RomRaider

I had to do something a bit funky to get the M62TU MAF to work correctly.

http://www.romraider.com/forum/viewtopic.php?f=58&t=15232&start=120

Read pages 9 through 12.

When Pazi originally tested this MAF he ended up connecting the MS41 MAF harness black wire to M62TU MAF pin 1 which is the built-in IAT.
Although it seems to work, it completely throws off your fueling as the temps under the hood start to rise.
The resistance on pin1 obviously fluctuates and throws everything off when the temp changes.

So I had to figure out a way with a FIXED resistance to make it work.

I read that this MAF should give you 1vdc when the keys are in the ignition without the engine running.
For me, a resistor of 1.25k ohms between ground and the MS41 MAF harness black wire did the trick.
* Do not connect the black and brown MAF harness wires together.
I then scaled Pazi's scaler accordingly.

So for me, I'm using the following pinout.

MAF Pin1 = (Not connected)
MAF Pin2 = +12v (Red) in MS41 MAF wiring
MAF Pin3 = Ground wire (Brown) in MS41 MAF wiring
MAF Pin4 = +5v (from TPS)
MAF Pin5 = MAF signal wire (Yellow) in MS41 MAF wiring.
MS41 MAF Harness Black wire = Pulled down to ground via a 1.25k ohms resistor.

I'm now running this M62TU MAF on my M52B28 / Eaton M90 supercharger setup and getting a tad over 1000 kg/hr at 9psi.

I'm very happy with it.

Hope this helps!

Yeah and in my case I already had a lower voltage so I didn't need to use a resistor.
Only thing to be aware about that maf is that it is too big for 2.5L engine and the idle tuning may be different.

@318Ti @dx4picco

Thanks guys, I will proceed with above pinout and measure the voltage output with ignition on to see if a resistor is needed or not. I can have a (used) genuine Bosch one for only like 30 euros, so will give it a try and feedback my results.

I am running a M52B28 with stock M52 intake, so it should be good for idling as wel I guess?

It worked fine for me before installing my supercharger, however my idle was raised to 850rpm.
Never tried it at ~700rpm.

Thanks for sharing. Am also already running 850rpm idle which made it more stable with my upgraded 440cc Bosch EV1 injectors.

Next step will be the M62TU MAF upgrade probably next week. If this runs all fine N/A, I will start installing my HX35 turbo.

Hope anyone can help me out here. Am trying to modify my software for the M62TU MAF.

Copying the M62TU scaling from Pazi88 into RR isn't possible since it then passes 1024 kg/h.

So from my understanding, is it correct to first activate 2048 kg/h method and then divide all values from your scaling by 2?

Am I then reading correct MAF values (or halved values)?

Found some time to start installing the M62TU MAF. With everything just installed for only testing. I measure 1.148 Volt with only ignition on and like 1.55 Volt on idle (MAF scaling not modified yet).

Looks like a bit on the high side. Is a resistor as @318Ti is using needed for sure or will this work without?

Simply scale Pazi’s scaler so that you get 17 kg/hr at warm idle.
It should be fine as that’s the value that he had at warm idle, but his voltage was more than likely different than yours.

Once that’s done, and your trims look decent, go for a drive and compare your load with known good logs that you have with your previous MAF.
It should be very close.

Simply multiple or divide the entire scaler by a set value if you want to change the scaler.
This way, the curve will remain the same.

Hope this helps!

That unfortunately won't work.

Since I am measuring like 1.6 Volt and ±40kg/hr at idle which is equal to Pazi's scaling. Multiplying the whole scaling by 0.425 will then end up in a maximum airflow value as the stock MAF...

Also, I did added a resistor between the black ground wire from the MS41 harness (MAF) and chassis ground so I measure 1.0 Volt between the yellow MAF signal wire and black ground. However, still measuring then 1.14Volt between brown ground and yellow signal wire as well as in RR logger.

Could you make a picture / scheme of how you connected this resistor?

Ok... Just make sure you have 1.00vdc in RR logger when keys in the ignition engine NOT running... You should have the same value between yellow and chassis ground.

Then, scale Pazi’s scaler to give you 17kg/hr at warm idle...
That’s exactly what I did and it works flawlessly.
Sorry, not gonna take a picture, my MAF harness is sealed with shrink tube now.
You have the exact connections that I used a few posts up.

I had read on another forum that this MAF should give you 1.00vdc when ignition on engine off +/- 0.01v or something like that ... can’t remember.
That’s why I used a resistor to bring the voltage down on MS41.

Hope this helps.

A bit more info to help you out...

At first, I used a potentiometer between the black wire in the MS41 MAF harness and chassis ground as I didn’t know which resistance would give me 1.00vdc.
After playing around with different values, it ended up being 1.25kohms for me.

However, it might not be the same value for you as no single MAF is exactly the same as another.

Thanks for your info @318Ti.

SHORT UPDATE: I already started adding a potentiometer yesterday, but did adjusted it when the car was on idle to achieve 17 kg/hr. For this 4.91 kOhm was needed and the fuel trims were decent. However, giving some throttle stand still it seems to become too lean (+25%)

Tonight I will retry to first achieve 1.0vcd with only ignition on (which yesterday didn't worked out) and then scale Pazi's scaling accordingly to have the right air flow at idle.

By the way, why does substracting a constsnt value from the whole scaling doesn't work? I am worried I have to multiply by a quite low value whereafter the whole benefit of adding bigger MAF is gone.

However, will see this evening. Thanks again for your info and will share my new results later.

Because it will mess up the polynomial curve of the sensor.

Another thing you could do is leave Pazi’s scaler as is and adjust the resistance via the POT until you get 17 kg/hr on warm idle.

Warning.... Be very careful if you do this with the engine running and make sure you have integrators running and set to 50 / -50.

Good luck!

Whichever way you decide to go, you will need to retune your fuel and ignition.

This I received yesterday already with the POT at idle. With a lambda integrator trim within +/- 5%. Giving it throttle already make it quite lean. Will go for a drive tonight to see how the fueling is.



Ok if that's the case I will probably proceed with above method and start retuning fueling.