Volvo 5.0 Gi PEFS running issue

[deh4170]

First thank you in advance for any help in resolving this issue I am having...I have a 2001 Chaparral 280 Signature with twin Volvo Penta 5.0 Gi PEFS with SX-M outdrives. Sorry to be long winded, but I think explaining what has happened up to this point may help in determining next course of action. At the beginning of this season I experienced an issue with my port engine...would run smooth and rev up just fine when in neutral...once I put engines in gear and advanced the throttle, port engine would die. Removed the fuel pump and replaced (disassembled old pump and the normal "paint" issue had the screens blocked)...once new pump was on all ran well for a few trips. Issue occurred again...started checking all connections and discovered the MAP sensor connector had corrosion on the ground lead...cleaned connector and engine fired right up and ran great. I thought I would check all connectors for corrosion and treat any signs of a problem. I had the port engine running and BARELY touched the (2) relays sitting in front of the TBI and the engine started missing and died. I first removed the relay on the left side (believe this is the ignition/fuel relay) and there was corrosion present and one of the tin plated spades on the relay had corroded down to the copper...checked the relay on the right (believe this is fuel pump relay) and no corrosion was present, but to be on the safe side I replaced both relays and everything was smooth as silk again. This past weekend took the boat out...noticed as I was getting on plane that things felt sluggish, but had just put in 400 lbs of fuel...so it didn't seem that big of a deal. As I was going down the lake I looked at the port oil pressure and it was pegged at 80 psi and then took a nose dive to 0 psi and then bouncing all around. I immediately came off throttle and could smell burnt oil for a brief moment...no smoke anywhere...no alarms...but engine was running rough. Last night I went up to the boat and checked fire at each plug with in-line tester (all ok)...pulled plugs and some appeared really sooted and plug in #3 cylinder had oil around the threads of the plug...so I changed them all. Pulled distributor cap and rotor...had a tiny bit of build up, but nothing big...was able to clean easily with emory cloth. Checked oil pressure switch, which had some corrosion that I cleaned off of the spade connector. Pulled the PCV and was able to blow through one and the air came back out the other...but I did notice that there was oil residue on the TBI, but unfortunately cannot take off the flame arrestor all the way due to clearance issues. After I did all of this, engine fired right up and ran smooth as silk...took the boat out and came on plane for about 4 mins oil pressure was steady and in sync with starboard engine...then pressure started bouncing...so I throttle down and engine was running rough again (still no alarms)...then I tried to go back on plane and the port engine would not get above 3000 rpm...no matter if I went full throttle. Could put port engine in neutral and easily hit 4000 rpm...but not if in gear and under load. When I turn the ignition switch I get the normal (2) chirps, but have never experienced an alarm on either engine. Could this be the S.L.O.W system? I plan on doing a compression test in a day or so, but if anyone has any ideas please share. Thanks again.

 

[Bondo]

Sorry to be long winded,

Ayuh,..... Welcome Aboard,...... Edit some paragraphs into that, I'll read it, 'n hopefully help ya,.....

I'm gettin' too old to deal with alphabet soup like that,....

I'll give ya credit, ya used punctuations,...

 

[deh4170]

At the beginning of this season I experienced an issue with my port engine...would run smooth and rev up just fine when in neutral...once I put engines in gear and advanced the throttle, port engine would die. Removed the fuel pump and replaced (disassembled old pump and the normal "paint" issue had the screens blocked)...once new pump was on all ran well for a few trips. Issue occurred again...started checking all connections and discovered the MAP sensor connector had corrosion on the ground lead...cleaned connector and engine fired right up and ran great. I thought I would check all connectors for corrosion and treat any signs of a problem. I had the port engine running and BARELY touched the (2) relays sitting in front of the TBI and the engine started missing and died. I first removed the relay on the left side (believe this is the ignition/fuel relay) and there was corrosion present and one of the tin plated spades on the relay had corroded down to the copper...checked the relay on the right (believe this is fuel pump relay) and no corrosion was present, but to be on the safe side I replaced both relays and everything was smooth as silk again.

