5.7GL V8 Power Issues

[sgnt_pepper]

Hi, My Volvo penta 5.7 is having issues with getting me moving. The engine runs ok unloaded but when I take the boat out the engine can't increase above 2000rpm and if I hold the throttle open the revs drop off to an eventual stall of the engine. The boat hadn't been used for nearly two years but was fine when I last took it out although it has been run on the mooring every week to keep thing lubricated and turning. It has just been cleaned, antifouled and serviced along with a compression check which were both ok, the 100 litre fuel tank was a third full so I filled this with fresh fuel and changed the filter but the problem remains. Any advice where to look next would be greatly appreciated

 

[1stboat]

the engine can't increase above 2000rpm

Sounds like its going into limp back mode. That happens when the engine overheats, there is not enough oil pressure, tps, or some other sensor is telling the computer that something isn't right. In may case it was the oil pressure sensor that was bad. I replaced it and it worked fine.

Search the threads here for how to hook up a led light up to the MIL on the engine wiring harness so you can see what sensor is giving the computer trouble.