[Khaner1999]

Hello everyone,

I recently acquired a new to me Honda Accord 9th generation i4. It has 117k miles on the odometer. As I mostly do city driving, the car is giving me 22mpg even with a light foot on the accelerator. On the freeway the car gives me 24-26mpg.

I have already cleaned the MAF sensor, throttle body and replaced the air filter which resulted in a marginal improvement of the fuel economy. The thing to note is that the previous owner removed the catalytic converter of the car, so could that be causing the poor fuel economy? If not, what could be the reason for the poor fuel economy?

 

[ttower]

The removal of the catalytic converter could cause MPG loss depending on how it was done. If the cat was just taken out and nothing else was done, with the CEL on and all, you will probably get worse MPG as the car is running in its "worst case scenario," ie less efficient, because of the CEL and bad readings from the 02 sensors. If the cat was removed and spacers were added, or the ECU was modified in some way to accept that change, then who knows.

 

[mtts60]

Is it possible to reinstall the catcon? Walker makes aftermarket cats for the Accord that are reasonably priced.

 

[Khaner1999]

Is it possible to reinstall the catcon? Walker makes aftermarket cats for the Accord that are reasonably priced.

How much does it cost for the cat install?

 

[mtts60]

I have no idea. It depends on the quality of the removal job. Did they unbolt the original and install a 'test' pipe (best way to do it) or did they hack it off and weld in a pipe with no way to remove it other than by cutting?

Go to a local muffler/exhaust shop and ask.

 

[Miker]

@Khaner1999

do you know the maintenance record for this car?

 

[200366HFP]

Probably stolen and they just put a pipe of some sort in there.

 

[browndogg]

Check out RockAuto also for them.

 

[KW2004Accord]

The cat being removed is causing the O2 sensors to send incorrect data to the car's computer. The price on replacing the catalytic converter will depend on what needs replacing besides the cat. As another poster has said, you need to take it in to a shop & get it up on a lift for an inspection. The cost of the cat may depend upon what state you live in. Don't buy the cat on Amazon / Ebay, buy it locally. Tenneco is the oem for Honda, they own Walker Exhaust though they aren't the same build quality as oem but can last as long. The price of labor in your area would be another factor as would be who supplies the parts (you or the shop). Walker On-Line Catalog

 

[capkirk123]

Is the check engine light on? If it's not on with the cat removed, then the car has probably been tuned or had something installed to fool the O2 sensor, which would explain the poor fuel economy. If it is on, then yeah the engine is probably very unhappy and running in some sort of failsafe mode that would also explain the poor fuel economy.

 

[WiiMaster]

There's some confusion here. The car should have 2 cats. One near the exhaust manifold and one underneath the car. Which one has been removed? The one underneath is not monitored so if that is removed, no CEL makes sense.

 

[Khaner1999]

The removal of the catalytic converter could cause MPG loss depending on how it was done. If the cat was just taken out and nothing else was done, with the CEL on and all, you will probably get worse MPG as the car is running in its "worst case scenario," ie less efficient, because of the CEL and bad readings from the 02 sensors. If the cat was removed and spacers were added, or the ECU was modified in some way to accept that change, then who knows.

Yes, sometimes the CEL does come on but goes away on its own.

 

[Khaner1999]

I have no idea. It depends on the quality of the removal job. Did they unbolt the original and install a 'test' pipe (best way to do it) or did they hack it off and weld in a pipe with no way to remove it other than by cutting?

Go to a local muffler/exhaust shop and ask.

I guess I would have to roll into a muffler shop and ask. I just do not want to get a cat installed if it doesn't improve the fuel economy. What does your fuel economy look like?

 

[Khaner1999]

@Khaner1999

do you know the maintenance record for this car?

The car has a rebuilt title but the service record looks pretty good to me. There were regular oil changes done and the transmission also seems to be in good condition due to fluid changes. The sparkplugs have not been changed as far as I know, but the car is not misfiring so I am not sure whether I should change them or not.

 

[Khaner1999]

Probably stolen and they just put a pipe of some sort in there.

Yeah could be, but the thing is would that affect the MPG? Shouldn't mpg be a tad bit better due to non restricted emission flow?

 

[Khaner1999]

There's some confusion here. The car should have 2 cats. One near the exhaust manifold and one underneath the car. Which one has been removed? The one underneath is not monitored so if that is removed, no CEL makes sense.

The one underneath the car has been removed. Would that effect the mpg?

 

[mtts60]

I get 30-32 mpg on average, sometimes as high as 35.

 

[Petey j]

Hello everyone,

I recently acquired a new to me Honda Accord 9th generation i4. It has 117k miles on the odometer. As I mostly do city driving, the car is giving me 22mpg even with a light foot on the accelerator. On the freeway the car gives me 24-26mpg.

I have already cleaned the MAF sensor, throttle body and replaced the air filter which resulted in a marginal improvement of the fuel economy. The thing to note is that the previous owner removed the catalytic converter of the car, so could that be causing the poor fuel economy? If not, what could be the reason for the poor fuel economy?

That's not bad mileage the car won't pass inspection without a cat converter. Check ignition parts plugs wires etc. Use 89 octane gas.

 

[HQAcritic]

That's not bad mileage the car won't pass inspection without a cat converter. Check ignition parts plugs wires etc. Use 89 octane gas.

I have the same vehicle and similar mileage. I get ~26mpg stop and go driving in town and 38mpg on freeway doing about 70-75 mph. No mods, no changes to stock configuration.

 

[Patwant]

Hello everyone, I recently acquired a new to me Honda Accord 9th generation i4. It has 117k miles on the odometer. As I mostly do city driving, the car is giving me 22mpg even with a light foot on the accelerator. On the freeway the car gives me 24-26mpg. I have already cleaned the MAF sensor, throttle body and replaced the air filter which resulted in a marginal improvement of the fuel economy. The thing to note is that the previous owner removed the catalytic converter of the car, so could that be causing the poor fuel economy? If not, what could be the reason for the poor fuel economy?

In my 2008 EX-L V6 accord, I was getting about 15mpg last two years. Worse in winter (in Calgary Canada). No change in highway fuel economy. City driving only. I did everything google had to recommend. Checked tire pressure, change air filter, checked O2 sensor, MAF sensor, changed spark plugs, repaired sticking brake pad. Ran 4 tanks with various fuel injector cleaners (2 tanks with Chevron Techron). After no improvement, I had it inspected from Honda last week. Turns out it was VPS front bank oil pressure switch failure. I have gone through half a tank since this repair. Looks like a made bit of a difference. I will know once I burn few tanks if VPS was the real issue.