Mpg problems after header install
Thread Starter
Staging Lane
Joined: Jul 2011
Posts: 69
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From: illinois
Mpg problems after header install as the title says my mpgs are all over the place after my lt and ory install. I also replaced the plugs but not wires they looked good. Any ideas as to why my mpg's have gone down like 40 miles for a half tank roughly, and like 60 when the light pops on?
Thread Starter
Staging Lane
Joined: Jul 2011
Posts: 69
Likes: 0
From: illinois
no i didnt get a tune. nowhere around central illinois and didnt really think it was necessary because its not messing with anything internal or changing anything besides deleting the rear o2's
You changed from stock manifolds to long tube headers. A tune would do a whole lot of good. Plus, if you just pulled the rear O2s, you didn't delete them...that has to be done in the ECU.
Thread Starter
Staging Lane
Joined: Jul 2011
Posts: 69
Likes: 0
From: illinois
Can you don this with say hp tuners, without having a shop fully tune it for the fact it is my DD? The closest reputable tuning shop is atleast 4 hours away. Kinda new to all this, didnt know if there was anyway of doing this without a tune or a tuneing shop.
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Have you checked for exhaust leaks? Air getting into the system will throw off your o2's and cause the car to run rich. Also like was already said you gotta tune out or get simulators for the rear o2's. What part of central IL are you from?
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Staging Lane
Joined: Jul 2011
Posts: 69
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From: illinois
about right in the middle between Peoria, and Springfield. Any ideas where i could get a set of o2 sims???
also will a leak after the o2's cause them to be thrown off? I havent welded it yet just got some clamps on it. Im going to weld it maybe this weekend.
also will a leak after the o2's cause them to be thrown off? I havent welded it yet just got some clamps on it. Im going to weld it maybe this weekend.
Leaks upstream of the front O2s are the most likely to cause problems, but a leak immediately downstream can also be a problem. Installing headers, even with no leaks, should cause it to run rich, and yes you gas mileage will suffer unless and until you get a tune.
By tune I mean adjusting the a/f ratio and whatever other changes the tuner makes to get the engine running parameters correct. The only purpose for A, turning off the rear O2s is to avoid the catalytic converter effeciency error/check engine light that otherwise sets.
Another option is the mail order tune from folks like Frost, Wait4Me, or Texas Speed (I think). With a mail order tune you either send them your ECM or in the case of Wait4Me they can supply a spare ECM to reduce downtime. Mail order tunes are not as good as the hands on tune, particularly if you have a lot of modifications. On the other hand, if you only few mods the mail order tunes can be acceptable.
Finally, you can get some software such EFI live or HP tuners and learn to do it yourself. I think you have do buy a license for each VIN number you tune in addition to the cost of the software. There is also the risk that you will damage you car if you mis tune it while learning.
Thread Starter
Staging Lane
Joined: Jul 2011
Posts: 69
Likes: 0
From: illinois
Ok you've been a tremendous help! last question and sorry if i sound stupid what so ever. Only mods to this date are headers with ory, free ram air, k and n filter. So, basically just headers and ory that really would cause problems. In your opinoin would a mail order tune suffice for my circumstances?
Ok you've been a tremendous help! last question and sorry if i sound stupid what so ever. Only mods to this date are headers with ory, free ram air, k and n filter. So, basically just headers and ory that really would cause problems. In your opinoin would a mail order tune suffice for my circumstances?
(I went to a professional tuner later as I did heads/cam/intake).
TECH Enthusiast
Joined: Jan 2010
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From: Corpus Christi, TX
yeah after my header install i immieditally got it tuned by frost so i really didnt drive it inbetween then but usually after a header install its a good idea to replace the o2's. When i started driving my car again i noticed the same thing u are bad MPG, and about a few months ago i finally got around to getting new 02 sensers and its back to normal