MAF elctric connections diagram

THE NEW GUY · #1 10-27-2011, 02:03 PM

Does anybody have the diagram to know what exactly does all the connectin pins in the MAF connector? Where to meassure voltage signal to the ECU and what voltages to expect?
thanks

Tapani · #2 10-28-2011, 09:23 AM

Pins are numbered 1 to 5 starting from the right, looking at the connector from the harness side.

+12V supply, red wire, pin 1
ground (shield), black wire, pin 2
ground, black/red wire, pin 3
MAF signal 0-5V, white wire, pin 4
not used, pin 5

Tapani

PS If you get the ECUtuner or something similar you can look at a lot of stuff with your laptop, including the MAF voltage.

THE NEW GUY · #3 10-28-2011, 01:22 PM

Quote:

Originally Posted by Tapani

Pins are numbered 1 to 5 starting from the right, looking at the connector from the harness side.

+12V supply, red wire, pin 1
ground (shield), black wire, pin 2
ground, black/red wire, pin 3
MAF signal 0-5V, white wire, pin 4
not used, pin 5

Tapani

PS If you get the ECUtuner or something similar you can look at a lot of stuff with your laptop, including the MAF voltage.

Man, that is exactly what I need: what is Ecotuner? is it a software? will I need a connector? Where to get it? thanks for your help man. Tell me one thing: The ECU varies the injection duty cycle accordingly with the MAF output voltage or mainly acoording to the throtle position or vacuum? I know all of them applies, but there's a prioryti...

Tapani · #4 10-29-2011, 12:16 AM

Oh,

Start by browsing all threads in the mod area, ecutune projects - lots of other info available too - do a search.

Lot's of more stuff:

www.ecutune.com (also the ECUtuner is available from Micheal)

and

http://www.alcyone.org.uk/ssm/index.html

to begin with :-).

There are plenty of more educated people on this forum than me, but the fuelling maps are three dimensional - rpm, load, AFR, and load is a function of MAF voltage. Most everyday driving is done in closed loop mode though, and thus AFR is controlled according to the O2 sensors.

Fuelling wise engine vacuum is only used to adjust the fuel pressure - and that is a simple mechanical FPR at the rear end of the RH side fuel rail. TPS signal is used for a number of corrections, but it is not the main parameter.

For a set of factory manuals pls refer to:

http://phantomotaku.com/SVX/

and chapter 11 fuel injection for a system description.

With the ECUtuner you are also able to monitor the ignition advance in real time - but take friend with you to play with the lap top or let her drive..... :-)

Enjoy,

Tapani

THE NEW GUY · #5 10-31-2011, 08:20 AM

My friend: please let me know if our MAF have a temperature sensor to inform the ecu about the air temp that is comming into combustion chamber.

Tapani · #6 10-31-2011, 09:00 AM

No, there's no air temperature sensor as such. Only speed - density systems need one to figure out the mass flow: Atmospheric pressure, manifold pressure and intake air temperature data are used to "look up" the air mass value from programmed engine volumetric efficiency tables. Both systems have their pros and cons - a Saab Trionic 7 has both (and lots of other interesting features)... :-)

Tapani

THE NEW GUY · #7 10-31-2011, 09:56 AM

ok, I see...
In my experience, the hesitation on the SVX below the 2500rpm appears or gets noticeable at low ambient temp. I don't feel it on summer. There's no temp info getting in to the ECU, but may be the great amount of oxigen particles on the air getting into the combustion chamber loans the mixture and make the engine loss power without being noticed by the ECU... any ideas?

Tapani · #8 10-31-2011, 10:10 AM

Get the ECUtuner, makes life a lot easier if you can see what's going on. Takes out the guess work and will save you money - no need to replace components in trial and error.....

If not, then start by checking all vacuum related fittings and tubing, as suggested.

Tapani

THE NEW GUY · #9 10-31-2011, 02:33 PM

Quote:

Originally Posted by Tapani

Get the ECUtuner, makes life a lot easier if you can see what's going on. Takes out the guess work and will save you money - no need to replace components in trial and error.....

If not, then start by checking all vacuum related fittings and tubing, as suggested.

Tapani

I'm afraid of damaging the ECU... besides, winter is here and I do not have a garage... Will have to wait untill next spring and save some money for the ECOTUNER chip

92snowmachine · #10 10-31-2011, 05:08 PM

a cheap part to check is your coolant temp sensor. there are two, one for the gauge and one for the ecu. make sure you get the right one. i replaced mine because it wasn't running right on cold starts. seemed to fix it.

Tapani · #11 10-31-2011, 10:20 PM

The ECUtuner os not a chip, but an interface and sofware just to monitor what's going on.

http://www.ecutune.com/ECUtuner.htm

This plugs into the yellow (?) diagnostics port behind the drivers side kick panel. With the ECUtuner you are able to see a lot of things in real time - there's also a separate definition file to monitor the TCU.

Works really well.

On the code 14 - have you done everything explained in the manual (before removing the injector from the rail)? I mean checking that the electrics work? The ECU can not see if one injector is plugged, sticking or dirty. It only monitors the electrical signal... maybe the connection or the coil is open (or partly shorted)? You should be able to hear the injector ticking. Remove the electric connector, measure the injector coil resistance. Then check the wiring.... Follow the instructions in the manual.

If one injector is not firing you should be able to see this with a diagnostic tool (like the ECUtuner) by looking at the O2 readings and especially the fuel trim, it's available for both cylinder banks separately and there should be a big difference if correct O2 readings are reached with only two injectors.

If you end up pulling your #1 injector (or all of them), be careful not to damage them if you do not pull the fuel rails too. The old O-rings bite real hard. Especially the drivers side is difficult - the AC low pressure hose is in the way.....

Tapani

Quote:

Originally Posted by THE NEW GUY

I'm afraid of damaging the ECU... besides, winter is here and I do not have a garage... Will have to wait untill next spring and save some money for the ECOTUNER chip

THE NEW GUY · #12 11-01-2011, 07:36 AM

Ok... I can see I'll need more time for this issue and research... I promised my wife and kid not to fall in love with other car anymore... but I can't help it!
This car is amazing! I'll get the ecotune asap.
I'll follow the manual. But before... I'll change both of my O2 sensors... is there a way to wash or clean it?
Dont you think I would notice when one injector does not work? Sometimes I feel like one cyl stop working but I press the gas and problem solved... Do you think this is the injector stopping injection? Buy why does the ECU remember the code 14 even after clearing the mem? this means the failure 14 is still present... ideas?

Tapani · #13 11-01-2011, 07:50 AM

Do not replace anything that's not broken, including the O2 sensors. Research and learn, then diagnose and fix only what's really wrong.

You will notice if one injector is stuck or otherwise broken, but the ECU code 14 is only related to an electrical fault in the electrics of the injector #1. The ECU only monitors the electric circuit.

So, it is either a wiring harness fault, a connector fault (at either end of the harness), an internal ECU fault or an open injector solenoid. All these can be checked without removing the injector from the fuel rail. Have you checked that the ECU connectors are fully pressed in?

Tapani

THE NEW GUY · #14 11-02-2011, 06:41 AM

Yes, I checked all the connectors and resistances... all OK.
I already had the two new O2 sensor so I decided to change it: 30% of the problem was solved but still not the same car.... May be you was right and I should not change it, but I had to start somewhere. Decided to swap the MAF with the one on my outback: problem solved completelly. At lunch time will clear mem on the ecu and look for new stored codes. I'll let you know.