nou dieselfde geld vir n enjin met ping.
Die rede vir die pieg wat kom en gaan,is die verskilende toestande wat jy ry en so dra die ecu ping hoor trek hy die timeing terug.Ook net tot op n sekere punt.Die ecu kan net 10grade tyd weg vat en as die kar nog ping kan die ecu niks daaromtrent doen nie en dit kan ly tot skade oor n lang tydperk.
Ek sal vir Pieter du Toit vra om my te help met n foto op die forum van die 4.5 se pistons wat gegroet het agv ping,ek het hulle darem nog.
Groete