1999 mercury 175 efi. S#og944201 issues

[lifetime1962]

Bulb tight, sometimes will run no problem,then when wot will cut back and may start back and run fine,then sometimes won't run at all ,like it bogging down,any ideas, have changed fuel separator

[lifetime1962]

Any ideas

[Champ 2001]

The experts will most likely chime in sometime tomorrow.

[EuropeanAM]

When it won't run at all, do you hear the FUEL PUMP running when you first turn on the key?

Moving your thread to the 2.5L Forum for you.

[lifetime1962]

Thanks for moving, if I lift the throttle it revs up fine ,only when I have it in gear does it bog down and don't know about hearing the pump

[JOE54]

need fuel psi reading under acceleration , as well as spark test when problem occurs

[lifetime1962]

I do hear fuel pump when I empty vst tank

[lifetime1962]

Changed plugs also

[lifetime1962]

Changed plugs also

[lifetime1962]

So far ,I have the vst tank off, it was good and clean inside, except for a little at the bottom , screen clean but I have ordered a new fuel pump,looks at if it was original since I was in it anyway, now waiting on pump and then we try again

[EuropeanAM]

That's a pricey pump to just replace....

[lifetime1962]

Serria pump lifetime warranty 93.00

[JOE54]

report back with outcome of repair /install of new aftermercet pump

[lifetime1962]

pump installed 39 psi now , check compression 119 on all cylinders, still doing same thing, have spark on all coils, have me stumped now , any ideas

[JOE54]

figured that was coming , spark on all when problem occurs ????? also very important to isolate which cyls stop working for further analysis , gotta spare ecu handy

[lifetime1962]

Changed a couple of fuel lines and tapped on the ecm and screaming down the lake now, thinking about unplugging and making sure connection is good and leave alone

[JOE54]

gotta spare ecu handy

when you have spark on all 6 when problem occurs and have verified compression , fuel delivery is problem , engines with 2 opposing cyls 5-6 ,3-4 ,1-2 likely have bad driver in ECU , i hope its a connection but dout it , it will repeat

[EuropeanAM]

+1... those Cummins ECU's are known for "loose drivers" on the circuit board. Temperature and/or vibration often trigger the intermittent failure.

[lifetime1962]

has anybody used SAI to repair ECM SIA Electronics | ECU Repair for all Makes and Models

let me know

[JOE54]

not I