Klde longneck running rich

[eunosklde]

Hey folks,Got a bit of a problem with my mazda running a little rich.Its a 92 mazda mx3 klde block number 815*** running a kl31 ecu,je50,and a jap spec long neck manifold and always use 98 octane fuel.Ive changed the plugs and leads,fuel filter etc.The thing is the car runs smooth no smoke coming out the muffler at all and no fuel smell.Its just that i only get 2800 ks to the tank,dosn't matter if a drive it hard or like a girl it still gets roughly the same econemy.Also dosent have the grunt down low that a KL's should have and top end.Ive checked the vris seems to be doin its job i even zipped tie'd them open but still dosnt give the power i should be getting.Try'd differnt ecu vaf combos,from K8 ecu and je50 vaf run very badly,KL02 ECU KL02 vaf no power,K8 ecu and KL02 vaf ran preety well could 135 wheel kw's,but it started leaning out out 5900 rpm.The KL31 ecu and ge50 runs smooth thu it surges at low revs when i put the foot down.Some days it has better throttle respons and power and most days it runs like a fairy.

[davmac]

Nothing definitive to offer but a few thoughts.
- where in the intake piping is the vaf? It needs to be pretty close to the throttle body.
- Generally matching ecu and vaf is a good combo
- did you do any port matching between the intake and the heads? Although I'm sure you're not the only one who may have slapped the oval port intake onto the square port head or vice versa.

Assuming 280 km / tank or about 11 gallons = 16 mpg. I agree that is pretty bad economy especially if as you say it runs like a fairy.

Sorry not more to offer. Hopefully others with broader experience mixing and matching these components will offer remedy.