So after doing a full tune-up on both my cars (plugs, wires, cap, rotor, all filters, all fluids, rebuilt injectors, valve adjustment, O2 sensors, cleaned ICV/TB/AFM) my vert is still getting consistently poor mileage, 20-21 MPG at best. The coupe on the other hand is getting it's normal 25-26 MPG. Now I know the verts are heavier by 250lbs or so, but that can't explain all of difference in fuel consumption. Both are running G260s with 3.73 LSDs too. What gives? I'm consistently getting 5-6 MPG worse, no matter the driving style, roads, fuel, etc. I've put the vert up on stands and can't detect any signs of a sticky caliper either. Do any other people out there who own both types of car notice such a big difference? Anything else I should be checking?
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Originally posted by kronus View PostCheck your fuel system. I'm not sure if the e30 one is pressurized, but my friend's e36 was getting like 22 mpg until he replaced the fuel cap, since the old one was leaking and decompressing the gas tank. He started getting around 28 mpg after the fuel cap replacement.
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Originally posted by Turf1600 View PostAccording to my OBC I got 35 mpg on the way home last night. I can get 400+ miles to the tank on my 90 325is if I drive with a light foot.
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I get 16-20 on my stroker and my tune is NOT fuel efficient - it runs 13-14:1 on overrun (stock ECU cuts the injectors, I haven't tuned for that yet), 13.5:1 at idle, 12.5-13:1 at WOT. I also have 4.10s, more drivetrain loss, and a stuck front caliper that I need to rebuild. so if you're getting that with a stock M20 and a 3.73, yeah, something is wrong.
The first place I would start is the tests in the bentley (I get the feeling most E30 owners don't have one..) There are tests for most of the sensors, the only ones you can't test are the AFM and O2. Coolant temp sensor will make it run rich if it's gone bad.
also, a clogged cat can make you get poor mileage too - might want to check to see if there's any loose honeycomb inside. I don't think E30 cats go bad very often though (at least they're worth a mint in scrap metals).
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Originally posted by kronus View PostCheck your fuel system. I'm not sure if the e30 one is pressurized, but my friend's e36 was getting like 22 mpg until he replaced the fuel cap, since the old one was leaking and decompressing the gas tank. He started getting around 28 mpg after the fuel cap replacement.
Originally posted by twothrees View PostAre your wheels the same size from coupe to cabrio? Would that screw up the odometer when your checking your mpg.
Originally posted by Turf1600 View PostAccording to my OBC I got 35 mpg on the way home last night. I can get 400+ miles to the tank on my 90 325is if I drive with a light foot.
Originally posted by RedStar240 View PostThe first big difference between the vert and the coupe is its a vert, it has way more wind drag. Especially if your cruzin around with the top down and all the windows down. Wind drag is going to kill MPG, although e30s are not the most aerodynamic cars.
Originally posted by nando View PostThe first place I would start is the tests in the bentley (I get the feeling most E30 owners don't have one..) There are tests for most of the sensors, the only ones you can't test are the AFM and O2. Coolant temp sensor will make it run rich if it's gone bad.
also, a clogged cat can make you get poor mileage too - might want to check to see if there's any loose honeycomb inside. I don't think E30 cats go bad very often though (at least they're worth a mint in scrap metals).
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Originally posted by Turf1600 View PostAccording to my OBC I got 35 mpg on the way home last night. I can get 400+ miles to the tank on my 90 325is if I drive with a light foot.
do verts have the same size tanks?
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