89 suburban . changed fuel pump now running fine but need to know a few things.
the fuel gauge when full reads very (high needle is horizontal) and when empty is at 1/4 full.
the oil pressur gauge also reads high. key on 30 lbs running 60 lbs
the speedometer is way low (reads 25 when doing 40).
what's the fuel tank capacity.

 

i'm surprised that nobody posted an answer 2 such a simple question 4 U B4 now.
the fuel capacity is 133L, that's 35 US gal.
hope this info is 'better late than never'.
i also have the same problem with the gauge not reading the correct level.when i had my tank resealed and the sending unit fittings replaced ('90 'Burb,380,000 kilometers on it-lotsa rust on those fittings!), my buddy installed the unit in the tank 4 me before i picked-up the tank-'did U a favor' he said, 'i installed the unit 4 U, no xtra charge'. thanked him, installed the tank (heavy sucker)and for some reason it reads high- at aprox. 1/8 left on the gauge i can put in about 120-130L (at first it was out by a little over 3/8, but it's gotten a little better on it's own). don't know why (i've cleaned the ground 2 the frame and everything else is good and clean), but i don't really care, i've gotten used 2 it. maybe if/when the pump fails, i'll drop the tank and fix everything, but until then, screw it-it's just 2 heavy 2 do by yourself and by hand (no jack)

 

sorry, i forgot 2 mention that B4 the tank was removed, the gauge worked perfectly (just incase that wasn't clear).