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4.8 fuel consumption

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4.8 fuel consumption

Postby b_killer » 25 May 2016 20:42

Hi everyone

So I'm on my second tank of fuel on my 4.8 so perhaps a little premature, but I managed 30l/100km or 3.34km/L on the first tank and the second isn't looking any better. I was expecting 4.8km/L given the engine, but something must be out of spec. What can I check before the next service which is still a few thousand kms away?
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Re: 4.8 fuel consumption

Postby Tinus lotz » 25 May 2016 20:46

Go make a turn at graham let him check the settings. ..if you drive it like you stole if it can even get worse WWW
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Re: 4.8 fuel consumption

Postby Alex Roux » 25 May 2016 20:51

b_killer wrote:Hi everyone

So I'm on my second tank of fuel on my 4.8 so perhaps a little premature, but I managed 30l/100km or 3.34km/L on the first tank and the second isn't looking any better. I was expecting 4.8km/L given the engine, but something must be out of spec. What can I check before the next service which is still a few thousand kms away?


That consumption is not normal by a country mile. Not even with a roof rack, big mud terrain tyres and a heavy foot.
What does the engine performance feel like? Is it weak or normal?
In my recent case, I had two problems. A weak fuel pump (that was on its way out), and the ECU setting being wrong. Both contributing to poor consumption.

Too much fuel pressure is also bad for consumption, but this is unlikely as the regulator should set that right (I assume the 4.8 has its own built-in regulator?). But a faulty underperforming fuel pump is a possible cause. This would however coincide with poor engine performance as well.

I do not know how easily the mapping of the 4.8 ECU can go wrong though. I think not, as I have not heard much complaining about that.
Last edited by Alex Roux on 25 May 2016 20:56, edited 2 times in total.
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Re: 4.8 fuel consumption

Postby Alex Roux » 25 May 2016 20:53

Tinus lotz wrote:Go make a turn at graham let him check the settings. ..if you drive it like you stole if it can even get worse WWW


Well, I guess Tinus knows better on that front. I did not even think a heavy foot can do that to a 4.8.

It looks like you live in PE?
In that case it may take too much petrol to get to Graham. There must be another solution.
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Re: 4.8 fuel consumption

Postby b_killer » 25 May 2016 21:18

Alex Roux wrote:
Tinus lotz wrote:Go make a turn at graham let him check the settings. ..if you drive it like you stole if it can even get worse WWW


Well, I guess Tinus knows better on that front. I did not even think a heavy foot can do that to a 4.8.

It looks like you live in PE?
In that case it may take too much petrol to get to Graham. There must be another solution.


Yes I'm in PE and not sure who Graham is. Performance feels okay for such a big vehicle, but something is up.

Any fault code checking that I can DIY?
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Re: 4.8 fuel consumption

Postby Tinus lotz » 26 May 2016 06:31

Sorry man didnt see you were far away....replace feul filters check feul pressure check timing have a look at aircleaner ... give graham cumming a call pathfinder on the forum he will assist you over the phone with all the relitive settings pressure ect ...mabe a bit of carb cleaner on the maf :think: o yes blocked exhaust also makes big problems
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Re: 4.8 fuel consumption

Postby Herrie » 26 May 2016 07:15

I think that you must check you Patrol's PCV valve as well because if the PCV vavle is blocked or very dirty your fuel concumption is bad.
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Re: 4.8 fuel consumption

Postby b_killer » 26 May 2016 17:59

Tinus lotz wrote:Sorry man didnt see you were far away....replace feul filters check feul pressure check timing have a look at aircleaner ... give graham cumming a call pathfinder on the forum he will assist you over the phone with all the relitive settings pressure ect ...mabe a bit of carb cleaner on the maf :think: o yes blocked exhaust also makes big problems


Thanks for the tips Tinus. I'm making a list for my indie. The Patrol is coming up for 260,000 km so I'll have him check the vehicle from front to back.

Interesting that you mention the exhaust. It has a viper 6-2-1 branch which goes into nothing more than a 50mm pipe with two rather small boxes. There are a few leaks around the welds on the boxes and the system in general is tired. Planning to replace as soon as I get my Pajero back from having a 3rd gear drivetrain vibration sorted.

What is the recommended diameter pipe and freeflow box combo for the 4.8? One spot in PE says 57mm and the other says 63mm.
















i
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Re: 4.8 fuel consumption

Postby b_killer » 26 May 2016 18:00

Herrie wrote:I think that you must check you Patrol's PCV valve as well because if the PCV vavle is blocked or very dirty your fuel concumption is bad.


Thanks Herrie. Will check it out
Every dog has his day!

1996 Pajero DOHC-24 V6 3500 LWB (my first) - Sold
2005 Patrol 4.8 GRX (my second) - Sold
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Re: 4.8 fuel consumption

Postby b_killer » 26 May 2016 18:04

Alex Roux wrote:
In my recent case, I had two problems. A weak fuel pump (that was on its way out), and the ECU setting being wrong. Both contributing to poor consumption.

Too much fuel pressure is also bad for consumption, but this is unlikely as the regulator should set that right (I assume the 4.8 has its own built-in regulator?). But a faulty underperforming fuel pump is a possible cause. This would however coincide with poor engine performance as well.

I do not know how easily the mapping of the 4.8 ECU can go wrong though. I think not, as I have not heard much complaining about that.


Hi Alex. I'll definitely check the fuel pump and pressure. Not sure how to check the ECU other than by checking fault codes if any?
Every dog has his day!

1996 Pajero DOHC-24 V6 3500 LWB (my first) - Sold
2005 Patrol 4.8 GRX (my second) - Sold
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b_killer
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