TPS Issues- What am I doing wrong

[Nikon Man]

OT948018
Brand new Merc TPS, digital volt meter, Merc TPS Harness, 2 Tan/Blk wires disconnected port side

Set TPS to .281V DC with harness connected locked TPS in place, verified still had a 2.75V reading slowly open throttle by hand to establish max voltage @ WOT, reading max's out at 3.46V @ about 70-80% full throttle then meter goes to OL (signal loss).

I probed the wires from the ECU looking for power,
Orange wire is 8.02V
Blue wire is 4.30V

[JOE54]

2 dc volt for seting /20 dcvolts for checking wot move slowly too wot

[Nikon Man]

2 dc volt for seting /20 dcvolts for checking wot move slowly too wot

My meter is an "AUTO RANGE" so no 2V option. I think I figured it out, on auto range need to set TPS to .280mv, feel'n kinda stupid right now.

Think I'll quit for a while and "MOW THE GRASS".....

[JOE54]

HEEEEEEEHHHEEEEEEEEE

[kls2020]

A reliable way to double check the TPS to verify proper operation beforehand is to check unplugged from the harness with the meter set to K Ohms
The full winding resistance of the TPS is 10 K Ohms . At idle the wiper will be at the Zero end of the Potentiometer so you should read a very low resistance . As you slowly increase the throttle the resistance should gradually smoothly increase to WOT without jumps or opens . Just a tip to double check yourself for "Cockpit error " before proceeding down a rabbit hole .

[Nikon Man]

A reliable way to double check the TPS to verify proper operation beforehand is to check unplugged from the harness with the meter set to K Ohms
The full winding resistance of the TPS is 10 K Ohms . At idle the wiper will be at the Zero end of the Potentiometer so you should read a very low resistance . As you slowly increase the throttle the resistance should gradually smoothly increase to WOT without jumps or opens . Just a tip to double check yourself for "Cockpit error " before proceeding down a rabbit hole .

Great idea, thanks. Would you happen to know what the color per wire (3 wires) does what on the TPS:
Orange-
Lt Blue-
Tan-

(Power/Signal/Ground)

[kls2020]

Tan = zero end

Lt Blue = wiper

Orange = 100% end

Tan - Orange = read 10 K ohms

Lt Blue - Tan = 0-10 K Ohms +/- throttle position to ECU

I should clarify you will not actually see 0 thru 10K OHMs when TPS is installed on motor as there is going to be overshoot at each end of travel when properly set . Testing with the TPS in your hand you will see 0-10K OHm with a good pot . It is spring loaded and loads the spring as you move wiper towards the 100% end of travel . Do not let go of the shaft and let it snap back to zero or damage can occur .

[Nikon Man]

Tan = zero end

Lt Blue = wiper

Orange = 100% end

Tan - Orange = read 10 K ohms

Lt Blue - Tan = 0-10 K Ohms +/- throttle position to ECU

Thank you

[kls2020]

Sorry Gary just saw the other part of your question .


Tan = ground , Orange = Power , and Lt Blue = signal

[Nikon Man]

Sorry Gary just saw the other part of your question .


Tan = ground , Orange = Power , and Lt Blue = signal

Thanks again, appreciate it very much...

[kls2020]

Hey Gary got my test notes out and here is what I read with the TPS installed on the motor and the head temp sensor unplugged .
At idle position I read 675 ohms and at WOT I read 1.473 K ohms ( this was after a "Key ON " calibration voltage reading of .250 v @ idle and 7.46 v @ WOT )

[Nikon Man]

Hey Gary got my test notes out and here is what I read with the TPS installed on the motor and the head temp sensor unplugged .
At idle position I read 675 ohms and at WOT I read 1.473 K ohms ( this was after a "Key ON " calibration voltage reading of .250 v @ idle and 7.46 v @ WOT )

Thank you for that info. I'll test mine again Monday and compare values.........

[SilverFox579]

A reliable way to double check the TPS to verify proper operation beforehand is to check unplugged from the harness with the meter set to K Ohms
The full winding resistance of the TPS is 10 K Ohms. At idle the wiper will be at the Zero end of the Potentiometer so you should read a very low resistance. As you slowly increase the throttle the resistance should gradually smoothly increase to WOT without jumps or opens. Just a tip to double check yourself for "Cockpit error " before proceeding down a rabbit hole.

This is one case where, IMHO, an analog meter excels and my vintage Simpson 260AF is awesome.

[Nikon Man]

Joe,

Per your request...........lawn is done.

[JOE54]

man that looks good

[Nikon Man]

man that looks good

Thanks Joe........ Neighbors have ask me before if I dye my lawn green since it's greener than anybody else's lawn, I said nope, just fertilize'n the crap out of it....

My issue story continues:
Side note, since I've replaced every electrical component thus far and tested each and everyone of them (ON MY FRESH BUILD MOTOR) with CDI parts, STATOR, TRIGGER, 2 REG'S, MERC TPS, EFI PUMP, PRESSURE REG, the only thing left is the ECU itself. New Fiber Reeds as well, lapped cages too.

BACKUP PLAN:
I have a known to be good 175 HP ECM coming (just in case it comes down to that after getting the boat wet again tomorrow (Tuesday), first outing after the new TPS install. So hang in there with me on my "ISSUE JOURNEY" to see how it pans out.......

[JOE54]

im in for the win

[Nikon Man]

And so it continues..................


Took the boat out again yesterday after installing the "NEW" TPS and........still, another fail.

I'm very upset right now because I'm either missing something rather obvious or I'm a total dummy !

It really can't be this hard can it ?????

Pulled the plugs after getting home, #1 was rich compared to 2-6 which were pretty clean, same as the last outing w#1 being rich.
Took a compression check (just to be sure), All 6 holes 137-139 .

Still waiting on the loaner ECU to arrive (today) as the last resort before I have to hand it over to a shop for repairs................
Don't have many good shops that have a good reputation around here.......

[JOE54]

dont do it , i m still concerned about mid section i know it looks cool but may not work on that set up , question is exhaust blocked off from going out prop completely ????

[Nikon Man]

dont do it , i m still concerned about mid section i know it looks cool but may not work on that set up , question is exhaust blocked off from going out prop completely ????

Joe, exhaust is still allowed to flow out the lower unit. I even put on a (borrowed) Mirage 21P prop for yesterdays outing, acted no different than when I had the 25P on it, that's what doesn't make any sense to me. It just has no balls at all to get up and go.