Does this sound like a fuel pump problem?

spott · Post by **spott** » 26 Apr 2011, 19:58

I think I might have a problem with my fuel pump, but I am unsure.

I've been having intermittent problems with starting my 2000 S70 (2.4L Turbo). It's making noises like it is trying to start, but doesn't seem to fire (forgive me, I am just really learning about car stuff). If I press the valve on the fuel rail, it will kinda sputter, but then run out. I've tried toggling the key into the 2nd ignition position without turning the car on a few time, and there is no change when pressing that valve.

This is only the second time this has happened. After the first time, some banging around the fuel filter area (probably coincidence?) and repeated attempts to start the car got it going again. I replaced the fuel filter and the spark plugs (figured it wouldn't hurt). Ran fine for a while. Until today. Started after the car was sitting for about 3 hours, started okay, reverse about 3ft and sputtered out. Wouldn't start again.

When I put the key in the 2nd iginition possition without starting the car, I can hear a high pitched noise from near the fuel rail. Noise will continue until key removed. What is this noise? Is this a symptom of no fuel in the line?

I tried to listen for fuel pump noises. It made a mechanical moving noise (similar in some ways to the antenna retracting, but it wasn't that). It made that noise on a couple of tries. Then failed to make any noises on repeated tries. My problem is I don't really know what a normal noise is? Is it supposed to make noise when it works or when it doesn't?

I also looked around the forums and found references to the fuel pump relay. I checked my main fuse box, but I didn't have that, or have a slot labeled for that. So, maybe a stupid question, but does this car have a fuel pump relay? Where is it if it's not in the main fuse box??

Sorry for the long post.
Thanks!

Post by **precopster** » 28 Apr 2011, 07:37

Welcome to MVS. The noises you hear from the engine bay are the Idle control valve (or IAC) which sits there humming with the ignition on.

The fuel pump will stop after about two seconds of ignition on if the ECU doesn't get the go-ahead from cam or crank sensor (indicating the engine is turning quickly) This prevents fuel spillage in the case of an accident when fuel lines can be ruptured.

The fuel pressure is regulated by a built-in pressure regulator in the fuel pump. The tire valve should squirt some fuel out but only a squirt. If the car is parked overnight after a run does it still squirt? If not the fuel regulator is faulty but you can fit an aftermarket one after the pump.

Have you pressed this valve during a no-start condition?? Let us know if fuel squirts during the problem phase.
If not the fuel relay is probably at fault (they are problematic on these cars) It is located behind the fuse panel under a cover with torx screws. It is usually pink in colour. The solder joints can be touched up (I did mine two years ago and no problems since)

Let us know how you go. Mike

Post by **jblackburn** » 28 Apr 2011, 07:49

The fuel pressure is regulated by a built-in pressure regulator in the fuel pump. The tire valve should squirt some fuel out but only a squirt. If the car is parked overnight after a run does it still squirt? If not the fuel regulator is faulty but you can fit an aftermarket one after the pump.

Just to eliminate confusion, there's a check valve on the pump housing that keeps pressure up, and there is a fuel pressure regulator up front that controls the fuel pressure to the engine, and returns the excess fuel pumped up back to the tank.

Did you pull off the cover to the top of the fuse box? It has a few Torx screws, and then the whole black cover lifts right up out of the way, and voila! Relays.

Post by **precopster** » 28 Apr 2011, 07:54

Woops Good thing you caught me on that, justin wouldn't want to misinform.

The fuel regulator is under the fuel rail, and is round usually gold zinc with a line running into it.

As jblackburn said the check valve may be the culprit if pressure can't be maintained.

Post by **jblackburn** » 28 Apr 2011, 08:01

You're good. And then there are the little differences between early and later models

On a 96-98 (at least; not sure what changed with the 99-2000, but they had no return fuel line from the engine itself), there is a regulator on the line coming up from the fuel tank - that location changed depending on the year/emissions code. My 98 has it near the power steering rack; some other 98's have it in front of the right rear wheel. There's also a "dampener" in place on these cars instead of the old regulator on 93-95 models at the fuel rail.

milesursogood · Post by **milesursogood** » 02 May 2011, 19:41

I have a similar problem. My 850 turbo wouldn't start w/ a new battery installed. The fuel rail's schrader valve would only squirt some fuel out. So that eliminates issue w/ the fuel regulator or fuel pump relay, right?

spott · Post by **spott** » 03 May 2011, 16:12

Thanks Guys!
I was able to track down where the fuel pump relay was and replace it. I replaced it a few days ago, and seems to be running fine now, kinda hard to say since it was a kind of intermittent problem.