Exhaust decreasing gas mileage?
03-26-2007, 01:15 AM
#21
5th Gear Member
Join Date: Jul 2005
Location: Georgia
Posts: 2,387
RE: Exhaust decreasing gas mileage?
ORIGINAL: josh662234
I just recently installed my exhaust and i have noticed a huge decrease in gas mileage. . . at the same time i increased the spark advace on my diablo tuner and i need to run 93. . . . after two tanks i figured i wasjust wasting gas romping on it to hear my exhaust. . . but i've been driving normal now and it is still horrible. . . anybody have any ideas? Or does it come with the mods?
I just recently installed my exhaust and i have noticed a huge decrease in gas mileage. . . at the same time i increased the spark advace on my diablo tuner and i need to run 93. . . . after two tanks i figured i wasjust wasting gas romping on it to hear my exhaust. . . but i've been driving normal now and it is still horrible. . . anybody have any ideas? Or does it come with the mods?
03-26-2007, 01:37 AM
#22
5th Gear Member
Join Date: Dec 2005
Location:
Posts: 2,791
RE: Exhaust decreasing gas mileage?
reelfast02cobra
your an idiot for thinkin there is a cobra in 2002. and dont come to our forums calling people idiots or bashing someone, everyone has the right to speak and the information that was provided was beneficial to this issue. Anyways I personally think its related to the tune or aexhaust leak. The tune is my number 1 guess though
your an idiot for thinkin there is a cobra in 2002. and dont come to our forums calling people idiots or bashing someone, everyone has the right to speak and the information that was provided was beneficial to this issue. Anyways I personally think its related to the tune or aexhaust leak. The tune is my number 1 guess though
03-26-2007, 01:57 AM
#23
4th Gear Member
Join Date: Sep 2006
Location:
Posts: 1,031
RE: Exhaust decreasing gas mileage?
ORIGINAL: cliffyk
[/align][/align]If the RTV sealant was not "sensor safe" you may have toasted the O2 sensor on that bank, a dead O2 sensor tells the PCM that the mix is lean and it will go as rich as can to compensate--have you pulled the codes to see what it's throwing?[/align]
ORIGINAL: josh662234
well i had a fairly bad leak where the h pipe connects to the manifold on the driver's side. no matter how much i tightened it it still leaked horribly. . . so i caked on some high temp rtv silicone and i cant hear it anymore. . . we will have to see if that helps. . .
well i had a fairly bad leak where the h pipe connects to the manifold on the driver's side. no matter how much i tightened it it still leaked horribly. . . so i caked on some high temp rtv silicone and i cant hear it anymore. . . we will have to see if that helps. . .
The silicon in some types of RTV contaminates the O2 sensors.
03-26-2007, 02:02 AM
#24
RE: Exhaust decreasing gas mileage?
reelfast02cobra
your an idiot for thinkin there is a cobra in 2002. and dont come to our forums calling people idiots or bashing someone, everyone has the right to speak and the information that was provided was beneficial to this issue. Anyways I personally think its related to the tune or a exhaust leak. The tune is my number 1 guess though
your an idiot for thinkin there is a cobra in 2002. and dont come to our forums calling people idiots or bashing someone, everyone has the right to speak and the information that was provided was beneficial to this issue. Anyways I personally think its related to the tune or a exhaust leak. The tune is my number 1 guess though
03-26-2007, 03:21 AM
#25
4th Gear Member
Join Date: May 2005
Location: Texas
Posts: 1,109
RE: Exhaust decreasing gas mileage?
ORIGINAL: reelfast02cobra
o
This guy's also a retard. Jesus christ. How many <b>noobs</b> this site?
ORIGINAL: 06mustang88
if anything, you should be getting better gas with the new exhaust. the new exhaust should be giving you better flow which makes the engine work less hard and burn less fuel. i would try to take the spark back to where it was before and see if the problem continues. that way you know if it's the exhaust or the spark that's decreasing your fuel economy
if anything, you should be getting better gas with the new exhaust. the new exhaust should be giving you better flow which makes the engine work less hard and burn less fuel. i would try to take the spark back to where it was before and see if the problem continues. that way you know if it's the exhaust or the spark that's decreasing your fuel economy
This guy's also a retard. Jesus christ. How many <b>noobs</b> this site?
03-26-2007, 10:13 AM
#26
3rd Gear Member
Thread Starter
Join Date: Dec 2006
Location: Plymouth MA
Posts: 572
RE: Exhaust decreasing gas mileage?
