300TDi reluctant cold starts

May I offer a dissenting voice to all this concentration on glow plugs?

My 200tdi started immediately all last winter without any glow plug use - they're not even wired up. It stands outside, and went a fortnight without being touched at one stage.

I can't see an engine taking 30 seconds to run properly at this time of the year, simply because there's a bit of unburnt fuel slopping around: a couple of firing strokes should clear any such stuff out of the cylinders. A petrol engine, with a manifold full of fuel - yes.

Sounds much more like air getting into the fuel system to me. I'd start by checking the bleed-off lines from the injectors - a tiny split will let just enough air into the top of the filter when it stands overnight to cause your symptoms, but may not leak diesel visibly when the engine is running. Can't picture the filter head on a 300tdi, but if it has a rubber button to prime the system, these can split and let air in. Aren't 300tdi lift pumps a bit notorious for failing, too? They're only about 20-odd quid from Paddock.

Reply to
Autolycus
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I'd tend to agree, but the 200Tdi starts much better than the 300Tdi for some reason - I've also never needed to heat my 200Tdi even on the coldest mornings. Bearing in mind that the Tdi's need far less time on the plugs anyway, I'd be ckecking the fuse as pointed out by an earlier poster, and I'd also be looking at the lift pump. It has a lever hand pump, and you need to be sure it is off the cam before checking it - the pivot on the arm tends to snap and can fool you into thinking its ok. Having said that, 200 and 300Tdi's only really need the lift pump when the fuel has run out for some reason (the injector pump has enough suck to do the job itself in normal use) so I'd also be checking for air getting in somewhere.

The cheap versions on the 300Tdi lift pump are problematic, I don't sell them unless specifically asked after a number of failures. You pays your money and takes your choice....

Richard

Reply to
beamendsltd

Thanks for all the very useful tips everyone.

I've been overtaken with a busy week but I'll be getting oily on Saturday and will be sure to report back to let you know what was going on.

:) K

Reply to
Kieran Turner

IME (of 20+ years of running diesels) the glow plugs CAN make a big difference to starting. Some years ago, I had a Renault 9 diesel which suddenly began to refuse to start (in mid-autumn, IIRC). I worked out it was a problem with the electrical supply to the glow plugs but I was a bit short of readys at the time and I started it from cold that winter by bypassing the relay to the glowplugs for 10-20 secs with a bit of domestic 240v 13A cable.

There was no way it would start from cold, otherwise. It would turn over for ages without so much as a cough and I think I could have run it down Mt. Everest without it bump starting. It would always restart OK if even slightly warm, which fits in with the original poster's experiences, I think.

Regards,

- Tom Bennett

Reply to
tom.bennett

Since this has appeared in the sub-thread under my posting suggesting these tdi engines rarely need heater plugs, I'd better re-emphasize: I _know_ that indirect engines usually need heater plugs, and I'd guess that the Renault 9 had an indirect-injection engine, but my 200tdi (direct injection) certainly doesn't, and I understand that many other direct injection engines, such as the Perkins Prima, don't, either. The

300tdi isn't intrinsically very different, but the fly-by-wire fuel pump may mess up its impeccable behaviour.
Reply to
Autolycus

Hmm. Well I cheered myself up today by looking at all the fine machines on Brighton seafront after the London to Brighton run.

I did not, however, fix my Disco. The relay is fine, the wiring (including earth strap) is fine. A bit of an argument between my toolkit and the top of my glow plugs means that I don't know if all the plugs are working. And I can't find a fuel leak (yet.)

I have established that no matter how many times I operate the glow plugs, there's no difference. I also *feel* that priming the fuel system by hand with my (six months old) lift pump helped a little. So I'm tending towards the air-in-fuel-system possibility.

Further investigation required; gonna bleed the fuel system properly and bung on a new filter before next attempt at starting. Then buy some decent spanners.

Thanks again everyone.

K
Reply to
Kieran Turner

Hi Kieran, don't forget to clean out the sedimentor at the back. It may pay to buy the small white plastic "plug" for the sedimentor as these tend to break easily, before starting the job. It is quite amazing what you can find in the sedimentor.

Cheers

Phillip

Reply to
Phillip Simpson

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