Hey guys, I'm finishing up a ZF-6 swap in my 2003 F-350. Everything is in and hooked up. I started it and drove it for the first time last night. It runs and drives, but there's a problem. The tach is not working.
So, when I got all the parts for the swap, it came with a PCM (ZDR3), from a 99 according to my research. I've read that the 99-01 get their tach signal from the CPS, but the 02-03 get it from somewhere else? Can anyone confirm or deny this? If this is true, I've read that there is a wire under the dash that is often used for remote start systems the gives a "clean tach signal". If I can figure out which wire going into the instrument cluster controls the tach, can I simply splice the CTS wire up into the wire feeding tach signal to the instrument cluster? The check gage light is on, but I'm guessing it's related to the tach issue. The CEL is on too. I need to get a code reader to check the code. Any suggestions on code readers? I'm hoping the CEL is related to the tach issue as well.

Thanks in advance for any help

 

I don't know if this also applies to our trucks but some vehicles get their signal from the Alternator.

 

Look up Tugly, he has a comprehensive thread for different code reader options, in his signature, some great info in there

 

The CMP sensor supplies the RPM signal on all 7.3 PSDs.

 

Have you checked all wiring to the PCM? Something that may have been pinched or otherwise during the swap? My first place to check would be the work I had done before it became inoperative.



The CPM generates a Hall-Effect Signal (on/off) as it passes by a window cut into Cam Plate. The Tachometer is controlled by the instrument cluster. The cluster receives electronic information, via SCP communications ( similar to aCAN BUS), from the PCM for the RPM of the engine. The electronic signal is a buffered representation of the Camshaft Position Sensor (CMP) signal.



To get a signal, there must be a buffer to receive the CMP Signal and pass it through as a constant signal which increases and decreases respectively.

On the 01 and later, the Cluster has the buffer soldered into the circuitry. As well, the PCM generates the signal as "raw" to the cluster.


A diagram is attached. If all else fails, which you will probably find the open circuit going back, after market Tachometers are available to convert Hall-Effect to continuous low voltage current.

 

I think this is the reason:

You may find you need a PCM from a 2002-2003 truck for the instrument cluster to work properly.

 

I think you hit the proverbial nail on the head

 

Sounds like you guys are right. I have a 6 position TS chip from swamps. I talked to Dave at swamps today and he said I need an 02-03 PCM or else the speedo and tach won't work and the charging system may not work either. Thanks for the responses.