2005 Nitro NX 882
2002 Mercury 175 EFI
That may very well be where the problem is. Absolutely necessary.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Motor: 2002 Mercury 175 EFI 2.5L
Serial #: 0T566138
Took me some time but I did perform a link and sync per the manual and I checked the fuel pressure with a gauge (these were done in my driveway last night, so I haven't had a chance to run engine in the water yet). One thing I noticed is that there is small puddle of fuel mixture at the bottom of the air handler, I looked inside with a flashlight while the fuel pump was running and did NOT see leaking fuel. I posted earlier in this thread that the injectors were sent off for service and reinstalled by Roy Roach (a member on this forum) and after I had the work done I don't remember having a warm start/ rich condition problem, I believe it slowly developed over time. In the past month I have rebuilt the pulse pump and checked all and replaced one temp sensor, however I am unable to check the MAP sensor. I did notice that occasionally the motor will want to bog when full throttle is applied to get on plane, I simply put it in neutral and throttle up again and it does fine, this may happen 5-10% of the time. Any ideas where to go from here?
Fuel Pressure results:
Idle 45 psi
Acceleration ~41 psi
Shutdown 41 psi
15 sec 40 psi
30 and 60 sec ~39 psi
Could I have worn reeds?
2005 Nitro NX 882
2002 Mercury 175 EFI
Possible... but reeds are seldom "intermittent" in nature.
Need to check for VACUUM on the pressure regulator nipple (at idle)... suspect there is no vacuum present (hose disconnected or damaged, fitting at other end blocked/plugged, etc).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Ok, I will look in the manual on how to do this. On a side note after the link and synch the warm start did get better, I can now start the motor 50% of the time when warm with one key turn. The rest of the time it takes mostly 2 sometimes 3 turns to fire up...used to be 3-5 turns of the key to start.
2005 Nitro NX 882
2002 Mercury 175 EFI
The Throttle position sensor (TPI) and temperature sensor located in the port side head make up a circuit providing feedback to the Injector ECU to enrich the fuel flow when the engine is cold . When once the engine is warmed up the temperature sensor resistance changes telling the
ECU to lean out the fuel delivery at low throttle settings . My TPI setting is .250 volts with the temp sensor disconnected and throttle closed per the manual.
The manual says to set TPI from .240 -.260 volts but from what I have read others say .200-.300 volts may be required to get better start when warm .
The TPI adjustment only affects starting and low RPM operation and if I'm remembering this right the higher the TPI voltage setting the richer the fuel delivery a start/idle . I see now you have 2002 EFI . I think I saw the newer EFIs do something different for cold temp enrichment ?
Last edited by kls2020; 11-02-2017 at 06:43 AM. Reason: more info added
According to the manual the TPS (throttle position sensor) is non-adjustable. At Idle the TPS should be .19-1.0 VDC and full throttle 3.45-4.63 VDC
From manual....
If the throttle position sensor is out of the intended operating range when the engine is
started, the Electronic Control Module (ECM) will sense that the Throttle Position Sensor
(TPS) has failed. The warning horn will sound, check engine light will illuminate, DDT will
indicate failed TPS and the engine will go into RPM reduction. When the engine is started,
the throttle arm on the engine must be against the throttle stop screw. Do not move throttle
or fast idle control lever forward.
2005 Nitro NX 882
2002 Mercury 175 EFI
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
2005 Nitro NX 882
2002 Mercury 175 EFI
Were you able to sort out your issue? Mine is doing the same thing.
Battery voltage during cranking will be about 10 volts depending where you check it, the higher the better, under 10 and things start to get tricky at 9.5 you have a real problem, follow the advice on posts,7,10,13,15,19 first esp. 15
It is impossible to have 13 cranking volts with a fully charged battery that has 12.85 volts for AGM batteries with a 150 plus amp starter draw
Thank You Leon Pugh
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor