5.0 Volvo Penta GXI rough idle and knocking

[dschnacky]

I recently bought a 2006 Azure 22ft with a 5.0L Volvo Penta GXi engine. Out on the water twice and it ran great both times. Until the end of the second run. We took on some water as the bilge pump failed but got it out and trailered up.

The engine stalled and couldn't get it going. We got it back home and dried it out. Tried starting a few days later and was able to get it started but wouldn’t idle. It stalls after startup. Today I checked fuel pressure both low and high side. Low side was 12-16 high side 55. Went through those checks and decided to crank it.

The engine started but runs with a high pitched air sucking sound. Knocks a bit and definitely shaky. I shut it down right away for fear of wrecking something further.

Any ideas on what to check?

I added a link to the video of it running.

 

[alldodge]

Check your oil level, sounds like its either out of oil, or water got into the oil

 

[dschnacky]

alldodge Thanks for the quick reply. The oil level is definitely low. I’ll go out tomorrow and remedy that and see if it has any positive impact.

 

[QBhoy]

Hi

that high pitched noise is the iac trying to control your idle.
the rough low rpm and poor firing suggests to me that you are running it on half fuel and the other half water.

 

[dschnacky]

I checked the oil level again after ensuring it was level on the driveway. Doesn’t seem to be low after all.

as for the fuel, I didn’t see any water in the fuel coming from the fuel pump. Anything specifically I need to do to ensure there isn’t water in the cylinders?

I have half a mind to replace the fuel filter and oil filter as well as draining the engine oil but don’t want to take needless steps either.

 

[alldodge]

I would change the oil and verify there is no water in it.

To see if water is in the cylinders, pull the plugs and check for moisture and rust. Can crank it over without the plugs to see if water shoots out

 

[joefro]

I am not a mechanic but was reading your symptoms on your engine, a few years back I bought a Baha cruiser with that same engine in it, the previous owner has passed away and I bought the boat from his wife who knew nothing about it. well when I got it home and dropped it in the water it seemed to have the same symptoms that your boat is having, well countless dollars and suggestions from people I finally broke down and brought the boat to an authorized Volvo dealer, the next day the dealer called and asked me "when do you want to pick up your boat"? I said "you fixed it that fast"?he said nothing was wrong except someone stuck in a small wire and jumped the computer to put the boat in "limp mode" he cut out the wire and reset the computer and I was good to go, and its been fine ever since. I'm wondering it your motor is in "limp Mode" and needs to be reset ? Mine made the "sucking" noise and was shaky and wouldn't Idle.it's worth looking into. hope it helps.

 

[dschnacky]

Okay. So I changed the oil. No water but definitely time for changing.

i pulled the fuel filter. Again no water. Pulled all 8 plugs and cranked the engine a few time to see if any water would come out. No evidence of that.

replacing 8 with brand new plugs as they were black (but not worn out)

new oil, new plugs, new cap and rotor if I inspect and it’s evident of corrosion. I’m going to try to crank it again today.

any benefit in disconnecting the battery to “reset” anything? Like this limp mode deal?

 

[alldodge]

any benefit in disconnecting the battery to “reset” anything? Like this limp mode deal?

No, won't help that I'm aware of muc
If the problem clears the motor should come back

 

[dschnacky]

New plugs, new oil, new fuel filter and oil filter, new distributor cap and rotor. It idles wonderfully now!

Question. Should I be able to throttle up and run this thing (on the trailer) or is that a bad idea?

 

[dschnacky]

Full clarity around the last post. I have the water hose hooked up and turned on to the flush port.

 

[muc]

New plugs, new oil, new fuel filter and oil filter, new distributor cap and rotor. It idles wonderfully now!

Question. Should I be able to throttle up and run this thing (on the trailer) or is that a bad idea?

Yes you can, but it really won’t tell you anything. If you must, stay below 2500 rpm and don’t move the throttle quickly.

And on this ECM. Turning the key off and then back on is the same as disconnecting the battery. Except NEVER disconnect the battery when the engine is running.

 

[dschnacky]

Thanks so much everyone for your help! Looking forward to getting her back on the water. Will update when I’m able to do that.

cheers!
danny

 

[BRICH1260]

Depending on how high the water was, check the crankshaft position sensor. it is located under the harmonic balancer and may have gotten water in it causing it to give a bad signal.

 

[QBhoy]

Excellent news.

 

[dschnacky]

Good news! Had it out on the river today and it isled beautifully. We putted around with the kids and has a relaxing evening on the boat.

only thing I’ll mention is I definitely hear the whine from my fuel pump. Might be time for a new fuel pump assembly.

other than that, original problem solved! Thanks so much for all your input. Greatly appreciated from a very novice boater.

 

[alldodge]

The while could be the need for another coming, but could also be the pump is sucking some air

In any case glad to know your boating

 

[dschnacky]

alldodge What's the easiest way to ensure we're not getting air in the fuel system? I primed in 10 times with just the key from off to run. all hoses and fittings seem tight. Is this something I can check or maybe an issue with the pump assembly itself?

 

[alldodge]

Connect a clear hose on the suction side going to the pump would be about the only way I know. Would not leave it there because don't know of much clear which can handle gas

 

[kdiddle]

Yes you can, but it really won’t tell you anything. If you must, stay below 2500 rpm and don’t move the throttle quickly.

And on this ECM. Turning the key off and then back on is the same as disconnecting the battery. Except NEVER disconnect the battery when the engine is running.

muc - can you clarify why its advised to not disconnect the battery while engine is running? I have two different batteries for my GXI going to a battery switch and occasionally I'll switch over (while running) to ensure my house/backup battery is charged. Just trying to determine if the momentary switch while running is enough to cause damage. I suppose I'll start shutting down and cranking off the house battery, just curious why its a no-no.