Flat Spot

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seadoolover

seadoolover

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Hi guys, i was hoping someone could help me with my 2001 GTX RFI. It has no rev range between 4300 and 5800rpm whilst ski is in the water...even when you go through the throttle up it goes from idle 1850rpm to 4300rpm but then you have no more power on throttle for a bit then all of a sudden jumps to 5800 rpm then good throttle till flat out 7000rpm.. same on powering down jumps from 5800 rpm back down to 4300rpm... i can't get it to rev in between these limits... so the ride is either too slow or too fast... i have taken it to my local seadoo dealer who has gone through the ski and can't find the problem.. says they've tried everything even changing parts off second hand skis that run perfectly... to no avail. so looks like its up to me to fix it.. they didn't charge me for it which was good of them i thought but the next dealer/tech is 1500 km's away. The problem only happens in the water... when you connect the hose to flush the ski it revs through the range perfectly... the techs' computer says it is running perfectly.. tps setting is good... clean fuel tank and filters... fresh fuel..clean oil and filters... cleaned injectors. new battery and leads and good earth lead. Checked rave valves and fuelpump/fuel/oil lines/ checked computer..and wiring loom.. new plugs... cdi is good.. nice blue sparks on both.. compression is perfect no water in the engine... starts first go. Same problem with one, two or 3 people on ski... it's got me stuffed? If the tech can't fix it where does this leave me? I had the same ski previously which had exactly the same problem and the problem just vanished.... i was hoping the same with this one but after 20 hours of use problem is still there... please help? Has anyone else had the same problem as me with their ski?
 
Good info?

You sound like you know what your talking about. And it's not very often you find a repair shop that doesn't charge when it comes to trouble shooing. The 787 RFI is a great engine. From your description, it seems you've covered all the basis that I'd cover.
It sounds like your saying that the revs are good on the tailor at home but show up when your trying to ride on the water, with a happy medium somewhere in between.
I have two ideas.......One, the possibility of a fuel injector sticking, not opening fully, to allow the variance of fuel. If the fuel reil or injector is sucking air anywhere, this can be a contributing factor. Here, cause you've done so much, I'd see if there was someway to inspect the injectors for precises operation. It must be uniformed and specific. No sticking. Two, the idea that your RAVE cap is not set right. My first idea was that you may have a dirty RAVE, but you say you've cleaned it. Do you know the postion of your adjustment cap? Did you check the bellows for damage or a hole in it? Also, have you checked to see if there may be something plugging the internal port, which receives the gases that make this valve work?
Other than that, this will be a hard to diagnose problem. You've given good info and I've not heard of this type problem before. I really wouldn't know where to go from there.
Your RAVE cap, let me know what the postition is. If you screw it all the way closed, count how many revolutions and re-post. Then, make sure you put it back the amount of revolutions you started from.
 
Flat Spot..( continued)!

Hi once again guys sorry about the long delay i've been busy working on my ski in conjuction with the seadoo mechanic to try to sort out this flat spot...
I did as u suggested SDsnipe and got the mechanic to redo the R.A.V.E. valves once again and also pulled out the fuel rail and injectors and took them to the shop and had them cleaned and flow tested and they were a little gummed up due to the indistinct flow pattern but nothing major but are now perfectly clean. I checked the R.A.V.E. valve turns and it looks like from all the way screwed in there is about 3 full turns outward ( turning the red cap ). The mechanic did them so i'm sure they are where they are supposed to be?? Anyhow after several trial runs on the water we have determined that the problem is that the ski won't ( memorize ) the tps setting... after 5 minutes of perfect rev limits the ski suddenly starts missing again and i'm back to the same old problem with no revs between 4300 and 5800 rpm. So i take the ski back to get the tps set again and.. you guessed it... its way out of whack again. Reset and ride.. fine for the first five minutes .. then missing and back to square one. Just to make sure.. i DIDN'T reset tps... let the ski cool down overnight and then put it in the water the next day and the problem was there immediately without the usual 5 minute wait.. so it's nothing to do with anything mechanical as far as we are concerned it has to be electrical.... no codes.. no warning lights... no beeps except the TWO when you first attach the lanyard cap. Tested everything electrical using VCK and B.U.D.S. everything reports fine. Any other sugestions....???

Also i am about to go premium and loking forward to reading the manuals!:hurray:
 
Tps....

O.K....then let me ask you this? If you've used the VCK to go in each time this problem occurs to find out the TPS (throttle position sensor) is out of whack, does the mechanic not think that maybe that sensor's ability to operate properly is "shot"?..........Seems to me, the problem has been narrowed down, I just wonder why the mechanic hasn't suggested to replace the TPS sensor..............
 
seadoosnipe said:
O.K....then let me ask you this? If you've used the VCK to go in each time this problem occurs to find out the TPS (throttle position sensor) is out of whack, does the mechanic not think that maybe that sensor's ability to operate properly is "shot"?..........Seems to me, the problem has been narrowed down, I just wonder why the mechanic hasn't suggested to replace the TPS sensor..............
Click to expand...
good point Louis. Im lost on memory isue. but tps is were I would start spending money in the dark. but not just yet I would need to further research.
 
Post 4....

In post 4, Robin, I believe he's got a good, narrow idea of what's going on. The issue now, why is it happening?.........There are 10 sensors and a total of 14 items the "engine managment" system uses to monitor and correct through the ECU (electronic control module) to make the adjustments. If the ECU is responsible to conitinue to make adjustments to the EMS because of input from the TPS, then my first thought is, has that sensor been tested/replaced?
 
