2002 mercury problem looking for some help solving

[johnb52]

0T591093 - 200XL EFI – 2002

Engine is not running on cylinders 2 4 6

Hot spark is present on all cylinders
Fuel pressure is at 42 lbs.
Ohm test of each injector passes
Wire test between injector harness and PCM passes
Swapped PCM with sister engine, problem remains
Cylinder drop test with MCDS shows these cylinders unresponsive
Swapped injectors from 1,3,5 with 2,4,6 and problem remains on cylinders 2,4,6
Compression is 115 lbs.
TPI voltage is correct and functioning
The injector plugs and the injector harness plug were all very wet with oil internally. This was cleaned and dried thoroughly, but had no effect. also disconnected the engine from the vessel and hooked it up externally and with external fuel supply . same issue

 

[Ant-Knee]

I have a 98 merc 150 witch has 3 carbs instead of EFI , Not sure if your setup is like mine,
But I believe I read in the manual that if cylinders 1 3 5 , or 2, 4, 6 are not firing, one of the power packs are bad...
Not sure if your engine has twin power packs,

Ant...

 

[Faztbullet]

When you said PCM that makes it a 3.0L,Index the fly wheel and check timing on all cylinders.

 

[Dukedog]

think he means "ECM"....plugs, cdms?, stator?, internal injector harness? "drop test"... fire with no change indicates plug and/or no fuel, timing.. usually

 

[johnb52]

thanks Guys for the input. according to my mechanic all of the above mentioned has been addressed and proven to be working. or so he says.
i will be bringing over a master tech from the states for a more professional opinion. i am sure he is missing something simple as he is only familiar with new products and not much for the old school motors

 

[johnb52]

update... all systems check out and are fully functional but still nothing to the # 2, 4 and 6 cylinders. motor only runs on the other 3. if you remove one of the spark plug wires from the left bank and plug it back in, which ever cylinder it is removed from., for a split second that cylinder fires off. this issue has been discussed with several mercury master mechanics and no one has an answer to what the cause my be. any inputs would be greatly appreciated.3 persons working on this had a full head of hair when we started

 

[enginepower]

Think I heard of this discussion before and they found it was a faulty cdm on the opposite bank