Challeger 1800 MPEM problem

[la_tim]

History of Problem

Boat has stopped two beeps when installing lanyard about 6 months ago. Boat has run well with no problems. Boat recently had continuous beep which indicates hot engine. Stopped boat immediately and brought home. Troubleshot and found bad engine thermal switch. Replaced both switches. Beeper started working. Went to lake and had problems with lanyard connecting and boat starting. I would have to put on and off several times. The beeper relay would pick up, however beeper wouldn't beep. Before leaving horn start beeping continuously. I brought home and replace lanyard post. I now put on lanyard and only hear relay pick up again. Any ideas?

 

[mobilefleet]

on mine, my lanyard literally fell apart, the rubber came apart. I had to tape temporarily until a new lanyard can be programmed. if it does not fit snug on the post I'd say it's time for a new lanyard for yours also

 

[la_tim]

Lanyard is find. Each time I put it on the relay clicks twice but no horn.

 

[mobilefleet]

Put mpem into diagnostic mode. With key not on post press either engine start switch 5 times. You should get a short and long beep to verify it entered diagnostic mode. Now put key on post and try to start either engine. If no start and you get beeps instead, report back what it does. It will be four possible code beeps: 1 long and 1 short, 2 shorts, 2 longs, or 3 shorts.

 

[la_tim]

When entering diagnostic mode, I hear the relay pick up but no horn. It appears to by short and long beep. When I put the key on the engines will start. I've tried diagostic in past and has always passed. The beeper seems to come and go as far as working. I always hear the relay pick up. Engines runs fine at lake, just hard to get the key to work and at the end of the day the continous beeps.

 

[Lumps]

I know you said that your beeper was working. but have you tried to test it separately? these fail all the time. maybe there is loose wiring?

 

[la_tim]

I agree, I need to test the horn. Where is it located and what is the best method to test. Also, I'm not sure of why the key doen't work at times and the continuous beeping last time at lake.

 

[racerxxx]

If you test the beeper it will probably work, but not in the boat. IF you test it directly to 12V and hold it on it will work, but the pulse is so short from the MPEM that it doesn't activate.....yes I had this issue on my 96 XP. But regardless, test it and buy a new one from Floyd bell, the mfg of it. Maybe you'll get a free one if you get luck, my bro in law didn't. They're fairly cheap shipped from them.

Next thing.......... Are you 100% certain it's overheating? Do you have a manual fuel selector or is it an electrical toggle switch on your dash board? The switch I think toggle flashes when the fuel is low and you need to press the electrical switch to say "yes, I know I'm low on gas" since it's not mechanical. So, you're light in the switch could be bad. Only reason I'm saking is my 99 Speedster will beep when I'm low on gas. I never knew it did it until 2 years ago when I got the gas low enough to have it alarm. Took me 16 years to finally run the gas low enough, LOL. Just listing you boat as a Challenger 1800 in your profile doesn't let me know the year, since they did change this from mech to elec on the reserve for the fuel. Again, the above is just a wild guess. Other than that I would get a non contact thermometer and check the engine temps after 5 minutes or so, then when it sounds I would check it again immediately.

 

[la_tim]

Thank you for your help. The boat is 98 Challenger 1800. We purchased the boat new. I don’t believe the boat ever run hot. I checked the temperature switch with a meter and it showed grounded. It was odd, one engine had an older style switch, 278000194 and the other engine had the newer style, 278000965. I changed both switches thinking it could be causing the problem. I will change the horn, could be an easy fix. I’m looking for a full electrical diagram. I have a manual but it mostly mechanical. It also it is missing the section on the MPEM. I'm hoping it not the DESS however just want to determine the root cause.

 

[Lumps]

I have the 98 manual but at the wiring diagram section it says it wasn't ready at time of printing and I never found any supplement.

I am pretty sure the 98 challenger didn't have an alarm for low fuel. The overheating alarm was based on a sensor that started to conduct at 95ish Celsius. But this means if it shorted it could set off the alarm.

If you are certain it's not overheating then maybe it's a short?

 

[la_tim]

Yep that's my fear. Just need a place to start. I thinking of isolating the DESS one thing at a time. Looking for troubleshooting DESS section. It be much easier then reinventing the wheel...

 

[racerxxx]

Ok, let's clarify something here. Is it a continuous beep....beep....beep....beep....beep

or is it a continuous beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeepp


From everything i have gathered from the service manual the 98 challenger SHOULD have the low fuel warning system. Without a manual fuel selector valve you should get an audible alarm warning you that you're low on fuel as well as a amber light flashing on the rocker switch.


You can check the temp of the engine when it happens, if you're in the 200 deg range its an over heat and you have an obstruction possibly

 

[TVKing]

My 98 challenger has a low fuel alarm, it also lights a light in the fuel gauge. When you reset it with the rocker switch it will not beep until you shut the boat off and start it again. Once you put gas in it it stops beeping. First time it happened to me it took me a couple minutes to figure out why it was beeping.
Terry

 

[Lumps]

sorry you are right. the 98 challenger has the manual fuel selector. the 98 challenger 1800 doesn't. I thought my user manual was for the 1800 too but its not

 

[la_tim]

My alarm was beep beep beep beep beep beep beep beep beep....not the continuous alarm that the hot engine gives....my fuel was a bit low maybe i did have low fuel alarm. I did find DESS troubleshooting guide...I'll let you know what I find...