wrong vaf causing poor fuel mileage?

[se7en]

okay, my k8 vaf crapped out, and I had a klde vaf, so I put it in....now it runs great again, but the mileage has got really bad! like over a tank of gas per week.

and I don't drive that much.

so is the vaf the problem? should I go to another k8 vaf again?

7

[Kirk95gs]

Well I would think it would give you inproper readings.. the k8 ecu is calibrated for the je50 vaf ( Variable Air Flow ) . So running the Maf ( Mas Air Flow ) would give a diffrent reading for the ecu.... so I would think it would cause the motor to run rich.. Are you pulling any codes??? I was always under the assumption that our cars would not work with the MAF from a klde..

[se7en]

well,,,it runs great, but the mileage sucks...it runs really rich.

[Nd4SpdSe]

Well I would think it would give you inproper readings.. the k8 ecu is calibrated for the je50 vaf ( Variable Air Flow ) . So running the Maf ( Mas Air Flow ) would give a diffrent reading for the ecu.... so I would think it would cause the motor to run rich.. Are you pulling any codes??? I was always under the assumption that our cars would not work with the MAF from a klde..

No, KLDE's also ran a VAF (Volume Air Flow) too, the only one to really use a MAF is the Millenia.

But as Kirk stated, your K8 ECU is calibrated and looking for the values from a JE50 VAF, runing anything else will cause your car to either run richer or leaner. Some people run a DE VAF with a K8 ECU on KLDE and KLZE swapped Mx-3's, along with many other combinations, but a stock motor in a stock Mx-3 with a stock ECU should really use the stock VAF, it's kinda what works best.

[se7en]

I'm not stock

7psi boost.....

[Nd4SpdSe]

Well how was it running with the K8 VAF?

[se7en]

ya, it ran better....mileagewise anyway....

I see your point...i will get the k8 vaf again

[Nd4SpdSe]

It's either than, a Fuel-Management System or a Stand-Alone ECU

[se7en]

ya, I may get the Msns from rebel2k4 in a few days, money allowing of course

7

[Kirk95gs]

No, KLDE's also ran a VAF (Volume Air Flow) too, the only one to really use a MAF is the Millenia.

I didnt know that ... I thought all klde's ran a maf... so that being the fact..

don't probes/mx-6,626 run a maf? I thought Millenias ran a maf too.. so is it the same je50 vaf as under our hoods.. or is it diffrent?

sorry for jacking the tread.

[Nd4SpdSe]

We can use all VAF's from any OBDI (up tp '95) Probe, 626 and Mx-6, but I don't know what they used in their OBDII systems, could maybe work, but that's something I've never looked into. The Millenia runs a MAF and a different pin-out ECU.

No, they use a VAF of different values, with different part numbers, but they're all pretty much the same. The most common is the KL02. As far as I know there's a KL01 VAF too.

Like I've mentioned, people have tried mixed ECU/VAF combo's with turbo and swapped. K8 ECU with a DE VAF is an easy fix for fuel milleage consumption on a KL swapped Mx-3. DE ECU with a DE VAF is quite popular and probably one of the better combo's to go with, and it's cheaper than KL31/36 ECU, which is suppose to be paired with the JE50 VAF that fortunately enough comes stock in the K8 MX-3.

Another option is a Probinator chipped ECU, they are hightly recommended amugst all KL Mazda groups and is the cheapest of all options (if you install it yourself), and with that chip, the ECU no longer becomes VAF specific.

[Daninski]

99 probe = KL02 VAF, if anyone still cares. lol

[ElectricEnergy]

I know we're kinda bringing back a dead thread but...

How would a MAF/VAF sensor cause the engine to run rich/lean? Wouldn't it see the problem with the O2s and fix it?

[hgallegos915]

I dont think he was turbo at the time, but if you use a klde maf on a k8 it will run rich for some reason.

[Nd4SpdSe]

How would a MAF/VAF sensor cause the engine to run rich/lean?

It has everything to do with it.. It measures how much air is coming in, and with that measurement, it knows how much fuel to use.