No power, will not plane

[aram]

2003 Volvo Penta 5.0 GXi-DF
3869218
4012094566

Power Loss/ no power at WOT( or anywhere in between) / will not plane

Compression 148-160

New- Plugs, fuel pump, cap and rotor,

Fuel pressure steady at 60 P.S.I.

Engine RPM fluctuation 535-640 (target speed 600RPM)
it has a slight "miss"? it is not a steady pulsing idle, smooth's out then it has a "miss? then idles up then back down to around 600 (No rhythm to this, it is at random intervals but not sporadic)


no engine codes

injectors cleaned

Power loss on each cylinder when shut down(I use DIACOM)


RPM "immeadiately" up to 2400 RPM range at WOT but climbs very slowly after that and peaks around 3200RPM not enough for plane.

@ WOT
ECT 159.8 deg f
Manifold Air Temp 49.1 deg f
Manifiold absolute press 29.1 inHg
map sensor voltage 4.0
injector pulse width 6.8 ms (both banks)
IAC posistion 138.0 #
Throttle Posistion 99.6%
spark Adv 27.7 DEG
cam retard 45.54 DEG
fuel flow 12.06 GPH
oil pressure sensor voltage 5 vdc
O2 sensor voltage (1)454mV (2) 464mV

Bellows replaced 2yrs ago

353 engine hours

While out yesterday I disconnected the oil pressure sensor and then the coolant temp sensor and no change in performance. No knocking, pinging, rattling, just the sound of a wide open throttle sucking massive amounts of air and giving no power in return.

I have had the well known fuel pump whine and replaced pumps twice so far. (None under warranty. unfortunately)
checked fuel tank vent
checked spark to plugs on all cylinders (inline spark tester)
vacuum test at manifold float's between 16-17 in Hg at idle with engine RPM fluctuating between 535 and 640.
cleaned the old paint chips from the fuel pressure regulator
checked and shortened the fuel line from tank to pump
new fuel filter/water separator with pump change

I have not tried yelling obscenities and hitting everything with a bigger hammer. I want to try everything else first.
What am I missing? Thanks for the help

 

[89retta]

Have you tried fresh gas ?

 

[alldodge]

injector pulse width 6.8 ms (both banks)
Throttle Posistion 99.6%
spark Adv 27.7 DEG
cam retard 45.54 DEG
fuel flow 12.06 GPH

This is what I'm seeing at 3200 RPM
Throttle position is WOT (good)
Spark advance is almost full but not quite there because RPM is not above 3700 RPM (good)
Cam sensor is retarding timing (not good)
Fuel flow at 12 GPH (good because ECU is trying to retard timing because of an issue)

Suggestions
Remove clean and reconnect cam connector on distributor
Replace distributor cap (the crab type caps are notorious at going bad) if it does not turn out to be the issue, it is a good thing to hang on to a spare when other things start happening

 

[aram]

OK, so "accidental" achievement and know lesson re-learned.
Distributor cap and rotor button changed about 3 weeks ago. Only 2 sea trials since. Both with same result as current symptoms and same "root" problem. No power.
I just did as suggested, "Clean cam sensor", while headed to clean the cam sensor I noticed the rotor button looked odd. Sure enough the center pickup has fallen off and fell beside the cam sensor. Luckily not damaging it in the process. So cleaned all connections, removed cam sensor and cleaned, (had small amounts of rust particles from rusty dist. shaft). Will order a new rotor button install and try that.
Lesson here, don't buy after market parts. Only buy OE. Duh. Hopefully this will resolve my issues. Thank you very much for your time and knowledge AllDodge
:facepalm:
89retta, good looking out on the gas side of the equation, however I keep the tank topped off, always use Stabil, rarely use ethanol blended fuel (only when in a pinch), and never Deep winterize the boat, I do partial winterizing because I use the boat almost every weekend and fill up after each use. Closed cooling so I drain all raw water and go with it. That has been working great for 5 years now. I learned early on that not using boats destroys them faster than most other things.
Thank again for your help guys.




85 Bayliner Trophy 2460 Hardtop 03 VP 5.0 GXi
91 Searay Weekender 280 Twin 5.7 Bluewater Mercs
88 Sprint Bass Boat 88Johnson SPL

 

[alldodge]

Will be good to replace rotor, but the caps is what goes out most often. they can llok great and still be bad, just info. Look forward to hearing how you came out

 

[kenny nunez]

I am just guessing but is the flame arrestor clean ? Does your boat stay in the water ? Or is it normally on a trailer ?
Is the transom flexing ? What brand of boat ?

 

[aram]

I am just guessing but is the flame arrestor clean ? Does your boat stay in the water ? Or is it normally on a trailer ?
Is the transom flexing ? What brand of boat ?

Flame arrestor is clean, throttle plate is clean, stays on trailer but hardly miss a weekend on the water. I do not believe the transom is flexing, I was thinking it may be the drive causing the issue but it all seems to be "loose" and fine. shifts smooth and quiet, it is the original 280 drive.
1985 Bayliner Trophy Hard Top 2460 2003 VP 5.0 GXi-DF

 

[Bondo]

Ayuh,..... Welcome Aboard,...... I guaranty the answer is in this list,....

As found in the Adults Only Section,..... [h=2]List of possible causes of low WOT[/h]

 

[QBhoy]

Another MPI/GI/GXI distributor post

 

[kenny nunez]

When you had the injectors cleaned, was there any rust particles in the inlets of the injectors ? I was at a friend’s shop and he showed me a fuel rail from a Volvo that was made of plain steel and rusted on the inside.
Mercruiser uses stainless steel for the fuel rails.

 

[frantically relaxing]

Some random thoughts based on days gone by:
Ignition module?
Crank sensor?
Knock sensor?
Something wrong with the prop and/or the drive aside from the obvious?

 

[kenny nunez]

Just a a question. If you release the gearshift so that the engine can rev up in neutral will it go over 3200 rpm ?
Since you have a later model fuel injected engine than the drive I was wondering if your engine’s control system is similar to a Mercruiser MPI where the engine cannot rev more than around 3200. There is a switch that must be closed to let the computer know that the outdrive is in gear.

 

[Stearns250]

I had the same issue, that's if you are still having issues, mine ended up being the coil, I changed the coil and got all my power back.

 

[bans25]

I know this is an old thread but aram what was the end result? I am having almost the same exact problem and about to hit everything with a really big hammer! lol

 

[GA_Boater]

I know this is an old thread but aram what was the end result? I am having almost the same exact problem and about to hit everything with a really big hammer! lol

Why we have a 90 day inactivity rule;

You're asking the OP to answer a question. Said OP last visited April 10, 2018 and didn't answer questions asked while we tried to lend a hand and you are expecting him to tell you the end result.

Adding insult to injury, you start off with acknowledging the thread is old. This thread is closed!