2003 5.7 GXi fuel pump/regulator issues

[BigDeal3315]

Hi everyone,

I ran into a fuel pump issue on my Volvo 2003 5.7 GXi this year. On vacation the boat wouldn't start. A mechanic diagnosed it as a bad high pressure pump and replaced just that pump. A few days later, it started running poorly again. I took it back in, and the pressure regulator screen was clogged with black goo that sounds like the paint issue everyone talks about. After cleaning that out, all seemed well. However, the boat started running poorly again, so I said to *#$& with it, and bought a new fuel cell.

Today I replaced the fuel cell, and congratulated myself when the boat started right up. I did a pressure test on both test ports, and was getting solid 50 psi on the high pressure rail. However, the low pressure side was showing 20 psi.

I took a break and came back out a while later, and the boat wouldn't start again! I hooked up to a portable tank to rule out the intake or bad gas, and when I try to start I'm now getting 20 psi on the high pressure port.

I'm at a loss as to what to try next. Tomorrow I'll look at the pressure on the low side, too. Could the pressure regulator have failed?

Any advice would be greatly appreciated.

 

[BigDeal3315]

Hmmm, looks like it might be a flaky electrical connection! I hooked a 12v supply directly to the high pressure pump, and it spun right up to 50 psi. Rules out the pump itself. On a lark I switched the connectors from the high and low pressure pumps, since my wiring diagram shows they're fed from the same source. The high pressure side was a solid 50 again. Puzzled, I switched them back, and the high pressure pump was dead again. I went to wiggle the connections, and when I pulled on the high pressure connection, it popped right out! The little spring clip that holds the connector together was bent and allowing it to wiggle loose, it seems. I fixed the clip and the connection is solid. Now I'm getting a solid 50 psi on the high pressure port, and the boat is running fine at the moment.

There are a couple little things that still bug me. One, the low pressure pump is putting out 20 psi, when everything I've read says it should be lower than that. This is a brand new fuel cell, so maybe the spec is different, I don't know. My trim indicator is also operating sporadically, jumping around quite a lot. This issue was coincident with the last time I had a problem on the water. The wiring diagram shows a common ground, could a ground connection be bad? I don't even know where to find it.

 

[BigDeal3315]

Well I tried an on the water test. Everything started out great - boat started right up, running smoothly, trim gauge rock-solid. Verified good full-throttle RPM. Not 5 minutes later the trim gauge started "jumping" and the engine got rough again. I shut down, and it took a couple tries to get the engine restarted. I also noticed that the red light on the active corrosion system was flickering. I'm not sure if that is related or even important, as it is never on in the driveway. I've never noticed it before, though.

Suspecting this is now an electrical and not a mechanical issue, I'm going to take it to a mechanic today. I don't have the means to diagnose a sporadic problem.

 

[BigDeal3315]

Well I tried an on the water test. Everything started out great - boat started right up, running smoothly, trim gauge rock-solid. Verified good full-throttle RPM. Not 5 minutes later the trim gauge started "jumping" and the engine got rough again. I shut down, and it took a couple tries to get the engine restarted. I also noticed that the red light on the active corrosion system was flickering. I'm not sure if that is related or even important, as it is never on in the driveway. I've never noticed it before, though.

Suspecting this is now an electrical and not a mechanical issue, I'm going to take it to a mechanic today. I don't have the means to diagnose a sporadic problem.

 

[BigDeal3315]

Well now I've stumped the mechanic. They have run the boat in the yard, started, shut down, can't replicate the problem. He's been wiggling wires, misting components with water with no effect.

The mechanic is wondering if the trim gauge jumping could somehow be the cause of the problem and not a symptom. He's suggesting I take it for an on-water test with the trim sender unplugged and see if the problem occurs. Another thing I notice is the red light on the active corrosion system flickering when the engine is running poorly.

Is this theory even plausible? The shop is going to get a diagnostic tester from their other shop to see if there are any trouble codes.

 

[BigDeal3315]

Sorry, duplicate reply.

 

[BigDeal3315]

An update... engine analyzer showed no stored codes, no codes while running, dealer was unable to replicate problem. Brought home to do an on-the water test.

