98 EK "hatchy" mileage dropping like pooball, what's happening?
#1
98 EK "hatchy" mileage dropping like pooball, what's happening?
So as everyone probably knows, our Civics are naturally talented machines which can go long distances without refueling, sometimes challenging hybrid territories. A 30+ MPG rating is normal, even after years and years of abuse.
However, my CX hatch has been dropping mileage, sucking up precious gas like it's SI brother. Right now, I'm only getting a disappointing average of 28 mpg...
Mind you, this hatch has seen no racing or modification. All bone stock and driven like the old man next door...any ideas to what may be going on? Maybe it's the fuel? (Shell/regular)
I can't put a finger on it. One day it shoots a 36, and then for a few weeks high 20's.
However, my CX hatch has been dropping mileage, sucking up precious gas like it's SI brother. Right now, I'm only getting a disappointing average of 28 mpg...
Mind you, this hatch has seen no racing or modification. All bone stock and driven like the old man next door...any ideas to what may be going on? Maybe it's the fuel? (Shell/regular)
I can't put a finger on it. One day it shoots a 36, and then for a few weeks high 20's.
#3
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Check your electrical grounds, every single one of them with an ohm/multimeter to the battery ground cable. If they're showing anything above 0 ohms, they need to be cleaned. ESPECIALLY check the ground ohms for the body of the o2 sensor to the battery ground. If the o2 sensor's body ground (screws into manifold) is above 2 ohms, the signal becomes so weak that the ECU for the most part will ignore output and default the car to idle at 750rpm instead of the stock 670rpm. Next thing I suggest is replace the PCV valve since I can guarantee it's clogged on that car. Clogged PCV valve will decrease fuel economy and performance. If you find your acceleration isn't smooth or you can't easily maintain speed on the highway, then the next thing up is cleaning the IACV. Let me know if you have any other questions as I've got this same engine in my civic.
#5
Honda-Tech Member
#6
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Those are all worthwhile maintenance items, but I don't think they will solve the problem. For example, a clogged PCV valve may cause idle and emissions problems, but is unlikely to have a large impact on gas mileage.
#7
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
I don't have all the know-how to fix everything myself, so I'll have to refer back to H-T or dig up some other useful information. But for now, I'll go and take a look via your methods fleabag. Gracias! But keep throwing ideas out if you can, maybe there's something that we may have overlooked.
Here's the little rascal
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#8
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
#9
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
I went from 28 mpg back up to 33....thanks to Gum Fuel Cleaner!
I thought the 110 heat was the source of the problem after getting a tune up...
my high is 37+
I thought the 110 heat was the source of the problem after getting a tune up...
my high is 37+
#12
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Nope just trollin'
I've noticed as much as 6 MPG difference between Sheetz (28 mpg) and Exxon (34 mpg)
I've noticed as much as 6 MPG difference between Sheetz (28 mpg) and Exxon (34 mpg)
#13
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
our car's use a 4 wire oxygen sensor pretty sure one of them is a ground. and wouldn't the dvom show infinite resistance ?
Last edited by canadaek; 08-16-2011 at 05:09 PM. Reason: ??
#14
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Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
there should be little to no resistance through the ground side of a circuit. ideally less than .2 ohms.
#15
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Wouldn't you like to know! My fuel economy plummeted 20% when my PCV valve got clogged, replaced it, fuel economy went back up to higher than where it was prior. Even better, not only did my fuel economy go up, but so did the performance.
#16
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
They may be 4 wire o2 sensors but o2 sensors still all work the same in that they use the exhaust manifold as a ground. 5 wire (7 wire) or 1 wire, they all utilize the body of the sensor which is screwed into the exhaust manifold as a ground and if it's poorly grounded, the signal won't get to the ecu.
#17
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Given the pure emissions function of the PCV valve, what's your theory on how replacing the PCV would have such a large impact on mileage.
#18
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
try all the easy things first. like the fuel treatment and filter. those are not expensive. im new to h-t and don't know how to quote. but they were right on the tune up, but also on cleaning your connections.
#19
Honda-Tech Member
Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
I'm surprised I'm being asked this question since I thought it was pretty well established that clogged PCV valves not only hurt performance and fuel economy but can also damage your engine since the crankcase pressure builds up and forces its way through unintended passages.
http://www.aa1car.com/library/pcv.htm
Last edited by fleabag; 08-17-2011 at 04:11 PM.
#20
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Re: 98 EK "hatchy" mileage dropping like pooball, what's happening?
Clogged fuel filter? Filthy air filter? Low tire pressure? Junk in the trunk? Driving with AC alot? Aerodynamics and weight reduction are things to look at when wanting more MPG..Perhaps rolling the windows up 75% while on the freeway and a good dump before the cruise!
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