Wiring on 750il MAF for m20 conversion

Post Mon Aug 27, 2007 2:29 am

Does anyone know the wiring setup on an 87-94 6 pin 750il MAF? I'm installing a digital fuel adjuster in my car (1989 e30 325i) to help me tune it a bit better for the cam (aftermarket). I'm also putting in larger 19lb injectors. What I was wondering is does the MAF have a single wire with changing voltage like the original AFM? My digital fuel adjuster works on a single input output system, can run 0-1V/0-5V/0-12V, has 128 load points and I can change each load point by +/-127. Its very tunable. Any help would be much appreciated.

Post Mon Aug 27, 2007 3:14 am

I found the pinouts for my bosch maf on a random site by searching google for part of the part number. The PDF wasn't an exact match in part number but the pins were the same. Looking at my stuff it's for a 5pin maf so unlikely to help but here's what I have:

1. temp (to ground)
2. 12v hotwire supply
3. gnd
4. 5v reference
5. signal

What is the fuel adjuster kit you're using ? It sounds similar to something I am (was) creating.

Post Mon Aug 27, 2007 10:52 am

Okay that's reasonably positive, at least I know I can use this adjuster with the MAF. Do you have the corresponding wire colours for those? The kit is from a place called Jaycar here in Oz. www.jaycar.com.au then search for fuel adjuster. Its a great little unit for what it provides. Were did you get your kit?

Post Mon Aug 27, 2007 11:01 am

Ah yeah jaycar - they do some great little projects. My kits was going to be a home build. Unfortunately it never even made it to prototype.

I still have the kit setup and plan to dig it out "one day"

Should be a simple project but my skills are limited at best.

Don't have any loom colours sorry mate.

Post Tue Aug 28, 2007 12:58 am

Yeah I had my kits (digital fuel adjuster, duty cycle meter, smart fuel mix and hand controller) sitting at home from about 6 months before I finally decided to build them...

I got a book "performance electronics for cars" from jaycar. It has all the projects in there with colour pictures, which makes it really easy to indentify components. I highly recommend this book for people wanting to fiddle with electronics on their car. Lots of detail and covers important base subjects ie, using a multimeter, how to solder correctly, correct order for soldering components etc.

Thanks for your help anyway, much appreciated!

Post Wed Aug 29, 2007 9:29 am

No worried mate - please let us know how you get on. Even with the EGO project to tune it that Jaycar kit is a cheap way to MAF your car.

Where abouts are you based by the way?

Post Sat Sep 01, 2007 6:44 am

I'm based in Adelaide Australia, which is a real pain $'s wise when it comes to parts etc. I did some testing of the completed unit and it wasn't pretty so I've gotta go back over everything. Its a cheap way as long as you can successfully build the kit... Which at the moment is not so easy hehe

Post Sat Sep 01, 2007 11:21 am

cool - please keep us posted about this!

I don't think you specifically need the 750 maf either. Any 5v maf that fits the pipework should be mapable.

Post Sat Sep 01, 2007 2:12 pm

i have a 750 maf for sale if it helps anyone.