3D Limp mode/One Cylinder

[j_smiley13]

Hi Everyone,

I'm having trouble with on of the two 3D's I recently purchased.

They are 2005 787 3D RFIs. The one Ski fires up every time first try no trouble. I can take it out and if I'm not driving it too hard it will run great the whole ride. If I go full out, in about 3 min it seems to go in limp mode, or possibly just run on one cylinder. The plugs don't seem to be fouled, and no check engine light comes on. I've read in the diagnostic procedures that the only time the ski goes into limp mode with no check engine light is if the battery has to much voltage, but it only limits the rpm to 5100. I would guess my rpm to be around 1500, and the motor is still running fairly smooth.

If I let the ski cool down for 15 min it fires right back up and runs like a top again for about 3min.

I've tried new plugs, swapping coils, water temperature sensors, and ECM's.

I'm not much of a mechanic but I'd like to learn, can someone point me in the right direction of where to start.

Thanks

 

[grinditout]

Check the Rectifier

 

[skidoox]

I am having the same problem, my 3D will run hard for 10 min then it will cut out on the top end.
I can go slow back to shore know problem, it runs good to 1/4 throttle.
The 3D only has 15 hours on it
If I let it cool down for 15 min it will run hard for 10 min then it will cut out on the top end.
It is at the seadoo dealer to see if they can figure it out what the problem is.
No codes in computer
No check engine light

 

[j_smiley13]

I'd like to hear what they say.
I swapped the rectifier out with my other ski and still had the same thing happen...

 

[j_smiley13]

Today I tried swapping out the fuel pumps, turns out that's not the problem either...

 

[skidoox]

Have you tried swapping out the fuel rail and injectors?
I talked to the mechanic Friday and he said they will get to it on Monday.
I ready showed him the problem in his PWC tank
The computer shows no errors

 

[skidoox]

2004 3D 787 RFI SURGE'S AT FULL THROTTLE


Here is something to always consider when diagnosing running issues. The exhaust system. If there is exhaust blockage or excessive cooling water entering the exhaust system, it can definitely cause running issues. In this case, a problem such as this could cause an engine to run fine until the airflow out could not keep up with the airflow in.

The 3D has a unique and complex exhaust system. Any one of the pipes, tubes, hoses, or chambers could cause blockage or leakage internally or externally.

1. The extension pipe that connects the tuned pipe to the muffler is water cooled. If water were left in the pipe and froze during storage season, it can crush the internal pipe reducing it's size therefore ability to flow air (exhaust).

2. Any rubber hose, if starved of cooling water can burn or blister causing an internal separation of rubber layers which can then "balloon" inside while under pressure and cause an internal blockage at speed.

3. Cracked or broken resonators allowing exhaust gases to escape into the hull can cause "pollution" of the fresh air the engine needs for proper combustion.

4. Cracks or breakage of cooling jackets can cause excessive amounts of cooling water to enter the exhaust stream effectively causing a reduction of exhaust flow.

A visual inspection would require each component to be removed and inspected, but on a 3D that's not so easy. It might be best to test the theory first, and that's what we have done in the past. To test for any of these conditions, sometimes it is necessary to fabricate a "makeshift" exhaust pipe, or tube and attach it to the end of the tuned pipe. (In the automotive industry several years ago it was common to install a "test" pipe to verify catalytic converter blockage in a similar fashion.) If by installing a test pipe the running issue disappears you can then dismantle the entire exhaust system and visually inspect each component to pinpoint the problem. We have seen all of the above conditions in the past. Consider them all and begin your step by step elimination of what is good, to determine what is bad.

Check out the 3D extension pipe that froze from improper storage. There is no visible damage on the outside, but after cutting it open, we found a "crushed" exhaust pipe which restricted the flow. This engine could not run full RPM.

 

[skidoox]

PWC Engine with Rough or Unstable Idle (787 RFI)

________________________________________
Summary:
If you have rough or unstable idle, extreme rough running at part throttle, or plug fouling problems, you may want to verify the closed TPS setting.

Unit: MY2000 to 2005 Models Equipped with 787 RFI Engines.