Well the mid pipe is an off road mac. . . so the 02's are turned off inthe rear. . . i have not driven a full tank of gas since "fixing" the leak . . . but i have to drive to NH today so i'll see what i get. . .
03-26-2007, 12:58 PM
#28
Join Date: Feb 2007
Posts: 12
RE: Exhaust decreasing gas mileage?
ORIGINAL: josh662234
well i had a fairly bad leak where the h pipe connects to the manifold on the driver's side. no matter how much i tightened it it still leaked horribly. . . so i caked on some high temp rtv silicone and i cant hear it anymore. . . we will have to see if that helps. . .
well i had a fairly bad leak where the h pipe connects to the manifold on the driver's side. no matter how much i tightened it it still leaked horribly. . . so i caked on some high temp rtv silicone and i cant hear it anymore. . . we will have to see if that helps. . .
03-26-2007, 05:17 PM
#29
4th Gear Member
Join Date: Sep 2006
Location: TAXO
Posts: 1,803
RE: Exhaust decreasing gas mileage?
ORIGINAL: reelfast02cobra
...umm... and you have room to speak?! Where's your proof??? I have proof that efficiency is in fact increased with tune, catback, and CAI... I drove from norfolk, VA to Upper Freehold, NJ which is a 310 mile hike... on a little over one tank of gas... I averaged my speed at about 70 mph.. but had a max of 110, when I was leaving the gas station on the turnpike, I filled back up at 1/4 tank at the first stop in NJ on the turnpike... and from there to home I used only a 1/4... so I used a total approximate of a whole tank...
And I drove my **** up your mothers stank on the hang low. She didn't complain. Who the **** gives you the right to criticize me?
...umm... and you have room to speak?! Where's your proof??? I have proof that efficiency is in fact increased with tune, catback, and CAI... I drove from norfolk, VA to Upper Freehold, NJ which is a 310 mile hike... on a little over one tank of gas... I averaged my speed at about 70 mph.. but had a max of 110, when I was leaving the gas station on the turnpike, I filled back up at 1/4 tank at the first stop in NJ on the turnpike... and from there to home I used only a 1/4... so I used a total approximate of a whole tank...
03-26-2007, 05:32 PM
#30
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
RE: Exhaust decreasing gas mileage?
Alrighty then,
If you have an exhause leak you'd know it. If you killed an O2 sensor you'd know that too because the CEL would come on. The fact you are using a catless system and only have the two front O2 sensors leads me to believe you might be running a bit rich, thus blowing extra fuel out of the tail-pipe that negates any extra fuel ecomony you would have hoped to gain in the first place. Check for black soot at your exhaust tips, that's a tell-tale sign you are running way rich.
As some suggested, put the stock tune back on. See if you mileage improves. If it does, then you should have a tune done with your car on the Dyno. If it doesn't, start testing your O2 sensors you could have a sluggish one and they do not always turn the CEL on.
I've never heard of people using RTV on their exhaust. If it's working now, it won't hold for long.To get the studs out of your manifold take two nuts that fit the stud, thread them both on about half way down. Then use an open end wrench or vice grips to grab the nut (inner nut) between the the manifold and the other nut and back it out. As you back it out it will tighten up against the outer nut and back the stud out with it. Or if they are the studs that are in the head, they should have a 6 pt head on them. Just use the appropriate socket and rachet to pull em out or use the above method for backing those out (knuckle buster way)
If you have an exhause leak you'd know it. If you killed an O2 sensor you'd know that too because the CEL would come on. The fact you are using a catless system and only have the two front O2 sensors leads me to believe you might be running a bit rich, thus blowing extra fuel out of the tail-pipe that negates any extra fuel ecomony you would have hoped to gain in the first place. Check for black soot at your exhaust tips, that's a tell-tale sign you are running way rich.
As some suggested, put the stock tune back on. See if you mileage improves. If it does, then you should have a tune done with your car on the Dyno. If it doesn't, start testing your O2 sensors you could have a sluggish one and they do not always turn the CEL on.
I've never heard of people using RTV on their exhaust. If it's working now, it won't hold for long.To get the studs out of your manifold take two nuts that fit the stud, thread them both on about half way down. Then use an open end wrench or vice grips to grab the nut (inner nut) between the the manifold and the other nut and back it out. As you back it out it will tighten up against the outer nut and back the stud out with it. Or if they are the studs that are in the head, they should have a 6 pt head on them. Just use the appropriate socket and rachet to pull em out or use the above method for backing those out (knuckle buster way)