GTX stalls after engine warms up

[Doctors Orders]

Hello all- I have a question that I'm hoping someone may have an answer for....
I have a 2005 Sea Doo GTX Wake... It has developed a stalling problem- BUT only once the engine warms up... Cold start is just fine and she runs normally at first ... After running hard for a good 10-15 minutes she runs a little sluggish and will stall as soon as I let off of the throttle... Then she won't start unless I give her some throttle while pressing start... She will run "OK" until I let off the throttle- then immediate stall... Once the engine cools down- back to starting and idling just fine.
Important note- the ENGINE TEMP on the gauge cluster reads 78' ALL THE TIME- cold start OR after running hard. That's impossible since the LAKE temp is 82' ... So I'm thinking maybe a failed engine coolant temp. sensor? Maybe that would affect the lean/rich mixture once engine has heated up ? There are no engine codes or check engine- but maybe staying at 78' wouldn't trigger that?
Ideas? I have already changed spark plugs and coils, and treated the fuel... Dealer reset the computer for me.
Thanks everyone for your help.
Tony

 

[Digdog]

Probably a sensor is out of range and causing your problem, if you have a manual and an ohm meter you can check them. A good start would be the temp sensor, didn't the dealer have any ideas?

 

[Craftyjoe]

I’m having this problem now, did you find a fix? Cheers

 

[ski-d00]

There is no engine temp reading on your gauge. EXT TEMP in exterior temp as in outside air temp.

 

[Craftyjoe]

Correct there is no eng. temp gauge. Are you talking about the engine air inlet temp sensor? Other wise i have function checked the Exhaust temp sensor and the water temp sensor. Thanks

 

[Craftyjoe]

Well I have replaced the fuel pump, coils, plugs and MAF sensor. See what happens now

 

[Craftyjoe]

Still no joy..

 

[skiasylum]

Are you guys getting any fault codes?

 

[Craftyjoe]

No

 

[skiasylum]

Closed throttle and idle actuator reset with buds or Candoo?

 

[Craftyjoe]

Closed throttle and idle actuator reset with buds or Candoo?

This is the next thing I'm going to check. (have to go to the dealer) I am now 80% sure that it's the Idle Actuator.

 

[Craftyjoe]

Throttle idle actuator replacement seems to have fixed the issue

 

[Craftyjoe]

Nope I was wrong, still can't find this bug. I'm about to burn this thing for insurance... Fuel pressure regulator is next!

 

[acooper]

If you look at PWS's or all vehicles in general:

1. I would suspect a vacuum leak that opens up when the motor reaches normal run temp. Is a cracked intake or hidden vacuum hose possible? similar to a collapsed automotive PCV hose or line?
2. It it even feasible to run (ride) a Sea Doo while on a BUDS or similar scanner? Does the PCM have that capability to show live data or is it KOEO "codes only" here? Just an overall question.
3. If the electronics are intact, could you have a loose or backed out pin in a MP connector? These connectors/ pins can certainly get pulled when working inside the ski. It's a PITA, but check them all.

I was thinking sticking IAC until you said it had been replaced. Unless there is a common problem known to techs that are working in the industries, I would always go with the basics; vacuum and wiring. Have to assume that the ski has decent running and acceleration performance otherwise?

 

[Craftyjoe]

I found the problem finally, faulty voltage regulator. Unplugged the stator while it was in the water and it ran like dream. went home and checked the resistance and voltages from the Stator to be all within limits. Very strange symptoms and cause!

 

[Milehighguy303]

Impressive work… the voltage regulator (rectifier) is susceptible to heat and that is why I think most or all are mounted on top of the air intake boxes and have cooling fins, so passing air keeps them cool. But yours must have had some kind of Issue that made it stop providing proper voltage to the electrical system when it got hot. Thanks for sharing the follow up.

 

[pierreye]

Good detective work. This would help in troubleshooting similar issues in the future.