fuel supply problem fuel pump relay or fuel pump?

These problem can be difficult, having many of theses cars in the shop I can tell you the main wiring harnesses had problems, here are the fuel pump relay and fuel pump location with a guide to check for power.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (Below). Please let us know what you find.

Fuel pump Location ???
Thanks.

the fuel pump is located in the fuel tank, on the top of it. you may have a access panel under the seat or in the trunk.

i have a s40 1.9d sport, a week ago it broke down going up a hill, there was a grinding noise at about 2-3000 revs and it just gave up! the garage then replaced the fuel pump and whilst driving home on a slight incline the same happened again changing from 2nd to 3rd grinding noise then cut out! so i took it back to the garage he told me he adjusted nothing but he had driven it for about 14mls , so i picked up again and now it wont start at all unless you pump petrol through manually ! and the grinding noise is still there, can you help please!!

Hi neilss40,

"it wont start at all unless you pump petrol through manually" You mean you use starter fluid to start? Or pumping the accelerator pedal to start?

Does it keep running after starting? Where is the noise coming from? Is it from the belting area? Check for a seized pulley bearing.

Two days ago on my way home my car stated losing power. The rpms would drop every time I would press on the gas pedal. I was able to limp it home by barely giving it any gas. Since then I have cleaned the throttle body, the IAC, the TPS, checked the FPR and replaced the fuel pump and fuel filter. Also checked the fuel pressure and it is at around 12 psi at the fuel rail and also right before the fuel filter coming right off the sending unit which seems rather low. Also took out and cleaned the spark plugs which were pretty black. After all that work the car will start but whenever I give it gas the rpms drop and it will not run steady at all. I pulled off the hose coming off the intercooler going into the throttle body and sprayed starting fluid into the intake and it wakes the motor right up. Also checked the plugs after just a few minutes of running the car and they have quite a bit of carbon build up on them after running it only a short amount of time. It seems like there is a fuel delivery problem but what else could be the cause??

The fuel pressure should be 43psi when the engine is stationary. IT should be between 54 and 57 when the vehicle is being driven. I would say the low pressure is causing the problem. As far as the issue, it could be a weak fuel pump or a bad fuel pressure regulator.

That's exactly what I thought. I've checked the FPR and there is no leaking gas coming out of the vacuum line and we replaced the fuel pump with a brand new one so I have no idea what else it could be. The fuel pressure is low at both the fuel pump and the fuel rail so what could possibly cause that?

Are you sure about that spec?
Here is what Alldata says........
Fuel Pressure, Engine Running
The pressure should rise to approximately 309 kPa (45 psi) immediately after the engine starts.

Fuel Pressure, Residual
The fuel pressure must not be lower than 200 kPa for 20 minutes after the engine is shut off.

With the new fuel pump it is still at 12 psi at the valve right before the fuel filter. It seems like the ecu might not be telling the fuel pump to send enough fuel to the motor. How is this possible and what will fix it?

The pressure I provided is from mitchel. It should be correct.

Other Category problem
2000 Volvo S40 Engine Size unknown Wheel Drive Type unknown Automatic 69,000 miles
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Hi,

Should my feul pump be running after the ignition is turned off? Seems like that is the reason why my battery keeps dying.'

Hi there, the fuel pump should not run with the ignition turned off, you may have a faulty relay. The fuel pump relay is called the systems relay No 2/14 below.

Start here, Mark (mhpautos)

I understand that the pressure needs to be a lot closer to 40 psi than 10psi. If my pump is working and the FPR is not bad anf teh filter is new then what could be causing such a low pressure reading right off of the fuel pump? Does the 2000 s40 even have a pump relay and if so would a faulty relay cause a problem with the fuel pressure like this?

Hi Mark,

Thanks for responding to my question. Is that diagram for S40 2000 model? We looked tried all the relays in the box, and removing one at a time, and none would stop the fuel pump.

In the diagram on my engine box that contains the fuses and the relays:
2/10= AC compress
2/11 = Radiator Fan 2
2/14 = Engine
2/15 = Radiator Fan 1

Nothing saying Systems relay or fuel pump relay.

It may not be getting enough power. Check to make sure there is 12 volts to the pump. And yes, it has a relay.

Hi there,

OK, i will get back into the data base and re check, the information did say that the fuel pump relay was called the system relay. I will look at the schematic drawing to see if anything else shows up, i will post my findings, soon. Just be aware that i am not in the USA, as there is a time difference to consider when posting.

Mark (mhpautos) In Australia.

There is a fuel pump fuse under the hood but I do not see an actual relay anywhere. Do you have any clue as to its whereabouts?

Hi there,

Fuel pump is powered by fuse No20 15 Amp. Fuel pump relay is Fuel system relay in fuse & relay box. This is the only information given, Now if the relay is pulled and the pump is still active, check for power at the red wire, terminal 3 of the relay, if this is active there is a back feed of voltage from another source, which will require investigation hands on by an auto electrician, The fuel pump will stop if fuse No 20 is pulled. as there is nothing else down line to feed power to the pump. The diagram is rather complex so i will take a bit of time to look for a likely problem where a back feed may occur.

Mark (mhpautos)

It's been awhile, but there should be a relay block under the hood. (i can't remember the 2000. I guess I'm getting old, but I think it was on the pass side inner fender.

Hey, Beggars can't be choosers. I appreciate any help from anybody anytime.

Thanks a lot!

Cyrus

So after days of research and trying different things to fix the issue I narrowed it down to the fuel pressure regulator in the actual sending unit. What happened was the FPR metal housing had broke loose from the plastic housing on the return line. The fuel was bypassing the FPR and it caused the pressure to drop dramatically. In testing the part it completely broke away from the FPR housing and obviously needed to be replaced. After finding a used sending unit on ebay I replaced the part and the car started up and ran even better than before since it now had a new fuel filter, clean throttle body, IAC, and TPS. I hope this will help someone that might have the same problem as I did.

Great, I'm glad you found the problem.