300 wont start when hot problem

[Landowner]

My Disco 1 has been giving trouble for a while and I thought it was fixed

Changed injector pump

new lift pump

bypassed sediment filter

new fuel filter.

Starts half a turn, bursts into life when cold in a morning, no problem

As the engine gets warmer it gets more difficult to start untill when at running temp it wont start at all

Leave it to cool a bit and it will start with difficulty

Leave it to go cold (temp on zero) and it starts straight away

Older pump fitted without the three wires and alarm box

Used one of the three wires as an ignition feed to the pump

Thanks....I'm beflumuxed

[Daisy90]

Tappit gaps too tight ? If its cold the gap will be bigger so allowing proper (ish) operation, as it warms up the gaps decrease holding the valves open therefore not getting proper suck bang blow :0)

just an idea and cheap n easy to check / rectify

[Landowner]

Well....

Had some old injectors in a scrap 300 so decide to swap tem and see what happened.

The injectors in my motor were covered in crud at the tips I presume from running bio,

I put the other spare injectors in and she fired first time and has been brilliant at starting all day so job done

Also cured the stalling problem when revved and let drop to idle:)

[Snagger]

A lot of people bang on about Tdis loving vegoil and running varying mixes up to neat SVO on a single tak system, but the reality is that it's a very bad idea to skimp on the mods required to do it properly. If you want to use vegoil, then a dual tank system with heat exchangers for the fuel is not optional, it's mandatory. Running the vehicle on vegoil without the mods will cause the severe coking of the injectors you found, but also of the rings, valves and turbo, and also causes vegoil to get down into the sump, polymerising the sump oil and turning into a jelly, which ultimately leads to engine damage.

[Landowner]

A lot of people bang on about Tdis loving vegoil and running varying mixes up to neat SVO on a single tak system, but the reality is that it's a very bad idea to skimp on the mods required to do it properly. If you want to use vegoil, then a dual tank system with heat exchangers for the fuel is not optional, it's mandatory. Running the vehicle on vegoil without the mods will cause the severe coking of the injectors you found, but also of the rings, valves and turbo, and also causes vegoil to get down into the sump, polymerising the sump oil and turning into a jelly, which ultimately leads to engine damage.

I think I'll stick to derv from now on, I've used up all the bio I bought anyway and it has cost in filters and a lift pump so the savings, are not as great as I expected.

[Snagger]

Ah, properly brewed biodiesel shouldn't cause coking, though it can cause problems with seals and o-rings ( I think it might be the ethanol that attacks them) - it's un modified vegoil, whether new (SVO) or used (WVO) . Some oils are wose than others, the worst being palm oil (the cheapest), followed by soya, while the best is rape seed oil. But all of those should only be used pre-heated to 80oC into a warm engine; even pre-heated, if injected into a cold engine the mist condenses onto the bores and rings as well as forming a nasty thick sticky black sludge that builds up in the head, exhaust manifold and turbo. Heating the vegoil helps produce a finer mist to match the diesel injection pattern, while ensuring the engine is warmed up prevents the condensation of the fuel. Of course, the injection system needs to be purged with pure diesel a little while before shutting down so that you don't cause the coking on the next cold start...

Basically, you have the choice of modifying the fuel to match diesel's viscosity, creating biodiesel, or modifiying the vehicle to run on plain vegoil. But one or the other must be modified.