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SRP ftw!
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Discussion Starter · #1 ·
my 92 civic gets about 12 miles per gallon, pretty much im driving a hummer. i seriously dont know what the problem is. i replaced the plugs from platnum to copper, and adjusted the timing (it may still be off a little though). it has an intake and i understand that will take off a little bit but not 50mpg! does anyone have any ideas as to what i can do or what the problem is?

thanks
92civiclx
 

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m3
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I would say it could be a timing related issue unless you have fuel pouring out the back of the car...or a fuel leak which you should be able to smell...if so? Does it run poorly? any misfiring or anything?
 

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TopperAlum
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do a full tuneup, new wires, cap, rotor, it must be throwing a code and running under open loop which makes it run rich as hell... check for codes or cel (check engine light)
 

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SRP ftw!
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Discussion Starter · #4 ·
yeah it was runnig rich so we changed the plugs. it may still be running a little rich. i know the timeing is off a little cause its idiling low, but would that really cause my mpg to drop that much? it just had a new motor from an automatic (mines manual) put in it and the only code it was throwing was a intake temp. sensor that broke inside the manifold. cap is brand new, new oil and filter, wires are the only thing that hasnt been changed.

thanks for your comments i need all the help and tips i can get.

92civiclx
 

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smarter than you
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you have to fix the intake temp sensor, the stock ecu looks for it or it will dump fuel. Could also have a dying o2 sensor, which could cause it to run overly rich.

I'd check timing as well. Could also be a stuck open injector as well.
 

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SRP ftw!
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Discussion Starter · #8 ·
yeah i knew how to fix it and all but i was kind of ignoring it cause i figured it wouldnt matter. but that does make sense about the ecu dumpin gas. yeah the o2 sensor was next on my list to check out. thanksseen4ever ill have to go hit up pull-a-part tomorrow.

thanks for the help
92civiclx
 

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SRP ftw!
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Discussion Starter · #9 ·
CIVIC SUCKS ON GAS: PART 2

ok so i listened to everything that i got from the last post and did the most of the stuff. the main one that i thought would fix my problem was the intake temp sensor. replaced it, took the check engine light off and then as im rolin down the road it came back on. it comes on after about 15 minutes of driving but goes off if i turn it off and back on. its really out of time but tht wouldnt cause me to get 12mpg ( i know it will hurt it but not that much ) dont smell gas any where so that kind of eliminates the injectors.

any other ideas?

thanks
92civiclx
 

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m3
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If the cel light goes off when you restart it only to return after a few minutes of driving. The code isn't being stored in which case you would not be able to determine why its coming on. I would first get the timing set on it since you have resolved the iat problem and go from there......Its probably something simple thing like a vacuum leak or your 02sensor. I would check to make sure the wiring connector for the 02 is securely attached at the front the head then make sure none of the wires are coming out of the connector. I have had that one before and the cel light came on after it was started but wouldn't stay on when restarted until it was running for a little while.

Do you have an aftermarket air filter if so is it attached properly? I only ask because I have seen some really rigged up units and they will have that vac line just punched through the filter creating a large vac leak...or have the vac line just laying there again creating another vac leak. This will affect your idle and in which case make it hard to properly adjust your timing off specs. I had a bimmer that had one and the cel would come on after running a little while and would go away on restart. I got rid of the vac leak and I got rid of the cel. It also made it idle real low which is what air leak will do. Its like running around with your valve cover cap off it will idle like crap.
 

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.
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i had the same problam and i changed the o2 sensors and it is good as new!
 

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Discussion Starter · #15 ·
yeah i keep hearing about replacing the o2 sensor. but that being bad, would that cause bad gas mileage??? the intake is on properly, the vac tube is in the tubing so thats all good.

also i replaced the spark plugs from platnuim to copper cause we thought the platnums were causing it to burn to hot, but i pulled one of the coppers out and their black on the ends just like the others. is that just caused by my other problem of burning gas or what?

ive replaced the intake temp sensor, plugs, and cleaned the injectors. thats pretty much all ive done right now.

just to add, ixer, when your cel came on after running it for a little bit could you feel anything when it came on? when my comes on i can feel a little kick but i dont feel any difference in performance.

thanks for your post
92civiclx
 

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.
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ya the o2 will mess with the gas. when mine happened i was getting bad mileage and one day the cel came on and it was a o2. do u have a mis or anything?
 

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m3
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is hard to remember if I felt anything because I was immediatly pissed as soon as I saw it....so blood pressure yes engine not so sure...I do know mpg was off.....check the wires where the 02 connect to the harness make sure they are tighly attached and make sure those wires are down in there sockets...The problem sounds more and more like the 02. If the air filter/vac leak is not the problem. Just because the car has to be running a minute for the light to come on..If you take it out I suggest first to spray it with PBBLASTER to make it easier to get out...also run the car for a few minutes to heat it up before removal....

Do not get anything like oil or pbblaster on the end of it when you have it out. It will damage it...
 

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SRP ftw!
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Discussion Starter · #18 ·
no shes not missing or anything. is extremely out of time. it died three times this morning on the way to school when the rpms would drop, it wouldnt catch itself and shed just die. but yeah ill definatly look into the O2, that sounds like -from what everyone is saying- my problem.

thanks ill keep you guys posted
92civiclx
 

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m3
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if it starts will a low idle now that you have the iat fixed turn up the idle....see if that helps. The idle can be adjusted by turning the two nuts on the end of the throttle cable.
 

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SRP ftw!
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Discussion Starter · #20 ·
well im pretty sure its just out of time i havent gotten a chance to adjust it with a timing gun since i got the new motor in. the timing belt itself may be off a tooth of two. cause the ends of my plugs are black.
 
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