Tachometer Problems Intermittent

W

WayneP

Member
Aug 20, 2019
32
Boat Info
2003 245 Weekender
Engines
383 MAG MPI
Hello:
Have a 2002 245 Weekender with intermittent tach problems. Seems like intermittent lack of Tach signal from the ECM 555. Needs to warm up 30 minutes for tach to work. My understanding is that the Tach signal comes from Pin 10 on Conn A of the ECM? Also goes to Pin 2 of 10 Pin connector to the dash? Correct? No tach wire on coil etc?
Also, where is the test point connector located? Cannot seem to find it. Is it a bullet or traditionally connector?
Appreciate any and all help.
Wayne
 
scoflaw said:
Traditional and it will have a cap on it.
Click to expand...
Hey thanks. Any clue where it might be located. Found a few? Any and all info appreciated. I assume the wire color will be gray?

Engine: 383 MPI MAG, around 2002 or so.
 
Misunderstood your question. I was talking about where to plug the scanner in. 555 will have a self test for the tach with the scanner hooked up
 
scoflaw said:
Misunderstood your question. I was talking about where to plug the scanner in. 555 will have a self test for the tach with the scanner hooked up
Click to expand...
Dont yet have a scanner. Looking now at the Smart Phone based version from Mercury. Any comments?
Yes, looking for the Tach connection point off of splice 113
 
I found a bullet style connector on the front port of the engine with what looked like a gray wire, BUT, I get no continuity between it and pin A 10 on the ECM, which is the Tach signal port?? Maybe this is the problem but want to be sure I found the right Tach test connector. Somebody must know where it is?????
 
Solution: I found the Tach test point. It is a bullet style connector at the front port side of the engine. Right near the outdrive lube bottle. Also found the problem.
The connection on PIN 2 of the tach signal in the large 10 PIN connector was poor intermittent. Brass pins and slightly corroded. Also expanded the pins for better contact. Now Tach works fine and oil pressure guag4e much more stable. Discovered problem by checking continuity between the test port connector and the TACH gauge in cockpit.
 
CatMan said:
Hello, Just purchased an '03 240 Sundancer. Where is this 10 PIN connector located?
Thanks
Click to expand...
Hello Cat Man:

My engine is a 383 MPI mag and the 10 PIN connector is located on the back Starboard side not far behind the throttle body air input. It is hard to miss. Quite large and mau be pressed into a U holder to hold it in place. Large brass pins/sockets that need cleaning and pins may need spreading. Slot in pins to spread but be careful not to break.
If this doesn't help let me know.
 
Hello Again: Insane great boat. Very solid and well made. Engine access can be a bit tight. For major repairs suggest removing engine cover/seat. I have learned a lot about this boat/engine combo so ask away. The 383 MPI MAG engine is very powerful and drives a Mercury Duo Prop.
 
WayneP said:
Hello Cat Man:

My engine is a 383 MPI mag and the 10 PIN connector is located on the back Starboard side not far behind the throttle body air input. It is hard to miss. Quite large and mau be pressed into a U holder to hold it in place. Large brass pins/sockets that need cleaning and pins may need spreading. Slot in pins to spread but be careful not to break.
If this doesn't help let me know.
Click to expand...
 
One end looks like this. See the split pins?
84812475A20__58268.1525960409.jpg
 
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