Thread: '98 P38 Overfuelling

Originally Posted by SteveFarmer

Hi

It may if it is causing a vacuum leak

There are some threads on here about how to get the buggers out on the Thor engine

Steve

Thanks Steve. I've cleaned the breather. Not too bad to get out just need to take some time, but I managed to pull the whole thing out without anything breaking. Gave it a good clean and popped it back in.



Drove around today, but not enough to make any assumption on changed fueling.



Got a new (used) MAF from Triumph Rover Spares in Adelaide. (Along with some other small bits). Popped that in. Doesn't feel any different to using the original (cleaned) one.



Concerning the tyres and trip computer: its been pretty much spot on for me. Comparing GPS kilometers and tank fills for the last 3 tanks the trip computer has been within 0.2 l every time. I was pretty impressed. Speed seems perfectly accurate too. Maybe the tyres are balancing the inaccuracies of the trip comp



Like I said it doesn't feel any different. Was running nice before I did anything though, so that's not much to go on. The only thing I seem to notice is that on a kick down, the power doesn't seem to be quite there. I can fully press the accelerator and the engine won't rev over 3k rpm. Is that normal?

RangerFelix, I've got a 1996 HSE (4.6 GEMS) running 91 octane petrol only. Put the foot down and revving to redline without a problem. As for fuel consumption, that comes back to how I am driving. If I drive sedately and dont get over 90 kph on a country road aside from annoying every driver in a vehicle behind me I can comfortably acheve around 13l/100K. Lift the speed to 110+ and a bit more aggressive with the right foot and the fuel consumption will move up to around 17l/100K. Those figures are whilst running with "standard" size tyres 255/55/18 highway tread. If I switch to the 265/75/16 Maxxis Big Horn muddies, firstly the speedo and subsequently the calculator is out by around 10% but using GPS and actual fuel being put into the tank I am getting around 18l/100K with highway speeds of 110+ kph.

On a trip that I did back in 2012 I had a fully loaded car plus roof rack also heavily loaded. 5629.7 K's and averaged 17.22 L/100k. That included driving around 1200 K's of gravel roads and around 250 k's of sand driving, I was then on Cooper ST's 225/75/16.

Gary

Gary. That sounds about spot on with what I get. Nice to see some repeatability.

Those figures you're reporting are what I'm expecting from this car. Sadly its not what I'm getting.



I've today just done about 30km on the highway and decided to see how the car is responding to the recent adjustment.

Result: I've discovered a complete lack of power. I may have just not noticed this previously, because I was driving the thing like a grandma to save fuel. So this may be a new issue or an existing one.

Basically what happens is it will go fine to about 100kph, albeit very very slowly. (like 30-40 seconds, bot like a 4.6 V8 should) This is with the gas pedal to the floor. The rpm maxes out at 3000. It feels like it is struggling hard to get to that speed.



I've just ordered new HT leads which I will hopefully be able to fit this afternoon.

Also just checked the transmission fluid: was low so I've just topped that up.



Any ideas? I love that range rover, but it really is a bit of a money sink

It's not unknown for catalytic converters to block up, especially if they've spent a number of years running rich, from short trips etc. If your engine is running at full throttle it runs open loop and rich so it only compounds the problem. You can either smash out their guts with a rod (illegal but invisible from outside), cut them out and fit plain pipes (more illegal and visible) or replace them with aftermarket hi flow cats. You could have a collapsed muffler baffle too.

What does exhaust smell like? What are your long term fuel trims? You really need to watch ODBII values for a while and Id suggest for a while to stop throwing parts at it. If it starts and runs well, it must be something small. Small vacuum or exhaust leak?

ODB LTFT will tell you if its both banks or just one. The bluetooth adaptors are cheap and can connect to Apple or Android or laptops. Itll be useful for other stuff too. The Kiwi one is excellent, flawless.

I have been chasing rich problems on both banks for months. I cant find it. My LTFTs are ~23%. And it smells rich, you can tell in the garage after only a few seconds. I have tried O2s, MAF and new inlet ducting. My last suspicion is inlet manifold.
http://www.aulro.com/afvb/p38a-range...trims-why.html

Good luck!

If it doesnt smell rich, and you havent got any faults, then it is probably not too rich?! Maybe dragging brakes, dud bearings, handbrake?

BTW: mine eventually throws fault codes on both banks, but does NOT fail into open loop mode. It stays in closed loop operation. And I have one knock sensor short to ground that I suspect is unrelated.

Right back on your first post you mentioned that the plugs foul up after 1500k's. Not normal. Are the gaps set correct and are they the correct plugs? If the car is stationary and in neutral will the engine rev over 3000 rpm or is it only when under load?

Gary