dt 150 throttle position sensor

[ORKA 600]

posted a thread couple of weeks ago,dt 150 efi 1998.
I was getting a beeping alarm code 2,4,6.purchased a monitor gauge and tacho gauge and found check engine fault code 2-1.which relates to the throttle position sensor.
when ignition turned on but not running alarm sounds,however if push throttle into gear and full throttle alarm stops.so I concluded that the sensor was faulty!
purchased a new sensor and a 12pin test lead to set up sensor.here`s the worst part ,new sensor exactly the same alarm.found that there is no voltage reading coming into sensor at 3 pin plug.
read manual which says that voltage comes from ignition control unit,but does anyone know which wires the voltage actually comes from.i am hoping its a bad connection somewhere but not sure where to start to look.
please help!have no money left to buy more parts and wife getting wise to my spending on boat.

[Solarman]

Sorry my motors have the ecm, not the ignition control unit.
Doesn't your manual show a wiring schematic, with the wires to the tps? unplug the tps, turn switch to on (first click) position set volt meter on 20 volt DC, black test lead to ground, and check each lead coming from control module to tps plug. Do this before adding wire you got with new tps. That should tell you which wire is sending the voltage. Not sure what voltage should go to tps? If not look at wiring schematic for the tps, it should show which wire is ground? I think it does. How many wires go to your tps? Ok, 3 pin plug, 3 wires.
Might be able to tell by setting on ohms scale, touching black lead to tps case (unplugged), and touching each pin in tps plug, full continuity should show ground leg? Unless all three wires are sending signals at different open positions, and the case ground is common to all wires?

Good luck, post back if you find anything.

[ORKA 600]

Throttle position sensor fault

hi,solarman this is the latest on throttle position sensor fault.mine also has ecm no ignition cu.
rechecked the voltage coming into sensor,have voltage coming in at 5.04 volts dc.read manual spec chart and 5.04 volt on v1 means v2 should be 0.605 volts.so adjusted sensor to give reading of 0.6 volt .also checked third green/red wire v3 to make sure voltage exact same as v2 and it was.but fault still there.i turned the tps unit to the very lowest v2 voltage I could and fault clears.voltage has to be below 0.5 for no fault.so I set the throttle closed at 0.2 volt which lets me throttle to 4000rpm before volts get high enough to set off alarm.problem now is engine stalling when I try to put in gear.
the local Suzuki main dealer does not even want to look at engine saying he knows nothing about engines that old.so im on my own here.any ideas would be appreciated as im at a loss to find cure.

[ORKA 600]

Dt throttle sensor

ok,after a while messing with positions of sensor two things happening.if voltage set to correct spec alarm sounding but engine revving fine and going into gear well.if set at lower voltage alarm disappears but engine runs poor and dies in gear.so I said to myself the spec voltage cant be wrong so set at spec and took boat out for spin,thinking it would probably go into failsafe due to alarm.IT DIDNT!engine ran perfect getting up to 4500 rpm no problem and sliding in and out of gear nicely.alarm is still beeping tps fault though.
at least I can get out fishing now but alarm driving me nuts.
is it a gremlin in ecu or wiring I just don't know.???

[Solarman]

Ok. Just for posterity. Check plugs on side of motor from wire harness for any corrosion our connection problem, and clean any battery connections. Then I might check/ clean connections at the monitor gauge, and tach (they work together in diagnostics).

Small voltage interference going into ecm, may effect output going to tps? I have seen stranger things occur. likewise, it is occurring with switch on, motor not running, which indicates it is related to power up from battery side of the voltage picture. So i'm thinking a dirty connector between ecm, battery, and gauges may be distorting the voltage signal just enough to prevent the code from clearing, resetting, or reading the actual voltage from the tps (which should do the same, clear or reset).

it is odd, but at small voltage levels, simple interferences do happen.

Yes, dealers don't mess with these 2 strokes, they're interested in the big dollars with the fours.

If you do find a connector problem, it may be necessary to reset tps reading again? Just a possibility?

