How to get rpm Signal on TDI ALH

Im trying to figure out how and where to get rpm signal off of a ALH tdi not hooked up to the original vw transmision if anybody could help that would be great.

rpm or speed signal? you mention the trans but the rpm signal has nothing to do with what trans you're using

I successfully modified the tach signal from the ALH 4cyl signal to a 6cyl Ford Ranger tach with a Dakota Digital SGI-5E speedometer box using the L-L setting and outputting an AC signal.

Nozzleman said:

I successfully modified the tach signal from the ALH 4cyl signal to a 6cyl Ford Ranger tach with a Dakota Digital SGI-5E speedometer box using the L-L setting and outputting an AC signal.

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Wow! So you were able to tweak the DD SGI-5E speedometer box to operate the Tach. Hmm!

Isn't a Dakota Digital interface for the Tach much cheaper? Such as the Dakota Digital Universal Diesel Tach Adapter Alternator Interface Unit DSL-1E

You can make an early 2000s Ranger tachometer 4, 6 or 8 cylinders depending on which ground wire is used.

To make a long story short, in my efforts to get a speedometer signal from this Ranger conversion I ended up buying a Dakota Digital SGI-5E. I am using a Jeep NV3550 with 16 pulse 3 wire sender to go to the Ranger which expects 12 pulse from a 2 wire sender.

I had been trying to get the tach to work unsuccessfully also.

The SGI-5E successfully mated the speedo and I thought "gee I wonder," so I put a two wire sender on the DD box and hooked it to the tach and it worked. hmmm

I called Dakota Digital and they suggested that since I had an unused stator (same as F) terminal (original Ford alternator), I should be able to use the DSL-1E. Apparently the signal is on the wrong side of the rectifier or something and it didn't work.

It was then recommended to run the SGI-8E but it wouldn't read the VW ECM signal. It would output a test signal to the tach.

Thanks to Alchemist and David for letting me know about the ground wires. I have a Ford dealer subscription service manual CD and have gone back and searched it and have yet to find the bit about the grounds for cylinder selection, but I did drop the one I had found that was pinned but not terminated on ground that I hooked up in the effort to get tach to work and now read correct.

And thanks to Summit Racing for letting me exchange the ones that would not work for my application. I kept the second SGI-5E for use on a later project.

Truck is running, driving and inspected. I am still working a few bugs out and need to time the pump before I drive it much. Then take care of some details as time allows.

Your 2002 Ranger's tachometer will work just fine with the ALH's tach output signal. The "C3" plug on the back of your speedometer, position 8 which should be BK/Y, if this is ground it's 6 cylinder tachometer operation and open it is 4 cylinder. That signal is 12V square wave.

To get the speedometer running, you need a three wire VSS and something to calibrate that. It's about 140Hz = 100km/h. This signal is also a 12V square wave. I used my Universal VSS ($60 USD) that reads the bolts on my drive shaft and a Hasenwerk VSS Korrekt ($90 USD) to calibrate the signal. The output of the VSS Korrekt is "strong" enough to drive both the VSS-in on the ECU and the Speedometer, however, the ECU will read about 40% high as it wants 100Hz at 100km/h for it's signal. For cruise control use it's not an issue, if you want 100% accuracy for OBD monitoring, a 2nd Signal signal processor would be needed.