2005 Cobalt LS 2.2l - 20k - Fuel consumption up, economy way down.
09-23-2007, 06:29 PM
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2005 Cobalt LS 2.2l - 20k - Fuel consumption up, economy way down.
Hi, Im hoping someone could give me some advice about my Cobalt.
Its a 2005 LS with the 2.2l ecotec and has 21k on the engine. I recently changed from synthetic blend 5w30sae, to Full Synthetic 5w30sae. I also changed the oil filter out for a fram weargaurd filter. I completely drained out the engine and added 4.4litres of full synthetic. At first the economy seemed about the same, a little better actually. But about 50 kilometers into the oil the economy completely tanked.
I went from 10.5-7 litres for every 100kms to 13.5-7 litres for every 100kms.
Im not sure the mpg that is, but it would be a very significant drop. I even stopped booting it around for a whole tank of gas. The 2005 has a 50litre gas tank I believe, this usually takes to 450-500 kilometers ona single tank. But not, I am just barely breaking 350 to 390km on a single tank. This is a incredible drop in economy.
I just changed the oil again, just to make sure there wasnt a problem with the engine oil, and make sure the oil pressure wasnt too high. And now my dipstick is sometimes BARELY registering oil in the resevoir. Before, it would be at full or a little above, so I thoguht maybe the oil pressure was too high and causing problems with the fuel injection.
But now, on this new oil, it is registering a notch above the add line, and two notches below the max line.
Im not sure what is going on? Could the problem be the oil filter? Should I buy a factory filter from a dealership and put that one in? Or should I take the car to the dealership and find out just what in the heck is going on with the economy?
Could my ECU have become corrupted? Could the filter be the problem? Could the oil pressure STILL be TOO high?
Any advice and suggestions would be greatly appreciated. Thanks.
Its a 2005 LS with the 2.2l ecotec and has 21k on the engine. I recently changed from synthetic blend 5w30sae, to Full Synthetic 5w30sae. I also changed the oil filter out for a fram weargaurd filter. I completely drained out the engine and added 4.4litres of full synthetic. At first the economy seemed about the same, a little better actually. But about 50 kilometers into the oil the economy completely tanked.
I went from 10.5-7 litres for every 100kms to 13.5-7 litres for every 100kms.
Im not sure the mpg that is, but it would be a very significant drop. I even stopped booting it around for a whole tank of gas. The 2005 has a 50litre gas tank I believe, this usually takes to 450-500 kilometers ona single tank. But not, I am just barely breaking 350 to 390km on a single tank. This is a incredible drop in economy.
I just changed the oil again, just to make sure there wasnt a problem with the engine oil, and make sure the oil pressure wasnt too high. And now my dipstick is sometimes BARELY registering oil in the resevoir. Before, it would be at full or a little above, so I thoguht maybe the oil pressure was too high and causing problems with the fuel injection.
But now, on this new oil, it is registering a notch above the add line, and two notches below the max line.
Im not sure what is going on? Could the problem be the oil filter? Should I buy a factory filter from a dealership and put that one in? Or should I take the car to the dealership and find out just what in the heck is going on with the economy?
Could my ECU have become corrupted? Could the filter be the problem? Could the oil pressure STILL be TOO high?
Any advice and suggestions would be greatly appreciated. Thanks.
09-23-2007, 06:34 PM
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Hi, Im hoping someone could give me some advice about my Cobalt.
Its a 2005 LS with the 2.2l ecotec and has 21k on the engine. I recently changed from synthetic blend 5w30sae, to Full Synthetic 5w30sae. I also changed the oil filter out for a fram weargaurd filter. I completely drained out the engine and added 4.4litres of full synthetic. At first the economy seemed about the same, a little better actually. But about 50 kilometers into the oil the economy completely tanked.
I went from 10.5-7 litres for every 100kms to 13.5-7 litres for every 100kms.
Im not sure the mpg that is, but it would be a very significant drop. I even stopped booting it around for a whole tank of gas. The 2005 has a 50litre gas tank I believe, this usually takes to 450-500 kilometers ona single tank. But not, I am just barely breaking 350 to 390km on a single tank. This is a incredible drop in economy.
I just changed the oil again, just to make sure there wasnt a problem with the engine oil, and make sure the oil pressure wasnt too high. And now my dipstick is sometimes BARELY registering oil in the resevoir. Before, it would be at full or a little above, so I thoguht maybe the oil pressure was too high and causing problems with the fuel injection.
But now, on this new oil, it is registering a notch above the add line, and two notches below the max line.
Im not sure what is going on? Could the problem be the oil filter? Should I buy a factory filter from a dealership and put that one in? Or should I take the car to the dealership and find out just what in the heck is going on with the economy?
Could my ECU have become corrupted? Could the filter be the problem? Could the oil pressure STILL be TOO high?
Any advice and suggestions would be greatly appreciated. Thanks.
Its a 2005 LS with the 2.2l ecotec and has 21k on the engine. I recently changed from synthetic blend 5w30sae, to Full Synthetic 5w30sae. I also changed the oil filter out for a fram weargaurd filter. I completely drained out the engine and added 4.4litres of full synthetic. At first the economy seemed about the same, a little better actually. But about 50 kilometers into the oil the economy completely tanked.
I went from 10.5-7 litres for every 100kms to 13.5-7 litres for every 100kms.
Im not sure the mpg that is, but it would be a very significant drop. I even stopped booting it around for a whole tank of gas. The 2005 has a 50litre gas tank I believe, this usually takes to 450-500 kilometers ona single tank. But not, I am just barely breaking 350 to 390km on a single tank. This is a incredible drop in economy.
