1996 challenger wont beep or turn over

[got_s54?]

Was out on the lake today with my wife and 2yr old and were having a great day until we were ready to head back. Once we cleared the 5mph buoys, I gradually increased throttle. All off a sudden, the engine quit.

I pulled the lanyard out, turned the switch off and back on, heard the fuel pump, put the lanyard back on and didn't hear any beeps. Repeated this a few more times and still nothing. Tried the spare lanyard and still nothing. I checked all the fuses in the front compartment; all were good. Then I opened the fusebox in the engine compartment and checked all those fuses too; all were good. The battery is brand new; I had power to the blower, lights etc. I even jumped the 2 large red wires that were in the gray box and that triggered the starter. But I simply couldn't get the system to give me the beeps. I noticed too that the speedo and rpm needles are stuck where they were at when the engine quit. Ive neer seen that before.

I ended up paddling for 30minutes until someone rescued us and towed us back to the boat launch. This boat has been in our family for 9 yrs and with me for the past 5yrs and has been a real champ till today.

From what I've been reading, could this be a bad mpem? Yet others with mpem problems still produce the beeps or even turn over; whereas mine does absolutely nothing.

Could it be something else other than the mpem? What else can I check for, and how do I go about those checks? Really appreciate any help. We have a camping trip coming up this weekend and a huge family reunion camping trip the following weekend. Today was supposed to be a practice run to make sure it was ready for the summer .

I'm a noob with boats, but used to tinker a bit with VW bugs and dirt bikes.

 

[Dr Honda]

Sounds like your MPEM gave up... but that's not common for them to just die. Most of the time, failure can be traced back to something else.

Personally, I would disconnect every electrical connection, clean them, and reconnect. I'm betting you will find a bad connection somewhere. They aren't always easy to find... but take you time, and tug every crimped connection while you are cleaning things.

If you have a bad MPEM... the older boat units are hard to find, so you will wind up replacing it with a Ski MPEM. That's not a big deal, but you will loose your neutral safety system.


OK.. I know this may sound stupid... but even though you didn't get your 2 beeps... did you try to start it? The beepers go bad all the time.

 

[got_s54?]

Sounds like your MPEM gave up... but that's not common for them to just die. Most of the time, failure can be traced back to something else.

Personally, I would disconnect every electrical connection, clean them, and reconnect. I'm betting you will find a bad connection somewhere. They aren't always easy to find... but take you time, and tug every crimped connection while you are cleaning things.

If you have a bad MPEM... the older boat units are hard to find, so you will wind up replacing it with a Ski MPEM. That's not a big deal, but you will loose your neutral safety system.


OK.. I know this may sound stupid... but even though you didn't get your 2 beeps... did you try to start it? The beepers go bad all the time.

Thanks for the reply!

Personally, I would disconnect every electrical connection, clean them, and reconnect. I'm betting you will find a bad connection somewhere. They aren't always easy to find... but take you time, and tug every crimped connection while you are cleaning things.

Do you mean every single connection on the entire boat? I did notice the round connector that plugs into the mpem looked like it had some type of grease on the pins. Is that there to protect from corrosion?

If you have a bad MPEM... the older boat units are hard to find, so you will wind up replacing it with a Ski MPEM. That's not a big deal, but you will loose your neutral safety system.

Im not much concerned about the neutral safety at this point. Is there a particular ski mpem that's compatible with my boat, or do I need a specific unit? And would it just be plug-and-play? Is the msd 4425 pretty much the same thing? If I get either one, do I need to have the boat re-timed? Everything is stock and original still (except the fuel lines). Are there any advantages between an oem ski mpem vs the msd? I'm looking for a quick, easy affordable solution to get this boat going again ASAP.

OK.. I know this may sound stupid... but even though you didn't get your 2 beeps... did you try to start it? The beepers go bad all the time.

Yup I did try starting even without hearing the beeps and there was nothing

 

[cheappc]

Oh wow, Thank God someone rescued you, sounds like you got your money out of that boat, which is good, and most importantly you and your family was safe. MPEM can always be replaced...

 

[got_s54?]

So after tinkering with it as much as I could and not getting anywhere, I took the boat to a shop. They called me the next day to tell me that they didn't find anything wrong with it; it fired right up. Go figure!!!! They suspect a faulty DESS post so I'm having it replaced (no charge for labor) just for piece of mind. They said that based on the issue I described, it doesn't sound like a bad MPEM since that usually manifests it's issues in other ways.

I pick it up on Friday then head to the lake for the weekend, then head again to the lake the following weekend. Will post back if it happens again.

