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2001 225 merc optimax , injector fault

S

salmonkiller

Member
i kepp getting injector fault on my smartcraft gauge, 2 mechanics have read the ecm and fuel injector 4 5 have faults, even after replacing the injectors. I have swapped all my sensors, tested the wiring with an ohm meter, I am at a loss. The engine run normal, smooth idle, reach full throttle but i hate looking at my gauges just to see injector fault.
Any info would be great
 
...tested the wiring with an ohm meter...
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That will tell you if the wires have open/closed circuit. Test them again on the lowest setting of the DVM to get an idea of what the good injector wires read and compare to #4, 5. The ECM is picking up an injector pulse fail code from the engine. Take voltage readings from the injectors when it is operating w/a good DVM and compare them. Inspect the ECM and cable connection for corrosion.
 
I checked voltage to the injectors, 1,2,3,6 have 13.6v on one wire and .01v on the other, injectors 4 and 5 have 13.6 on one wire and .4 on the other wire. Tests performed on running engine. Where to go from here??
 
...injectors 4 and 5 have 13.6 on one wire and .4 on the other wire.
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Do you have a wiring schematic? The 0.4 vdc makes the wiring suspect. Trace the wires back to wherever they go. Open up the wire looms and look for bare wires rubbing together or a small amount of corrosion. If you trace the wires back to the ECM w/o finding any wire issues then it is suspect. You may need to probe the wiring for voltage readings. I use a sewing needle held with a small vice grip to probe and check voltages. Seal the probe holes w/liquid tape.
 
I also found that my ignition ground has .02v in it. I am going to disconect any shared grounds with the boat to isloate the engine, if that does not takes ground volts to zero, I will start disconecting engine electronics to hopefully find the cause.

I have traced the injector wires back to the ecm plug and all are good, ohmed the same as all other injector wires. Mercury marine does not think it is the ecm.
Make sense?? I hate electrical trouble shooting. But I really appreciate the help.
 
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...ohmed the same as all other injector wires.
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Did you ohm the wires end-to-end w/the wire connectors disconnected on both ends...the injectors and the ECM? Which wires (by color code) had the 0.4 volts. I have a wire schematic for 2000 and up 90-150 HP. The wiring should be the same even if you have >150 HP. The injectors are listed as 1, 2, 3 and 1, 2, 3 and not 1, 2, 3, 4, 5, 6. The 0.4 vdc screams to me "electrical short" from corrosion between two wires or connector pins or on the ECM board where the harnesses connect.
 
I do have the schematics for my 2001, I ohmed from the ecm harness pins to the injector pins, but as you bring up I never ohmed the wires in a criss cross( each injector has two wires i haven't ohmed across them to see for contact) Makes sense will try tomorrow and reply and thanks alot for more input!!!:)
 
i tested the injector wires and there is no continuity between the wires for the injectors( too see if the plugs are shorting out)
So i decided to test the ground on my slave solenoid for the starter( the one below the ecm). Well i found the ground on it had continuity to the other 2 other posts on it.One going to the starter and the small post that must be the trigger power for it!!! Atleast now I have narrowed it down to either the solenoid or something attached to it hopefully!
 
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I was wrong tested good as per manual.
salmonkiller said:
i tested the injector wires and there is no continuity between the wires for the injectors( too see if the plugs are shorting out)
So i decided to test the ground on my slave solenoid for the starter( the one below the ecm). Well i found the ground on it had continuity to the other 2 other posts on it.One going to the starter and the small post that must be the trigger power for it!!! Atleast now I have narrowed it down to either the solenoid or something attached to it hopefully!
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fixed it finally! Not sure what exactly it was but I went thru all my wiring again looking for problems and did not find any. cleaned all the plugs again (ecm,injectors,coils,sensors...) fired it up and no faults. Just going to re-install everything and have my fingers crossed.

Thank for all your inputs and help! Great forum and great people!!!!:)
 
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still have the injector fault, i just changed my wiring harness, cleaned every connection.
So far I have replaced engine wiring harness, swapped every engine sensor, new fuel filters, tested fuel air pressure 92 fuel, 89 air, cleaned battery connections, changed injectors, changed injectors (air and fuel)with engine running to see if the fault goes away(nope). cleaned and tested vst high pressure, low pressure pump and the mechanical pump. Has new fuel lines from tank to racor to engine with new fuel bulb.Tested harness to key switch, tested key switch. New alternator.
Engine runs great.

Is it normal to have some condensation come out of the air shrader valve(definetly not fuel, moisture)
Do the coil drivers have anything to do with the injector driver?? Short to ground in the ecu???
Any additional help would be great.
 
I pulled my fuel injectors to get them cleaned and noticed tiny gold(metal) particals in the fuel rails where the injectors go in, also washed some off the injectors, am I looking at a compressor failure or high pressure pump. Help
 
Well the tiny gold shaving were from pulling fuel lines off my vst tank last week!doooh. And my injector fault was caused by spark plugs, why who know but it was my last ditch effort before handing it over to mercury for repairs. Anyways hope this helps someone else. BTW I feel quite confident tearing apart my optimax now.!!
 
I have about 60 hours on them, obviously too many. I just dont get why plugs would cause an injector fault but they do. I am sure it was the plugs this time that made the fault disappear.
 
Just curious...were they platinum plugs? What were the plugs' condition and burn pattern and did the gap get out of tolerance when you pulled them?
 
the plugs were the irridiam, proper gap. They all had the same burn pattern,but do to constant starting trying to solve this they were all a little sooty on the electrode. i run the merc oil dfi synthetic stuff(60 bucks a gallon).
 
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