Advice needed before i I sell this piece of s*#%

[Patrol'n]

Hey guys,

Desperately need some advice and or help please. Despite running brilliantly, my fuel consumption (Carbied RB30), has been getting steadily worse for some time... I just topped the tank up and it used a staggering 26.5 litres per hundred for low revs / stress 2wd suburban driving.

I cannot keep up with such huge fuel usage, particularly when it doesn't have the power / torque normally associated with that kind of fuel bill... It's no TB48. It also means that even with my long range (147 litre) tank, I cannot get more than the high 500 kilometre mark from a tank, which sucks!

I can't think what else to check, I've gone over the mix, (near perfect and carby only professionally rebuilt late last year), timing, vac advance, filters, new oil, distributor cap, rotor, new spark plugs correctly gapped, leads aren't old, took the foam sock off the snorkel, drove it hard, drove it gently, loaded, unloaded checked tire pressures, rotated tires, don't seem to have dragging brakes etc etc.

I must be missing something, but I can't think what could be causing such high figures all the time. I love my patrol and don't want to even consider selling it but nothing seems to improve it, best I've had for a while has been around 20-21 litres per hundred and not often...

Now I do have a 2 and a bit inch lift, and 32 inch BFG's (around 20k on them), and a rhino roof rack. It has a safari snorkel, and extractors, but otherwise is a stock engine. That said, these things haven't changed and my usage figures used to be somewhere around 17-18 MAX.

I have had conversations with a mechanic or two now, and had the car looked at, but they couldn't offer any other ideas, and I can't afford right now to start replacing parts that don't need replacing if it doesn't fix the problem. I don't expect to be doing any serious fuel economy runs, but it is ridiculous now and making me a bit crazy...

Sorry, rant over, Does anyone have any other ideas or can someone recommend a really good mechanic in Perth who can actually resolve the problem? I don't mind paying to have it fixed, but I don't want to pay for non-fixes. Please.........

[Turtle_au]

Do you feel like you are filling it up more often? Maybe the odometer is reading wrong and you are actually travelling more kms than it is showing. Check the speedo againest a GPS.

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[Patrol'n]

Thx mate, yeah speedo is slightly out, at 100 indicated, I am travelling about 103/104, that variance shouldn't make such a big difference I'm guessing?

[UncleFrosty]

Left-field... pinhole in a fuel line somewhere?

[mudnut]

Fuel pump slowly failing?

[TPC]

Fuel pump slowly failing?

What economy do you get?

[mudnut]

Anywhere from just under 14 Highway to around 18-19, offroad driving.

Maybe the fuel return solenoid is stuck open, making the fuel pressure too low, so you need to put the boot in it to get power. A dynotune or a fuel pressure guage might be the best guide to show whats up.

[Patrol'n]

Left-field... pinhole in a fuel line somewhere?

Thanks, I will look over the lines, I have replaced the hoses in the engine bay, feed and return, but never know, or maybe the hoses near the tank, I will look in daylight

[Patrol'n]

Anywhere from just under 14 Highway to around 18-19, offroad driving.

Maybe the fuel return solenoid is stuck open, making the fuel pressure too low, so you need to put the boot in it to get power. A dynotune might be the best guide to show whats up.

Thanks mudnut, hadn't thought of the fuel pump or solenoid, the throttle response and power aren't a worry, it holds highway speed and accelerates pretty well for such a heavy vehicle. Regards the fuel pump, it's electric and in tank isn't it?

Maybe I'm tired but how would the pump slowly failing cause poor economy? Not doubting, just curious, and how would I test the pump?

I may have to find a dyno tuner in Perth that can work on Carbied motors, anyone know a good one?

[mudnut]

Easy and cheap to replace. I just had to recently, because on a long trip mine failed then came good, failed then and we made it home. If it isn't giving the right pressure, the engine requires more fuel to run.
Also check that the pre-heat flap is closing off when the car is warm.
The fuel pump is in the top of the tank under the rear compartment. There is a cover that gives you access. Just lift the carpet and you will see it.