I usually do not allow my tank to go below 40% before I refill because there have been cases of fuel pump failure when the fuel level gets down to 20 or 10%. No mechanic have been able to find a lasting solution to fuel pump issue so I have decided to always refill once the tank gets slightly below half tank and it has always worked for me.

My major concern now is that I discovered few months ago that the SUV have become a gas guzzler. For instance, I made a short trip from Ajah > Ikeja > Isolo > Ojodu and back to Ajah. Total km covered was 97km. While total liters that was consumed for the 97km trip was 37lts. How did I arrive at this calculation? I filled my tank with 38 ltrs at 118034 on my way out, and also refilled with 37ltrs at 118131 upon my return. I used AC throughout. Every other thing works fine. It doesn't emit any smoke at all. Engine runs fine. Tyre pressures are normal and also monitored. The question now is, what could be the reason for this high fuel consumption and, why does the fuel pump fails before it gets close to reserve tank level?

Still waiting for ur advise.

Your Lexus RX300 is supposed to do 18-22 MPG but its doing less than 6.5 MPG. Something is definitely wrong somewhere. Suggest you scan it or go for a pressure test.

@Joy2Dwise,
Surprisingly, 11.5 is usually displayed in the screen on city driving while 14.7 is often displayed while on highway. Getting a combined milage of 6 MPG is quite worrisome.

Fabulous Autos:

@Joy2Dwise,
Surprisingly, 11.5 is usually displayed in the screen on city driving while 14.7 is often displayed while on highway. Getting a combined milage of 6 MPG is quite worrisome.

I mean 11.5 & 14.7 is often displayed on the dash screen as Average MPG.

just a question: are you sure they didn't cheat you at the pumps?

Your in-tank fuel pump has failed and thats why the fuel cuts off once it reaches half tank. Its a symptom of in-tank fuel pump failure. If i may ask, how many fuel pumps does your SUV have? Most Euro cars/vehicles use two fuel pumps: in -tank & main/external fuel pump. If the in-tank pump fails or loose connection, the main pump will still suck fuel to engine bay, resulting to low fuel pressure. But as soon as the fuel in the tank reaches halve tank, the fuel would cut off. Its called fuel starvation. Thats what your SUV is suffering from. Also, if the in-tank fuel pump fails, the main pump whinning sound would increase/ becomes noisier. It left unfixed, the main pump would die soon, since its overworking itself to do two functions, the in-tank is suppose to assist.

Fuel starvation can also make a vehicle run very thirsty.

Ikenna.

Ikenna351:

Your in-tank fuel pump has failed and thats why the fuel cuts off once it reaches half tank. Its a symptom of in-tank fuel pump failure. If i may ask, how many fuel pumps does your SUV have? Most Euro cars/vehicles use two fuel pumps: in -tank & main/external fuel pump. If the in-tank pump fails or loose connection, the main pump will still suck fuel to engine bay, resulting to low fuel pressure. But as soon as the fuel in the tank reaches halve tank, the fuel would cut off. Its called fuel starvation. Thats what your SUV is suffering from. Also, if the in-tank fuel pump fails, the main pump whinning sound would increase/ becomes noisier. It left unfixed, the main pump would die soon, since its overworking itself to do two functions, the in-tank is suppose to assist.

Fuel starvation can also make a vehicle run very thirsty.

Ikenna.

Thanks for the detailed explanation. This is very helpful.
I just called my mechanic to find out how many fuel pumps the suv uses and he said it’s one. Asked if there is any in-tank fuel pump and he said ‘no’, that it has two fuel gauges and one fuel pump. I can’t bet my wallet that he is very sure. I’ve used him for almost 6 years now and he has proved himself as a reliable mechanic. He seems to know his onions when it comes to Japanese cars but he’s uneducated though. I’ll do some research and find out if its got an in-tank pump.

He suggested that we service the nuzzle and also replace the plugs. The plugs, according to him has not been changed since 3 years ago when it was bought as Tokunbo, but that does not explain why the pump fails before the fuel gets closer to reserve tank.

George_D:

just a question: are you sure they didn't cheat you at the pumps?

Nope. I discovered this problem many months back but I have not really sat down to take the record untill this weekend.

Your mechanic could be right. Your SUV might have only one fuel pump. Its very common with Japanese vehicles. But its weird for him to say the fuel pump is not in the fuel tank. Please, i want anyone here to correct me if am wrong, because am yet to see or hear about a Japanese vehicle, especially cars, that doesnt have its fuel pump inside the fuel tank. Ask those that own Japanese cars here that have once changed thier fuel pump where thye pumps are located. Unless the Japanese SUVs fuel pump position differs from their cars. Well, I may be wrong anyway.

