2002 Volvo penta 5.0 GXI Problem

[joefro]

I have a Baha cruisers 251GLE with a Volvo 5.0 GXI engine it Idles at 1100 RPM and there is a loud sucking noise from the throttle body, anything we have tried to reduce the Idle has failed, changed the fuel cell, new plugs , new cap, changed TPI, Temp sensor, Idle air sensor, and other sensors. If I rev the engine up quickly a few times the sucking noise stops and when I reduce the throttle the engine will momentarily lower to an Idle and die, it has the mechanics stumped . any one familiar with this problem and any Ideas as to whats causing it ?

 

[wkb2460]

Sounds like a vacuum leak.

 

[bajaunderground]

Cable sticking?

 

[joefro]

wkb2460 Thanks, Thats what I was thinking , a Vac leak but the mechanic claims he check for a leak and found nothing, This problem has cost me in excess of $1200 in parts and labor so far and lots of grief. and the problem still exists, now Im told to try a new computer $2000.:facepalm:

 

[joefro]

bajaunderground That was the first thing I tried...disconnecting the throttle linkage, actually looking into the throttle body , the butterfly is almost closed completely.

 

[wkb2460]

Use some carb cleaner and spray around the base of the intake, See if the RPM's rise.
In your first post you say you hear "noise from the throttle body". Is your engine Throttle body injection?
I thought the GXI had intake manifold. I would check that for a leak too.

 

[joefro]

wkb2460,yes it's throttle body injection, the noise I hear is a loud sucking noise, almost as if its starving for air. The mechanic working on it says he checked for a vacuum leak by spraying all around the intake manifold with cleaner and then used water , says no leak. I'm going to buy a couple cans of that carb cleaner and try it myself this afternoon. I bought the boat this past spring, the original owner passed away and I purchased it from his wife, the boat sat unused for nearly 2 yrs, so no info on if there were any problems with the engine when he had it. one thing I did notice looking at the engine was silicone goop smeared around and dried oozing out as if someone had removed and replaced the Manifold at one time or another. Vacuum leak is a good possibility , I'll try spraying it again . Thanks

 

[ericga]

There is a vacuum plug at the base of the throttle body. Did you check that as well?

Is the IAC (Idle Air Control Valve) operating properly? Make sure the pintle and passage are clean, connection is good and o-ring or gasket is not missing. Also make sure you have the right IAC for your application. Some IAC parts really look alike but have a different pintle shape and/or different operating length.

A mechanic stethoscope would definitely help you finding where the leak is.

 

[joefro]

Hi, well, I was at the Boat again today :frusty: Thanks for the suggestions , all the important sensors and controllers were changed ie:TPI, IAC, Temp sensor, still high Idle 1100 RPMs, I also sprayed all around the throttle body, and front , rear, and both sides of the intake manifold with carb and choke cleaner, didn't detect any change in the Idle, I sprayed directly into the flame arrest-or , it almost stalled out. So, I took off the ECU and I'm going to bring it into a dealer to have it checked/re flashed and see what kind of results they might come up with. It's a Delphi MEFI-4 Hopefully it can be redone and not have to be replaced. I will come back with results.:facepalm:

 

[ericga]

If sucking air hard from the throttle plates at idle that means no air is coming from the IAC. You can see if the IAC is operating properly with a good marine scanner and manual. Note that a bad IAC won't necessary trigger a fault code.

Unless your ECU is unable to control the IAC I doubt it will fix the problem. Check harness, inspect connector, re-seat connections and connect it to a scanner.

 

[joefro]

No Title

Hi again, well, I didn't get the ECU checked, was told by a few Techs that it may not be the problem. I went to the boat and re-installed the ECU again, this time I removed the flame arrest-or I pinpointed the large sucking noise per my photo I covered the hole with my finger, Idle dropped to a normal speed, so I plugged the square hole with a rag, Motor ran fine, if you remove the rag the Idle shoots immediately up again and the loud sucking noise resumes. I removed the IAC valve and checked its movement with the engine off and just key on, it doesn't seem to come out far enough to make any difference in the amount of air entering the throttle body. Now this is a new part, changed by the original Tech.I'm wondering if there is a part that fits in that square hole that someone left out ?Trying to find a blown up diagram of the parts in a throttle body.

 

[Thalasso]

There supposed to be a foam piece called a muffler that goes in there. It quiets it down

http://www.ebay.com/itm/Genuine-Merc...FS~563&vxp=mtr

Merc and Volvo is the same. It's a $3.00 that they usually never put in for some reason

 

[joefro]

Hi again, I've been checking out that foam filter, no mention of it for a Volvo 5.0 throttle body, I see it for the Mercruiser

, but I will cut a piece of foam and try it in mine. Now My big question..seeing that I block that square hole and cut off the air thru it , would that clarify that I have a Vacum leak from someplace ? Being with that square hole blocked the engine runs fine. I can adjust the Idle to normal and rev the engine bringing it back to neutral position with out stalling, though I haven't tried the engine under a load to see how it reacts.

 

[joefro]

Took the boat out today to try it with the foam filter in place, got the Idle down to 650 RPM, was able to shift to forward and reverse no problem. The engine runs smooth, no shake or anything, well, opened it up, can't even get on plane max RPM is around 2800 and that's it. had my nephew open the engine compartment while I kept throttle wide open and had him pull out the foam filter, no difference ! Well, Ive had it, Tuesday I'm taking it out of the water and bringing it to a Dealer, it cost me too much in replacing parts so far, the days of diagnosing engine problems may be gone for me, Fuel, air, and spark just doesn't cut it now on these newer engines.

 

[Thalasso]

Let us know what you find

 

[Pete104]

I don't think you should put "just any old kind of foam" in there. Get what they recommend!

 

[joefro]

Well I'm Back again, Finally broke down and brought the Boat to a Qualified Volvo Dealer (should have done this 2 months ago but I'm hard headed) Well, they hooked it up to their computer and found that someone had put in a jumper wire into the Diagnostic plug on the engine putting it into Limp or service mode, maybe because of a previous engine problem, which I suspect was the Fuel cell(which I changed). Dealer cleared a few codes and cut out the jumper wire and the boat runs great ! Drove it at least 30 miles yesterday with no problems.Moral of my story is ....The simplest problems can be the biggest expense, That little jumper wire cost me $1569 in parts and half the summer season.... I want to Thank everyone that tried to help me solve my problem.:yo:

 

[joefro]

Pete104, I searched for any reference to a "muffler" foam piece in a Volvo Penta 5.0 GXi-D, looked at all the parts diagrams, did not see any mention of that part, I stuck the piece of sponge in that hole just so it would Idle down enough to be able to shift and control the boat to get it on my Trailer, I mentioned that Muffler to the dealer and I see he did install a Merc Muffler filter in that hole so apparently one does go in that hole... Thanks.

 

[Poco2]

Glad to hear you got it fixed. When you buy used you are not sure what previous owners have done. Always a challenge. My understanding is the 2002 VP 5.0 GXi is a 270 HP multiport fuel injection. My daughter has the 1998 VP 5.0 GLi 250 HP which is throttle body and it does not look like the picture you showed.

 

[joefro]

Poco2, Thanks. My biggest problem was the Previous owner passed away while I was contemplating buying the boat, I bought it from his wife a few months later, it sat shrink wrapped in a Marina for at least 1 year 150 Miles from me, when I finally went to see it I had to buy it ! I figured for the price I paid even if I needed to replace the engine I would still be ahead of the game.