1999 Challenger 1800 no spark both engines

[tonymaud]

You guessed it. It'll be too quick to register a correct voltage. Do you have anything like an LED test light or a beeper? Something that will take minimal current to turn on or off? A regular light bulb will require too much current and won't flash with that quick of a pulse.

Is it a 12V pulse?

 

[Hemidakota93]

.3-.5vac trigger to rpm circuit.

 

[tonymaud]

You guessed it. It'll be too quick to register a correct voltage. Do you have anything like an LED test light or a beeper? Something that will take minimal current to turn on or off? A regular light bulb will require too much current and won't flash with that quick of a pulse.

How about from RPM circuit to coil?

 

[Hemidakota93]

I never caught the voltage. I just know it's higher than 12vdc.

 

[pocketear]

did you ever get this fixed mines doing the exact same thing.

 

[tonymaud]

So I neglected to work on it at all this winter but finally got back to it this past weekend. I purchased a Power Probe III and monitored the trigger coil output to the MPEM and saw some activity there on the probe's meter (can't hear any beep change because of the engine noise) but I'm not exactly sure what I should be seeing with that probe though. After probing around a while and disconnecting and reconnecting the connectors on the MPEM I decided to check the trigger pulses again and while doing so I started getting spark and both engines started. So something is definitely intermittent. I figured it is probably a flaky wire at the MPEM so with the engine running I started wiggling wires hoping to isolate one that would make the engine quit.
Good news is, it didn't quit. Bad news is, it didn't quit. I'm afraid it will stop working again when I am out on the lake.
So a couple questions,
With the Power Probe, what should I see from the trigger coil at the MPEM input?
What mode should the probe be in?
Is there an easier place to probe those signals? I ended up wedging a paper clip through the rubber seal on the MPEM connector to get to the contact.
What exactly should I see at the Ignition coil input (Output of RPM circuit)?

When it doesn't work it affects both engines so its something in common. All power and grounds look good.
What else is in common. I feel like I'm overlooking something simple.

 

[mark32141]

So I neglected to work on it at all this winter but finally got back to it this past weekend. I purchased a Power Probe III and monitored the trigger coil output to the MPEM and saw some activity there on the probe's meter (can't hear any beep change because of the engine noise) but I'm not exactly sure what I should be seeing with that probe though. After probing around a while and disconnecting and reconnecting the connectors on the MPEM I decided to check the trigger pulses again and while doing so I started getting spark and both engines started. So something is definitely intermittent. I figured it is probably a flaky wire at the MPEM so with the engine running I started wiggling wires hoping to isolate one that would make the engine quit.
Good news is, it didn't quit. Bad news is, it didn't quit. I'm afraid it will stop working again when I am out on the lake.
So a couple questions,
With the Power Probe, what should I see from the trigger coil at the MPEM input?
What mode should the probe be in?
Is there an easier place to probe those signals? I ended up wedging a paper clip through the rubber seal on the MPEM connector to get to the contact.
What exactly should I see at the Ignition coil input (Output of RPM circuit)?

When it doesn't work it affects both engines so its something in common. All power and grounds look good.
What else is in common. I feel like I'm overlooking something simple.

 

[mark32141]

Hi, did you ever find the problem? I have the same issue