96 Challenger no spark

[Eric in Ohio]

I'm a new guy and I need help. I have a 96 Challenger with a 787. I've had this boat for about 7 years. It has always had an intermittent no start problem. Very frustrating. It would leave me stranded on the lake or work fine one day and not the next. It always fixed itself. I'd tow it to the shop for no start and it would fire right up for the mechanic. A couple years ago I melted a cylinder and parked it for a couple years. I have installed a rebuilt motor (SBT). It worked for a short test run. I took it to Ocean City MD for the holiday and it ran for about an hour while I worked on breaking in the new motor. I parked it for a couple hours and it wont start again. It cranks fine. New battery this month and the starter is only a couple years old. New Plugs, new gas. It looks like I don't have any spark. I put a plug on the wire and hold it against a ground and I don't see any spark. What's the next step? new MPEM?

 

[m.colley]

not sure if this will help or not but worth checking. On my Sportster 1800 I found a ignition coil/cdi ground problem. On the bottom of my CDI there is a ground lug that had become corroded enough that mine would turn over but not fire. After cleaning the lug thoroughly I discovered that the screw and insert had become so corroded that it wouldn't even tighten up.I made up a new ground and it fired right up.

Martin

 

[Eric in Ohio]

Thanks for your reply Martin. Not to sound stupid but what is a CDI and where do I find it? Since I did my own engine swap I'm pretty familiar with the engine compartment but I'm still learning my way around this thing.

 

[m.colley]

on my sportster its in the black box directly in front of the engine. If you trace your spark plug wires back from plug end you should be able to find it. CDI stands for Capacitor Discharge Ignition and is similar to a coil pack. It boosts the voltage provided to your plugs so that they fire correctly. Not sure if this is your problem but worth checking.

Martin

 

[Eric in Ohio]

Martin, Thanks again, My boat does not have CDI. I have an MPEM with a separate coil. My electronic box looks good. Like brand new in fact. No corrosion or loose terminals that I can see. I have not disassembled anything in there yet.

 

[Eric in Ohio]

Ok. After looking at some more no-spark/start threads I guess I do have a CDI. (I'm still new at this) Everything LOOKS good in the electric box. Can anyone tell me anything about after-market MPEMs?