Please, the problem with your car is not an ignition issue. So there is nothing wrong with your spark plugs, unless if the engine rough idles and misfires under load or acceleration. Please, dont let him touch the injectors (by the way, its injectors not nozzles). Your injectors are not causing the fuel starvation, but the fuel pump, unless you have not told us all the symptoms the SUV is giving. Yes, improper spray pattern of injectors could make a vehicle run rich, but it would always show in acceleration. Deal with the fuel pump first. Its what i would do.

Are you sure your mechanic understood what you asked him about the "in-tank" pump? Ask him again whether the pump is inside the fuel tank or bolt into the fuel tank? Or whether is located far away from the tank? If its outside the tank, may be he doesnt know that the vehicle have another pump inside the tank. There are many ways to know if the in-tank fuel pump it still working. But you need to ascertain first if it has in-tank pump first. Google it or check the wiring diagram or workshop manual.

Ikenna.

Thanks Ikenna. I think its time I look for a more experienced mechanic to look into this, but before I do that, I'd like to run a full diagnostic test on the suv. Can you recommend a reliable mechanic to me? I live around Lagos Island.

Sorry, I stay in Abuja.

Ikenna.

@Ikenna,
Its OK bro. Thanks once again. U've given me enough tips and clues already. I'll make some inquiries and I'm sure to find a good one here. Will come back here to update you guys.
God bless U all.

Ok. I went to. Ladipo and was referred to a mechanic who told the engine and emission are in good working condition and will not need to be tampered with. I was advised to service the nuxxle and injector at Mobil filling station, Gbagada and it cost me 5k to do that there. When I discovered that there was no improvement, I did what I should have done earlier and the result shows, P1155 Air/Fuel sensor Heater Malfunction, Bank 2 Sensor 1.

Can someone pls interpret this for me.
Thanks.

You need to replace your air-fuel sensors. It happened with my 99 Camry and after I replaced the AF sensors the problem was solved. It takes a while before your ECU will adjust to the new sensors and start giving you the the expected fuel consumption though.

There are two of these sensors and they both cost me 54,000 naira here in Port Harcourt. The earlier you replace them the better for you because even though they are expensive, the increase in fuel consumption will cost you more in the long run.

Send me an email or post ur pin. My email is ekenetagbo@yahoo.com

Am sure I can help.

Have u changed ur fuel filters, air filters. I have had similar problems. D last straw was that my air flow meter was not working well.

Am not a mechanic but I can change fuel pump up to 15 times or more in my car cos of mechanic wahala. Pls I am not going 2 CHARGE u. So relax.

Send me an email or post ur pin. My email is ekenetagbo@yahoo.com

Am sure I can help.

Have u changed ur fuel filters, air filters. I have had similar problems. D last straw was that my air flow meter was not working well.

Am not a mechanic but I have changed fuel pump by myself up to 15 times or more in my car cos of mechanic wahala. I learnt it from them after watching a couple of times. Also I noticed that my engine rpm was low for my car and that was one of d causes. Pls I am not going 2 CHARGE u. So relax. My pin: 2298865D

Onyema

My fuel pump is inside my car.

Possible causes:
1. Your rpm may be too low to sustain fuel pressure. My car will start is a nissan. It had to be increased a little.

2. For fuel consumption, have u had injector issues? Clean ur air filter, if it has torn, replace it.

3. There is a sensor in that air filter casing, make sure it hasn't cut. (It affects d smooth running of d car)

4. Check ur plugs. Worn out plugs definitely make cars to use more fuel. If d plugs are brown at d white layer( d part that stays inside d engine b4 d filament) change it.

Update:

My fuel pump is inside my car.

Possible causes:
1. Your rpm may be too low to sustain fuel pressure. My car will start but d engine was low. Always had issues when climbing a hill at least every 1 month (a nissan). D rpm had to be increased a little.
that solved d problem like 70 percent.

2. For fuel consumption, have u had injector issues? Clean ur air filter, if it has torn, replace it.
Change ur fuel filter every 3 months


3. There is a sensor in that air filter casing, make sure it hasn't cut. (It affects d smooth running of d car). If it has change it. This brought my car back to life.

4. Check ur plugs. Worn out plugs definitely make cars to use more fuel. If d plugs are brown at d white layer( d part that stays inside d engine b4 d filament) change it.

chiebube: Update:

My fuel pump is inside my car.

Possible causes:
1. Your rpm may be too low to sustain fuel pressure. My car will start but d engine was low. Always had issues when climbing a hill at least every 1 month (a nissan). D rpm had to be increased a little.
that solved d problem like 70 percent.

2. For fuel consumption, have u had injector issues? Clean ur air filter, if it has torn, replace it.
Change ur fuel filter every 3 months


3. There is a sensor in that air filter casing, make sure it hasn't cut. (It affects d smooth running of d car). If it has change it. This brought my car back to life.

4. Check ur plugs. Worn out plugs definitely make cars to use more fuel. If d plugs are brown at d white layer( d part that stays inside d engine b4 d filament) change it.

You've got mail bro. Would like to call you.