TPS Problem F115AET

[bocashippie]

Hello again from Panama.

I apologize if I came on a bit wordy on original post (see below). I was trying to give as much previous trouble shooting and part changing info I could with the hope someone has run across this problem before. Well, since the last post I have been diligently checking and rechecking wiring both positive + and Negative - grounds. My problem is still the same. I can’t get the TPS Sensor (old one or new one) to adjust within limits when installed on the throttle body. I can however remove the TPS sensor and manually turn it approximately 10 - 15 deg past the maximum adjustment range (Screw Slots) and I can then clear the TPS code. If doesn’t matter if I use the Old or New ECM or the Old or New TPS sensor.

I’m completely stumped Now...If someone could send me to a link where I can confirm whether I am installing the TPS sensor correctly or incorrectly onto the throttle body, or explain why I can’t set the TPS Sensor within the adjustment range (screw slots). Don't be shy, I am open for any guesses, suggestions, on what to test, change, any books, website, pay a mech, etc.

I really do need some help, we are down hard and the boat is our only transportation.

Cheers from Panama

Ken Hamilton


Hey guys,
I need some help! First, I live in the country of Panama and there are No competent shops/mechs here. I am the only one that I know of here that has the YDIS program/cable. Here's the problem in sequence of events.

For several weeks this was the problem.
1. Erratic Idle - 700 - 2000 RPM
2. Sometimes when it started the idle would be correct at 700 - 800 and then sometimes as much as 2000 RPM. Turning the key switch off and then on (restarting) would 98% of the time reset it to the normal 700 RPM. Also, when correctly Idling at 700 RPM, driving the boat and pulling the throttle back to Idle it would sometimes drop to 700 but then again it would be as much as 2000 RPM. With no Check Engine light. As the weeks went on with this problem, I would sometimes have to restart it 2-3 times to get the RPM to drop back to 700. NOTE: At this point There was No Check Engine Light.
3. On at least 3 occasions I hooked up the YDIS and found No Codes. Thinking maybe the interment RPM problem was in the ECM, I ordered a new one $$$$ and just for sport lol, I ordered a TPS and Multi Sensor (MS). I changed the ECM with no change in the erratic idle described above.
4. I then Changed the TPS and Multi Sensor and then test drove it. No Change! Still erratic idle.
5. I reinstalled the original ECU, TPS and MS. I was able to clear both codes after the parts were changed. I test drove it twice within an hour or so, turning the power on and off. So I thought everything was cool. Wrong, the next day I went out to drive the boat to dinner and here we go...... Check Engine light!
6. That's the History - Now here is the BIG PROBLEM...Now Neither the Old or New TPS when installed on the Throttle body will adjust within in the required Range (Verified by the YDIS Active Test) so now of course I can't clear the Codes. However, I can connect the TPS plug (TPS not installed on the Throttle Body) on the old or new TPS and turn the slot with a screw driver and get the required Voltage (verified by YDIS) and clear the codes/Check engine light. When I try and install either TPS on the Throttle Body I can get enough movement within the slot range to get the correct voltage. I have tried this with the old and new parts (ECU, TPS, Air Press Sensor) in different configurations. Unlike before when I was swapping out the TPS, I was having no problem taking one (TPS) off and putting on another on and setting it (clearing codes)

At this point I can't understand why I cannot get the TPS to set on the Throttle
Body but it will set by turning it with a screw driver. Note: The rotation difference between installing the TPS on the Throttle Body and making the adjustment verses using the screw driver (TPS off the Throttle Body) cannot be more then 10 -15 deg. QUESTION, is there a specific way of installing the TPS on the Throttle body.

Well that's all I can think of..
Note: I have worn the Wiring Diagrams out trying to figure this out. I know until the ECU reads the correct voltage coming from the TPS, I can't reset the codes etc.. I am open for any suggestions of what to check next. This boat is my
car...there are no roads where I live...

Thanks in advance.

Ken

[bocashippie]

TPS Proiblem Solved

Problem Solved - After 40 hours plus time spent Testing and Changing parts, I found the problem with the TPS. The optional Water Press Sensor I installed about six months after installing the engine had failed, Note: I never got any Fault Code showing on the YDS for the Water Sensor only the TPS system. I unplugged the Sensor and All is well. If anyone wants futher info please contact me.

Cheers,

Ken:

[boscoe99]

I missed your original post.

Early water pressure sensors and speed sensors were known to fail. Water got onto the electrics side and caused mischief. The sensors have been updated to improved versions.

If Yamaha US was called with a report that a motor was doing some strange things that made no sense at all, the first question asked was "are the optional sensors installed"?

One other point for anyone that reads this later, if a sensor is not providing the correct output value then check the input value. Junk in equals junk out. So, check that the correct input is getting to the sensor. The failed pressure sensor more than likely skewed the input voltage to the TPS sensor.

If I were you I would carefully inspect the wire harness connectors that get connected to the sensors. Also, remove the ECU connector and carefully inspect it. Water can migrate from the sensor over to the sensor connector, up the wire harness and make its way to the ECU. Catch and clean it early and no harm no foul. Fail to catch it and the wire harness and the ECU can be damaged.

[99yam40]

So you bought a TPS for nothing?

No. he bought a spare for good money, not nothing

[boscoe99]

Where can I buy brand new parts for nothing?

[rodbolt17]

and whats funny, the YDS did show it.
it most likely showed a funny baro and or intake air pressure readings.

a quick check of the TPS 5v ref would have nailed it.

I just did an F250txr.
symptom was rough idle, stalling and no power sometimes.

after about 1 1/2 hours of run time the symptoms occurred.
when it stalled the baro reading was 29.6 but the intake air was 15" and drifting around with key on engine off.

that told me I had an issue with the air pressure sensor or sensor circuits.

hooked up the old trusty multi meter to the APS 5V ref and an hour later it failed again.
the 5V ref had dropped from 4.98V to about 3.1V.

quickly unplugged the water pressure sensor and bing, 4.98V again and the motor ran well.

same as the TPS, that 5Vref dropped and the tps output went out of range and the ECM defaulted.

YDS did NOT say the TPS was bad, it said the feed back V was out of range.

however the TPS,like the ECM, garbage in equals garbage out.