Detailed engine computer sensor tuning information

[Painless]

I found this Word document on the yahoo watercar forum today and thought that I should share. It's pretty detailed and gives a lot of information on ECU and sensor operation and the various ways of fooling the computer.

Had to convert to a .txt file as the word doc was bigger than the upload limit.

Thought it would, at the least, make interesting reading.

Russ.

[Stratous]

Post a link?

[Omega]

A link would be nice; the formatting is a little off, so snagging a good copy would be great.

Thanks for the info!

[Phantom240]

I don't know what all kind of vehicles people drive here... but there's a little device made by Apex'i called the SAFC and SAFC-II. SAFC stands for "Super Air Flow Converter". They're quite popular on the 'tuner' cars as some people call them

What it does is interprets your MAF signal through your RPM band, and you can adjust the signal using the SAFC (I or II) to make the ecu think it is getting either more or less air. Paired with a wideband o2 sensor, I think you could get some amazing results.

[Painless]

Post a link?

Unfortunately, the file was from a yahoo forum that requires registration (free), I'll upload the file to my webserver and post a link for the original word doc.

[Painless]

Ok, here's a link to where I hosted the original word doc:

http://www.moore-or-less.org/~russ/d..._Computers.doc

[gheuett]

This is really interesting stuff. Thanks for posting Painless! I'll be interested in hearing others' take on this but what I'm picking up from this is stay away from EFIEs, extenders and go with a resistor on the Barometric pressure sensor (first time I ever heard of that one!).

Others?

Thanks!
Gib

[hhojoe]

This is really interesting stuff. Thanks for posting Painless! I'll be interested in hearing others' take on this but what I'm picking up from this is stay away from EFIEs, extenders and go with a resistor on the Barometric pressure sensor (first time I ever heard of that one!).

Others?

Thanks!
Gib

When leaning the engine you have to be sure you don't lean it too much to the point where you burn your valves. Think of it like an acetylene torch, when you add oxygen the flame gets really hot. In small planes there is an exhaust gas temp gauge, if the temp gets too high you need to en richen the mixture to cool the engine (put simply).

On many of today's cars the MAP sensor is the Baro sensor. when you first turn your key and before the engine starts the computer reads the static barometric pressure from the MAP sensor to use as its base. This always struck me funny because what about if you are driving from the bottom up to the top of Pike's Peak???

There are some O2 sensors where the resistor trick won't work. On my 2006 Subaru for instance if I want to lean it out via the O2 sensor I must INCREASE the signal. This trick only worked for a while (about 20 miles) until the computer 'learned' to compensate for this change. How did it do that? It looks at the signals from all the other sensors and based on their readings figures the reading from the O2 is 'off' what it should be and changes the mappings. Took me some time to figure this out but what I ended up doing is buying a cable and software that would allow me to modify the maps. Still a work in progress.

These tricks work better on older cars where the ECU isn't as smart as some/most are today.

[Phantom240]

These tricks work better on older cars where the ECU isn't as smart as some/most are today.

lol. Early 90's japanese cars triumph again!

[hhojoe]

lol. Early 90's japanese cars triumph again!

I hate you