Flat Spot... ( continued)

Hi guys and thanks once again for your input. As SDsnipe suggested we would think the problem lies with the tps sensor... and the answer to your query is "YES".. that's the first thing the mechanic did was install a new tps sensor back in September last year... it never solved the problem though unfortunately. So retested another new sensor just to be sure.. but to no avail... it's now been 6 months we have been working on this problem. In this time we have done everything except rebuild the engine... but i'm not going there!! We would likely rebuild it and have the same problem still...! Would be keen to hear any other suggestions/ideas though. Also i have upgraded to premium and am pouring over the seadoo manuals into the early hours!!

INPUT!! NEED INPUUUTTTTT!!!:ack:
 
I would find a mechanic that had another ecu on hand that would not mind useing as a test to see if yours is bad or even better I here alot of people by these of ebay and if is not there problem they can easyly sell them again on ebay. sory I just do not have enough expereince in this area.
 
In agreement....

I think I"d have to agree with Robin here. Since you answered my question in the TPS replacement. I don't think it's a mechanical problem in the engine itself, so no reason to rebuild it. This is obviously electrical. If you replace the TPS and the use the VCK and B.U.D.S. to reset your codes and retune the engine, it runs fine for several minutes or for ever how long, then it goes back to running like crap. A second go round point to the TPS again, this sounds like a component of the EMS, which, with the ECU making the adjustments to the engine, ......this seems to be then next step. I'd have to be sure though, cause I bet that ECU is a bit costly.
I wonder, did the B.U.D.S. not pick up any shorts or bad circuits in the ECU?
 
sounds like it needs to be tested in the water. is this possible Louis? I do not know if the seadoo tester can be taken onto the water
 
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Unfortunatly, no...it cannot...

No, I don't think that can be done. But the mpem is suppose to keep in it's memory, all the stuff going on.
The VCK (vehicle communication kit) is only a link between the engine and a computer. Once attached to a computer, the VCK is attached to a computer. Where it uses a special software, B.U.D.S. (bombardier utility diagnostic software) to diagnose and make engine changes.
So I don't think taking it on the water is an option.
But this problem is preplexing............
I see your in the manual now. If you have any problems interpreting information, give one of us a shout and we'll try and read the pages with you to help out!.........
 
I went fishing I wonder what kind of bites I will get

bite 1 Did they check the normal stuff like the fuel pressure? It has a in tank filter and mine had dead spot turned out to be the pressure sensor. Once the tps is zero'ed out and reset it shouldn't change and with it on the programer they should be able to see if the value's change. I don't no much just the proplems that I have run into. I hope we get more bites and they help. robin
 
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flat spot (continued)..

Thanks once again for your input guys... to answer your question (robin) we have changed the ecu .. we've changed just about everything on the ski in fact apart from the engine and body.. with parts off another gtx rfi that is running perfectly.... for you (sdsnipe) B.U.D.S.says everything is as it should be. As for taking a computer on the water the mechanic does bring a portable computer with him on the water to make the final adjustments.
I pulled the tank out myself and cleaned the pump... changed the filters.. even cleaned the regulator by flushing fuel through it... there was dirt there..
that's why i then went on to clean the fuel line .. injector rail and injectors just to be sure there is nothing in there. We didn't think it would fix the problem but did it anyway to eliminate this possibility.. along with a lot of other things... just to eliminate the posibility.. apparently one of the mechanics is now going to reset the tps manually... by using an ohm meter and going from the throttle valve to the tps itself... bypassing the V.C.K. as this isn't working obviously. I didn't think this was possible... but apparently he has done it before... would he be correct in saying that it could be done manually?.... i suppose we're going to find out. I'll keep you informed of the outcome...:)
 
Flat Spot (continued)...

Well the mechanic didn't bother with the ohm meter as he suggested... so i got the sh*ts with it and bit the bullet driving the 1500 km's to BRISBANE with the ski in tow to see if the techs herecan fix the problem.. wish me luck!!:rofl:
 
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No More Flat Spot!!

G'day again guys.... was told today from brisbane seadoo that my problem was a simple hose blockage to the rave valves.. the blockage was causing the rave valves to remain open all the time thus causing the flat spot and missing etc... i'd really like to know why the local seadoo mechanic didn't pick this up? It's ended up costing me a fortune and about 5000 kilometres ( 3500 miles ) in towing the ski around the state. Says a lot for the local mechanic doesn't it. I'm really happy it is now fixed.. but p*ssed off that such a simple thing can cause such a HUGE drama!! Anyhow i'll put it down to experience. I'd like to thank you guys for all your information and help in trying to get this problem sorted...as for me... u can catch me on the water!!:hurray::hurray:
 
Seadoolover....

I see your a premium member. I'm not saying I was right, but I appreciate the credit Robin. My point is, as a premium member, you don't only have access to the manuals, but to your own virtual mechanic. If we can't answer your question here, there are a couple mechanics associated with the forum. If you don't have the mechanical apptitude in trying to troubleshoot, then it's understandable to take it to someone who can help. But a large percentage of the time, the members here are pretty good.
What I see is the biggest problem, and believe me, I'm the same way a lot of the time, is that there are some that haven't the patience to try to find the problem themselves. There was one guy I worked with for 3 weeks. It was an electrical gremlin and after several attempts at this and that, he finally got to the bottom of it (it was on the M-2 engine). But I bet, he saved almost $1000 dollars in expenses...........:cheers:
 
Flat Spot..

Thanks Louis.. i am a pretty patient guy... working on this problem for 6 months says so i suppose. Anyhow after some chat with the sales rep from Brisbane Jetskis i now am the proud owner of a new 2008 GTI.. I pick it up on Saturday. This is the first ski i would have owned from NEW... so i will know the in's and outs of it from day one. I'm going to have to start reading up on the manuals now for this ski. Once again thanks for all your input everyone. ohh and I'll be keeping a close eye on the forum too... see you on the water:cheers:
 
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