2005 sportster LE DI does not crank

[dthsmarsh]

Hello ... I just picked up a 2005 Sportster LE DI with the 951 DI engine. It's a long story, but when I bought it, the boat did not have the MPEM or DESS key with it. Otherwise the boat was complete and in decent shape. I got it at a great price and worth the risk to me as I jumped the posts of the solenoid, and the engine cranked fine with compression.

Fast forward to I bought a used MPEM and matching DESS key off ebay, and although it gives me the double beep saying the boat is ready to run, it does not crank over. The fuel pump primes when I put the DESS key on, and when I hit the start button, the fuel pump runs, but no click or clunk of the solenoid. I have checked everything I can think of ... 100% good battery, good grounds, all fuses, battery box connections, MPEM wiring, DESS key post, start switch, Neutral Safety Switch (NSS). Even though it ohmed out OK, I bought a replacement battery box and new solenoid. Still nothing. I even went as far as to disconnect the NSS, and provide a ground there that the MPEM would normally do, and the engine cranks over great. The only thing left in the circuit is the yellow/red wire from the NSS to the MPEM that provides the ground for the solenoid (solenoid normally has 12 V from MPEM, and verified many tiimes that is there) See attached picture.

So I thought OK, I got a bad MPEM from ebay (known to happen). I return the MPEM, and find another one on ebay, I buy that one, put it in, and ... still no crank. Exact same symptoms as before (double beep, fuel pump primes, fuel pump runs when start button is hit, no crank or solenoid movement). I completely ohm out everything (again), and this time I jump the yellow/red wire from the NSS to the MPEM thinking maybe that wire is bad, and still nothing. If I ground the NSS, and it cranks fine (everything else in connected in normal way). So I would think it is another bad MPEM off ebay, but what are the chances? The MPEM's off ebay were from skis not boats, but I have confirmed the part numbers from online sources are correct.

Can anyone think of something I am missing? The only think I can think of is maybe the pin on the MPEM harness connector (3-15) is not making good contact, and thus not providing the needed ground for the solenoid? I am not sure I could fix the connector, and also, I am not sure there would be a used harness out there for sale. Thanks for any help, and sorry for the long post but I wanted to provide enough details so I don't get the usual "check the battery" replies!

 

[dthsmarsh]

So I thought I would update in case someone else is having a similar issue in the future.

It did in fact turn out to be a bad connection on MPEM connector 3, pin 15! It was a bit maddening troubleshooting this, as the wires would ohm out fine connector to connector, but the female socket pin on the MPEM had elongated just enough to not make contact with the male pin on the MPEM, even though the harness connector was secured attached/locked to the MPEM connector. I popped the socket out of the connector, and physically tried to slide it on the MPEM pin, and sure enough there was just enough play to cause a bad connection. I slightly closed the socket with a pair of needle nose pliers, inserted it back into the harness connector, hooked it all back up, and she fired up immediately!

Now the engine runs, but it immediately goes to full RPM (4500+) even with throttle lever at idle. I have to hit the stop switch or I feel the engine would run away after a few seconds. Is it as simple as the new MPEM has to be calibrated to the engine Throttle Position Sensor (TPS)? Or are there potentially other bad connections I need to worry about? I have read that after a MPEM change, the boat needs to be brought to a dealer or shop that has the software to calibrate the TPS, but I thought maybe that meant it would run a little rough at idle, not run to full throttle without any movement of the lever.

 

[Raven888]

Good detective work! The engine will rev up high if it is out of the water. Maybe you could call a dealer and talk to someone in the service department to get some answers.
It's pretty hard getting answers on this forum. Most questions go unanswered or get very limited responses.

 

[dthsmarsh]

Good detective work! The engine will rev up high if it is out of the water. Maybe you could call a dealer and talk to someone in the service department to get some answers.
It's pretty hard getting answers on this forum. Most questions go unanswered or get very limited responses.

Thanks for the info. I do not think it is tied to being on the trailer versus in the water, as this sounds/feels like it will run away and implode if I don't shut it down. I am not sure if the TPS calibration would cause this issue or not. I have verified that the throttle plates are closing, so not sure why it is running so high, unless I have an air leak somewhere (visually everything looks good). All the seadoo shops around are completely straight out and cannot take it for weeks. And they all say $125/hr shop rate so that's where it would begin.

I was thinking of biting the bullet and buying the Candoo software, although at $400+ it is tough to pull the trigger. But if one shop visit is $200+, it may turn out to be worth the investment.

You are correct, I was hoping this forum was more active, but if anyone has thoughts please feel free to chime in.