4.3l Temp Sensor ?

[tahoejag]

Previously posted had overheating issues, thinking impeller, clogged risers, t-stat, etc...Was running on muffs today and noticed gauge was flucuating i.e....160 to 180 and back and forth then would settle down 160 -170 degree when i would wiggle the BROWN wire (stbd side) to sender. At one time the temp gauge would just quit (drop)...like no power to it but still connected and running. So I am going to start replace sender unit. MY QUESTION - Am i replacing the correct sender (the one with the single brown wire that when disconnected, kills the temp gauge) b/c there are two temp senders (one on each side of t-stat housing). One has a single brown wire to it (pn 806490t stbd side) and the other (pn 805218T port side) with two wires to it...yellow and black. I do not know which sender is exactly for what, being there are two??? Also parts are listed for a dual station sender in place of 806490t...what is that??

2006 4.3l carb
eng ser #ow380643
160 deg t-stat
alpha i gen ii

 

[Don S]

Re: 4.3l Temp Sensor ?

806490T is the gauge sender for your engine, should have a Tan wire going to it.
The one with the yellow and black wires going to it are for the TKS carb. temp.
Dual station is if you have a flybridge or something, and two control stations (aka dual station)

 

[tahoejag]

Re: 4.3l Temp Sensor ?

806490T is the gauge sender for your engine, should have a Tan wire going to it.
The one with the yellow and black wires going to it are for the TKS carb. temp.
Dual station is if you have a flybridge or something, and two control stations (aka dual station)

Don S...thanks for the feedback. I gotcha on the dual station thing. I am still am confused about the senders in question though. The one single wire to sender stbd side is dark brown and not tan (but not a biggie, for that is the wire that controls the gauge when disconnected/connected). I have seen on mercruiserparts.com that there is another sender that is located right behind the t-stat housing directly in the intake manifold on stbd side that is listed as such (# 87-866089 THERMAL SWITCH, (Normally Open 130-110 degrees), Turn Key Start). Is there TWO senders for the TKS carb..one from t-stat housing and intake manifold?? thanks in advance for all the input!

 

[Don S]

Re: 4.3l Temp Sensor ?

Yes, there are two, one has a yellow wire and a black wire, the other has an orange wire and a white wire. And yes they work with the TKS system, and no, I am not going to explain how they work together and what each does.

 

[tahoejag]

Re: 4.3l Temp Sensor ?

Yes, there are two, one has a yellow wire and a black wire, the other has an orange wire and a white wire. And yes they work with the TKS system, and no, I am not going to explain how they work together and what each does.

LOL!.....thats ok. I like to obtain as much knowledge as possible about how things work. I'm just curious what sender/sensor triggers the engine overheat alarm.

 

[Don S]

Re: 4.3l Temp Sensor ?

Here's a link to the manual for the system, http://www.4shared.com/office/GQGy_NeR/41_TKS.html? should help you understand how it all works together.

 

[tahoejag]

Re: 4.3l Temp Sensor ?

Yes, there are two, one has a yellow wire and a black wire, the other has an orange wire and a white wire. And yes they work with the TKS system, and no, I am not going to explain how they work together and what each does.

Don S....I looked at the t-stat housing sensors...stb side is a single tan wire (which is for the temp gauge/sensor). port side on t-stat housing does have a YELLOW wire and BLACK wire connected to a sensor. This is where I am confused... The manual states for the yellow and black wire (#26) should be for the oil pressure switch (why would that be hooked up to a t-stat housing?). As for the Orange wire and the White wire (#19) temperature switch according to the manual (could this orange wire and white wire be the temp alarm switch?). PLEASE help me on this....

 

[Don S]

Re: 4.3l Temp Sensor ?

I would say the manual has them labeled wrong. I just can't see a temp switch controlling the fuel pump. The switch with the orange and white wires controls the fuel pump, and that isn't done by a temp switch, it's done with an oil pressure switch.

 

[tahoejag]

Re: 4.3l Temp Sensor ?

