2000 dt225 momentary power loss

[superheat216]

Running twin dt225's with , I think less than 100hrs, but stored for about 3 years before I bought them. Stbd engine starts idles and trolls all day without issue, but when rpm increased above about 1500 there is an occasional decrease in rpm of 300-500 for I-2 secs with an accompanying check eng light and no audio alarm. If throttle is quickly advanced eng returns to normal. There are no stored problem codes when turning key on but continues to happen about every 15-30 secs at all rpms from 1500-5200. Engine feels like it has lost a few cylinders but within approx. 2secs instantly returns to set rpm. Motor does have a new set of plugs.

[Solarman]

Sounds like something is breaking down at that 15/30 sec interval. Is it only the check engine light, or is another light flashing when that light momentarily flashes? Temp light, oil light?
If only check engine, it might be gear counting coil, or pulse coil, couple of injectors, a plug coil, a TPS, or a number of issues? If also temp light, a sensor? If oil light also, a oil sensor?


Post back when able.

[superheat216]

Only the check engine light and it runs very rough during the episode. The engine was in salt water use then stored for an extended period so I will take all connections apart and check for corrosion. Let you know as soon as I can get to it.

[superheat216]

Checked all grounds and plugged connections all looked pristine. Traded ignition module with other engine and am still getting check engine light with associated power loss, high pressure fuel pump?

[Solarman]

I doubt the hp fuel pump, unless you're hearing it cut in and out at those rpms.
I'm thinking probably sticking, or breaking down injector(s), or gear counting coil (first choice for swap). With a second motor you have the ability to swap items. The gear counting coil (usually) one of the first items to fail on these motors would be my first choice. But anything you swap do it by the manual, the gear counting coil is a specific distance from flywheel. Also when swapping items, look for possible pinched wires, and when swapping items like spark plug coils, swap all from one side of motor at a time, if problem shifts to other motor, then focus on that item swapped. If swapping injectors, swap one bank (all three on each side separately, 1-3-5 & 2-4-6, do not mix them up) at a time. Again, if problem shifts, then focus on those three individually.
The rectifier the second choice,
Plug coils, each bank separately, fourth.
Then injectors, one bank at a time.
Then come back for more items, if not found.

I'm assuming you have already swapped fuel supplies between both motors, before swapping ecm's? If not, start here first. It's always the first thing.

Good luck, post back what you find.

[superheat216]

Thank you for the trouble shooting logic, it really helps to get info from someone who has worked on these engines before. Aside from the fuel consumption and a couple of minor issues they seem to be great engines, are quiet, smooth and run strong, will get back when I get it resolved.

[Solarman]

Not trying to change anything previously posted here, but if you have/or haven't changed plugs recently, that might be a good start. It is not impossible to get a lemon plug, or two that might do strange things if not good.

Good luck.

[superheat216]

plugs have been changed twice to no avail, engine quit on way back from trip recently and was found to be bad ignition switch. Switch was swapped and solved that prob but momentary power loss remains. An annoying issue but not requiring immediate remedy as it is not getting worse.

[Solarman]

Superheat, i am not sure if your motor has a neutral shift sensor, but look it up if you have a manual. If you have one swap it out, I am thinking your motor seems to cut out between 1500 - 5200 rpms, and though it is odd, if one is on your motors it is connected to shift linkage, and if weak contacts it could affect that rpm range intermittently with a check engine code. Can check it by the manual if listed, although the 15-30 sec interval may only relate to ECM diagnostics check?

Post back what you find. I'll keep running your senerio through the logic process. Good luck.

[superheat216]

I see no neutral switch anywhere in the engine shift linkage, only in the remote control quadrant. May be standard setup but both engines must be in neutral in order to start either one.

[Solarman]

I'm not seeing one (neutral switch) listed on your motor for 2000.

However, you do have 2 solenoids near, or plugged into your fuel injection unit. Lets unplug both & label which is from where, and which plug each went to. Then swap both with their exact counter part from other motor.

This is trial and error of injector solenoids.

If you haven't swapped out your heat sensors yet, you will need to do this also. This trial or the next. Maybe CDI(s) next, or same time? Will look up?

This is what you will have to do until you run into what item causes problem to move over to your other motor.

I'll be looking up other items that trigger check engine light and might cause your problem.

Hang in there, you're lucky you have twin motors. Most don't. This could be helpful for all that have similar motors.

Good luck, keep us posted.