2004 XC70 no start - faulty fuel pump and/or electrical connections? Topic is solved

[enotslim]

Found this discussion that sounds relevant: https://volvoforums.com/forum/volvo-xc7 ... toms-2933/

Fuel pump symptoms sound identical to this thread. A key section is:
"...Even when the pump does not start it is getting power, it's just that the pump does not engage. I have a 12VDC power source that produces 13Amps that I used to jump directly to the fuel pump leads. When the pump is in its non-starting mode the power source trips out due to overcurrent, and the pump will not run...."

Sounds like an intermittent short within the pump that might easily be fixed but likely is not worth fixing (although opinions may differ about this).

This may not address the issue of multiple seemingly unrelated codes that have tracked with fuel pump failure through several cycles in this thread. Could these codes be secondary to fuel pump failure/shorting out?

[enotslim]

I use this cheap siphon rig, works well on P2 cars (S60, V70, XC70 01-07). Just did an S60 fuel pump with it this weekend. The nylon tubing I just had laying around, not sure the dimensions, but 7/16 OD x 1/4 ID is close. With the tubing cut to an angle on the input end, the point slips right past the flapper mentioned by volvolugnut.

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Thanks. And can the fuel be returned to the tank simply by reversing the pump?

Any recommendations for temporary storage of fuel removed from the vehicle? I see so many complaints about spilling from "no-spill" safety containers.

[cn90]

Temp fuel storage? I'd ask any neighbors if they need fuel for lawn mowers etc. I hate storing fuel in my garage. Not worth the risks. Plus, insurance issues too.

[enotslim]

Temp fuel storage? I'd ask any neighbors if they need fuel for lawn mowers etc. I hate storing fuel in my garage. Not worth the risks. Plus, insurance issues too.

By temp I meant a few hours while replacing the pump. But neighbors are a good idea.

[enotslim]

Different sources say the tank should be < 1/4 full or < 1/2 full to avoid spills when accessing the fuel pump. Is this car model dependent. My tank is just under 1/2 full now. I'll probably slightly loosen the plate over the left-side of the fuel tank and look for a small leak.

[erikv11]

Yes, can siphon it back in but you'll need to put the gas container up high, like on top of the car. That's what I did. I just used an old plastic gas can, it wouldn't be great for long term storage but for the day (or a day or two) it's no problem at all. Also, would make much more sense to just put 5 gallons into another car than walk around the neighborhood filling a bunch of lawn mowers etc.

Your XC70 fuel gauge just under half will be fuel level right near (or at?) the top of the fuel pump hole. So you may be able to open it without spilling, I'm not sure. You have to actually unscrew the fuel pump to find out, just lifting the cover lid only exposes the fuel pump. Personally I would feel better getting it to near 1/4 but your idea to check carefully should work. You'll definitely want to siphon some out anyway once you open it up, otherwise you'll get gas all over the inside of the car during the job.

On my S60 the gauge was just under half, then I siphoned 5 gal out of the fuel pump side. Then when I opened it up the fuel pump half of the saddle tank was near empty but the other side with the fuel level detector was very near the top . DIdn't spill out into the car but was near the top.

You'll also want to siphon as much gas as you can out of the fuel pump assembly, once you open it up. Otherwise it's like a small bucket dipped into a well, and gas will slosh and spill into the cabin as you jockey the fuel pump out of the hole.

[erikv11]

Finally! After 6 months of prefect behavior the car finally failed to start yesterday, with very strong cranking, reproducing the issue that initiated this thread. In my driveway with the tank half full. Removed the rear seat and fuel pump electrical plug to discover the pump is receiving a ~1-second 12-volt burst (actually 11.8 V) at ignition - but doesn't pump. Simplifies things enormously.

However, and oddly, cruise control also stopped working on Tuesday, numerous codes are now present that were not there last week, and I saw for the first time ever the message "IMMOBILIZER SEE MANUAL". (Two different keys that both worked last week now fail to start.)