Good luck, let us know if you find anything.

[BillCon]

If, you have the TPS that is inline with the oil flow sensor, would it be worth a try to unplug it, and test and set only the TPS while running, its possible that it maybe steeling voltage off the line causing a reason to set it incorrectly or even the triggering the alarm?

[ORKA 600]

Tps fault

Hi,billcon.just read your post about oil flow sensor.when the engine first started giving trouble I checked wiring first off.maybe coincidence but the oil flow sensor had one leg of wiring detatched.i plugged back in thinking this was problem.maybe previous owner knew something else.
went out with boat yesterday still running with tps alarm sounding,noticed engine vibrating and shaking boat at low rpm.also only went for short distances as sea fairly rough but engine drinking fuel extremely heavily.
got rid of mercury black max v6 last season and went for Suzuki efi to try and ease up on fuel cost.
the throttle manifold opening seemed wet around butterfly with oily residue,and spark plugs seem slightly oily too.
is this all down to tps and ecu messing with fuel mixture?
please tell me this engine isn't as thirsty as a black max

[ORKA 600]

tps fault alarm.still not cured.

tried unplugging oil flow sensor ,gear sensor and oil level sensor all have no effect on voltage.have cleaned all contacts still same readings.alarm will not clear unless tps reading below 0.5v or above 1.8v.really don't know where to go next.should I buy a new wiring harness or start looking for ecu?
I read a post somewhere that there is a procedure that can reset fault on control module by grounding out a wire before disconnecting voltage,does anyone know of this?

[Solarman]

Did you clean connections at tach? Look for a rubber plug on back, under plug a switch. Flip it back and forth, but put back in original position. I'm thinking you may be getting some small interference from tach, throwing TVs signal off. Also clean any connections.

I'm not sure what's causing your alarm to trigger, but think it's just a minor feedback between tach, monitor, and ecm connections.

Don't know anything about grounding any wire for reset, have heard people connecting wires wrong and blowing fuses, and smoking wires. If that reset is in the manual, can try. But grounding any wire is wrong if current is still on it. It could cause major damages (costly too). Stop looking for ways to reset ecm, it is not going to help.

It doesn't cost to try the tach. Good luck, post back if find anything.

[ORKA 600]

Dt 150 efi tps fault

hi all,back again with same problem.gave engine to marine mechanic who had engine for 12 weeks and did nothing to solve problem.so back in my yard again.
engine starts and runs although very heavy on fuel,but tps fault still present.
I have test lead (09930-89940)hooked up to ecm.have reading on yellow green stripe and light green black stripe of 5.03volt.
seloc manual states that orange yellow stripe and light green black stripe should read 0.605volt.which it does.but fault still present.there are various other coloured connectors on this lead if anybody has value for what each one should be then I can check also.
I have done the following things to try and find fault-
changed battery cables for new.
disconnected all monitor gauges from engine.
disconnected the power to trim relays.
disconnected the power to coils.
disconnected the remote from engine and linked out pins to power up engine.
removed wiring harness and metered out all cables.
the only thing I did find was on the starter solenoid there was a resistance reading of 5.03 from yellow green wire to gnd.whereas all other gnd wires reading 0.2 or 0.3 ohm.dont know if this is normal or not.
sorry for extremely long post but want to try and get to bottom of this.august now and used boat once.

[ORKA 600]

Dt 150 throttle position sensor update

hi,just an update in case anyone encounters same problem.
engine sending out fault on tps,as you can see in previous posts I replaced everything from tps,harnesses battery cables etc.
my tps was reading the correct value but ecu reading a fault in this value.
the marine mechanic who had my boat for three months said he swapped ecu to test and still same.he was a liar.after I exhausted all other parts I decided there was nothing left but ecu.bought a second hand one from stroud marine(good service).and you guessed it fault gone and engine running like a clock.
the moral of the story is that ecu's are not bulletproof and buy a genuine manual to check all electrical specs.if they are correct ecu bad.
thanks.