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V/p 5.7gi fuel in map sensor vacuum line

Schoorthing

New member
Was out for a ride today boat was running great, shut down for about an hour upon restart boat would not plane, no power. Grabbed a mooring to check things over, everything plugged in all ok. The boat started and ran great, I was about an hour from the inlet so I went for it, I ran 25mph all the way back in. When I got to the no wake zone it was running rough at idle and really rich. When I got to the dock I grabbed my scan tool, code 33 for map sensor. I pulled the vac line off the map and it was full of fuel. Any ideas or advice would be much appreciated. I have not had a chance to check fuel pressure yet but I will. Thanks!
 
Might be best to give the year of the boat and the specific VP engine model number. You will typically get more help that way.
 
The boat is a 96, the model numbers are worn off the cowl. I bought this boat last year with a bad engine and repowered it. The previous owner had no record of the model number. I am guessing early build 96 or 95 because it is coupled to a dp-c1 drive. Hope this helps that's all I have. Thanks!
 
Good chance you fuel pressure regulator shares the same vacuum line with your map sensor.

The regulator may have started leaking and pushing fuel back through the vacuum line into the intake and into the Map. Pull the line off the regulator and plug it. Attach another line to the regulator and put it in a container, fire off the engine. Watch for fuel coming out of the line from the regulator.
 
Do you have one of these reservoirs mounted high on the back of your motor? They often flood fuel back into your intake and give you a rash of problems. Remove the line running from the reservoir and see if you have fuel coming out of it. If you do, your needle valve is likely stuck.
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Are you talking about the rubber fuel hose that goes from the base of the tbi to the top of the vst? Appears to be a vent? I pulled the line and there was fuel in it. I swapped the map with a known good and the boat runs great, pid readings at idle on the old sensor where 16.9hg 4.99v on new sensor all in range at 10.3hg and 1.3v. My worry is that the failed map is not the root cause, just result of fuel contamination.
 
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Are you talking about the rubber fuel hose that goes from the base of the tbi to the top of the vst? Appears to be a vent? I pulled the line and there was fuel in it. I swapped the map with a known good and the boat runs great, pid readings at idle on the old sensor where 16.9hg 4.99v on new sensor all in range at 10.3hg and 1.3v. My worry is that the failed map is not the root cause, just result of fuel contamination.
Where are you located?
 
If it's the vent line from the top of the reservoir to the intake, then , there should not be fuel in there. Again there is a needle valve in the top of this reservoir cap that controls that. Often times that needle valve will get stuck open and allow fuel to flow in and flood the engine.
 


Thanks for the info, that makes perfect sense to relocate the vent line. Now to find where to do so!! I would like to think the float is not sticking, I had the vst out when I repowered the boat last year and the float and needle where ok. I would hate to remove the cover to check unless absolutely necessary.. that gasket cost me $60 something bucks lol..
 
Go to eBay and search "VOLVO PENTA 3850374". Unfortunately the kit will not come up right now because no one has one for sale. They are a bit hard to come by. But you can "save this search" and be alerted as soon as one is listed. You will see that I just got someone hooked up with the whole kit for $28 by doing this. It may take a while, but when that kit pops up for sale, I recommend you buy it, even for insurance as long as the price is reasonable. These kits are going extinct.

Not just for this part, Entering VP part numbers and saving the search is great for the hard to find parts. You know as soon as they pop up, and you can often get deals. Especially in the off-season.
 
Go to eBay and search "VOLVO PENTA 3850374". Unfortunately the kit will not come up right now because no one has one for sale. They are a bit hard to come by. But you can "save this search" and be alerted as soon as one is listed. You will see that I just got someone hooked up with the whole kit for $28 by doing this. It may take a while, but when that kit pops up for sale, I recommend you buy it, even for insurance as long as the price is reasonable. These kits are going extinct.

Not just for this part, Entering VP part numbers and saving the search is great for the hard to find parts. You know as soon as they pop up, and you can often get deals. Especially in the off-season.


Ok will do thanks! If I find a rebuild kit would you recommend returning the vapor hose to the original location or just leave it vented to the tank?
 
It seems to be the opinion of many that returning the line to the gas tank is best. So far I have done neither. I have the kit in my drawer as "insurance", but either way I still plan on running the line to the gas tank. That way the thing can flood from here to eternity and it will just run back to the tank and your boat won't stall out because you're not flooding the engine. In a sense, your bypassing the part of the system that is most prone to causing you breakdowns. I'll be running my line to the gas tank this off season when it's not 109* outside.
 
It seems to be the opinion of many that returning the line to the gas tank is best. So far I have done neither. I have the kit in my drawer as "insurance", but either way I still plan on running the line to the gas tank. That way the thing can flood from here to eternity and it will just run back to the tank and your boat won't stall out because you're not flooding the engine. In a sense, your bypassing the part of the system that is most prone to causing you breakdowns. I'll be running my line to the gas tank this off season when it's not 109* outside.

Alrighty, I'll let you know how I make out. Thanks for your help.. much appreciated
 
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