Trying to track down a slow starting problem on my '03 TD6. It has to turn over for 10 seconds before it fires and once it idles it feels like is hunting with the revs going up and down a bit.

Using IID Tool suggests the Low Pressure Pump pressure is fairly stable but the Main Pump Pressure varies from 4100 psi t0 5100 psi, although usually between 4300 psi and 4700 psi.

I'm not sure if the Fuel Compensation for the different cylinders is relevant but cylinders 2, 3, 4, & 5 are around 655 mm3 whilst cylinders 1 & 6 is 2 mm3.

I'm guessing Fuel Pressure Regulator or Main Fuel Pressure Pump but would like to hear your suggestions.

Hmmmm..... I wonder if it could be the in line fuel pump on its last legs?

Jim

Is that the main fuel pump in the engine bay or the narrow long one next to the tank?

It’s situated under the car in the vicinity of the rear near side passenger seat. There is a plastic cover held closed by 2 10mm bolts.

You should be able to hear it ticking with the ignition on.

Jim

How did you get on Mike?

Jim

As Jim's suggested, the lift pump (Primary pump) may well be on its way out. As the name suggests, the lift pump sucks the fuel out of the tank and delivers it to the high pressure pump. If the lift pump fails the high pressure pump has to do all the sucking as well as pressurising the fuel and delivering it to the injectors. Can take a lot of cranking to overcome this.
You can sometimes have a situation where the car won't restart for a couple of hours after a particular set of circumstances; car up to full temperature then switch off, then start again after a minute or two then switch off again, leave for five minute and then try and start it again. You'll often find it won't and it's usually because the lift pump has failed.
Let us know how you get on.

Thanks for the advice. I'm finally going to try to pull the fuel pump out.

Any recommendations as to where I can send it to get it tested and rebuilt or should I buy an already refurbed/new one?