pcmhacking.net

Myself and a mate both have the early model petrol Prado that run no cats or oxy sensor, they use a heap of fuel and stink doing so. Finally got the shits with it so started looking at ways to improve it. AFAIK the ECU uses a OTP custom MCU so gaining access would not be worth it, couldnt see a way to log data either. Chucked a wideband on it using an Innovate exhaust clamp and it said it was running pig rich - 11:1 cold start, 13.5-14 at cruise and 10.8 WOT. I have since found that the Innovate clamp mounted WB reads totally different to what a WB in a bung further up the exhaust reads (at cruise with 14:1 on the clamp was 15:1 using a bung, but WOT is identical). I will be doing some more testing with this but looks like the Innovate clamp is a pile of shit - and on a car with no cats it really should work ok.

Anyway, before finding out the clamp read wrong I made this little device up...



It takes the 0-5v MAF signal and can modify the output +-50%. Also has a few other inputs to make it more tunable - RPM, VSS, Inj DC, TPS and wideband. It has USB for logging and uses TunerPro to edit and log with. Am still playing with the firmware but its getting there slowly. Its happy making changes to the MAF voltage, car runs identical with 0% adjustment and no CEL

XDF and Cal.. Logging..

my question is how much improvement can you get out of the prado from it!

Hopefully a bit at cruise (will have a lean cruise function) and maybe some more HP at WOT

Any chance of fitting a map sensor and removing the maf all together.
Just an idea

There is a MAP sensor input In the logs it shows just 10kPa all the time as no sensor is connected yet. The plan is to drive around in its learn mode sampling MAF voltage vs RPM and MAP and then change to MAP mode to have the MAP take over as the load input to the the adjuster. Just gotta get the wideband bung put in first.

Just had a close look at pcb and is shows maf2map should have looked first.
been discussing a ford v8 / v10 with twin turbos in a F series truck.
now this would make it easy with no maf

great little side project vl400 allways playing with something hehe.it still doesnt make it easy easy you really need to get inside the ecu as well as maf does more than just fueling on most vehicles your adjusting spark trans pressures and lots of other things as well thats why i generally throw piggybacks in the bin LOL.

http://www.mapecu.com/ ive pulled a few of these out over the years LOL but the damage was allready done low oil pressure from hammered bearings and slipping transmissions etc it will work you just have to use some thought and at least need to be able to log engine data from the ecu you cant just tune them blind

Getting inside the ECU is a lost cause It looks like a one-time programmable custom MCU so for the effort would be better to just delco it and adapt it to the trans and transfer case. Oh and cant find any info if there is data you can get log.

Am only making small changes to gain some fuel economy at cruise speeds (seeing a nice lean cruise AFR of 17 instead of 14.5 now). All the high load stuff is being left alone for the reasons you mentioned, its changing airflow/load and not just injector rate for fuel

Here is an example of a -5% change of the MAF voltage - so MAF volts in to the adjuster is 2.832v and the output is 2.696v. With a slightly modified antus OSEplugin it does RT changes. At a steady speed while on cruise and on a flat road just hit the current cell (data tracing) with -5% for instant change....

Nice work there vl400.Very clever.
Does it have a frequency to voltage convertor so you can connect it to a maf that outputs frequency.