Im gonna go have a look and c what exactly is where and hooked up to what. Will keep ya posted what I found.
Thanks....
John

 

[tahoejag]

Re: 4.3l Temp Sensor ?

I would say the manual has them labeled wrong. I just can't see a temp switch controlling the fuel pump. The switch with the orange and white wires controls the fuel pump, and that isn't done by a temp switch, it's done with an oil pressure switch.

My findings.....the only discrepancy that coincided with the manual was the yellow wire and black wire that is connected to the port side sensor on the t-stat housing (pic #2). While the Orange wire and white wire are connected to a sensor on stb side top of intake manifold - right behind t-stat housing (pic #1).

The 3rd attch. shows a black wire (possibly the engine ground?) was just hanging there (not hooked to anything). Where would I attach this wire to??? Is it necessary??? I believe that it was like this since day one.

*note* I hope these attachment pics showed up....never posted attachments or pics b fore. :/

 

[achris]

Re: 4.3l Temp Sensor ?

The 3rd attch. shows a black wire (possibly the engine ground?) was just hanging there (not hooked to anything). Where would I attach this wire to??? Is it necessary??? I believe that it was like this since day one.

Plenty of spare ground wires in the harness. Mine's got the same.... I think they have a 'one harness fits all' and just use the appropriate wires for the engine configuration, and leave the rest unattached.

Chris......

 

[Don S]

Re: 4.3l Temp Sensor ?

The switch with the yellow and black wires even the one with the orange an white wires has nothing to do with your gauge fluctuation. The sender with the tan wire does.

 

[tahoejag]

Re: 4.3l Temp Sensor ?

As further looking into this...just is not making sense. After reading TKS suppl of wiring diagram and colors of wire and where they go. they do not list for a 4.3l carb TKS the wiring for the audio alarm. They have some color codes that do not match up to what I have. I finally figured the TKS temp and oil sensors. I still am trying to locate the water temp sensor/switch that triggers the audio alarm in a overheat cond. 1) p/n 806490t strb side of t-stat hous (single tan wire) controls temp gauge. 2) p/n 802218t port side of t-stat hous (dual wire..one black/one yel) according to manuals that is ALSO a coolant temp sensor for temp gauge....this is listed for engines that have EFI/MPI's....which I do not. 3) p/n 48952 is a water temp switch for audio warning...which cannot find in any manual for my engine type. Should this be the sensor/switch that is supposed to be in place of the one as seen in the pic? This is a link to show that the one I have is listed for a EFI engine. http://www.marineengine.com/parts/m...s/mercury-mercruiser/mercury-catalog01004.htm

There are wires to the oil sensor and lube reservoir that are tan and blue that trigger the audio alarm. Such wire for the water temp switch for audio warning does not exist. My only recollection is this said yellow and black wire that connect to the t-stat housing is it. I cannot get these wire to trigger the alarm in any way though. I'm just looking to make sure that all my senders/alarms are working and working properly for peace of mind. Engine Ser # OW380*** Thanks in advance for feedback...
John

 

[Fun Times]

Re: 4.3l Temp Sensor ?

I still am trying to locate the water temp sensor/switch that triggers the audio alarm in a overheat cond. 1)

3) p/n 48952 is a water temp switch for audio warning...which cannot find in any manual for my engine type.

The orange wire and white wire are connected to a sensor on stb side top of intake manifold - right behind t-stat housing (pic #1).

You found it! The yelow and black wires you're seeing is now the new style overheat sensor and triggers the alarm through the ignition control module. The manual is incorrect. #26 should read temp sensor not oil pressure switch like #15 does. Also your marineengine link is incorrect. it reads as a coolant temperature sender for (analog) gauge uses, it's actually a sensor used for a digital read for the ICM, ECM, etc.

(pic #1) The intake manifold temperature switch allows positive current to flow to the TKS heater module to prevent the additional fuel flow path from opening during hot re-starts.

