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Blown fuses in 2002 PCM Inboard

RickR90s

Contributing Member
hello everyone,

I have a 2002 MB Sports 190 Inboard with the PCM 350 Chevy motor. Its fuel injected with a throttle body and has 786 hours.

Last Friday night my buddy and I went skiing and I pulled him with no issues. When it was my turn, the running engine stalled and he could not start it again.

We pulled the air cleaner to see if fuel was spraying on engine cranking but it was not.

So we got towed in and on Saturday I went about troubleshooting. First I added fuel in hopes that maybe my fuel gauge was stuck at 1/2 and I was out of fuel. But it wouldn't start.

Then I checked the fuses at the rear of the engine and both the 15a for the fuel pump and 10a for the ECM were blown.

I pulled the fuel pump relay and it ohmmed out perfect.

I re-inserted the relay and installed new fuses and it started and ran fine. I took it around the lake for the next 1/2 hour with repeated stops and starts and there were no issues.

Since I know that fuses don't blow for no reason, I think I need to troubleshoot further.

And I think I might replace the fuel pump (in the fuel control cell) and/or the low volume fuel pump.

And I'm still confused why the ECM fuse would blow IF it's a fuel issue.

Thoughts please.

Rick R90s
 
I'd say you're on a viable path....fuses blown when their current rating is exceeded....why isn't always obvious as you've learned....

Sometimes, corrosion can degrade connectors and increase their resistance.....a thorough inspect may be in order.

If you can't find the root cause, you may want to consider installing circuit breakers in lieu of the fuses....I'd suggest finding some military surplus 28V types....most will stand up to the marine environment very well and you can reset them if the intermittent persists....
 
Thank You for the reply.

I talked to a PCM representative and they suggested a couple of things. 1st, the low volume fuel pump has a strainder/screen on the inlet side that might be clogged, raising the current draw needed to supply fuel to the fuel control cell. (I never knew there was a screen there). 2nd, Instead of the 15amp fuse, they recommend a 20amp as both the low volume fuel pump and the FCC are on the same circuit (hot side of the fuel pump relay). 3rd, I'll verify fuel pressure to the throttle body is around 40psi.

I'll update with my findings.

thanks,

RickR90s
 
It was the low pressure fuel pump. On a 2002 PCM with a Fuel Control Cell, there's a low pressure pump to pull fuel from the rear tank to the FCC. I talked to Aqua Sports Marine in Fenton, MI (incredible service department!) and they said, there should be an internal screen or filter on that pump. I removed the pump but didn't see anything on the inlet side, just a male hose connector.

So I decided to take it apart and sure enough the screen is internal and was filthy.

Cleaned the screen and no more blown fuses.

RickR90s
 
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