Installing MPGino in 2002 Golf TDI

[dcb]

No prob. If you have an opportunity, would you be willing to try pin 9 on the ecu for the injector lead? A needle/sewing pin and an alligator clip should do nicely for a test.

If not no biggie.

[yetimus]

Originally Posted by dcb

Yup. Do you know if your 96 passat ecu plugs look like that? And if pin 9 is what is connected to the mpguino? (and which one is the vss?)

Sorry for the delayed response. Yes, after checking the Bentley, the consumption signal is located on ECM pin 9 on my '96. The VSS, again according to Bentley, does not go to the ECM. It feeds through the firewall directly to the cluster - which is where I tapped it.

Not sure if my ECM plug is similar to the one you posted. FWIW, the schematic indicates a 68-pin plug on the ECM.

[dremd]

Just got word that the o-scope probes have arrived!
Should be able to use them in a few days.

[rmccomiskie]

Originally Posted by dcb

I would suggest the following setup values for vw/audi(rest at default). Must get through all items to store.

VSS Pulses/Mile=13406
MicroSec/Gallon=0128800000
InjTrg 0-Dn 1-Up=1

FYI, the signal rmccomiskie and yetimus describe sounds like a wire from the ECU that should incroproate all the fuel variables into a basic duty cycle representation of fuel consumption for an onboard mpg gauge, that never gets installed in the states.

I just noticed this thread. VSS=13406 is dead on for my Audi. My speedometer has "K=6703" on the face of the speedo gauge. That's the number of pulses per mile. I doubled that to get 13406 since the MPGuino counts both rising and falling edges of each pulse.

Check the bottom front of your speedo face. See if it has "K=????". It could be hidden by the instrument bezel so poke around.

MicroSec/Gallon is most likely very different for your TDI. In order to get "in the ballpark", here's what I did:

1. From experience I know that I get about 21 MPG at 75 mph on level ground.

2. Calculate GPH: 75 mph/21 mpg = 3.57 GPH.

3. Set uSec/Gal to some number. I suppose 128800000 is as good as any.

4. Go for a drive at 75 MPH on level ground and watch the GPH reading on the MPGuino. If it's greater than 3.57 then increase the uSec/Gal number. If it's less, decrease the number.

The idea is to get close to the correct GPH at a speed where you know the MPG that you should be getting.

[dcb]

FYI, I just poked around my new 2001 tdi golf for a bit (as has dremd on his '02), I do not see any evidence that the ECU is creating a fuel consumption signal in post '99.05 vehicles. Will probably start trying to figure out what the deal is with the quantity adjuster signal(s) and maybe blend that with RPM.

[tasdrouille]

How about tapping the needle lift sensor on injector #3?

[dcb]

Yup, that's a thought too, similiar to the piezo tach sensor that diesel_john mentioned (though I haven't yet sorted out that signal yet).

I would like to know why the modulator (variable quantity adjuster) branches into two leads going into the ecu.

I need to understand more details on the various signals though, hopefully my picscope is up to it. Might as well get probing

I did get the instrument cluster out, was pretty trivial, so vss,batt/ground, and even rpm are easy to get to. But the ECU under that plastic thing was a royal pain, will probably work off the pump connectors and the cluster. Need to route kill switch leads through the firewall anyway (think I will leave the intake diverter valve out of it for now) This thing has a lot going on, that is for sure.

[yetimus]

Originally Posted by dcb

FYI, I just poked around my new 2001 tdi golf for a bit (as has dremd on his '02), I do not see any evidence that the ECU is creating a fuel consumption signal in post '99.05 vehicles. Will probably start trying to figure out what the deal is with the quantity adjuster signal(s) and maybe blend that with RPM.

I don't own an MK4 TDI, but this link leads me to believe that some sort of fuel consumption signal does exist. Of course, the cluster pinout provided in that thread does not indicate a fuel consumption signal, but how else would the cluster retrofit be able to calculate fuel economy?

Actually, I just bought an 99 Audi A4. I'll check out the Bentley and see if it may indicate a fuel consumption signal on the ECU schematic. Mine has factory MFA. I imagine it would be very similar to the VW setup.

[mikeross]

I have seen the link and it makes me think that indeed the fuel consumption signal really exists. But that depends on the car's setup or configuration, right.. turn signal switch and all that?

[dcb]

the signal is not on the dash connector in US cars is my understanding, I couldn't decypher the ecu connector to see if maybe it actually was there.