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High Fuel Consumption on a 1.0cc

T

twaanchi

Junior Member
Hi there. I recently got read of a bigger engine and got me a second hand Toyota Duet mainly because I was interested in the fuel economy and low maintenance costs. Funny thing is that the car consumes almost as much as my previous BMW318i 2.0cc. When I got it, we discovered that engine oil had exceeded maximum. I later on drained out some of it to bring it back to an acceptable level. I thought that would be linked to its high consumption, but it has remained quite the same.

Today as I was doing a few check ups on it and replacing a few unrelated items, I decided to ask the mechanic what his opinion was. He revved up the engine and discovered it had some black smoke emitting. He went ahead to say he thinks it maybe that the nozzle (I guess by nozzles he meant the fuel suppliers into the chambers), need servicing/changing, hence the smoke. He said he didnt suspect any engine related trouble.

This advise contradicts the first one which was that due to the high oil level, the oil had been suplied in areas where it isnt ideal for it to go and so cleaning using carburetor cleaner should help solve the problem.

The other thing is that, attributed to the same high oil level is the check engine signal on the dash board. When we ran diagnostics, the diagnostic machine did not pick any error, yet the check engine light is on. Did I make a mistake to buy this car, maybe I should have held on to my 318i...lol. Please advise before I go to another mechanic with a new theory.
 
If the injectors are spraying excess fuel into the cylinder(s), it is possible not all of it is being burned. The fuel that is not being burned will then go past the rings hence the overfilled crankcase. The injectors can be cleaned and checked to to make sure they are still serviceable. They have to be removed from the engine to do this. The actual cleaning cost per injector is around $30-50 . The removal and replacement is additional.
 
Most of your post is confusing and odd. First we can completely ignore the other vehicle and your motivations and only focus on the vehicle in question and whether it is behaving as a typical example of that vehicle would.

Apparently by "oil had exceeded maximum" you mean it was overfilled. We may have a language barrier that makes this topic difficult.

We can ignore what state the oil level was previously and now only focus on what it is doing with the correct oil level. Monitor the oil level to see if it is going down. Some engines normally burn oil, research in a forum specific to your vehicle and that engine if that is normal for it.

A mechanic revved the engine, suspected something but did not investigate further? Is this due to your not wanting to pay for further diagnosis at that time? Otherwise I do not see the point of now taking it to another mechanic to begin the process from scratch again unless you were already dissatisfied with this mechanic?

There is something wrong with the diagnostic machine or person using it to not be able to pick up an OBDII trouble code when the dash light is set. As long as it is set you may have the computer operating in open loop mode and not get the fuel economy you otherwise would. You need to determine the trouble code and proceed from there.

There is no point in speculating or making theories until you know the OBDII trouble code, though it is possible you have a cylinder misfire but it could be unrelated to the oil level, and may or may not be related to a clogged or stuck injector.

There are multiple things that can cause a misfire and one cheap/easy thing to do if there is space to get to it, is pull and examine the spark plug. You did not mention the age or miles on the vehicle so we can't guess if the plugs are due to be replaced yet but looking at them should tell you if they are in good condition and in some cases the residue on them can indicate a fault in that cylinder.

Fuel injectors, you can swap the positions of them to see if the fault follows the injector, but again you need the OBDII fault codes to see if there is a misfire and which cylinder if there is. Sometimes a scan tool capable of live data is helpful to diagnose this while the engine is running.

I would not bother telling mechanics theories, only what direct evidence you have observed and then let them formulate their own theory.

Unless you have a fouled spark plug(s) from the excess oil, I doubt that it is any longer an issue. It shouldn't hurt anything to use some carb cleaner on the intake (put it in after the MAF/airflow sensor) but I doubt it will make a difference.

If you have a clogged injector that is spraying uneven or sticking open, some fuel injector cleaner in the tank might help and is one of the cheaper things you can do before paying a mechanic to diagnose, but once again I would do nothing until after you have the OBDII code identified to hint at where to proceed next.
 
mindless1 said:
Most of your post is confusing and odd. First we can completely ignore the other vehicle and your motivations and only focus on the vehicle in question and whether it is behaving as a typical example of that vehicle would.

Apparently by "oil had exceeded maximum" you mean it was overfilled. We may have a language barrier that makes this topic difficult.

We can ignore what state the oil level was previously and now only focus on what it is doing with the correct oil level. Monitor the oil level to see if it is going down. Some engines normally burn oil, research in a forum specific to your vehicle and that engine if that is normal for it.

A mechanic revved the engine, suspected something but did not investigate further? Is this due to your not wanting to pay for further diagnosis at that time? Otherwise I do not see the point of now taking it to another mechanic to begin the process from scratch again unless you were already dissatisfied with this mechanic?

There is something wrong with the diagnostic machine or person using it to not be able to pick up an OBDII trouble code when the dash light is set. As long as it is set you may have the computer operating in open loop mode and not get the fuel economy you otherwise would. You need to determine the trouble code and proceed from there.

There is no point in speculating or making theories until you know the OBDII trouble code, though it is possible you have a cylinder misfire but it could be unrelated to the oil level, and may or may not be related to a clogged or stuck injector.

There are multiple things that can cause a misfire and one cheap/easy thing to do if there is space to get to it, is pull and examine the spark plug. You did not mention the age or miles on the vehicle so we can't guess if the plugs are due to be replaced yet but looking at them should tell you if they are in good condition and in some cases the residue on them can indicate a fault in that cylinder.

Fuel injectors, you can swap the positions of them to see if the fault follows the injector, but again you need the OBDII fault codes to see if there is a misfire and which cylinder if there is. Sometimes a scan tool capable of live data is helpful to diagnose this while the engine is running.

I would not bother telling mechanics theories, only what direct evidence you have observed and then let them formulate their own theory.

Unless you have a fouled spark plug(s) from the excess oil, I doubt that it is any longer an issue. It shouldn't hurt anything to use some carb cleaner on the intake (put it in after the MAF/airflow sensor) but I doubt it will make a difference.

If you have a clogged injector that is spraying uneven or sticking open, some fuel injector cleaner in the tank might help and is one of the cheaper things you can do before paying a mechanic to diagnose, but once again I would do nothing until after you have the OBDII code identified to hint at where to proceed next.
Click to expand...

Thank you for your response. Turns out you are good with odd and confusing after all! You sorta conquered your language limitations! Nonetheless, glad for the info, will make out what’s useful from your deep end English!
 
Stuck on injectors can allow a lot of fuel to go into the crankcase, making it seem like the oil is overfilled.

Hopefully you mean litres instead of CC's.
 
It’s a
LTC8K6 said:
Stuck on injectors can allow a lot of fuel to go into the crankcase, making it seem like the oil is overfilled.

Hopefully you mean litres instead of CC's.
Click to expand...
1.0 litre sir, I don’t know if that is the same as 1.0 cc
 
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