Solution

The throttle position sensor senses how far the throttle is open. The throttle position sensor adjustment must be performed each time the throttle body, electronic module, or TPS sensor is loosened, removed and/or replaced. The adjustment of the throttle position is extremely important. If it is not correct the fuel delivery will be incorrect, not only at idle but, throughout the entire operating range of the throttle. Needless to say the engine operation will be extremely poor.

Setting the TPS with B.U.D.S.

Connect to a computer using B.U.D.S. L 3.3.0. The MPI-2 must be used for this adjustment procedure with the D.E.S.S. Post Interface hooked in line. This can be accomplished thru either the D.E.S.S. post or by installing the D.E.S.S. 4 pin adapter (P/N 529 035 685) and hooking it between the D.E.S.S. post wires and the MPEM.

• Press the start / stop button to wake the MPEM up.
• Install the D.E.S.S. lanyard and choose the D.E.S.S. protocol in B.U.D.S. Be sure the MPI is hooked to the computer in a proper manner. Read data.

• The throttle cable needs to be removed from the throttle body bell crank to ensure the throttle body butterfly will close completely and then back off the

idle set screw on the throttle body making sure there is clearance between the bell crank and stop screw. Snap the throttle bell crank a few times gently to ensure the throttle plate is completely closed. Go to the "Settings" screen.
• Click the "Reset TPS Setting" on the screen.
• Reinstall the throttle cable.
• Go to the "Monitoring Page" and place the cursor over the TPS gauge.
• Monitor the TPS percentage displayed in the TPS gauge. The cursor will need to be moved over the gauge several times to continuously update the reading.

Turn the idle set screw until a reading of 6.7% is recorded in the TPS gauge. Lock the lock nut on the idle screw and be sure the reading has not changed. If so readjust the idle screw and lock nut. Start the unit and verify the unit idles properly and the throttle is working correctly.

This procedure works on all RFI models up to model 2004.The latest models do not have an adjustable screw. .

 

[skidoox]

The Problem is the exhaust, check out the picture of the exhaust hose. It is the hose that runs along the gas tank
I am going to build a new exhaust.

 

[j_smiley13]

Thanks, Im going to take a look at it today.

 

[j_smiley13]

You were right on the money with that one. The pipe looked exactly like your photo. Thanks for the help.

 

[skidoox]

I found that the 3 welsh plugs on the bottom of the pipe had holes in them letting the water out of the pipe so the exhaust was not getting cooled.
The motor only has 15 hours on it, I am not sure why the welsh plugs are corroded already.
I welded the plus and replace the bad hose with a silicone one. I also pulled out all of the resonators.
I am hoping to try it out next weekend.

 

[j_smiley13]

A week after I replace the exhaust hose I finally got to test drive my 3d. I was dissapointed to find I'm still having the same problem. I haven't checked the welsh plugs to see if there corroded yet but I cant see burning up my new hose in 5 minutes. Maybe? I'm going to try getting rid of all the resonators and see if I can find anymore burned up hoses.

 

[grinditout]

Mpem failing?
Bad ground's
Compression test? < SHOULD BE THE FIRST TEST IN DIAG.
coil?
What is your voltage dc @ 1500 before and during this problem?

 

[skidoox]

I would check all of the exhaust for holes, I had stuff melted all the way to the exhaust exit. If you fill the engine compartment with exhaust fums the motor will not run.
Check all of the band clamps, mine were all loose

 

[j_smiley13]

Started pulling exhaust apart again and I quickly found the problem. I read on a forum somewhere on here that rad hose would work as a fix. Apparently only for 5 minutes. Ive got some marine exhaust hose on order now. lesson learned.

There is not a chance I would have found that hose. It was such an easy fix once you pointed it out.

Thanks for all your help.

 

[skidoox]

If you do not have water going into the exhaust no hose is going to last very long.
You need to pull the pipe and check the water lines and the elbows that are connected to the pipe, make sure they are clear so the water can flow into the exhaust and keep it cool.

 

[j_smiley13]

I pulled the tuned pipe, one of the welsh plugs was corroded. I welded it, and replaced the exhaust with proper marine exhaust hose, (20$ from marine supply store, 75$ from sea doo dealer) then pulled all the resonators out. Final result, ski works better than ever.

Thanks again