2007 mercruiser 5.0 alpha TKS system

[Searaytally]

Is the TKS temp sensor open or closed when cold?

 

[alldodge]

Welcome
It's open when cold

After motor warms up it closes to keep voltage on the TKS module to keep it from adding more fuel

 

[Searaytally]

Welcome
It's open when cold

After motor warms up it closes to keep voltage on the TKS module to keep it from adding more fuel

I am having issues with TKS system. The motor will not run with both the diode and temp sensor connected. if I have on or the other disconnected the motor will run at high idle. The sensor does not close at operating temp. If I have the motor running with the diode disconnected. I gave 13.5 volts on both side of the diode. If I plug I the diode the motor dies. Any thoughts?

 

[Fun Times]

Most likely, the diode has failed.

TROUBLESHOOTING THE TKS DIODE | Service Bulletin | Crowley Marine

31-JUL-2006 - Manufacturer Service Bulletin: TROUBLESHOOTING THE TKS DIODE

www.crowleymarine.com

 

[alldodge]

block diagram

 

[Searaytally]

What purpose does the diode serve?

 

[alldodge]

What purpose does the diode serve?

Diodes flow current in only one direction. So key ON current starts flowing to TKS module.

Motor warms up and temp switch closes also sending current to switch.

Key off temp switch current continues and diode keeps it from Flowing back to motor. If diode shorts then motor can't be shut off