Logo
Click for Volvo Penta parts and manuals!
Results 1 to 16 of 16
  1. #1

    Default V/p 5.7gi fuel in map sensor vacuum line

    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!

  2. #2
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.

  3. #3

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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!

  4. #4
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,567

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  5. #5
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.
    Click image for larger version. 

Name:	ScreenShot001.jpg 
Views:	15 
Size:	60.3 KB 
ID:	16401
    Last edited by Chris Rohde; 08-29-2017 at 10:11 AM.

  6. #6

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.
    Last edited by Schoorthing; 08-29-2017 at 10:54 AM.

  7. #7
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,567

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Quote Originally Posted by Schoorthing View Post
    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?
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  8. #8

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Newburyport Massachusetts

  9. #9
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.

  10. #10
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    You might also want to read this thread. Particularly from post #17-32.

    http://www.marineengine.com/boat-for...r-to-Fuel-Pump

    Also this one.

    http://forums.iboats.com/forum/engin...-0efi-stalling

    And this one.

    http://forums.iboats.com/forum/engin...r-modification

    All will apply to yours as long as you have this reservoir.
    Last edited by Chris Rohde; 08-29-2017 at 04:03 PM.

  11. #11
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    4,567

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Quote Originally Posted by Schoorthing View Post
    Newburyport Massachusetts
    Assuming you are at sea level...You need to know what the atmospheric pressure is where you are. Here at the Jersey Shore it is 14.6 to 14.7. Your map should read what your pressure is Key on engine off and it should match actual pressure.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  12. #12

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Quote Originally Posted by Chris Rohde View Post
    You might also want to read this thread. Particularly from post #17-32.

    http://www.marineengine.com/boat-for...r-to-Fuel-Pump

    Also this one.

    http://forums.iboats.com/forum/engin...-0efi-stalling

    And this one.

    http://forums.iboats.com/forum/engin...r-modification

    All will apply to yours as long as you have this reservoir.

    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..

  13. #13
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.

  14. #14

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Quote Originally Posted by Chris Rohde View Post
    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?

  15. #15
    Join Date
    Jun 2014
    Location
    Arizona
    Posts
    113

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    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.

  16. #16

    Default Re: V/p 5.7gi fuel in map sensor vacuum line

    Quote Originally Posted by Chris Rohde View Post
    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

Similar Threads

  1. 1998 8HP 2-stroke vacuum-testing lower unit - how much vacuum?
    By whitegreg56 in forum Mercury Mariner Outboard Forum
    Replies: 8
    Last Post: 01-08-2017, 07:54 AM
  2. Replies: 3
    Last Post: 09-04-2015, 05:29 AM
  3. Sealed fuel systems and vacuum...
    By Eric.C in forum Crusader Marine Engine Forum
    Replies: 13
    Last Post: 11-05-2010, 08:59 AM
  4. TACHOMETER amp FUEL AND VACUUM GUAGE SET
    By roscopico in forum Yamaha Outboard Archive
    Replies: 2
    Last Post: 07-22-2008, 05:24 PM
  5. Vacuum gauge on fuel filter
    By reelfishin in forum Detroit Diesel
    Replies: 7
    Last Post: 05-06-2006, 10:17 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •