Volvo Penta 5.7 GXi-C won't idle

[NAIA2]

2002 VP 5.7 electronic fuel injection w 450 hrs. I replaced fuel pump, rotor and distributor cap last summer. Has been running great . Got back to marina after running smooth/great for hours, turned off motor, went to re-start 2 minutes later and wouldn't idle and difficult to start. I could keep it alive by pumping throttle in neutral. 2 days later ran great for hours, no problems. 2 days after that, ran great for hours, then same thing. It wouldn't re-start or idle without pumping throttle in neutral and was very rough for the 5-10 seconds it would run. I Thought since problem came on intermittently, it may be sticky IAC valve. Replaced that, and presumably reset it [turned key to first position where fuel pump beeps twice for 5 seconds, then OFF position for 10 seconds] but no change. It will start with aggressive pumping of throttle [in neutral] and runs for about 5-10 seconds. Big sucking sound at throttle body when it dies. Thanks for any help

 

[NAIA2]

Just working on it now, when it is running, it is smooth, not rough, but requires pumping throttle to keep it going. Notice loud sucking sound near or at throttle body when running, increases when dying. No obvious hose off or anything. PCV valve? I would guess both [low and high pressure] parts of fuel pump are OK if will start and run for a few seconds?

 

[NAIA2]

Reading links in forums, Starting to think it may be the fuel pump. Can anyone explain briefly how to test via Schrader valves? Can I pick up the gauge at an auto parts store or do I need a special piece/part. I'll remove and clean the fuel pressure regulator first, seems like it should be easy[?]. BTW, the antisiphon valve was replaced last year. I'll check pump fuses too.

 

[NAIA2]

update. pump fuse OK. cleaned pressure regulator, carb cleaner to throttle body etc. no change. noticed wire harness to pump looked a little kinked, maybe a bit warm. moved it around a bit and straightened out. boat started like new, ran for a bit then stopped. started up again, ran rough, ran back to straighten the harness while running and ran great. seems weird, but i think the wiring is kinked or something. will re-wire and recheck tomorrow. I am glad i didn't spend $700 on a new pump before figuring this out. Just 1 more thing to check if there is a problem w fuel pump.

 

[mandmj]

have you tried pulling the codes? Rinda codemate will do this for not too much money, but you can also do the same w/ an LED and a paperclip if you google MEFI code reader...

 

[NAIA2]

mandmj, thanks. I have no idea what Rinda codes are, but now that I know the term, I can look them up and figure it out. BTW, I cut out the quick connector between the Hi press pump and wiring harness [which was getting hot] and reconnected the wires and now runs good. Seems strange to me that this would be the culprit...although it did save me $1000 for the pump, so far. the guy at the marine shop thinks its just a coincidence, we'll see. He also said always clean the pressure regulator when changing the pump or it will result in increased pressures and shorter life. I didn't do this last year when I changed the pump. I wonder why connector went bad ? drawing too much current due to problem w pump[?] or just went bad. the heat suggests increased resistance. The hi press pump is warm ,not hot. any thoughts?