V40 starting problems

I have bought a 2003 Volvo V40

1.9 diesel from auction. It has 100,000 miles and a vague service history. It was OK for a couple of days, then developed a starting problem. Some days it would start, others it would not. Twelve months ago, it had a new AA battery and it turns the engine over well. There is 12.7 volts on battery, 14.4V with engine idling.

On some days I can start the car easily. It fires straight away and runs fine, not lumpy or missing. During the day, the engine can be restarted a number of times with no problems. But if left for 2-3 hours, it may or may not start. Once in ‘no start’ mode, it will then not start for the rest of the day. Next day, it would start straight away! Then, on another day, it might not start at all. At all times cranking speed is good.

At first I thought it was an immobiliser problem. On one of the first ‘no starts’, the immobiliser flashed at me for five seconds before going out. Then the next day it started OK. Since then, the immobiliser light will come for 3-4 seconds and then go out, as per the handbook. There is no management light illuminated. When I try to use my basic code reader, it comes up ‘link error’, so I think it's not OBD-II compliant.

I think I might have a fuel supply problem. On my Vectra C petrol, when I turn on the ignition I can hear the in-tank fuel pump run for about five seconds then switch off as the fuel gets to pressure. On the Volvo I can hear nothing, not even with the rear seat removed and my ear three inches from the pump.

When the car won’t start, I turn off the ignition and disconnect the fuel pipe where it goes into the high-speed pump, turn on the ignition and nothing comes out of the pipe. If I crank the engine, nothing comes out. If I squeeze the priming pump, fuel comes out. When the car does start, if I turn off the ignition and disconnect the pipe, nothing comes out. If I start the engine, it runs on the fuel in the highpressure pump for a minute or two, then stops and nothing comes out of the pipe. Connect the pipe again and it starts again.

If I put a meter across the tank pump, I get 845 on the 200 ohm scale (84.5?). There is an earth on one of the wires to the tank and, when I switch the ignition on, I get 8-volts on the other.

I have no wiring diagram for this model and Haynes does not cover diesel. Should there be 12-volts at the pump and should I be able to hear it run? Is there a fuel pump relay that may be faulty and, if so, where is it? Do you think I have a fuel supply fault? I believe that when it starts, the high-pressure pump is sucking fuel out of the fuel tank. When it doesn’t start, the high-pressure pump just can’t manage it. Or am I going mad?

Roger Poore

From your description and from the tests you have already carried out, the problems do seem to be associated with the lowpressure fuel pump.

According to my wiring diagram, the feed for the fuel pump should be in the passenger fusebox, position number

17. The feed wire to the pump is blue and the fuel gauge wires are yellow and yellow/black. There should be a 12V supply to the pump feed wire.

I would start by checking the feed at the fuse to ensure a 12V supply is present. I would also check the main fuel pump relay in the engine compartment fuse/ relay box. As all of the power supplies are controlled by the ECU, it would be worth checking the system using a dedicated Volvo diagnostics reader.