Unexplained loss of power 4.7lt V8 petrol

[Spudman]

I have just arrived in Perth 3000 kilometre trip, sat on 115-120km/h the whole towing a trailer and got 22 litres per 100k and it ran perfectly the whole way,

While driving around Perth it's already down to 18 litres per 100k.

Car is booked into Toyota on Thursday getting the fuel pump replaced, so it will run even better soon

 

[LCKID]

Lckid
Did you try driving it around without the chip, drive it for about 50k and see if it does it again, at least that way you can eliminate the chip, also show Toyota dealer my photos although I'd be surprised if your pump would be as dirty as mine.

With so few k.s on the clock Toyota should be doing a whole lot more

problem is iv'e put the TRD SC on it and shipped it to Europe where neither the 5.7 nor the SC is common.


i have dashcommand permanently logging so if/when the codes are thrown it wil hipefully have record of the events that lead up to the "too rich" codes being thrown. at the same time, those codes are shown as always "pending" for some reason.

dealer wants to change the fuel filter as the next measure, after that he says it will have to be the fuel pump ("could" have been damaged by bad fuel...????)
entire situation is far from ideal.

any insight appreciated!

 

[Spudman]

I have a scanguage in my rig and when I check the codes heaps of codes come up as pending but nothing is ever logged, so I was thinking its normal to do that.

Hopefully you'll notice a change with changing the fuel filter, I certainly have

 

[Spudman]

Ok fuel pump fitted yesterday and early indications are good driving around the suburbs coming home it's already down to 16 litres per 100 kilometres.

The big test will be driving home in a couple of weeks

 

[ihatemud]

Hi Spudman

From your original post you mentioned the engine RPM increased but the speed vehicle didn't. Sounds like a torque converter or a box problem to me.

Cheers

Paul

 

[Spudman]

Hey Paul
Not sure about that but I will discuss it with my mechanic when I get back, thanks for your comments mate.

It's just that since we've replaced the pump and filter it's running perfectly and getting good fuel economy for a 3 tonne V8

 

[Spudman]

Ok so it's been a week since the new fuel pump was fitted, and I've gotta say this truck is awesome, it was awesome before the pump was replaced, but I'm referring to the acceleration, it's now instant and has so much more power than before, so it was pretty obvious to me that pump had been blocked for quite sometime

I'm still getting around 16 litres per 100 kilometres in the city and I'd never seen it before below 20!

Still gotta do the drive home on Wednesday, and I reckon that'll all be good

 

[Spudman]

Well drove 900 kilometres today to Carnarvon, averaged 17 litres per hundred kilometres, pretty sure the good book says the 4.7 V8 should average around 16 litres, so gotta be happy with that

 

[Spudman]

Drove it about 1100 kilometres today, gave it some stick during the hot temperature which was around 41degrees outside and car performed really well, went upto 18 litres per 100, but I expected that at around 135.

So one more day tomorrow and home, that will be through the heart of the Kimberley around 45 degrees this time of the year so hopefully all will be ok

 

[Spudman]

Well completed the final part of the drive today in 44 degree heat, I also gave it a bit of stick to make it work harder and the truck performed perfectly, no signs of the dreaded loss of power.

So that's it, I'm convinced that it is totally fixed.

Hopefully this may help out another mudder if they ever have the same problem

 

[elaroo]

Well completed the final part of the drive today in 44 degree heat, I also gave it a bit of stick to make it work harder and the truck performed perfectly, no signs of the dreaded loss of power.

So that's it, I'm convinced that it is totally fixed.

Hopefully this may help out another mudder if they ever have the same problem

We are having this exact problem and it started with loss of power with codes indicating catalytics on exhaust so replaced them then got the p1071 and p1074 banks 2 lean have replaced intank filter, inline filter ,pump ,pressure regulator on rail and airflow meter,still codes and loss of power.
Changed the inlet manifold gasket and codes have gone but power loss under load is still there fuel pressure is down under load(putting the boot into it) but car will drive brilliant at normal speed and idle.
The only thing not changed is the little valve in the tank which is also called a pressure regulator.any help appreciated

 

[Katkon]

It looks like you guys may have isolated the problem but just wanted to chip in: my wife and I experienced identical symptoms in her '11 Audi Q7 just two weeks ago. Dealer had trouble diagnosing the issue, as did Audi North America. Turns out it was a combination of a couple of factors in the end: a faulty injector port and a crappy spark plug. Basically, the engine was being flooded with fuel, and replacing the injector port and a spark plug fixed the issue. In this particular case the car self-identified the faulty injector port, but not the spark plug issue... That was identified through trial and error, as replacing the port didn't resolve the issue 100%.

 

[elaroo]

We are having this exact problem and it started with loss of power with codes indicating catalytics on exhaust so replaced them then got the p1071 and p1074 banks 2 lean have replaced intank filter, inline filter ,pump ,pressure regulator on rail and airflow meter,still codes and loss of power.
Changed the inlet manifold gasket and codes have gone but power loss under load is still there fuel pressure is down under load(putting the boot into it) but car will drive brilliant at normal speed and idle.
The only thing not changed is the little valve in the tank which is also called a pressure regulator.any help appreciated

 

[elaroo]

We have solved the problem replaced the whole fuel sender unit in the tank and now its running like a dream thanksvto all for info

 

[dwigt]

Hey, our landcruiser is acting doggy after it warms up, but it's sporadic, and sometimes just limps home. The code says too lean, cleaned filter, replaced pump and sensor, still sporadic. Checked gas cap too. Any thing else we might've missed?

 

[VooDoo2]

IF its reving up but not accelerating there is slip. Either the torque convertor isnt locking and its slipping or the clutchpacks in the gearbox. When it does it, can you remove your foot and let revs drop, then put foot down again and it free revs? Is it holding a gear? Is it not increasing revs and holding static?

I would remove the unichip to remove it from the equation, ive seen LOTS of issues with them, especially with bad connections. They only use 30 or so but every single wire to the ECU is extended. Check the ECU side and see if there are any signs of water damge and corrosion.