Fixing up a 99 Challenger

[Cooper cobra]

Hello all. New member here. Recently bought a 99 challenger that looks good from 8 foot but the closer you get you begin to see its age. Boat overall is in good shape no holes and seats are all there and no tears. The guy I bought it from said it needed two new batteries and one starter was hanging up.

The wife and I first started by giving the boat some TLC just to really clean it out. I then started looking into the engine. Pulled the old batteries out and noticed extta wires. Found a sub and 2 amps for tunes. I swapped out the old batteries as they were junk and put in two new ones. Before I turned the power on I checked all the fuses I could see. I found 3 blown 10amp fuses on the ECU. Swapped them out and I attached the key hoping to here two beeps or some action on the dash at the very least. Nothinh happens, turn the lights on and the did turn on ut nothing on the dash. It did come with two keys so maybe one is defective. Nope same thing.

I turned power off and disconected the batteries. Both batteries are good and showing 12.7+ volts. Havent touched the starters yet but have two new ones ready to install. I started checking ground wires and cleaned any corrosion I did find. Some of the wires ends were coocked. I degreased engine and gave it a good scrubbing to clean it since I might be spending some time in thers. I pulled the plugs and tried turning by hand whiched worked. I then traced the coil wires to the electrical boxs and found both were full of old rusty water. Now here is were my heart starts to sink. Can kinda see all the power lines are pretty corroded and one snapped off when disconnecting the baterry terminal. Had to cut off a good 3 inchs before it was semi good wire.

I found 2 new/used electical boxs complete on Ebay so I did the right thing and bought. The photos showed identical units and no corrosion. The rubber seal wasnt on good on the one but the other seemed like it should have kept water out. No other flood damage from what I can see. So not sure how both were filled with water. Is this common to get a little bit? I let the electricals dry out and cleaned the connectors best I could but didnt want to try and crank boat over heven though I wanted to try.

Could this be the reason nothing turned on besides the safty lights and what sounds like a bilge pump. Both units being filled I am guessing is what poped the 3 fuses but even after I changed the fuses there was no dings when dess key was on. Guess I am just not sure what to do next until the electrical boxs come in and test them to see if they are working.
I have a bad feeling about the dash not powering up and am thinking the mpem is shot. Would any of the other electrcal amke the dash not light up or does it confirm my suspicion on the mpem? Any thoughts or advice on how to proceed? I did find a shop manual I downloaded and looking at a real one on ebay.

Thanks

 

[Cooper cobra]

Well new electrical boxes installed with new starter selonoids and power cables. Both batteries charged full. When i check for power the hot side has power and the circut is closed. When push start is pushed and check other side of selonide test light does not light up. Removed plugs and tried jumping selonide and engine did not turn over and starter didnt even try to engage.

Does anyone have a diagram of stock battery lines and how they were run. The person before me installed multiple amps and has the wiring a mess. I would like to set up batteries and grounds back to stock to see if something just isnt wired correct. I have a shop manual otw and downloaded an ereader. Not really finding the information I am looking for.

Only have one battery shut off that I am aware of but it seems like dash wont power on when I turn power on. Light swicth works and the pump but none of the other switchs do anything. Tachs and gas light do nothing. With dess key on there is no beeps. No clicking noise when push start buttons pushed. Seems like an electrical issue which leads me to think power cables are not right, unless I am way off and someone has an idea?

 

[rusty nail]

You have multiple things going on here. you will need to start at the beginning and trace where you get 12v.

If you tried jumping the solenoid and get nothing (as long as you have power to the one side of the solenoid and your grounds are in place ) your starter is bad ( or your motor is completely seized) because you are directly sending the juice to the starter. with the spark plugs out you should be able to turn the drive shaft easily by hand to see if the motor is free.

These things need to function to get your starter to turn. Dess post and dess key, fuses, proper grounds and hot wires with clean connections, Mpem, functioning main shut off switch, solenoid, good battery. I cannot remember if the neutral switch (forward reverse controls) operates as a kill switch as well and will not let the power through if the control is in forward or reverse).

once you get the motors to turn you can begin to see if you have spark......have fun.

If you have the proper service manual the wiring diagrams are in the back of the manual.

 

[rusty nail]

be careful, if you have bad wiring you can blow up those mpems with a small surge. always disconnect the battery when working on these and never boost.

 

[Cooper cobra]

Thanks for reply. One engine is spinning freely with plugs out. The other wont budge. 1 piston is at tdc so the other is on the bottom stroke. I tried filling cylinders with atf but the other cylinder just pours through.

When i bought the boat they told me the starter on that engine was toast. Hoping it's just hung up and that is what is seizing the motor. I have no hoist so finding its not a lot of fun hanging down in the engine bay. Props to those that do this all day. My next plan is to swap in new starters.

 

[rusty nail]

I have had jet pumps seize which is why the motors do not turn. Easy to pull off the jet pump and drive shaft then see if the motor turns