(pic #2) Goes to the ignition control module for the overheat sensor.
Mean-Best-Timing (MBT) Spark Advance During light load cruising, the ignition module maintains optimal ignition timing by
making small spark advance adjustments. At a given RPM, the module will add a small amount of advance and wait to see if there
is an RPM change. If RPM increases, it will increase timing more. The module will continue to advance timing until it no longer
gets an increase in RPM. Conversely, if it senses an RPM drop, it will start to retard some of the spark timing. Between 1200‑4000
RPM the ignition module can add approximately 10‑15 degrees of spark advance to the base spark timing curve.
NOTE: The Audio Warning System is also connected into the ignition module circuit. If the audio warning system becomes
activated by the closing of one of the audio warning system switches, the MBT feature is deactivated.

(pic #3) Is normal and goes to nothing.

 

[Don S]

Re: 4.3l Temp Sensor ?

The manual is incorrect. #26 should read temp sensor not oil pressure switch like #15 does.

I mentioned that was probably the case earlier. Do you know if Merc sent out a change to the paper manuals that doesn't show on line? Or is this just one of those things that will never get changed. Much like the labeling of the ignition switch in the manuals. About half the manuals still have the I and the B terminals reversed in the drawings.

 

[Fun Times]

Re: 4.3l Temp Sensor ?

Do you know if Merc sent out a change to the paper manuals that doesn't show on line? Or is this just one of those things that will never get changed. Much like the labeling of the ignition switch in the manuals. About half the manuals still have the I and the B terminals reversed in the drawings.

I don't recall any updated papper material coming in to update manual 41.

Awhile back now merc did mail out a very nice MerCruiser Color Diagram Binder with all the engines so that a tech could take it to the boat and draw/wright/trace with a sharpie type pen, get grease/oil on it and easily clean it off to use next time. I believe the binder is correct now.

Ignition System Wiring Diagram
For 10‑pin and 14‑pin ignition system color wiring diagrams refer to the MerCruiser Color Diagram Binder.

Also i just edited some more info to my above post about the ICM.^^^

 

[tahoejag]

Re: 4.3l Temp Sensor ?

You found it! The yelow and black wires you're seeing is now the new style overheat sensor and triggers the alarm through the ignition control module. The manual is incorrect. #26 should read temp sensor not oil pressure switch like #15 does. Also your marineengine link is incorrect. it reads as a coolant temperature sender for (analog) gauge uses, it's actually a sensor used for a digital read for the ICM, ECM, etc.

(pic #1) The intake manifold temperature switch allows positive current to flow to the TKS heater module to prevent the additional fuel flow path from opening during hot re-starts.

(pic #2) Goes to the ignition control module for the overheat sensor.
Mean-Best-Timing (MBT) Spark Advance During light load cruising, the ignition module maintains optimal ignition timing by
making small spark advance adjustments. At a given RPM, the module will add a small amount of advance and wait to see if there
is an RPM change. If RPM increases, it will increase timing more. The module will continue to advance timing until it no longer
gets an increase in RPM. Conversely, if it senses an RPM drop, it will start to retard some of the spark timing. Between 1200‑4000
RPM the ignition module can add approximately 10‑15 degrees of spark advance to the base spark timing curve.

NOTE: The Audio Warning System is also connected into the ignition module circuit. If the audio warning system becomes
activated by the closing of one of the audio warning system switches, the MBT feature is deactivated.

Very good knowledge!! To bring up another ?, if the warning system is activated and deactivates the MBT feature, does the MBT need to be re-set in anyway or does it re-activate itself when all is well or next time engine is running.

 

[Fun Times]

Re: 4.3l Temp Sensor ?

Very good knowledge!! To bring up another ?, if the warning system is activated and deactivates the MBT feature, does the MBT need to be re-set in anyway or does it re-activate itself when all is well or next time engine is running.

Nothing for you to worry about, It will take care of itself without the need of turning off the engine, etc, that is once the sensor sees the has engine cooled down of course.

 

[tahoejag]

Re: 4.3l Temp Sensor ?

Thanks....appreciate all the feedback and input!!!!

 

[Billy5810]

On the subject of pic#2 with the yellow and black wire... could this fail and cause the ecm not to give spark to the engine after engine is at operating temp (170-180 deg)?