I got my first electronics training courtesy of Fender.

Always worked on cars and worked my way up from part time mechanic to shop manager, to being one of the guys that run Caltrain and SamTrans in the Bay area.

I have about ten guitars and about the same with ukes.

The guitar I pick up every night is a 1920 Koa Martin 00.

But back to the knock sensor. If I had the problem of it picking up too much noise I would attempt to isolate it before removal.

I like knock sensors more the older and deafer I get.

As they say there are lots of ways to skin a cat and many things would work.

After spending(or should I say wasting) some time under the hood, I realized that I could not find where the IAT is in my 97 OBW engine.

 

So...

Looking through some manuals and schematics for earlier model, I found that there is no pin for IAT sensor in ECM connector.

 

At this point, my guess is that MAF sensor does not need to air temperature information (thus no IAT sensor) while both MAP sensor and flap type AFM need air temperature calibration. Those 2 hot wires in MAF are temperature sensors themselves anyway.

 

By the way, thanks for answering my rather personal question!

 

I had done DSP and microcontroller programming for a decade, but it was for small consumer electronics products and not something anywhere big as a car engine. For the past 4-5 years, I've been writing device drivers for a living.

Though this has nothing to do with this, iwould just like to say:

 

 

Blitz!!! ---Joe Strummer!!!!!!! (R.I.P) the clash are my altime favorite band and i wanted to meet him... Yeah I m friggin jealous oh my gosh, i would've given my left.... and well sheryll is pretty cute bu, Joe strummer. WOW you ar my hero!!!!!!!!!!!!!!!!!!

 

 

 

By the way i am twenty and have worked at a bike/ ski shop for 7 years. Not to mention manage it. No electrical work though. I am scared of being shocked.

Absolutely right, the MAF doesn't need to measure the air temp. It kind of all comes out in the wash with the "hot wire" set up.

 

Any idea why they went to MAP? In industry, mass flow is one of the best ways to go when measuring flow for combustion.

Originally posted by robm

Absolutely right, the MAF doesn't need to measure the air temp. It kind of all comes out in the wash with the "hot wire" set up.

 

Any idea why they went to MAP? In industry, mass flow is one of the best ways to go when measuring flow for combustion.

 

It's a tradeoff. MAF is a more accurate system than MAP on account of it measuring the actual amount of air ingested, but it restricts the airflow somewhat, and the sensor is relatively expensive, delicate and is easily damaged.

 

MAP essentially extrapolates (makes a really good guess as to) the fuel requirements, so requires help from temp sensors, barometric pressure sensors, etc.

 

It's a safe bet that MAP-based systems will become more prevalent as underhood computing power grows exponentially.

Will this mod only work with OBD-II? I have a 93 Impreza (EJ18) and a 98 OBS (EJ22)? I now my 93 dont have a knock sensor, actually I'm not even sure it has an IAT?

Well, you might want to check the manual for each model to make sure but I'm fairly certain that MAF-type FI systems don't include (or require) an AIT sensor. The '93 is almost certainly a MAF system, but I'm not sure about the '98. Sorry for not being much help. :-\

 

You really need to own a manual for each vehicle you own, if you plan on mastering that little technique of "do-it-yourself" type problem attack. It costs a bit for sure, but it's well worth it over the long haul.

I do own them but I don't fully understand what you have, do youhave a web page explaining anything? It seems like you have an ingenious mind.

In a nutshell, I added resistance in series with the IAT sensor. This is a pretty long thread. Read back through it, then copy and paste the part you don't understand, and I'll gladly work you through it.

I just got an '00 OBS and am looking for cheap ways to improve performance without losing too much gass/mi .. would this work for me.

 

I am no electrical master but i'm pretty handy, usually only with mechanics though. do you think a layman can do this mod? and if I mess up what can the consequences be?

 

I only have a basic idea what these MAP MAF and whatever else are, and no idea where to locate them. What is a good shop manual for subys?

Adding resistance in series with the AIT sensor will advance the timing, so you might actually see a slight mileage improvement. You will however need to use premium fuel.

 

As far as whether you are capable, only you know that. I'm a firm believer that a person can accomplish anything they want to.

 

The worst consequences of a mess-up? Well, you could poke your eye out, scratch the paint on your fender really bad, and completely toast your ECU. Just don't mess-up. Problem solved.

 

The best manual is probably the factory manual, unless someone else has a better suggestion.