240hp merc M2 jet (2001 Challenger) - HELP
Posted 16 July 2012 - 10:39 AM
One other thought - when you push the throttle forward and the engine begins to bog down, are you pushing the throttle slowly? What happens if you push it forward quickly? When it bogs down does it stall out, if you keep pushing the throttle? and if you pull the throttle back to neutral, does the engine stop chugging and idle at @1000 rpm?
You asked about the TPS earlier, and depending on your responses to these questions, it could tell if perhaps that is the problem. When my TPS went bad, I could idle at normal rpm and didn't really have a problem until I tried to accelerate. In my case, when the boat started to stall, I could get it to lurch back to speed, by pushing the throttle forward quickly before it stalled out. Because it ran great at idle and at also at wide open, zeroing in on that being the culprit took a while.
It doesn't sound like you can jump past the chugging, to get to wide open though. But then again, if the TPS has a large bad spot in the winding, or is just plan shot, that could be a problem, According to the service manual, one way to check the TPS is to use a volt/ohm meter and rotate the post to see if the resistance value goes up smoothly as you rotate it. I will tell you that when I tested mine that way, I wasn't able to detect inconsistant resistance as I rotated it, but I swapped it out - and the end result was that it worked. When tested using my diagnostic tester, showed it was reading a lower voltage value than it should have though.
Sorry, I couldn't recall if you had that part diagnosed or not.
Posted 16 July 2012 - 04:15 PM
Posted 18 July 2012 - 10:14 AM
Once you are sure that they have a computer - have them check the trigger, stator, TPS, voltage regulators, and control modules (ignition control and main EFI module).
Yes - TPS is a more expensive part. Try looking for a used one from someone parting out a blown or bad engine - they do get posted once in a while but you have to search for them. I wouldn't buy anything else unless the diagnostic testing shows it is bad or at least suspect.
If you are able to - check the vacuum tubes that control the MAP sensor that is located inside the main EFI module. One vacuum tube is on the back lower going into a hole on the Control Module - you have to remove the control module to get to it. The other small vacuum tube is connected to the manifold behind the main EFI module. Check all for cracks and that they are pushed in. Something as simple as a vacuum tube associated with the MAP Sensor could also screw up the EFI Control Module and not allow the engine to advance when the throttle is asking for more fuel/spark/air mix.
Good Luck and I hope the issue is resolved soon.
Posted 23 July 2012 - 11:46 AM
Curious for anyone who replaced a bad TPS what are the symptoms of a bad TPS? As it is electrical, does it just stop working at some point or is it a gradual thing?
Posted 06 August 2012 - 07:45 AM
Posted 06 August 2012 - 02:12 PM
I wonder if the pump had been going bad on the initial ride - where you indicated that the longer you drove, the slower it went.
Could have been the pump going at that time - slowly.
Knock on wood, I haven't had any trouble with the pump end of the system, so I can't speak to what could have worn out or broke.
Sorry to hear the bad news - Hope you can get it resolved and back on the water before summer is over.
Posted 10 August 2012 - 03:34 PM
Posted 24 September 2012 - 09:51 AM
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