5.0Gi PWTR mystery problem - Fuel sys??

[asmith147th]

I?ve got a problem with my 1999 Volvo Penta 5.0Gi PWTR that is in my 22ft Sea Sport. My mechanic hasn?t been able to fix, so thought I?d ask the forum for any ideas. I?m convinced this is a fuel supply issue, but I guess it could be electrical. It began with not being able to start ? I?d run it in the driveway before a trip. It would start easily and run smooth in the drive, but when I got on the ramp, the engine would just crank and never catch. I?d get it back out of the water and sometimes it would start, sometimes not. I?ve replaced the high pressure fuel pump twice and the low pressure pump once. My mechanic has replaced the relay twice, after which it seemed to start and run fine. But then when I took it out, after perfect operation for about 30 minutes, the engine quit suddenly while cruising at 3200rpm ? no cough, no rough running, no warning ? and wouldn?t restart. This has happened twice, each time after my mechanic has gotten it running again by replacing a relay. I?ve cleaned the fuel tank pickup tube, cleaned all debris from the tank, made sure the tank vents are clear and removed the check valve ballbering from the pickup tube on advice of my mechanic. the fuel filters were changed out less than 50 hours ago. I see no water in the fuel I drain from the filter.
When I turn on the ignition, I do not hear the electric primer pump that I usually hear before starting so am guessing another relay is blown.

any ideas at this point would be greatly appreciated.

 

[Don S]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

When it doesn't start, does it have spark? If it does, does the fuel injectors squirt fuel while cranking?

 

[Tail_Gunner]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

high pressure fuel pump twice
low pressure pump once
replaced the relay twice
When I turn on the ignition, I do not hear the electric primer pump that I usually hear before starting so am guessing another relay is blown.

Your blowing a lot of electical components way to many...Know if that was your car would you take it back to the same shop....I would identify each component in the system and make sure it belonged there and not some substituiton...Next would be to get out the meter and check for the short you seem to have going on.

Are you sure those components were blown.....

 

[Don S]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

I'm curious as to WHY you changed the parts. Were they tested bad or just replaced because the tech didn't know how to test anything?

 

[asmith147th]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

When it doesn't start, does it have spark? If it does, does the fuel injectors squirt fuel while cranking?

I haven't checked for a spark or pulled an injector. I sprayed ether into the barrels of the carb when it quit at sea the last time and the
engine ran briefly - until the ether was gone I assume. this leads me to believe that there is spark and that no fuel is getting past the high pressure pump. I'm not a mechanic but I will check for spark - not real confident about pulling an injector though.

 

[Technologic80]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

I haven't checked for a spark or pulled an injector. I sprayed ether into the barrels of the carb when it quit at sea the last time and the
engine ran briefly - until the ether was gone I assume. this leads me to believe that there is spark and that no fuel is getting past the high pressure pump. I'm not a mechanic but I will check for spark - not real confident about pulling an injector though.

Suspect a failing coil or a failing ignition module (should be IN the distributor - Delco EST) or even a failing coil pickup. Do NOT just start replacing those parts, unless you have an unlimited supply of money...lol..there are test procedures for determining which is bad.

However, ignition modules can fail intermittent (my experiences) and be hard to determine via tests.

 

[asmith147th]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

I'm curious as to WHY you changed the parts. Were they tested bad or just replaced because the tech didn't know how to test anything?

my mechanic tells me he tested the pumps and both failed pressure tests. he also says the relays he replaced were bad - I've got the old ones and will test them myself as soon as I figure out how and get a decent multimeter. the mechanic I've been using is the most
knowledgable in my town - I've been through the rest. that doesn't necessariy mean mean much since I live in a fairly small town.

 

[jerome radtke]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

Is this a carbureted engine. If so, it almost sounds like a stuck float needle valve. Which does not allow fuel to enter the carburetor. The fuel float area remains under pressure, which in turn is the reason the fuel pump does not run. If the needle valve is not opening , there is then no fuel in the carb for the engine to use. Hence why it runs on ether but then stops.

 

[Tail_Gunner]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

Have a read and take a look at your fuel cell...http://forums.iboats.com/showthread.php?t=545407&p=3819171#post3819171

 

[asmith147th]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

thanks alot for your response. going to ask the mechanic to check the coil, module and pickup on monday. just a few questions if you're still willing. when I look at the ignition schematic I see two coils - I'll try to post the schematic. is that right? this thing has two coils? one is wrapped around the spindle??? never seen a coil that looks like that before. and my second questions is, when you say "pickup" do you mean the cable between the ignition module and the coil? thanks again for your help.

 

[asmith147th]

Re: 5.0Gi PWTR mystery problem - Fuel sys??

yeah, thanks. I had seen that post before - evidently the fuel cell shown in the pictures attached to that post isn't on the PWTR version of the 5.0Gi, but I do have a fuel reservoir directly under the high pressure pump and have wondered if I might have the same problem. the reservoir is a different shape and a little harder to get at though, so haven't gone there yet. have you heard of the flaking paint issue affecting other versions of the 5.0Gi? mine's a 1999.