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Bad gas mileage after rebuild?


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How much less? Variations could be from driving / location / route changes

How long have you monitored ?  Variations could be from fuel itself

 

Rebuilds in general should make things better

 

Run a vacuum test on your engine and see if there are any issues to be considered.

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Depends on how tight the pistons are and how coarse the rebore/rehone was. Also valve seating, etc. Generally we see a reduction in fuel economy for a few thousand miles when we knurl the pistons on the EJ's. Were the pistons knurled? What was the ring gap and how were the cylinders setup? Have you compression tested it?

 

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Are you wearing heavier boots? On a serious note, how did you do your rebuild? New or reused pistons? Valve job? Perfect bore and hone? Deck the block and mill the heads? Worse milage after a rebuild is not right. Check ignition timing, run higher octane fuel, check plug gap, pcv valve. If you haven't already, install new plugs, wires, cap & rotor, fuel filter, amd air filter. Give it a good oil change after 500 mile break in.

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1. you are comparing last summer (before you took car off road for rebuild) with summer blend gases to winter blend gas you've been running since the rebuild this winter.  for the eagle eye hyper milers, it should go up any day now as stations start switching.

 

2  maybe it's not actually getting worse mileage - you love that new go pedal feel and can't get your foot out of it...or the old engine was such a basket case you were driving cautiously. 

 

what all did you do to the engine?

 

post previous and current gas mileage - is this a 0.5mpg difference or 10 mpg?  how many miles have you put on it? 

 

have you driven enough to get an accurate measure - consistent highway miles or inconsistent urban/mountain driving?

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How much less? Variations could be from driving / location / route changes

How long have you monitored ?  Variations could be from fuel itself

 

Rebuilds in general should make things better

 

Run a vacuum test on your engine and see if there are any issues to be considered.

It's like a 5-10 mpg difference
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