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97 258 vista 7.4 VP DP

Been having problems with the fuel pump making a wizzing noise at any RPM. It starts and idles fine but when I slam it down to full throttle it doesn't give it? It will eventually get it to a high RPM but takes longer when the pump seems to be making that wizzing sound.

I've also noticed that once in a while the noise will stop but just before it does the motor cuts for a half second and runs fine after that with no restrictions.

I did replace the fuel filter 2 weeks ago

My fuel cap is always tight and I never really use more than 1/3 of my gas tank before I fill it up. Each time I fill it up without a miss gas will always spew out of the air valve. No mater how slow I go it never fails to splash me....... Just saying maybe that could be a part of the problem don't really know anyone else who constantly gets splashed.

I tried locating my anti siphon valve just it case it was that but had no luck finding it if anyone has my boat and could point it out it would be nice.

I did how ever try tapping the fuel pump and the noise did change pitch and sometimes completely stop following the gentle taps.

Anyone have any ideas? From what I read on here it does not appear to be a fuel problem.

Would like to know where to begin looking for clogs? Can I just take it apart one piece at a time and check all the gas hoses for blockages?

Has anyone come across this wizzing noise?

Thanks for the help

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

If you can hear the fuel pump while driving the boat, it's probably going bad. I've replaced both of mine on my '98. I've also had problems with the check valves sticking. I've had rings of varnish stick them closed and also rings of varnish break loose and keep open. When stuck open, vapor lock is a bigger problem on a hot day since the gas can be pushed back into the tank easier. The new pumps have a little more pressure than the originals, which seems to help with the vapor locking too, if you've ever experienced it. I don't have any vapor lock issues on the hottest days with the new pumps.

The check valve should be the fitting on the tank that your rubber fuel hose connects to. You can remove it and you should be able to tell if the ball/spring are working correctly. If it smells like varnish, you can clean and reuse.

As far as the gas vent goes, you should not be getting sprayed. It's possible that the maximum fill level for your tank is higher than the vent, which could cause this. I had a smaller boat that did this and I added a check valve in the vent line that was made for fuel vents and took care of the issue. I'd install one of these or relocate the vent if you don't find any other problems, but before doint that, you should examine the routing of the vent hose to make sure it's not kinked or doesn't have any dips in it that would hold gas - kind of like a p-trap in a sink drain does. The pressure of the gas going into the tank could be pushing some gas stuck in the vent hose out.

Hope this helps...

Joe

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USCG 50 Ton Master Inland/OUPV Endorsement+Towing

1998 278 Vista - Twin 4.3 GLs, Kohler 4KW Gen, AC/Heat.
1999 Yamaha Waverunner SUV
2003 Yamaha Waverunner SUV w/MR-1 HO conversion

Any clue on the the whereabouts of the anti siphon valve?

On a scale of 1-10 how hard was it to replace the pumps? If you did the work yourself....

Thanks

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

The check valve is the barb fitting on your gas tank that the rubber fuel line clamps to. When you un-screw it from the mated fitting, you should see a ball and spring in the base of it.

The fuel pump should be easy to change yourself. I'm not sure where the pump is mounted on the 7.4L engines, but on the 4.3L engines it's right on top on the front of the engine so everything is easy to get to. If your pump is mounted to the top of the filter housing, yours is similar to mine and shouldn't take but 30 minutes or less to install.

Joe

_________________
USCG 50 Ton Master Inland/OUPV Endorsement+Towing

1998 278 Vista - Twin 4.3 GLs, Kohler 4KW Gen, AC/Heat.
1999 Yamaha Waverunner SUV
2003 Yamaha Waverunner SUV w/MR-1 HO conversion

Looked over everything and looks like I have 2 pumps on there. One at the front right over the fuel filter and the other at the back of the engine close to the distributor. Sucks that the one making noise had to be the one at the back............... Both parts seem to be installed the same but from what I've read one has to be high pressure and one low? Anyway I can't get to the part # I have to take it apart to see it.

I was maybe thinking of adding some additive in there to MAYBE!!!!! clean it out but at 17$ a bottle for sea foam I'm thinking I should just change the part right off instead of putting $$$ in additives.

Might try to disassemble this afternoon its pretty tight but looks like there is only a couple bolts holding that together.

Could someone advise me if I need to bleed anything first I imagine only the gas in the lines will flow and nothing else?

Thanks

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

The one at the front is the low pressure one.

Graham

Finally found the part # its 3855399 but it was changed to part # 3855958. Anyone know of a place where I can get non Volvo replacement parts? I saw a couple places that were selling regular automotive parts but they didn't have my model on hand. Its half the price of the Volvo OEM parts.

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

The Sierra replace part number for that pump 18-7330. There are several places through Amazon, plus iBoats, etc. that have them for $160-$190. My local Napa can even get Sierra parts sometimes overnight but they are usually higher priced.

You should not have to bleed anything when replacing, but just in case there's some pressure built up in the line, you might want to put a rag over the outlet fitting when you loosen it.

_________________
USCG 50 Ton Master Inland/OUPV Endorsement+Towing

1998 278 Vista - Twin 4.3 GLs, Kohler 4KW Gen, AC/Heat.
1999 Yamaha Waverunner SUV
2003 Yamaha Waverunner SUV w/MR-1 HO conversion

Took the darn c clamp or what ever you call that retainer on the electric fitting and lost it in the engine..............@#$% It didn't fall thru to the bottom and I can't find the part # for the dealer and my local auto parts have never seen such a clip............

Just one of those weeks I guess...........

I'll have to improvise

Does anyone know what I'm talking about and have the part #?

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

If you haven't tried already, get one of those inspection mirrors that telescope and see if you can find it. You might have to use a flashlight along with it.

_________________
USCG 50 Ton Master Inland/OUPV Endorsement+Towing

1998 278 Vista - Twin 4.3 GLs, Kohler 4KW Gen, AC/Heat.
1999 Yamaha Waverunner SUV
2003 Yamaha Waverunner SUV w/MR-1 HO conversion

I finally did find it but I have to admit I was close to being stuck in there. It was wedged in between 2 hoses.

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

The low pressure pump feeds the high pressure pump, if the low pressure isnt pushing enough or you have a restriction it will cause that issue.

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Brian Borchik
The Winds of Cold Springs Harbor Marina
Baldwinsville, NY

So the problem could also be the low pressure pump not feeding enough to the high pressure?

Could that be the cause of the noise?

If its a restriction how would I go about determining where it was?

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

That is correct, the low pressure pump feeds the high pressure reservoir. I would start at the pickup at the fuel tank, there is a tube that goes down into the tank that has a screen on it that could be plugged. There is also a anti-siphon valve on top of it that the fuel hose goes onto that could be plugged with debris. Next step is testing the low pressure and making sure its running and if so if it has the proper fuel pressure. If all that is good then you need to take the lid off the fuel reservoir and look for debris or water. If you dont see anything easy then chances are you may want to either get a service manual or take it to a dealer or someone who has the manuals with all the specs on it.

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Brian Borchik
The Winds of Cold Springs Harbor Marina
Baldwinsville, NY