High fuel consumption rate-96 Model Camry

[justgbenga]

My fuel consumption rate is now very high, despite the fact that i still maintain the same driving habit & i drive on the normal terrain(tarred road). Please help!!!! To the best of my knowledge i've done all i can to make it come back to normal but it never dropped(i always ensure that my tyres are well inflated(2mths old tyres), serviced the 4 noozles, checked silencer for leakages, changed my plugs, used 2 gallons of ejector fluid cleaner. And another key thing i noticed when this started is that,my exhaust pipe is now black(filled with carbon)...which is a sign of incomplete combustion of fuel.

[rivalred]

How many miles are on the vehicle? Have you ever thought maybe your valve clearances need to be redone or even a fuel filter problem?

[nnamdi]

Fuel filter?? Dont get that fully, please shed some light man. I would have thought the exhaust ports were getting tired or his O2 sensors were acting up.???

[justgbenga]

Should i have the oxygen sensor changed also? I have changed the 4 noozles on saturday(27/05) and i still can't see any improvement. Note that the take-off speed is now swifter and smoother with the new noozles but the fuel consumption rate is still on the high side(exhaust pipe is still very black)

[marc780]

Look at your spark plug tips. If they are black, yeah, you're running rich. Should be tan or light grey. Things that can cause this, plugged PCV valve, dirty air filter, dirty TBI butterfly and IAC valve.

Excessive fuel use can also be caused by dragging brakes so i would check that, jack up each wheel and spin it. A light drag from the discs is normal but if it seems excess dragging on one wheel, or the pads on one are worn more than the others, this caliper may be sticking.
Also you may want to do a compression check, to find out about your engine's overall health. If the readings are low, maybe you have your answer because it means you may need an overhaul or a valve job (hope not though).
On the 4 cylinder the reading should be like 180 psi for a healthy engine, minum 145, for the V6 it is 218 psi, minimum 145.

[justgbenga]

Thanks for the extensive detailed explanation of all the necessary things that could cause an increase in fuel consuption. I would get my techie to start looking at all these tomorrow morning. Please confirm that if all these is done, that it would clear the carbon on my exhaust pipe9and it would be clear like before).

Many thanks

[justgbenga]

Thanks for the extensive detailed explanation of all the necessary things that could cause an increase in fuel consuption. I would get my techie to start looking at all these tomorrow morning. Please confirm that if all these is done, that it would clear the carbon on my exhaust pipe(and it would be clear like before).

Many thanks

[SAM-RAI]

Originally Posted by justgbenga

My fuel consumption rate is now very high, despite the fact that i still maintain the same driving habit & i drive on the normal terrain(tarred road). Please help!!!! To the best of my knowledge i've done all i can to make it come back to normal but it never dropped(i always ensure that my tyres are well inflated(2mths old tyres), serviced the 4 noozles, checked silencer for leakages, changed my plugs, used 2 gallons of ejector fluid cleaner. And another key thing i noticed when this started is that,my exhaust pipe is now black(filled with carbon)...which is a sign of incomplete combustion of fuel.

First of all which engine is it on the Camry, a 4 cyliner or V6?
This question relate to what plugs you should use, platinum etc.

Since you mentioned some of the thing you've done already. There are two more that need to be check or replace. One is the air filter and the other is the exhaust O2 sensor. Normally, the 02 sensor's will be the main cause in high fuel consumption if they're old, dirty or just plain bad. Most people will never consider changing this part when in fact it needs attention just like any other parts when it comes to regular maintenance. The O2 sensor works like your nose in human except this design for a vehical were it detect fuel ratio from the exhaust gas. If it's too rich or too lean, it will send signal to the computer to calibrate it for the optimum setting per factory spec. But if the O2 senor's is bad or dirty, then it doesn't do the job as was designed and should be replace with new unit. Manufacturer's of O2 sensors usually recommend replacing this part at or around 75K for most vehicle to get the full benefits and efficiency, but as we all know, no one really pay attention to it and that's including the dealerships.

I hope this is helpful.

[justgbenga]

It's a 4 cylinder Camry.

Thanks for the detailed feedback, note that the only thing left that i've not changed is my exhaust O2 sensor. Because i have replaced the filter with a new one.

I don't seem to understand the plug(platinum etc) part of your explanation, could you please expantiate.

Many thanks

[SAM-RAI]

Originally Posted by justgbenga

It's a 4 cylinder Camry.

Thanks for the detailed feedback, note that the only thing left that i've not changed is my exhaust O2 sensor. Because i have replaced the filter with a new one.

I don't seem to understand the plug(platinum etc) part of your explanation, could you please expantiate.

Many thanks

Regarding the plug, I wanted to make sure you use the actual recommended plugs and not gap it if it's a platinum. In the past, I've found people trying to cut corners by going with aftermarket plugs and gap it when in fact Toyota recommended Denso or NGK platinum and it's electronically pregap. That's where my concern was with the question to platinum plugs.

Your 4 cylinder Camry should average in the high 20's MPG with combined driving on FRWY and local streets. If it's way below that after everything was done to it (tuned up etc.), I can only think it's your O2 sensor's that's might be bad. Considering the black smoke from your exhaust pipe, it's more than likely the engine is running very rich because the O2 sensor's is not working properly. Remember, your engine will still run normal even if the O2 sensor's is not in perfect condition, but the result will be poor gas mileage due to inefficiency to detect exhaust gas with the fuel mixture ratio so it can be send back to the computer for calibration.

Hope this helps.

[justgbenga]

Once again, thanks for your concern....i'll have the 02 sensor changed on Saturday.

[SAM-RAI]

Great! Keep us posted how it come out after the change. You will see improvement within a couple hundred miles after the computer calibrated the fuel ratio mixture.

Here's a tip: Use Mobil 1 or Castrol Syntec "5W30" oil for better lubricants and slightly better gas mileage. This should help and better your engine protection from oil breakdown.

[marc780]

Thanks for the extensive detailed explanation of all the necessary things that could cause an increase in fuel consuption. I would get my techie to start looking at all these tomorrow morning. Please confirm that if all these is done, that it would clear the carbon on my exhaust pipe9and it would be clear like before).

The exhaust pipe will never be "clear" in any car that gets driven. Tan or light grey is the color you want to see at the tail pipe. This indicates good combustion is taking place.
But on most cars, it is indeed black or dark grey, even when nothing is wrong. Must be the city driving i guess.

[justgbenga]

Alas.......thanks you're a star!!! I changed the two 02 sensors on Saturday and i can see a great improvement at the rate it's consuming fuel now. Although i've not driven it on a long distance yet, but i'll be taking the Car out for a long trip over the weekend. By then i'll be able to confirm the changes very well, but for now i'm happy, because it now seems as if my fuel gauge has refused to move{unlike before :-) }

Yes i know the exhaust can't be crystal clear(it's now light grey - You're right)

One more thing, i changed my 4 shocks, brake pads and the shaft head the same day....but since then, i hear a wobbling(not too loud) sound when i'm taking off from a stationary position. what could be causing this?

Also, i drove the Car through a big flood(the water level was up to my headlamps) last week and it soaked the interior of the car(but i've dried it up) but since then my "air bag(red indicator)" and my "bulb(yellow indicator)" refused to go off...what do i do?

Warm regards to all....;-)

[SAM-RAI]

I'm glad to hear the improvement.

As for more questions, I'm not quit sure there, but I hope some others can help.
The best thing is to take it to the dealership and see what they say.