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Sounds of impending failure from my fuel pump

Fjergus

Fjergus

New member
Joined
Dec 5, 2014
Location
Seattle-ish
My fuel pump is making a very unhappy squealing, grinding noise. I noticed it today in the drive through at Taco Bell. I'm wondering if it's the pump itself, or if it's a clogged filter or the pump relay doing something strange. Anyone else noticed horrible noises coming from their pump? What was the deal?

I replaced the sender pump a year or so ago, so I'm pretty sure that's not it. I'll check it tomorrow when I'm less buzzed. Haha
 
Never turbobrick while drunk, not smart.

My wagons fuel pump is kinda loud but I'm not sure why. I'd replace the filter before a pump because it's like $12 and easier.
 
In my case (or in the case of one of my 240s a 1989 wagon), the humming noise from the main pump was accompanied by loss of power when trying to maintain speed going uphill (as if not enough fuel was getting to the engine) but only when the tank was less than half full. Naturally, I thought it was the in-tank auxiliary pump as it's well know than when it fails you get the symptoms I was getting. Well, the in-tank pump has been replaced now twice and I know the second one in pace now works fine, as proven by a good flow of fuel from the connection to the file line when tested, a flow that stops when the corresponding fuse is removed. Yet the main pump was still humming very loudly. The main pump has been replaced now twice too, and while it was quiet to begging with, it began to hum little by little as the previous pumps....the loss of power, although not that noticeable now, is still present when the tank is less than half full. It is frustrating. It cannot be either one of the pumps and the problem necessarily has to be between the two pumps or before the main pump. The filter is fine (and it would not produce these symptoms in any case). Any ideas or better solutions than constantly filling up the fuel tank and waiting for the main pump to fail completely? Thanks!!
 
xq240+240 said:
-It cannot be either one of the pumps and the problem necessarily has to be between the two pumps or before the main pump.
Click to expand...

Did you replace the short piece of hose between the in-tank pump and the metal tube? That hose needs to have a full immersion in fuel specification. Otherwise it will leak or completely separate. Then no fuel to the main pump unless the tank is more than half full.
 
The main pump will cavitate on a low fuel tank even when both pump and sender is in good shape if you have a crusty tank pump fuse. And if that car happens to be LH2.4 and a 240 (we always wonder) that fuse 4 problem will make the thing run poorly as the oxygen sensor loses its supplemental heat. And of course, like all poor connections, it may come and go with the weather as it pleases.
 
TestPoint said:
Did you replace the short piece of hose between the in-tank pump and the metal tube? That hose needs to have a full immersion in fuel specification. Otherwise it will leak or completely separate. Then no fuel to the main pump unless the tank is more than half full.
Click to expand...
The whole ensemble, sender, pump and accessories like the hose and sock, was replaced...the fuel gauge was not working and replacing the sender was the first thing I thought of doing. Because of the "stuttering" under load, the idea was to replace everything, including the sock filter and the hose.

I'll check the fuses again and replace them if needed. The thing is, the in-tank pump actually "spits" a nice stream of fuel from the exit spigot when tested.....

One detail is that I got this second 240 (a 1989 wagon) a couple of months ago, believe it or not with only 57K miles. It was stored in a garage since 2005 (the re-registration list of fees was one page long.....). Of course I imagine that such long hibernation is the reason of the troubles (I should have thought about it and before even driving it again should have cleaned well the tank...). I've heard of cases where the main pump and the filter had to be replaced several times in a row and every time there was a lot of "dust" clogging the parts. Perhaps I should try to use one of these fuel cleaner solutions? Do you know of any such product that might be of help in this case?
 
lummert said:
Replacement 240 sending unit assemblies have been known to have the pump wired backwards.
Click to expand...
But if that was the case on any or the two sending-pump sets installed there would actually be no fuel pumped through the spigot when testing it....on the other side, I know that at least one set is OEM...

I wonder if I could get any benefit from adding a fuel cleaner solution to the gas....are these products any effective? which one is reliable and good for volvos 240?
 
You might try pumping a couple gallons of gas from the tank to a mud bucket. Terrible things can happen to cars in storage for years.

PB101370.jpg


No fuel cleaner is going to fix a rusty tank.
 
Pull out the tank pump and check. Did you use hose that's rated to be submersed in gas? I had a very noisy tank pump every time the tank got below 1/2 a tank along with bucking and hesitation accelerating from a stop and WOT pulls. Pulled it and the hose connecting the pump was corroded terribly. Replaced it with SAE 30R10 fuel line, clamped the hoses and reinstalled. It did not cure any of the symptoms and replacing the tank pump was the solution.
 
TestPoint said:
You might try pumping a couple gallons of gas from the tank to a mud bucket. Terrible things can happen to cars in storage for years.

PB101370.jpg


No fuel cleaner is going to fix a rusty tank.
Click to expand...
Today I drove without the fuse #4 and it doesn't make any difference in noise or performance. It is beginning to lose power now even with a full tank and on flat terrain when pressing on the gas pedal suddenly.....I'm beginning to think the problem is either that the line between the two pumps is clogged, the fuel check valve is failing, or something else beyond the pumps (both of them have been replied twice now. I'm afraid the problem is looking to be far more complicated than I thought, which is concerning...

Checking the fuel pressure on delivery to the injectors makes absolute sense, although he mechanic I ask for help for the things I cannot or don't dare to do myself (too many..), a Swedish guy who worked for the original Volvo company for over 20 years, told me the pressure was fine. However I'm beginning to think that perhaps when he doesn't suspect something is wrong he tells me it's fine without checking...in any case, how do you check the fuel pressure (I know the basic concept but not the type of pressure gauge you can use, etc)?

Thanks for all your comments and help!
 
When I was messing around trying to repair a fuel pump check valve I installed a spring that was too long and the engine didn't run well and the main pump made lots of noise. If you can remove the pump and filter with cradle as an assembly you can easily replace the check valve.
 
Hoo, I kinda forgot about posting that. Whoops. On the other hand it was surprisingly coherent, if a little sloppy. :lol:

Anyway, it hasn't failed yet. I'm hoping to get a chance to replace the filter tomorrow after work (I actually have one, I just never got around to installing it), so we'll see if that fixes the problem. I can't tell if the sound is the result of cavitation (which would most likely be caused by a clogged filter) or a failing bearing (which would mean the pump itself is dying). I can't actually hear it when I'm sitting in the car unless I'm idling next to something for the sound to bounce off of (like the wall at the drive in at Taco Bell) and I have the window down, so I'm not really sure how long it's been doing it. It must have started since the last time I was screwing around with the mixture, because I would have heard it while standing outside the car.

Speaking of mixture, mine is perpetually lean. I've replaced most of the sensors and whatnot that control the mixture (see my earlier posts for details), but I still can't get that damn test light to blink properly at idle. Would a plugged filter/dying pump cause a lean condition at idle? Seems like it would only really make a difference after a few seconds of full throttle, but I don't know. I guess we'll see.
 
Is the LED on your tester on or off most of the time? I have some experience with setting the base mixture. When you say you replaced most of the sensors, does this include the O2 sensor?
 
The light never comes on at idle, even with the idle mixture potentiometer dialed all the way rich (unless I unplug the MAF, in which case limp home mode does make it super rich). I replaced the block coolant temp sensor, the O2 sensor, the MAF sensor, the engine wiring harness, the fuel injector o-rings, the IAC valve, the TPS, the intake bellows, the intake manifold gasket and the throttle body gaskets. Most of those had problems, but none of it made any change to the mixture. It started lean and it's still lean.
 
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