OM602 Possible Air Leak won't start.

[Chuckster]

We have a 1991 Mercedes 2.9 Hymer Motorhome. All has been fine until recently, now when its parked on a slight incline the engine starts immediately and runs for a couple of seconds then stops. It then needs cranking and cranking until it starts again. The longer it is left the longer it needs to be cranked. Believing it might be air getting in the system and draining the fuel back to the tank I fitted a non return valve in the feed side - no difference. I fitted an on/off valve in the return line (its is 12v powered to open when ignition is turned on and closes when turned off) - this seems to help. I have replaced the Fuel line from tank to pump and from Filter back to tank with new clips - no change. If the vehicle is parked on the level or facing slightly down hill it is fine, but if it is 6" higher front to back it has the starting issue. Any/All thoughts are welcome (apart from telling me to always park facing slightly downhill !!!!)

 

[om613]

Air ingress. The OM602 is as basic as they get.

Check the leak off hoses and any other fuel lines for degradation and use of crappy fuel line clips.
Then fuel filter for over tightened / leaking / mashed seals.
Then for dampness on top of the injector pump, as IP delivery valve seals will 'do air'.

 

[Chuckster]

Thank you. Interesting read. I have replaced the feed pipe from tank to pump and return pipe from filter to tank with new quality hose and clips. I have replaced the bleed off hoses and the blank. I have new seals for the fittings to the top of the Fuel Filter so I will replace those and as you have suggested I will remove and refit a new filter.

 

[brianbrian]

Have you done the filter in the tank.

 

[Chuckster]

Yes it has been removed.