Hey Mr scotty sir, I'm a relatively new addition to your channel but i have come to learn alot from you and i trust your honest opinion. I recently bought a used Honda crv model number RE2 with an R20A1 engine with 86000kms on it has been mostly used in the city. Changed the engine oil and used liqui moly engine flush due to having some carbon sludge, change the transmission fluidc differential fluid. It appears to have been in a minor accident and had a slightly bent fron crossmember that has been straightened out. Changed the engine mount, spark plugs and cleaned the EGR and PCV valves. But for the life of me cannot figure out the cause of the low mileage i get less than 5km per litre this is unusual given this is a 2l 4 cylinder engine. My mechanic say the transmission is good as it shifts smoothly at 2000rpms or less. At this point im stumped as its hogging more gas than a V8. I used a scan tool and see the short term fuel trim is arounf negative 2 to negative 5 percent and recently tried to check the spark plugs and they had a lot of carbon and changed the airfilter as i saw it was a bit dirty and funny thing is after doing so the car ran smoother at idle. The only inkling i have is brake pad drag as the cars brakes are very very sensitive a slight press and you come to a screeching halt almost going out the window. This car has the honda awd and has both fron and rear break discs and i have noticed that even when i drive for short distances( 1-2km) the front rotors get too hot to touch unlike the rear ones. There is rust on some of the pads too ane some rust streaks on some rotors. Can break drag be the cause of my issues as im almost at my wits end. Oh and my brake fluid is dark brown in color Kindly help sir
The only inkling i have is brake pad drag as the cars brakes are very very sensitive a slight press and you come to a screeching halt almost going out the window. This car has the honda awd and has both fron and rear break discs and i have noticed that even when i drive for short distances( 1-2km) the front rotors get too hot to touch unlike the rear ones
Your front brake calipers are probably sticking closed when you attempt to let off the brakes.
Oh and my brake fluid is dark brown in color
That means you need to start considering a time to replace your brake fluid. You should completely replace it every 5 to 7 years with brand new, unopened fluid. Brake fluid is hygroscopic and tends to accumulate water with time.
Thank you kind sir and could this be the reason for the horrendous gas mileage?
If it's stuck brake calipers, absolutely.
Thank you again sir, lastly should the calipers be replaced and the hoses as well and if it does get fixed what is the realistic gain? can i expect the gas mileage to double as 5km/l is about 11miles per gallon ryt now
A lot more than 11 mpg, I know that much. It depends on your driving style. Instead of driving, you're generating A LOT of heat and the engine has to work a lot harder. My 1979 Pontiac with a V8 and a 3-speed is more efficient than that at highway speed, and it's a carburetored engine. Change the brake calipers. You may want to consider changing hoses as well. You left that part out in your original question. I'm not up to date on Hondas.
Much obliged sir
I managed to get the fluid changed and the mechanic checked the calipers as well as the replaced the brake pad with quality pads. Jusdging from the dash the mileage hasnt changed much but we just recently noticed a slight hum when driving like growling sound and the mechanic claims the wheel bearings might have issues and if thats the case could changing them also imprive the mpg?
Not by that much.
Noted sir
And could an exhaust leak cause these issues
No. Your brakes are most likely to blame.
Sorry i noticed another thing, when the car is at idle for a while when i pop the hood its very very hot and i noticed the milage meter gets worse at high speeds vs when with low speeds like 20 miles/hour. Could there be a block in the exhaust system
If you're driving faster, more heat will be generated. The equation for kinetic energy is Ke=½m*v². It order to go twice as fast, you need 4 times more energy. Partially blocked exhaust would cause the engine to stumble revving high. None of that exists. Did you check your brakes? If your front caliper on the driver's side is sticking it will generate all kinds of heat, it can quickly turn red hot. You described a problem with your brakes.
used a scan tool and see the short term fuel trim is arounf negative 2 to negative 5 percent
Did you check or change your air filter?
Yes i did and it now fluctuates been positive 1 and 2
You didn't specify your model year. 1 or 2% is normal for an older vehicle. It's no big deal until it starts getting into the teens and will trip the check engine light once it reaches + or - 20%, and you will notice your engine not running correctly.
milage meter gets worse at high speeds
yes