I just changed the oil again, just to make sure there wasnt a problem with the engine oil, and make sure the oil pressure wasnt too high. And now my dipstick is sometimes BARELY registering oil in the resevoir. Before, it would be at full or a little above, so I thoguht maybe the oil pressure was too high and causing problems with the fuel injection.
But now, on this new oil, it is registering a notch above the add line, and two notches below the max line.
Im not sure what is going on? Could the problem be the oil filter? Should I buy a factory filter from a dealership and put that one in? Or should I take the car to the dealership and find out just what in the heck is going on with the economy?
Could my ECU have become corrupted? Could the filter be the problem? Could the oil pressure STILL be TOO high?
Any advice and suggestions would be greatly appreciated. Thanks.
09-23-2007, 06:38 PM
#3
i don't know what the liter conversion is, but i would make sure it converts to over 5 quarts. also, make sure there's no leak. leave something like a cut up cardboard box under your car overnight, check it in the morning to see if there's oil spots on it.
liter conversion seems dead on, maybe add a little more. was it registering as full when you fist changed it, then it got low? or was it always just low since you changed.
liter conversion seems dead on, maybe add a little more. was it registering as full when you fist changed it, then it got low? or was it always just low since you changed.
Last edited by D4u2s0t; 09-23-2007 at 06:38 PM. Reason: Automerged Doublepost
09-23-2007, 06:38 PM
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09-23-2007, 06:41 PM
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check tire pressure. I check mine every week.
I normally average 450km - 500km to a tank, depending on how spirited my driving is.
I had a drop like that, 370ish KM to 1 tank, I had a slow leak in my back right tire got that fixed and i'm good now.
I normally average 450km - 500km to a tank, depending on how spirited my driving is.
I had a drop like that, 370ish KM to 1 tank, I had a slow leak in my back right tire got that fixed and i'm good now.
09-23-2007, 06:41 PM
#7
does the car drive any differently? have you done any mods? did you try resetting your dic lately? driving habits, even varied SLIGHTLY can have a big difference in mpg. i can cruise on the highway in my 2.0 and get 33 mpg, in my 2.2 i used to get over 35 mpg on the highway sometimes. other times, i get 20. even a LITTLE more gas here and there will drop the numbers.
09-25-2007, 06:42 PM
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From everything I can see I dont have any abnormal exhaust smoke, there are absolutely no leaks of anykind, im sure off, because I park my car in a garage every night and there are never any new oil spots.
My tire pressure is good, I keep it around 30psi, although im sure i'd probably benefit traction wise if i had it a little lower.
The only "mod" that I did was I took off the Air Intake Silencer about a month or so ago because It sounded from all the posts that it gave the engine a nice groan to it(which it does btw).
My dad is trying to argue with me that this in itself is the problem, but to be honest I find that hard to believe considering a performance cold air intake from GM would just bypass the air intake silencer in the first place making it redundant equipment.
As for the dipstick problem, the oil is pretty clean right now and I dont know what to make of it. Right now it's registering a FULL resevoir, but if your guys cars sound like its taking about .35 litres more, and some even sound like they are taking almost a quart more than I have added into my car.
Could low oil pressure be causing a low fuel injection vacuum making my ECU compensate by spraying more fuel?
Anyways, I hope you all can help me out with this, Im not too keen on having to take my car to a dealership, i'd like to fix this problem myself. off to class now.
My tire pressure is good, I keep it around 30psi, although im sure i'd probably benefit traction wise if i had it a little lower.
The only "mod" that I did was I took off the Air Intake Silencer about a month or so ago because It sounded from all the posts that it gave the engine a nice groan to it(which it does btw).
My dad is trying to argue with me that this in itself is the problem, but to be honest I find that hard to believe considering a performance cold air intake from GM would just bypass the air intake silencer in the first place making it redundant equipment.
As for the dipstick problem, the oil is pretty clean right now and I dont know what to make of it. Right now it's registering a FULL resevoir, but if your guys cars sound like its taking about .35 litres more, and some even sound like they are taking almost a quart more than I have added into my car.
Could low oil pressure be causing a low fuel injection vacuum making my ECU compensate by spraying more fuel?
Anyways, I hope you all can help me out with this, Im not too keen on having to take my car to a dealership, i'd like to fix this problem myself. off to class now.
09-25-2007, 09:48 PM
#10
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It wouldnt be related to your oil change, unless you severly OVER filled your crankcase. Dont add oil ubless you are BELOW the full mark and if it's more than 1/8" OVER full on the dipstick- you should drain a little out.
Your fuel reduced fuel economy can be due to a number of factors. For instace even driving in the rain can reduce your economy by 5%. So start making ACCURATE records of yourfuel consumption between fill-ups by recording the mileage and number of gallons/liters added. If there IS a problem you will need these records if you want your dealer to even look at a MPG issue.
GL
WopOnTour
Your fuel reduced fuel economy can be due to a number of factors. For instace even driving in the rain can reduce your economy by 5%. So start making ACCURATE records of yourfuel consumption between fill-ups by recording the mileage and number of gallons/liters added. If there IS a problem you will need these records if you want your dealer to even look at a MPG issue.
GL
WopOnTour
09-29-2007, 08:31 AM
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Thanks everyone for your suggestions. I think I am going to try draining a little of oil out, changing the oil filter and replacing the air filter at the same time. I'll also start recording my MPG accurately incase it doesnt clear up.
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