VP 8.1GXi Fuel Pressure / Hunting at Idle

General repair/maintenance/upgrade information exchange.

Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby Muddy Blues » Thu Aug 09, 2018 2:40 pm

Wow, that takes the term "water hazard" to a new level!

Glad you made it out alive! I can't imagine how frightening that must have been, especially with golf clubs strapped to your back. Here's wishing you a full recovery.
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby gofast24 » Fri Aug 10, 2018 11:01 am

Also glad your OK! With your current luck with golf and the VP nightmare may be time to talk to a lawyer? Ya, I know some folks wont like this statement but that is what I would do if in the same situation with your vessel!
My history = I had to have two Mercrusier 502 V8 factory re man engines installed (not at the same time ), neither one made it out of the no wake zone out of our marina, sized up after about 5 minutes! At that time I had a 1992 Python 24" Cuddy cabin with a single 502 Bravo 2 drive. Finally wrote Mercury Marine a nice letter, after about two weeks called and they authorized a "new" 502 V8 (only had two new left in their inventory), paid all R + R costs, etc. Moral of story, write VP corporate a nice letter indicating your problems, send copy's of all conversations/documents you have with the letter, and possibly CC it to a lawyer of your choice. I think VP should compensate you for all the aggravation and lost sailing time with a new engine (or two) . Might want to mention the Regal Owners Forum comments! Good luck and keep your fairway shots down the middle.
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby JNelson90 » Tue Aug 21, 2018 1:51 pm

Update: so the apparent conclusion by Volvo Penta was to remove and tap off the vacuum line between the intake manifold and the fuel pressure regulator. Then, bump up the fuel pressure on the high pressure side at idle until it smooths out. They bumped it up to 48 psi and the idle was acceptable (spec was 40 psi +/- 4 psi). The reasoning? They feel that the re-manufactured long block had the cylinders bored out allowing for more air volume. Removing the vacuum line "tricks" the engine into thinking it is under load 100% of the time. If they jacked up the psi at idle and did not remove the line then it would go even higher when under load and apparently be at risk. I still feel that a computer change would have been a much better fix to deal with a different fuel air volume / mixture. Unfortunately, fixed is far from where I am at now - please read on to find out whats wrong now.....

So we took the "fixed" boat out for a 2 hour cruise; closely following the VP break in procedure. Running about 3,200 RPM (about 3/4 throttle) and occasionally returning to idle to allow for cooling. During the first hour the engine ran cooler (new exhaust manifolds and riser; I suspect) and it also consumed less fuel. When running at 3,200 rpm it was using about 1.2 gph LESS than the starboard engine (Starboard was the original engine - Port was has the replaced long block). I attributed this to to the newer long block and improved efficiencies internal to the engine. Just about 1 hour into the cruise the fuel consumption changed; the port engine started consuming more fuel (I suspect something went wrong at this point). The port engine was using about 1.3 gallons MORE gas than the starboard engine at the same RPM.

When I pulled into the marina to put her in back in her slip (it had been more than 2 months since she has been back to her normal home/slip) I noticed the transmission clanking when I put her in forward or reverse at idle. I later noticed (once I entered the engine room with the engine running) an engine knocking sound close to the flywheel side of the engine. After speaking with the mechanics they feel the rough running engine at idle was causing the transmission noise (since it is a planetary transmission) and don't suspect an issue with the transmission but the engine could be another story. I had recorded a video for them to see / listen to the engine but until I get the boat down to their marina and they can physically see what's going - all bets are off.

I now feel like I probably won't have a working boat for weeks now if it is indeed a lower engine issue with the new long block. I am feeling jinxed at all the issues I am dealing with. I wish that VP would stand behind their product and put these issues to rest.
Kindest regards, Jeff

2006 - Regal 3860 Hard Top
2009 - Yamaha Waverunner FX SHO
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby Seven » Mon Aug 27, 2018 9:34 am

Sorry to hear this Jeff. It's not the way to end the boating season especially after all the issues you have been going through on and off the boat. I am crossing my fingers its an easy fix and hopefully gets corrected quick.
I am wondering if the engine needed to be broken in properly and now you can replace everything back to factory specs and put the vacuum hose back.
They could be correct about the noises. Mine also make noise when I pull the throttles back to idle. My surveyor said the noises were normal when I pointed them out before purchase.
--2002 3880 Regal Flybridge | Twin Merc 8.1HO| **Seven**
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby gofast24 » Sun Sep 16, 2018 11:29 am

Seven wrote:Sorry to hear this Jeff. It's not the way to end the boating season especially after all the issues you have been going through on and off the boat. I am crossing my fingers its an easy fix and hopefully gets corrected quick.
I am wondering if the engine needed to be broken in properly and now you can replace everything back to factory specs and put the vacuum hose back.
They could be correct about the noises. Mine also make noise when I pull the throttles back to idle. My surveyor said the noises were normal when I pointed them out before purchase.

When pulling both our throttles back to idle no noise from the engine room or the ZF V drive transmissions, either in gear or neutral? Something funny still going on with the OP's propulsion units? The reason that I lost 2X new Merc 502's in succession was that the dealer doing the first engine swap connected the remote oil filter hoses backwards, therefor no lube oil to the engine or engine oil cooler, go figure!
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2001 Regal 4160
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby JNelson90 » Fri Sep 21, 2018 7:51 am

Sorry for the delay in updates but my frustrations have peaked as our engine problem is still not resolved. I decided to get fully involved and got all the contact information and email threads between my marina mechanics/management and Volvo Penta. I finally got to speak with the upper management at Volvo Penta and to make a long story short, the regional service manager from Volvo Penta is currently scheduled to show up at the marina to investigate the problem with the local mechanics. I will reserve further comments until I have some results on Monday. I am hoping for the best but with the history of let downs; I am not getting my hopes up. Maybe next year I will be able to start boating again :(
Kindest regards, Jeff

2006 - Regal 3860 Hard Top
2009 - Yamaha Waverunner FX SHO
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Re: VP 8.1GXi Fuel Pressure / Hunting at Idle

Postby timp4411 » Fri Sep 21, 2018 8:03 am

Good Luck Jeff.

I hope they resolve your problem so you can enjoy the rest of the boating season.
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