This past weekend took the boat out...noticed as I was getting on plane that things felt sluggish, but had just put in 400 lbs of fuel...so it didn't seem that big of a deal. As I was going down the lake I looked at the port oil pressure and it was pegged at 80 psi and then took a nose dive to 0 psi and then bouncing all around. I immediately came off throttle and could smell burnt oil for a brief moment...no smoke anywhere...no alarms...but engine was running rough. Last night I went up to the boat and checked fire at each plug with in-line tester (all ok)...pulled plugs and some appeared really sooted and plug in #3 cylinder had oil around the threads of the plug...so I changed them all. Pulled distributor cap and rotor...had a tiny bit of build up, but nothing big...was able to clean easily with emory cloth. Checked oil pressure switch, which had some corrosion that I cleaned off of the spade connector. Pulled the PCV and was able to blow through one and the air came back out the other...but I did notice that there was oil residue on the TBI, but unfortunately cannot take off the flame arrestor all the way due to clearance issues. After I did all of this, engine fired right up and ran smooth as silk...took the boat out and came on plane for about 4 mins oil pressure was steady and in sync with starboard engine...then pressure started bouncing...so I throttle down and engine was running rough again (still no alarms)...then I tried to go back on plane and the port engine would not get above 3000 rpm...no matter if I went full throttle. Could put port engine in neutral and easily hit 4000 rpm...but not if in gear and under load. When I turn the ignition switch I get the normal (2) chirps, but have never experienced an alarm on either engine. Could this be the S.L.O.W system? I plan on doing a compression test in a day or so, but if anyone has any ideas please share.

Also, I did oil/filter change on both engines at winterization last fall. The Volvo manual states that the engine holds 6 qts with filter change...so that is the amount I placed in the engine. With that amount, the oil level is above the full mark on both engines...actually about what I would consider a quart more. Now, when I checked both engines the starboard oil is still extremely clean (only put @ 28 hrs on engines this season) and the port oil looks as if it was never changed. One thing that really stood out to me when I checked the oil level in the port right after this started is that there was oil almost all the way up the dipstick when I took it out...made me think oil was being forced up the dipstick tube. The oil viscosity appears to be consistent with the starboard engine and no milky appearance in the oil...just that it is dirty looking. Should the oil level should be within the hatch "safe" marks on the dipstick or should the oil level be above the "full" mark? When I have drained the oil previously, I can hear the pump sucking air from the oil pan...so I feel that very little old oil remained in the pan.

 

[dypcdiver]

My initial response is that you may have a piston ring problem. I suggest you have a compression test done on the offending engine which might give a clue as to what is the cause.

 

[deh4170]

dypcdiver...did a compression test yesterday and all cylinders tested @ 150psi except for #3...only about 10-15psi. So definitely a dead cylinder...can anyone advise if I can tell if it is a valve issue versus a piston problem? Also...I did have too much oil in the engine and pumped out old oil and replaced with new...made 100% sure level was within "safe" level on dipstick. After I tested each cylinder, I placed new spark plugs and now they all burn really clean except #3, which was wet with fuel...just curious if I could have a stuck valve? Going to possibly get inspection camera to see if I can tell which end the issue is coming from. Ran the boat and it runs pretty darn good just on 7 cylinders...its really hard to even notice because there is no obvious miss in the engine.

 

[revillot1]

If you put a little oil in the #3 cylinder and do a compression test, you should be able to tell if it is rings or not. If compression goes up, it's the rings. If not, probably a valve, rocker or pushrods or maybe a broken valve spring.
Can you take the valve cover off?
If so, watch (while turning engine over with coil wire off) the pushrods and rockers to see if they are going up and down. Also watch the valves and springs to make sure they move
Just my first thoughts of what I would check to get you back on the water again
Tony

 

[dypcdiver]

A stuck valve would not pressurise the crank case, which is why the oil creeps up your dipstick and gets dirty. But yes, do the test again with some oil in No. 3.

 

[deh4170]

Put the inspection camera in the cylinder and definitely saw damage around the outside edges of the piston...at this point cannot tell if it was a ring problem or pieces of a valve...will have to have the engine pulled at the end of the season to be for sure...thanks for all the help from the FEW that responded. Thanks again.

 

[dypcdiver]

Be careful running your boat with a duff cylinder as the fuel will still be getting in there but not burning, It will wash any lubricant off the cylinder walls and you then risk a seized motor. Also unburnt fuel can get into the crankcase and dilute the oil to the point where it cannot lubricate the rest of the engine. Your choice.

 

[deh4170]

dypcdiver...I am not sure if I can just bore #3 and replace piston in that cylinder...and remove the head and rework the valves...or if I should just replace the entire engine. Any suggestions on just reworking that cylinder?

 

[dypcdiver]

Not heard of anyone just re-boring one cylinder! You may find that there is little or no damage to the cylinder walls and a new piston and honing the bore will be all that is needed. A reasonable machine shop will be able to advise once they have seen it. You will have to plan on pulling the motor, as to change the piston will require the sump to be removed and there is seldom enough room on a boat for that to be done in situ.