Dead PCM computer module

[grivera]

Good day. I need some help replacing/repairing the computer for my 240EFI engine. The boat just turned off while in idle, kept turning off, now it wont start. My mechanic connected to his computer to diag and the issue he and could not connect to the PCM/computer. NEW spark plugs, sensors and fuel filter. Any experience/ thoughts with this issue?
Thanks
G

 

[Shortrun]

Good day. I need some help replacing/repairing the computer for my 240EFI engine. The boat just turned off while in idle, kept turning off, now it wont start. My mechanic connected to his computer to diag and the issue he and could not connect to the PCM/computer. NEW spark plugs, sensors and fuel filter. Any experience/ thoughts with this issue?
Thanks
G

Hi. I hope you get some real answers from knowledgeable people.
But while you are waiting for them you might try this. Depending on your mechanical skills, how far you like to get into things.
Since you say it appears to be an intermittent (or it started that way) problem and something to do with electrical. Then I would think the first step is to check all the ground connections. Disconnect the negative of the battery first. Very important. Leave it disconnected until you are all done what you are doing.

And the positive too since you should clean that as well.
Then go throughout the engine compartment looking for all wires that get grounded to the chassis. Remove them, sand the wire lug and metal till they are clean. If you want to do a very good job get some dielectric grease (NOT normal grease) and apply it to the metal and reattach.
You might get lucky and find your problem.
Good luck.

 

[Tim75]

Good day. I need some help replacing/repairing the computer for my 240EFI engine. The boat just turned off while in idle, kept turning off, now it wont start. My mechanic connected to his computer to diag and the issue he and could not connect to the PCM/computer. NEW spark plugs, sensors and fuel filter. Any experience/ thoughts with this issue?
Thanks
G

The good news is these ECMs (front of engine) are pretty robust and seldom fail.

There have been several people here that thought their ECM was dead and had it tested. Came back 100% functional.

Check the wires coming from trigger/timing base. Those old units had terrible insulation that crumbled over time that caused MANY problems. Six wires coming out from under flywheel, starboard side. Since those wires move, check for chafed spots.

I agree with Shortrun. After disconnectiong the battery, start checking the ground wires. There are at least 3. Then check the round connector (in a bracket/clip starboard side). Many pins. No green ones allowed. Be careful. That round nut has a tendency to split.

Check emergency stop switch. Trace black/yellow stripe wire. That is the engine kill wire. You could try disconnecting it (aft of flywheel) and go for a test run.

As for fuel filters; are you aware there are 3 filters?

 

[grivera]

Thanks for the feedback. I will do some homework and try once again before shipping out the ECM.

 

[brevard2002]

my experience was the high pressure fuel pump wasn't running when key was first turned on, had 12v on both pump terminals, turns out the gnd wire for ECM is this rather skinny wire, goes to side of side of starter motor with other gnd wires. the wire was broken inside insulation where it was crimped to lug.
Once fixed the ECM was happy and pump was running

 

[Tim75]

my experience was the high pressure fuel pump wasn't running when key was first turned on, had 12v on both pump terminals, turns out the gnd wire for ECM is this rather skinny wire, goes to side of side of starter motor with other gnd wires. the wire was broken inside insulation where it was crimped to lug.
Once fixed the ECM was happy and pump was running

Love a cheap fix. Is engine running now? Are you getting proper fuel pressure?

 

[brevard2002]

yes. all good after that fix