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what the hell! why am i getting such bad gas mileage?

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Old 03-19-2010, 10:35 AM
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Default what the hell! why am i getting such bad gas mileage?

k so i have a 1998 that i just put a new motor in...doesnt even have 500 miles on it yet. has everything new. performance distrib. ignition kit, e3 diamond fire plugs, bored TB, K&N cold air, banks header, new dodge neon injectors(installed yesterday), new torque convertor, plus tons of other crap...and im still only gettin about 11.5 MPG!!! WTF? just had alignment done also so i know tires are at correct PSI. also ever since i had the new torque convertor installed my check engine light stays on and is tripping codes for the torque convertor silenoid and the trans control module...could this be whats making my mileage so bad??? sorry for the long post....
Old 03-19-2010, 10:43 AM
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if the torque converter lock-up doesen't work you get bad mileage
Old 03-19-2010, 10:44 AM
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e3 plugs..
and get the trans checked out.

Could try resetting the ECU and seeing if the same codes come back.
Old 03-19-2010, 11:22 AM
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how would i tell if the torque convertor isnt locking? and got an appt. monday to have the tranny looked at. and back to good ol' champion copper plugs is what your telling me. well what should i gap them too then .045 or .055? and reset the ECU yesterday when i installed the new fuel injectors and guy at autozone reset it after pulling codes and still comes right on.
Old 03-19-2010, 11:25 AM
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It's not even fully broken in yet, your rings are not fully seated, nor are the valves. Be sure to change the oil at 500 miles to get all of the assemply lube and metal shavings out of it.
Old 03-19-2010, 11:28 AM
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so basically its all in my head and i need to be patient is what your saying. and changing the oil later today, has about 460 miles on it maybe. ive never broken in a new engine so dont know what to do really, just got told to baby it for the first 2500 miles or so. it's the first motor ive rebuilt ever so im just being really **** about it...
Old 03-19-2010, 11:28 AM
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driving in fourth (OD) at 1500rpm, take the foot off the gas and put it back on. If the jeep keeps revving at the same speed and you feel a little bump the LU works, if the tranny shifts briefly in third and then goes back in fourth (revs go up and then back down) the LU is not working.
Old 03-19-2010, 11:31 AM
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Originally Posted by fantic238
driving in fourth (OD) at 1500rpm, take the foot off the gas and put it back on. If the jeep keeps revving at the same speed and you feel a little bump the LU works, if the tranny shifts briefly in third and then goes back in fourth (revs go up and then back down) the LU is not working.
k..ill check that right now...on way to auto parts store...place is like my second home...they even offered to feed me lunch the other day lol
Old 03-19-2010, 12:25 PM
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well as far as i could tell the torque convertor is locking up so i dunno....gong to change the oil i guess.
Old 03-19-2010, 03:13 PM
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The rings may not be sealed all the way yet, giving you lower CR. This can lower your gas mileage.
I would go back to Champion plugs, the manual calls for .030 Gap


IIRC, if the solenoid voltage or Resistance is out of specs it will throw a code.
Old 03-19-2010, 04:18 PM
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Originally Posted by My375hp302
It's not even fully broken in yet, your rings are not fully seated, nor are the valves. Be sure to change the oil at 500 miles to get all of the assemply lube and metal shavings out of it.
x2 ......... give it a few thousand miles to loosen up and see how it does.
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