96’ EFI 200 mystery problem they can’t figure out

[Sluggo42]

Greetings, OG350972 1996
My 200 EFI now has 2 “dead” cylinders. #2, and #5. Been to 2 shops now and they don’t know why they won’t work.

compression is ~ 130 across the board. One shop mentioned that it could be some kind of main seal somewhere?

#1 and #4 have higher voltage at coil than the rest. One shop said they introduced fuel “somehow” into 5, and said it fired. They switched coil wires and plug wires and still found higher voltage at 1 and 4, indicating the coil packs are OK.

they scanned the brain with a little scanner, and felt that the limited info they got seemed good.

it seems to my teeny brain that there are injector problems? Is it difficult to check or clean the injection system?

needless to say it’s driving me nuts.
I desperately need to sell this boat, but cannot sell with a motor that doesn’t run well. I can idle around, but cannot get on plane at all…

can anyone share a thought as to other things we could check? Or does it sound like we need to start taking things apart, which i really shudder at that thought…

it’s starting to get expensive with no results.

thank you in advance…

[Sluggo42]

Other thoughts…

boat has run like a superstar for18 years since I’ve had her, but about a year ago, she started missing on a cylinder. So I could put it in neutral and Rev it a few times, and it would seem to clear up and run ok, this has continued and become progressively worse, to where now they won’t work at all. The plugs look clean, whereas all the other plugs are fairly dark in the tip. One mechanic felt it was running too rich…

[EuropeanAM]

Moving your post to the correct forum (2.5L) for you.

#2 and #5 are on separate injector pairs. In order to drop fuel supply to both of those cylinders (it sounds like that's what you're hinting they suspect), it would either have to be restricted/stopped-up injectors, broken reeds, disconnected injector electrical connectors, or short/open in the harness to those two injectors.

There are resistance tests that can be done externally to see if two injectors are on the circuit- see Service Manual and Diagnostic Manual for details.

Otherwise, it might need to have the fuel system pulled down for inspection and cleaning/testing/servicing of the injectors (this is a fantastic time to inspect reeds).

Please be sure to update your post with the engine Serial Number.

[Sluggo42]

OG350972

thank you! I’ll pass this along to current mechanic…

[Marc Marcantonio]

I knew Don would get you on the right track!

[ChrisCarsonMarine]

Your motor has 3 triggers in the trigger assy.They each fire 2 cylinders,1/4,3/6,and 5/2.Very likely you have a bad trigger,and this is how it would present,Chris

[EuropeanAM]

Your motor has 3 triggers in the trigger assy.They each fire 2 cylinders,1/4,3/6,and 5/2.Very likely you have a bad trigger,and this is how it would present,Chris

This should also be evident in a SPARK TEST... thought he said that was verified but ABSOLUTELY wise to triple check spark and/or trigger.

[Sluggo42]

New stator and trigger - no help…��

[JOE54]

proceed with pulling the injectors and number each one with respective cyls send them all to be verified and tested thoroughly

[Sluggo42]

proceed with pulling the injectors and number each one with respective cyls send them all to be verified and tested thoroughly

is it prudent to try all electrical first before going to the injectors? I have very little idea how difficult they are to pull and test etc…
but, my small brain agrees that it could be fuel related. Previous mechanic stated that he was able to make 5 fire by artificially injecting fuel into #5, but I have no idea how he did that…

[Sluggo42]

This should also be evident in a SPARK TEST... thought he said that was verified but ABSOLUTELY wise to triple check spark and/or trigger.

Super interesting how one of the trigger assy fires #2 and #5- as they are the two dead cylinders…
now being the a new stator and new trigger didn’t change anything, that rules out the actual trigger component? Current mech did something with long needle nose pliers, by touching two parts on each coil. This resulted in nothing on the two dead holes, but a marked miss when applied to working cylinders, which instantly ran again then pliers were released.
Now, what about the little boards the trigger wires land on? I’m talking about the two identical sized stacked boards that all the wires attach to (don’t know the actual name of them) would these be the next logical place? But the current mechanic spent a lot of time checking them with his meter, but I don’t know what he was doing, but he did say we should probably try new/different ones.

[JOE54]

is it prudent to try all electrical first before going to the injectors? I have very little idea how difficult they are to pull and test etc…
but, my small brain agrees that it could be fuel related. Previous mechanic stated that he was able to make 5 fire by artificially injecting fuel into #5, but I have no idea how he did that…

you see those lil black rubber caps on the fittings that are on the side of the block that would be my suggestion on how to do it , the way i do it anyway

[JOE54]

Super interesting how one of the trigger assy fires #2 and #5- as they are the two dead cylinders…
now being the a new stator and new trigger didn’t change anything, that rules out the actual trigger component? Current mech did something with long needle nose pliers, by touching two parts on each coil. This resulted in nothing on the two dead holes, but a marked miss when applied to working cylinders, which instantly ran again then pliers were released.
Now, what about the little boards the trigger wires land on? I’m talking about the two identical sized stacked boards that all the wires attach to (don’t know the actual name of them) would these be the next logical place? But the current mechanic spent a lot of time checking them with his meter, but I don’t know what he was doing, but he did say we should probably try new/different ones.

those are switchboxes not the problem ,,,,,,if the dead cyls have voltage at the + connection on the coils and you have spark at the plug and have good compression its a fuel delivery issue from the injector or the plenum harness failed

[EuropeanAM]

those are switchboxes not the problem ,,,,,,if the dead cyls have voltage at the + connection on the coils and you have spark at the plug and have good compression its a fuel delivery issue from the injector or the plenum harness failed

+1

Just for the record, though: "New" does NOT necessarily equal "Good". That error has cost many a tech days of wasted time.

[ChrisCarsonMarine]

Call me,305-394-3354,Chris

[leonreno]

You can send your Ecm out to be checked before buying a new one. Or find someone with the same motor and borrow a known good ecm and try it out.

[Sluggo42]

We tried a different ECU- no change