30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
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30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
My daughter's car had a sudden drop from 30 to 20mpg. I changed spark plugs, distributor cap/rotor, pcv valve and air filter is new. That got it back up to 24mpg.
The car does throws code P1457 every 400 miles or so. I can't find the evap problem but have tried multiple gas caps and never overfill the tank.
The car was throwing a code for the secondary o2 sensor on catalytic converter and I did the non-foulers trick to stop it.
I ran seafoam thru the vacuum hose off brake booster and noticed that smoke came out of catalytic converter area. Never have seen this happen.
I have driven minimally on hwy and my gut says it gets in the 30's on hwy, need to test that out.
Appreciate your input.
-william
The car does throws code P1457 every 400 miles or so. I can't find the evap problem but have tried multiple gas caps and never overfill the tank.
The car was throwing a code for the secondary o2 sensor on catalytic converter and I did the non-foulers trick to stop it.
I ran seafoam thru the vacuum hose off brake booster and noticed that smoke came out of catalytic converter area. Never have seen this happen.
I have driven minimally on hwy and my gut says it gets in the 30's on hwy, need to test that out.
Appreciate your input.
-william
#2
Re: Drop In Gas Mileage 2000 Civic 1.6
check for cracks in the exhaust manifold...
also, check fuse #15
https://honda-tech.com/forums/showpo...50&postcount=1
also, check fuse #15
https://honda-tech.com/forums/showpo...50&postcount=1
#3
Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Sounds like an exhaust leak near the primary O2 sensor. That will definitely kill gas mileage. When you fix the leak, adjust the ignition timing to spec and consider also replacing the spark plug wires.
P1457 can also be caused by a vacuum leak. Is the engine having any idle problems?
P1457 can also be caused by a vacuum leak. Is the engine having any idle problems?
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Can the catalytic converter be welded/fixed or does it have to be replaced?
Also, is the poor mileage caused by the "brain" making adjustments based on the information coming back from the primary O2 sensor?
thanks, I like to understand what is going on.
-william
Also, is the poor mileage caused by the "brain" making adjustments based on the information coming back from the primary O2 sensor?
thanks, I like to understand what is going on.
-william
#6
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
if the only problem with the cat is the crack along a seam, i would guess rewelding it would be practical.
but you gotta think, a cat as old as that one may be time to get replace anyway
but you gotta think, a cat as old as that one may be time to get replace anyway
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
I did two (2) 100 mile runs on the highway this week. The first one on level payment and I got 37+mpg.
The second was from Spg to Branson (big hills) and I only got 27mpg (car was downshifting to get up some of the hills).
If I'm going to replace the cat, where should I be looking to find a new one? My civic is the DX model.
-wgc
The second was from Spg to Branson (big hills) and I only got 27mpg (car was downshifting to get up some of the hills).
If I'm going to replace the cat, where should I be looking to find a new one? My civic is the DX model.
-wgc
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#8
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
I did two (2) 100 mile runs on the highway this week. The first one on level payment and I got 37+mpg.
The second was from Spg to Branson (big hills) and I only got 27mpg (car was downshifting to get up some of the hills).
If I'm going to replace the cat, where should I be looking to find a new one? My civic is the DX model.
-wgc
The second was from Spg to Branson (big hills) and I only got 27mpg (car was downshifting to get up some of the hills).
If I'm going to replace the cat, where should I be looking to find a new one? My civic is the DX model.
-wgc
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Here's the photo....
Does it look like someone had done a cheap fix with some type of epoxy or something similar?
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
I'm reading that the manifold is cast iron and that makes it difficult to get a good weld.
Other option I see is getting another 'system' for an EX and adapting it to the car.
BTW, I live in MO
Other option I see is getting another 'system' for an EX and adapting it to the car.
BTW, I live in MO
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
I can see bolts where the manifold connects to the cat canister. Sure looks like it would come apart in 2 pieces. * you can see three in the picture.
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
I have a little 110 mig welder, so I gave it a shot. In the meantime, I'll be looking at my options for replacing it. I'll let you know if the MPG changes. I did reset the ECU after welding it.
#17
Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Right, I forgot DX's are one in the same, just the top of it in the pic threw me off, plus I have an EX. Those are a pain the ***, and no wonder no one tunes DX's lol.
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
After 1 tank of good gas mileage, the next one fell flat! Down to 22 mpg. I can't see that the weld has lifted off or anything. I don't understand it at all.
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#22
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Fill gas tank to completely full. Reset trip odometer. Drive. Fill up gas tank again to the top. Note miles you drove. miles/gallons=mpg. So if you drove 300 miles and you filled up with 9 gallons, your mpg is 33.
Edit: **** I forgot, you have a check engine code coming up with the EVAP system... Uh, maybe you should replace the vacuum hoses that go to the EVAP system since they could be old/cracked, creaking a vacuum leak (waste gas), generating CEL, and possibly causing the EVAP system to malfunction.. I can't believe nobody addressed this issue in this thread. That EVAP working could be very temperature dependent. If you get the EVAP system fixed, you'll probably fix your problem.
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Hey Fleabag,
For a couple of days I noticed the car was not turning the starter over as quickly as it should. So, I broke out the multimeter and started checking out the grounds that you suggested. While I did this, I noticed a crack around the positive pole of the car battery. So I bought another one and when I was taking the positive clamp off the old one, the entire pole lifted out of the battery.
Now that I've changed the battery the car is back to getting mid 30's in the city again.
What do you think about that?
thanks,
-william
For a couple of days I noticed the car was not turning the starter over as quickly as it should. So, I broke out the multimeter and started checking out the grounds that you suggested. While I did this, I noticed a crack around the positive pole of the car battery. So I bought another one and when I was taking the positive clamp off the old one, the entire pole lifted out of the battery.
Now that I've changed the battery the car is back to getting mid 30's in the city again.
What do you think about that?
thanks,
-william
#24
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
Hey Fleabag,
For a couple of days I noticed the car was not turning the starter over as quickly as it should. So, I broke out the multimeter and started checking out the grounds that you suggested. While I did this, I noticed a crack around the positive pole of the car battery. So I bought another one and when I was taking the positive clamp off the old one, the entire pole lifted out of the battery.
Now that I've changed the battery the car is back to getting mid 30's in the city again.
What do you think about that?
thanks,
-william
For a couple of days I noticed the car was not turning the starter over as quickly as it should. So, I broke out the multimeter and started checking out the grounds that you suggested. While I did this, I noticed a crack around the positive pole of the car battery. So I bought another one and when I was taking the positive clamp off the old one, the entire pole lifted out of the battery.
Now that I've changed the battery the car is back to getting mid 30's in the city again.
What do you think about that?
thanks,
-william
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Re: 30 mpg to 20 mpg Drop In Gas Mileage for 00 Civic
For the exhaust manifold check out the Dorman OE replacement ones on ebay/amazon. They go for about $200 and are OE fit and quality.
http://www.amazon.com/Dorman-674-439...f=pd_rhf_p_t_1
http://www.amazon.com/Dorman-674-439...f=pd_rhf_p_t_1
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