MPI 5.0 No spark from coil AFTER coupler replacement

[jbroadhurst1967]

I had a local mechanic replace a bad coupler on my 2002 Sea Ray 220 BR this week. The engine was running fine before but since the engine went back in I have no spark from the coil wire. I have swapped the ignition module, coil, and crank position sensor with known good parts and still have no output from the coil. I have 12v on coil and ignition module on the correct wires by the diagrams. All the swapped parts work fine on the other engine. If anyone has any ideas I'm open to anything at this point!

 

[TowRoper]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

try taking the grey wire off your tach it worked for me

 

[proxyx]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

you probably had to disconnect the shifter prior to repair... your issue may be interrupter switch

"I have swapped the ignition module, coil, and crank position sensor with known good parts"
hmmm... way too many parts to be replaced in one shot, likelihood of so many to go bad is close to ZERO, you have another issue

strike wht/grn from module to the ground, if you get spark on the coil your ignition is ok
check these threads where I explained how I have dealt/or how to deal with ignition troubleshooting



http://forums.iboats.com/showthread.php?t=349622
and the linked thread in my post

 

[Don S]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

strike wht/grn from module to the ground, if you get spark on the coil your ignition is ok

That might work great on a Thunderbolt IV ignition, but he doesn't have Thunderbolt ignition of any kind on his MPI. He has the HVC ignition.

jbroadhurst. Go up to the Adults only sticky at the top of this forum and download manual #36. It details out how to troubleshoot the ignition system on your MPI engine. Start on page 2A-8 for the diagnostics.

 

[proxyx]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

sorry I missed the "crank position sensor" portion of the post... distributor-less, bit different animal... my bad, and I have even quoted the passage, haha, must have been late at night...

similar principal though, I think you may cheat the crank sensor with a piece of metal or a magnet to trigger ignition without cranking, will look into this...
you get my drift? it's simpler then most think

edit: you actually should be able to trigger the crank sensor with a magnet passing in front of it

 

[jbroadhurst1967]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Thanks for all of the ideas. I have traced all of the wiring by the #36 service manual and all looks well. I will see if a local boat shop can run the diags on the ECM. I will post the results soon. Thanks again for all the help.

 

[jbroadhurst1967]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Thanks again for the ideas...I couldn't get any boat shops locally to scan the ecm today due to the holiday, but I did fix the problem today. I used the #36 manual and tested every circuit and finally found a missing ground on the oil pressure switch on page 3A-28. I repaired the ground and everything is right with the world! I assume Mercruiser engineered the ecm to kill ignition on loss of oil pressure. Very interesting.

 

[TowRoper]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

ahhhhhh nothing sounds better then a dead engine coming back to life

 

[proxyx]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Thanks again for the ideas...I couldn't get any boat shops locally to scan the ecm today due to the holiday, but I did fix the problem today. I used the #36 manual and tested every circuit and finally found a missing ground on the oil pressure switch on page 3A-28. I repaired the ground and everything is right with the world! I assume Mercruiser engineered the ecm to kill ignition on loss of oil pressure. Very interesting.

Congrats, I could feel frustration.
Is this listed as a possible reason for spark loss in the service manual?

 

[jtybt]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Gee, I would have expected the alarm to keep going off if the ECM didn't detect oil pressure.

 

[JustJason]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Yep... Its part of the guardian system. Oil pressure, over heat, low drive oil, will all cause some kind of power reduction via spark.

 

[proxyx]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

1.0 Lanyard Stop Switch in wrong
position
1.0 Reset lanyard stop switch
1.1 Weak battery or bad starter
motor. Battery voltage drops
below 8 volts while cranking.
1.1 Replace or recharge battery.
Inspect condition of starter motor.
Inspect condition of battery
connections.
1.2 No fuel 1.2 Key ON engine to verify fuel
pump operates for 3 seconds.
Check fuel tank for fuel. Verify
fuel pressure is 43 psi. Listen for
fuel pump relay to click.
1.3 Blown fuse 1.3 Inspect engine harness and
electrical components. Replace
fuse.
1.4 Main Power Relay (MPR)
malfunction
1.4 Listen for MPR to click when
the key switch is turned ON.
1.5 Crankshaft Position Sensor
(CPS) malfunction
1.5 Inspect for loose connection
or corrosion.
Inspect continuity between
sensors and ECM.
1.6 ECM malfunction 1.6 Check battery voltage.
Check for blown fuse.
Check battery voltage to the fuse
from the MPR.
Inspect harness connections.

Says oil pressure will throw the code, nothing about effect on ignition... another example how the manual can lead you deeper into the woods... not impressed.

 

[JustJason]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

another example how the manual can lead you deeper into the woods... not impressed.

You need to remember that the manuals are NOT written for the end user. They ARE written for somebody who HAS BEEN through marine/merc school.

1 other thing... alot of MEFI engines require 2 manuals to correctly diagnose them. If you only have 1 of the 2 you may get lucky or you may not...

 

[jbroadhurst1967]

Re: MPI 5.0 No spark from coil AFTER coupler replacement

Congrats, I could feel frustration.
Is this listed as a possible reason for spark loss in the service manual?

Neither of the 3 manuals I used listed this as a cause of no spark. They just listed the codes that would be stored if there was an error with this circuit. Hope this helps someone down the road (or water!)