Afternoon Guys and Girls,
Brief history of time first......I fitted a new (Delphi) lift pump about 3 months to go to remedy a problem where the fuel would drain back to the tank after a few hours when left switched off. The change immediately fixed the problem, and all was well in landyville. Anyway fast forward a few weeks, and my 90 became very sluggish, as if she was drawing a 3 tonne trailer. It would always get to full speed, but took significantly longer than normal. I've looked at the turbo, and intercooler, the hoses etc, and all seems to be ok.
So fast forward to yesterday .... the 90 was starting perfectly. First crank, and bang away she went .
So today, I decided to change the fuel filter incase it had become clogged through dirty fuel as there was one day when I almost ran out of fuel, and I worried this was the cause of my reduced power. Anyway, filter changed, and I tried to prime the fuel system using the lever on the lift pump, but there was no pumping action at all. It didn't feel as though it was 'off' the cam, as it had a certain resistance, but it just wasn't doing anything. I tried brute force cranking it but the engine just wont start. Usually when operating the lever, I could hear any excess fuel draining back into to the tank, or with the bleed screw open on top of the fuel filter head, I'd get a little stream of fuel. Not today though. I cranked the engine to try and ensure the lift pump was definitely on the cam, but it made no difference at all.
So.....I'm wondering.....has anyone seen a brand new Delphi lift pump go bad in a very short space of time?......And if the lift pump DID go bad, would that explain the reduced power over the last few weeks, and would it lead to me being unable to prime the system to get it to start? I know she's been starting fine since the lift pump was changed, but perhaps a fully primed fuel system can work on the vacuum created by the injection pump in full chat, even if the lift pump has laid down?
Any thoughts??
Regards
Mark