Thread: Fuel consumption

Originally Posted by Red90

It is EFI. You are best to go through the EFI troubleshooting steps in the manual or have someone do it for you. This makes sure that all components are working. There are a bunch of things that could be off.

As above make sure the fuel return is not blocked. Check MAF. Check O2 sensors. Make sure air filter is clean.

You should be 14 to 18 l/100 km.

No O2 sensors in Oz, no closed loop (apart from the legendary Phillip A thread, where he actually did it and posted how).

The blocked return line is very common where it goes into the tank.

Because efi in Oz does not involve O2 sensors it'll run as rich as it likes.

DL

If you're getting better than an avg of 20L/100km then I'd simply suggest that you sit down, relax, have a nice hot cup of tea and contemplate your navel.


Even my 375000km non-rebuilt POS has bearable figures. Paying attention to servicing and doing it thoroughly as well as catching up on tall the 'serviceable' items that have been neglected by the ghosts of previous owners past will ensure you have a relatively dependable vehicle.

service your distributor and perform the bee-utey shaft modification and module relocation. check for side play and end float, make sure it is well within factory spec. if not, fix it. clean and relube the mech. advance, ensure the vac advance is working and use a genuine lucas rotor and cap (yes probably the only lucas part that is better than aftermarket) correct plugs and decent quality leads.

Ensure the engine bay electricals are in good condition - i.e. fix any aged brittle or cracked wiring or connectors. replace the temp sensors, for the ECU and the thermofans. make sure the oil sender is working as well as the tach output from the alternator. make sure the voltage regulator on the alternator is correctly set / functioning (depends on your alternator) all battery and chassis earth points and cables are thoroughly clean and tight. Check the starter cable for corrosion, oil and damage to the solenoid. the fuel pressure regulator is functioning, and that your injectors are not leaking.

Once you have performed the basic 'additional' serviceable items (the stuff that noone does because it's not on the 'list') make sure you have a new fuel filter and oil filter, and that the wiring to the fuel pump and the inhibitor/rollover switch is clean and there is the appropriate voltage at the pump.

Battery is serviceable and will take a full charge.
transmission has been serviced, along with transfer case (fluid flush and trans filter)
differential fluids replaced, CV joints drained and flushed, wheel bearings lubricated, universal joints greased, brakes are correctly functioning and not dragging (including the handbrake!)

Pretty much the only way to commence diagnosing a fuel economy issue is to ensure that your baseline is a completely serviced vehicle and all the systems are operating within their correct tolerances.

Usually servicing will reveal many little issues which may not seem significant, but can have quite a negative impact on your consumption figures if they were left alone unattended.

Just as an indicator, a full fluids change on my RRC (diff/cv/engine/trans/tc) as well as fan belts netted me a 2.5L/100km improvement in fuel economy. that's over 10,000km so you might be surprised what a full service can achieve.

If you discover your injectors are leaking or the spray pattern is junk, then replace them.

If you have no evidence of a top-end service on the engine, then perhaps a proper inspection of the camshaft and rockers is warranted, along with a leakdown test on all cyls. These engines are notorious for eating cam lobes and as a result the engines become quite lethargic, regardless of the condition of the rest of the engine.

The best way to improve things is to take some time to actually learn how the engine is behaving, to spend time developing mechanical sympathy and becomeing a whole lot more proactive about your routine inspection and maintenance intervals on all the mechanicals.

Just start with a clean sheet, assume that nothing has ever been serviced - ever - and then inspect, service and correct any problems as you come across them.

It's not difficult, but you do have to apply some LR logic to diagnosing systems... i.e. eliminate one at a time - because usually there are multiple issues caused by multiple failures and they all only get fixed when you've finished replacing everything from the front grille to the rear tailgate lock.

sounds like an exaggeration, but it is only a mild case of poetic license.


I get somewhere between 20 and 24L/100km in high range depending on the terrain. add roughly 8-10L/100km for heavy low range work.

It makes no difference regardless of the throttle application, the difference between best figures and worst are not indicative of the driving style, but more to do with the terrain and the need for lower gear selection and higher rpm.

Originally Posted by DoubleChevron

What cliff did it fall off to get 14L/100kms

From personal experience driving a V8 for many years. 14 to 18 on the road. More if going off road. If you are getting worse, there is a reason (driving habits, extra wind resistance, bad calculations, engine in bad tune).

Yep I have to agree with Red. From my experience a Rover V8 will get about 14L/100km on the highway and about 18 to 21L/100km normally around town.

Just going off the fuel gauge doesn't give very accurate reading of anything. I know going on the fuel gauge on my RRC for the first half of the tank I could go 250km but on the last half, it would be lucky to get 100km.

If your getting anything worse than what I've mentioned you have an issue and you'll have to look further into your engine health.

mine is a 95 soft dash, 4.6 with a Haltec piggyback ecu, up graded injectors, injected lpg, front bar with lights, roof bars, rear bar with wheel carrier. I continually get 14 on the highway at max highway speeds. 19 when on lpg. Around Sydney, work, loaded etc, I get about 20 on petrol and about 25 on lpg. I am happy with that because I love driving it.

Mine I’m sure will improve. Just came back after a month away there’s a stink of petrol in garage I attribute this to the “new” old victa in the garage. But today poking around there’s a new wet stain on concrete under front of fuel tank. Have a look Fuel slowly dripping out sender unit area running down to floor tightened the big captive ring that hold sender in got about another 1/4 of a turn. Hopefully fixes leak- and helps the economy

the simple fix to it all is the installation of a hi-clone.

I saw it on tv out in the bush.

I never see it advertised in the city areas.

Originally Posted by Meccles

Mine I’m sure will improve. Just came back after a month away there’s a stink of petrol in garage I attribute this to the “new” old victa in the garage. But today poking around there’s a new wet stain on concrete under front of fuel tank. Have a look Fuel slowly dripping out sender unit area running down to floor tightened the big captive ring that hold sender in got about another 1/4 of a turn. Hopefully fixes leak- and helps the economy

Not sure what tank you have, but a 74 ish metal tank will leak where the return line enters the tank at the front.

The tank thread rusts and blocks the fuel return line (carb and efi) at the front of the tank then leaks.

DL