While prepping for the test I started the boat in my driveway a couple of times, and began having issues. When turning the ignition on the system did not do its double beep indicating the fuel system was pressurized. Searching for intermittent fuel pump issues brought service bulletin P37-2-2 to my attention. I am practically certain this is the issue and will be replacing this part as soon as possible.

 

[DCinVA]

Gosh.... You have not gotten much help here, but thanks for sharing what you found. Its posts like this that help the community resolve issues by using the search facility.

 

[BigDeal3315]

Thanks for the encouragement! I replaced the fuse box this week, and the engine is running fine (so far). I'll need to do a sea trial to be really confident. The new box has 8 rubber bushings that isolate the box from engine vibration, and was a breeze to install. A good suggestion I found on this forum was to take a little glue or gasket sealant and glue the bushings to the bottom of the box so they don't fall off during installation.

A buddy of mine that used to be an electronics technician said the symptoms sound like soldered joints shaking loose. He said when a part is cold, everything will be contracted and since good contact is being made, everything will be fine. Then when things get hot, the joints expand, and the part will fail. When it cools down, things may again be fine. That mirrors my experience, where I would start in the driveway and everything is OK, but five minutes after being on the water things start to get bad. The mechanic tested on cool days, and to run the boat on the flushing attachment had to have the engine cover up. The fuse box may have never become hot enough to fail! My last test was on the hottest day of the year, and I immediately replicated the problem.

This is a summary of the sequence that happened to me over the course of two months:

1) Boat stumbles at ~1200 RPM, sounds like it is running out of gas but keeps running fine.
2) Later in day boat will not start. Turns over, tries to start, but won't stay running.
3) Mechanic diagnoses issue as bad HP fuel pump. Replaces it.
4) Boat starts running rough AGAIN. Took to mechanic.
5) Mechanic diagnoses clogged pressure regulator screen. Cleaned it, boat running fine again.
6) Boat stumbles at ~1200 RPM, sounds like it is running out of gas but keeps running, but noticeably rough.
7) Replaced entire fuel cell, performed pressure regulator E-clip mod. Took old fuel cell apart, definitely paint issues!
8) After fuel cell replacement, had odd problems where HP fuel pump isn't running. Checked relays, swapped connectors, came back to life.
9) Sea trial confirms boat STILL not running right. Noticed electrical side-effects on trim gauge and corrosion protection.
10) Took to mechanic for diagnosis. Unable to reproduce problem. No engine codes present.
11) At home immediately reproduced symptom on hot day, confirmed HP pump not running.
12) Google searches bring me to this forum and I find Volvo bulletin P-37-2 mentioned.
13) Replaced fuse box per Volvo bulletin.
14) ???

I sure hope 14 becomes "went on sea trial, boat running perfectly!" My boat is a 2003 and has about 570 hours on it, and this is the first major problem I've had on the engine side. I'm hoping the new fuel cell and fuse box give me years of smooth running!

Anyone with an intermittent problem with their fuel pumps should be on the lookout for this as a potential cause. On my boat the low and high pressure pumps share the same relay, so if one works and the other doesn't check to see whether you're getting power to the pump. No power can be a symptom of bad connections inside the fuse box.

 

[DCinVA]

Intermittent issues can be vary hard to track down. It sounds like your research paid off. I hope this resolves your issues and you have a great fall boating season.

 

[Five O'Clock]

BigDeal - any luck with the fuse box replacement? I'm going through this now, same issue, same engine, same year, and I'm having trouble. Thanks.
Dan

 

[GA_Boater]

BigDeal - any luck with the fuse box replacement? I'm going through this now, same issue, same engine, same year, and I'm having trouble. Thanks.
Dan

Five O'Clock

It's a big deal! BigDeal has been MIA since this thread a year ago. So it must be fixed or he would be still looking. Please read the Help Tip on top of the page.


Closed.

 

[BigDeal3315]

Thanks to a PM from five O'Clock I realized I left this thread without posting a final resolution. Indeed the fuse/relay box fixed my problem, and the boat ran flawlessly at the end of the 2014 season, and all of 2015 and 2016 seasons too!