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787 RFI low power
- Thread starter mattrourke
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mattrourke
Member
Mine is a little different then pedec. Mine seems to rev up quite well on the trailer, out of water. Put it in the water and it seems to not hit the higher RPMs and once it peaks at a mid rpm and is on plane cruising it will start to miss. when it is missing, it is not rhythmic or in a pattern, just random misses. I will do some more swapping today.
mattrourke
Member
Is the ECU the box with the fuses on it right in the peak of the bow? Then there is another box with two round connectors on it on the right hand side, further back.
mattrourke
Member
Sorry, I see now that the one on the right is the OTAS control.
I tried to cover up intake and run ski and it ran the same or worse. I then took duct tape off and there was no real change. Lots of smoke while running on the hose. I swear I swear I could feel a blow out intake when I took duct tape off is that normal.
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Ok just tested again with intake covered like in pic and a piece of paper on side of duct tape to see if sucking or blowing and it sucking paper in. Once I take duct tape off intake seadoo seems to run not as rich revs a little higher but still bogging or not revving up. Still seems to have a little blowback out intake while running or idling. The tape over intake made 3d even run richer.
Please start your own thread. It gets confusing when there’s two different people working on different skis in the same thread.
mattrourke
Member
Which of these is the ECU? 
mattrourke
Member
Or this one?
mattrourke
Member
@Poormanracing Might finally be on to something here. This is the new info I have:
Installed the fuel pressure gauge and I get about 55 psi with it running and it barely leaks down anything after 10-15mins after shutting down.
I decided to pull the electrical plug off of injector #2 and the ski started without that connected and just running on cylinder #1. However, if I pull the plug on injector #1 the ski will not run or will run for a second or two and then quit. So, this tells me (correct me if I'm wrong) that cylinder 2 is not running due to spark or fuel. To double check, the good ski will run on either cylinder when performing the same test.
I installed the inline spark testers and both have consistent spark from what I can tell. Sooooo, I would have to guess that injector #2 is the root of the problem. Does this seem logical to you?
Installed the fuel pressure gauge and I get about 55 psi with it running and it barely leaks down anything after 10-15mins after shutting down.
I decided to pull the electrical plug off of injector #2 and the ski started without that connected and just running on cylinder #1. However, if I pull the plug on injector #1 the ski will not run or will run for a second or two and then quit. So, this tells me (correct me if I'm wrong) that cylinder 2 is not running due to spark or fuel. To double check, the good ski will run on either cylinder when performing the same test.
I installed the inline spark testers and both have consistent spark from what I can tell. Sooooo, I would have to guess that injector #2 is the root of the problem. Does this seem logical to you?
mattrourke
Member
I know they idle on one but the good ski I have will idle on whichever one I have plugged in (leaving one at a time unplugged). The ski I'm working on will only idle on the #1 cylinder. Might fire for a couple second on #2 but then quits. I'll try and swap them and see if that changes the outcome.
mattrourke
Member
Swapped the injectors and the problem stays with cylinder 2. Will not run on cylinder 2. I feel like this is why I feel like I have half the power across the full range. Is the ECM the next logical thing to swap if it seems like I'm getting good spark but not fuel? I will swap the coil in the meantime just so we can eliminate it.
mattrourke
Member
Is there a way I can volt test the injector plug-in to see if it's getting the right volts fr the computer?
mattrourke
Member
Yeah, I'm testing with unplugging one injector at a time and mine will only idle on the front cylinder (mag?). If I unplug the second injector it won't run. So I feel like maybe my problem all along has been only running on one cylinder... Or the second cylinder working intermittently.
mattrourke
Member
If I choke the airbox while trying to only run on cylinder 2 it still won't run. I've also since put a brand new spark plug in to eliminate that.
mattrourke
Member
I have now switched the ECM, the OTAS (pictures attached) as well as the coil, the plug wires, new plugs, fuel pressure tests at 55psi and drops to about 30 after 30 seconds of turning it off now. Seemed to hold longer before but that's what it is. Fuel pressure stays constant from idle up to as high RPMs as it will go and whenever it misses, there is no change in the fuel pressure. I was looking for the water regulating valve to see if maybe the exhaust is filling with water and not draining causing me to not hit the higher RPMs but can't find it.
Also, if it had kicked into limp mode at some point, does it auto reset or do I need a scanner to get it out of limp mode?
Also, if it had kicked into limp mode at some point, does it auto reset or do I need a scanner to get it out of limp mode?
mattrourke
Member
I couldn't see in very well but maybe I will pull the raves again and take a better look. Both cylinders tested the same at about 135 with a cheap tester.
mattrourke
Member
Starts with no effort everytime. Will sit and idle well too.
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