 

[soccerdan90]

Glad to hear that it started. It seems like they always run great when at the shop.

 

[got_s54?]

Glad to hear that it started. It seems like they always run great when at the shop.

Seriously! Gremlins must be scared of mechanics.

 

[soccerdan90]

I hear you on that. Hopefully you dont have my luck and next time you go to use it it wont start and then I take it back and it starts again! HAHA.

 

[got_s54?]

Unfortunately, I'm having to resurrect this thread. So the DESS post was replaced last year with a brand new one as I mentioned. And for the most part, the boat worked fine the rest of the time we took it out last summer, except that I experienced the same issue once - where I simply got no beeps with either lanyard on the DESS post. But eventually, after trying and trying, the boat started and was trouble free for the rest of the year.

This weekend, I pulled the boat to the lake to take it out. The battery was in my garage all (California) winter with me monitoring it closely - I'd connect the charger every few weeks, so the battery was always charged.

Anyway with the boat on the ramp, I turned on the red switch, heard the fuel pump run, waited till it stopped, connected the lanyard to the DESS post, heard the 2 beeps, then started it up with the choke on. After a few cranks, the boat fired up and sounded great. I killed it after a few seconds, backed it up in the water then hopped on the boat. With the boat floating away from the trailer, I started it and slowly reversed away from the ramp. I went into foward and headed to shore. I killed it as it approached the beach. I removed the lanyard from the DESS post, turned the switch to off, and pulled the boat up to shore. I setup our campground, then got the family into the boat to head out. I pushed off, hopped in, turned the switch ON, then put the lanyard on the DESS post, and all I got was silence - no 2 beeps. ARRRGGGGGHHHHH!!!

At this point, we're floating away from shore, so I jump into the water and tow/swim the boat back to shore. Things I did after:
1. checked all fuses - all were good
2. disconnected the main harness to the electrical box and reconnected it - still no beeps
3. disconnected the neutral swtich from the lever, jumpped the connections (bypass), still no beeps
4. disconnected the DESS post connector and re-connecteded it. still no beeps
5. disconnected the battery for an hour, re-connected it. still no beeps
6. tried both lanyard keys - still no beeps.
7. disconnected the red switch and jumped the connections, still no beeps.

The battery was strong, and I'd hear the fuel pump run whenever I'd turn the red key to the ON position. And also, the blower and lights worked when I turned the switch ON.

Does it sound like the MPEM has finally and permanently died? Is there anything else I can check to get the system to beep when I connect the lanyard?

 

[Seadoobuddy]

Check the ground from the battery to the starter area.
I had same problem last year. I replaced the post and cleaned up the main ground connection...so far so good.

 

[got_s54?]

Sounds good. I'll try cleaning up the ground connector tonight and hope that's all it is.

 

[got_s54?]

I disconnected the ground wire tonight and it was clean with no corrosion. I sanded it down a bit anyway with 600grit sandpaper. Reconnected it, but still get no beeps when I connect the lanyard. Any other suggestions or ways to tell if not getting any beeps is for sure a bad MPEM?

 

[cheappc]

I disconnected the ground wire tonight and it was clean with no corrosion. I sanded it down a bit anyway with 600grit sandpaper. Reconnected it, but still get no beeps when I connect the lanyard. Any other suggestions or ways to tell if not getting any beeps is for sure a bad MPEM?

Funny I had a somewhat what you describe, and your not going to believe it, I moved all the cables around (specially the ground cables), and bam it started... sucks, but it could just be a wire not connecting correctly...

 

[got_s54?]

when you say you moved "all the cables around", are you referring to the ones in the electrical box where the MPEM is? or ALL the cables in the engine compartment? did you also move around any of the cables inside the dash/steering console?

BTW, I took my battery to autozone today for a load test and it checked out good.

So I tried to do the MPEM diagnostic by having the lanyard off, and pressing the start button 5 times. I got nothing - no beeps. Do the 3 wires of the DESS post connect to the MPEM? I read on some other thread that I should get specific beeps if the DESS couldn't talk to the MPEM, and some other beeps if the DESS detects the MPEM is bad. Does that apply to the 96 Challenger 787 system?

If the 3 wires of the DESS post go into the MPEM, does that mean the DESS system is part of the MPEM? What's the proper way to make sure my MPEM is getting power? Check for voltage at the negative post inside the electrical box against the 5A fuse holder for the MPEM fuse? If so, and if I get 12V there, does that mean my MPEM (and DESS) is dead which is why I'm not hearing any beeps?