Current new codes:
ECM-9400 Brake pedal sensor: Signal too high
ECM-4007 EVAP system ; Signal too low
REM-8D11 High mounted stop lamp ; Faulty signal
BCM-0012 Wheel sensor, left front ; Mechanical error
BCM-0011 Wheel sensor, left front ; Faulty signal
BCM-0103 Pedal position sensor ; Faulty signal
BCM-0065 Stop (brake) lamp switch ; Signal outside its permitted range
CCM-0021 Air quality sensor ; Internal fault

Are all these errors/codes just coincidental? I don't think they're real. Is it possible that some electrical aberration disabled several components/systems, including the fuel pump itself, in a reversible manner? I ask because I had numerous unexplainable codes during previous no-start episodes but I have had none for months (without fixing anything relevant to the codes). And now everything "fails" all at once. The fuel pump failure has been reversible through 3 or 4 cycles of this stuff.

During the past six months I've had explainable codes for the headlight level sensor and a blown headlight ballast. Both conditions were repaired/replaced, codes cleared and I was code-free. A code for left front ABS resolved when I fixed a leak in the exhaust flex pipe. That was a strange association/coincidence but the ABS error remains gone. Otherwise I've been code-free until this week when the fuel pump failed and everything else above happened.

Removing the pump now seems inevitable but I don't want to replace it and have the same failure occur. Is there some component of the pump (disassembled) I can examine for reversible failure?

Finally, is there some way to remove fuel from the half-full tank so it doesn't spill when the fuel pump is removed. Dealers must have a way to prevent spillage.

Thanks.

I do agree that none of these codes seem related to a bad fuel pump. So you could be seeing some kind of module communication problem like you said, and the pump is actually fine, but I don't know much about responsibilities of the different modules. And your observation that there is voltage at the pump without it engaging is pretty clear.

Those also all look like nuisance codes, in different modules, so unless it's like a central module problem they may be coincidence. Surprised there is no misfire or fuel code with a dying pump.

disclaimer: I didn't read though this whole thread, so could easily be missing something important

[enotslim]

Replaced the fuel pump today. Car starts fine. It actually "jumps to life", starting noticeably more quickly. Only time will tell if this corrects the problem. The old pump cycled between fail/good for at least 2 years with good cycles being up to 6 months long (like the most recent cycle). I'm optimistic.

- Didn't remove any fuel (gauge was reading just under half full) and the levels were near the rims but did not spill into the interior when the pump and nonpump sides were opened. But it was close and a small amount did spill during removal and installation. Siphoning after opening (as suggested above) would have been a good idea. Read that activated charcoal can hasten removal of fuel odor from the interior. Not sure I'll need it. We'll see.

- First try could not pull the suction from the pump to the nonpump side using a messenger line. Tried for at least 30 minutes. It was hung up on something.Triple-gloved, shredded glove fragment(s) fell into the left fuel well. I think I got it all out. Removed everything and repeated by first pushing from the pump side and then taking up the slack from the nonpump side. Inch worming like this worked in about 2 minutes. I suspect the full level floated the suction line with plastic fitting so it snagged on the underside of the interior of the fuel tank. Another reason to do this job with less fuel in the tank.

- The fuel level may (or may not) now be reading slightly less than before installing the pump. Went from slightly less than half full to between 3/8 and 1/2 full. Could be actual loss of fuel (2 "pump buckets" were removed -caught in a plastic bin, not the interior of the vehicle) or slight misplacement of the level sensors. Watching the level as the tank empties and is refilled should clarify things. Underestimating fuel as may be happening should reduce the risk of running out.

- Cleared codes and will see what returns.

Thanks for all the help above. Hopefully this brings to a close the saga of the haunted fuel pump.

[erikv11]

Nicely done, sounds like you work carefully. Hope it fixes it!

[awizarddresden]

I know that this thread is kind of dead but I was just curious if replacing the fuel pump did end up solving the issues permanently? I've got exactly the same issues and this thread is the most complete I've seen.