Volvo Penta 5.7 GSI PEFS fuel problems

[Shedrico]

Hi there looking for some help

My friend has just bought a boat and asked me to have a look at it as wasn't running right.

The inital problem was that it was running a bit lumpy and wouldn't reach full RPM and was a bit smokey. Apparently the boat had been sitting for two years but was winterised. After a bit of investigation i found that two of the HT leads where round the wrong way and the distributor had been adjusted. So i removed the spark plugs and one of them was gunked up.

I replaced all 8 spark plugs and leads, distributor cap, rotor arm and coil pack and this seamed to solve the engine running lumpy and RPM issue.

The problem now is when it idles it stinks of petrol/Gas but runs ok, there is also alot of unburnt fuel coming out the exhaust. When I lift the spark arrestor on the carb it looks like there is two much fuel coming out the injectors at idle. Took the boat out for a run and it was ok for a bit then RPM has dropped again.

Don't have the diagnostic software to to plug in but i am hoping its something simple like a faulty sensor. I don't want to start changing control moduels etc

Any help would be greatfully appreciated

 

[ericga]

Start by checking the fuel pressure. You'll then know if you are dealing with a fuel or sensor/ingnition issue. There should be a shrader valve on top of the high pressure pump to connect a gauge. Should read 28-31 psi when pump is running.

 

[Shedrico]

Thanks ericga I don't have a gauge at the moment to stick on it but i will get one and try it to see what the pressure is. I will let you know what readings i get. Thanks for the reply.

 

[ericga]

I found mine on amazon for 20-30$ I believe. It's difficult to troubleshoot electronics without a scan tool but an easy check would be the MAP sensor. There is a hose going from the throttle body to the map sensor (usually attached to the exhaust manifold bracket). Make sure connection are tights and hose is leak free. Also the coolant sensor (the one on the thermostat) is a common failure. You may want to inspect it. Both can make your engine run rich.

 

[Fun Times]

^ +1 (really good advice ericga, :thumb
Also ensure the engine is actually getting up to temperature as a stuck open thermostat would allow the engine to run to cool causing fuel fouling. Using an infrared temperature gun is usually the easiest way to check engine temp.http://www.harborfreight.com/catalogsearch/result/index/?q=infrared+temp+gun

 

[ericga]

Thank you Fun Times. There is also a way to test the coolant sensor by measuring sensor resistance when cold and compare values when hot. Accessing the inside of the sensor connector with ohmmeter probes could be challenging.

 

[Shedrico]

Thanks ericga and Fun Times for your suggestions I have tried everything both of you suggested, fuel pump pressure is ok, Ohm's of temp sensor relate to water temp according to the chart, checked the IAC valve, throttle position sensor, MAP sensor and hose and also went through ignition system again bit still the same. I don't think it's temperatue related as its doing it from cold to warm and the sensor is ok. I got a EFI diagnostic manual which has loads in it but not very much on over fueling.

The manual keeps asking for DTC's Diagnostic Trouble Codes which i don't have the scanner or code tool to read so we may need to get the experts in to read the fault codes.

Thanks for your reply guys if i get to the bottom of it I will let you know.

 

[ericga]

Give the flame arrestor a good bath if not done already. When you say too much fuel coming from the injectors there is no dripping right? Also check the knock sensor and make sure connection is good.

Engine Won't Reach Operating RPM. Check

http://forums.iboats.com/forum/engi...ves/302506-list-of-possible-causes-of-low-wot