1999 Volvo Penta 5.0 Gi bogs

Frickenrob · Jul 12, 2012

1999 Volvo Penta 5.0 Gi when at full throttle from idle bogs down. When I pull back to idle n then slowly increase rpm's it runs fine. I just had brand new low pressure and high pressure fuel pumps installed. Problem is still there. I installed a new fuel filter water seperator when getting my boat ready for the season after sitting for 5 months. Stabilized fuel before storing although I must admit I did not fill the tank to full. I have installed a throttle sensor from another boat and that's not the problem either. Spark arrestor is clean and I just replaced the plugs, rotor n distributor cap. Only thing I can think of is the ECM??? Very pricey tho. Anyone have any suggestions as I have exhausted my resources for my level of mechanical aptitude.

dypcdiver · Jul 14, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Ok I'll reply to you, but cannot be of much help as I have a similar problem which I think is related to low engine temp. I have no problems with WOT of 5000 Rpm, but pulling a mono skier up it bogs down for 1 or 2 seconds and then acts normally. I had an impeller shed some vanes and suspect there might just be a blockage in the thermostat housing bypass passage. I'm waiting on gaskets and a new stat before I can confirm. My motor is also a 1999 5.0 Gi with 500 hours and runs at between 120 and 130 degrees.

Frickenrob · Jul 14, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Thanks for replying. My engine temp is fine. Just wondering if the ECM might be the issue. Of course I am hoping for a different solution as Volvo does not make the one I need anymore. Instead they have come up with another model that apparently has a different wiring harness than the original so it's a cou

Frickenrob · Jul 14, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

....couple gran by the time it's all said n done. Ouch!!

Iamwildman · Jul 16, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

I have all the same symptoms you have dypcdiver. My port side engine is bogging down when I try to get out of the hole and my temp is low aswell, around 120 when underway (port side aswell).

Frickenrob · Jul 17, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Ok. It's not the ECM. Installed one from a like boat and still bogs down at WOT. Still have no clue what it might be. My thoughts are leaning toward electrical. Where's Don S when you need him most.

Tail_Gunner · Jul 17, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Not your ecm dont worry. Id be willing to bet it's your fuel cell they were painted internally and the paint degrades clogging up the whole system. Ahh now the bad news take it apart and clean it and that takes a bit of skill and knowledge of gasketes.

You can also take the cover off your tbi...put a neon light on the spray pattern...look for drips and a uneven spay pattern. They could very well need cleaning there 15 yrs old and in a marine enviroment.

Frickenrob · Jul 18, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

If by the term fuel cell you mean fuel pump, I have changed out the low pressure as well as the high pressure pumps with brand new ones.. The problem still exists. One of the injectors is not working properly but the injector has been checked out and is fine. It's somethng else which is why I'm assuming the electrical signal that
makes it work properly is the culprit. the fuel is good too. I have run it from another tank with brand new clean fuel.

JON NEELEY · Jul 18, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Frickenrob said:
If by the term fuel cell you mean fuel pump, I have changed out the low pressure as well as the high pressure pumps with brand new ones.. The problem still exists. One of the injectors is not working properly but the injector has been checked out and is fine. It's somethng else which is why I'm assuming the electrical signal that
makes it work properly is the culprit. the fuel is good too. I have run it from another tank with brand new clean fuel.

I have a 5.8 vp in a four winns that does the exact same thing. It will pull me up on my ski but it bogs exactly as you described and I too have done all the maint you have done as well. The engine runs awsome at any speed but the one thing you didnt mention that mine does is come down to 500 at idle and should be 600. Are you idling low at temp?

Frickenrob · Jul 20, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Problem fixed!! The culprit was a bad oil pressure sensor which is located on the block which sends a signal to the ECM which tells the engine to not fire on 4 of the 8 cylendars as a protection mode while in WOT. My warning alarm wasn't working so then the engine protects itself from over pressurizing by doing that. Thanks to all for your input. It sent me down the right path......ARRRRRRRRR!!

PS: Good luck to all!!

JON NEELEY · Jul 20, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

I was wondering if your oil pressure guage ever showed low pressure or is there a seperate signal to the guage?

Frickenrob · Jul 20, 2012

Re: 1999 Volvo Penta 5.0 Gi bogs

Not really sure cause I never heard the audible alarm that is inop. Whatever the case, I do know that it was never too far outta wack or I am sure I would have noticed. The lesson learned for me is if it ever does that and you can't figure it out, it is probably because your boat is protecting itself. Probably electrical in nature if it is not the fuel pump. Apparently it is the exact same symptom of needing a new fuel pump (I now have a brand new one-of course) which is way more common. From this point forward though I am going to run Sea Foam or Berryman's in my fuel every other fill-up due to what I have learned what ethynol can do to your fuel system. It's worth looking into if you like your boat and don't like costly repairs. ARRRRRRRR!!!!

1999 Volvo Penta 5.0 Gi bogs

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