Diesel engine starting / first start of the day problems

[Aeron]

Hi, I’m new to the forum, and no mechanic, so please be kind!

Vehicle in question is a 1999 T35 Renault Master 2.5 D.

It has had first start issues since I’ve owned it, with white smoke (un-burnt fuel I’m told) bellowing out of the exhaust when the van finally kicks into life after allowing the glow plugs to warm for 20+ seconds, regardless of ambient temperature. After it’s started once however it’ll start on the button all day long.

Recently I decided to do something about it, so perhaps naively got the glow plus changed. Now it won’t start at all! Without the help of Easy Start anyway! I now understand that faulty plugs were unlikely the cause of the initial problem.

The glow plugs appear to be all working and the relay appears to also be doing its job and intact (no breaks). The battery is also new and not a suspected cause.

So… I’ve trawled many forums, and got a bit of a list together, but I’m unsure which of these faults are (most) likely to be the cause, and which order to try them in, or if there are other solutions I should be investigating. Please help.

• Fuse for glow plugs is damaged or broken
• Glow plus are giving a false positive reading and are actually not glowing
• Temperature sensor is faulty
• Coolant temperature sensor is faulty
• Issue with starter motor
• Issue with fuel line or pump

[andyiley]

Do you still get the clouds of white smoke (unburnt diesel) when it starts on easy start then?

Have you actually checked if the glow plugs are getting power/glowing?

Has this engine a traditional diesel fuel system, or is it one of the newer type of common rail type systems?

Edited by andyiley on Tuesday 14th April 09:32

[Aeron]

Hi, thanks for the reply. I still get white smoke with easy start. The plugs have been tested as far as they are drawing power, but TBH I'm just not sure, after reading many posts, that they were the original cause as many people are saying the glow plugs should not really be needed for ignition in temperate conditions. maybe this is not true, or not true with older vans?

The glow plugs fitted were however very cheap, bought off the internet jobs, so maybe they are giving a false positive?

Edited by Aeron on Tuesday 14th April 10:05

[andyiley]

TBH I am no diesel expert, but if I were to guess where to look, I would be looking more towards fuel timings, hence why I asked the above about common rail or not.

I base this on the fact that you are getting unburnt diesel smoke out.

A diesel (pretty much) only needs atomised fuel/air mix to be there in the combustion chamber when the compression stroke occurs, so on a traditional type diesel fuel system if the injection of fuel happens toat the wrong time, surely this is a likely candidate for your attention.

I am sure others will be along soon who know much more than me though.

[Aeron]

Hi, Thanks. really appreciating your help with this. I have since discussed with a Renault mechanic and he concurs with you that it's likely a fuel pump / timing issue. I have the number of a diesel injection specialist, so I'm going to give him a ring and see if he can sort it!

[andyiley]

Sounds like a good step in the right direction IMHO diesel pump timing on an old-school diesel system fits the description of what you are seeing, once again IMHO.

[geeks]

Glow plugs shouldnt be needed unless its around below 5 degrees celecius from memory..

I woul dbe checking and changing the fuel filter, I would then be making sure the system is completely and properly blead and then see how long it takes for it to become difficult to starrt.

My guess is that you have a crack or dried out cracked/past useable life pipe in a diesel return line or a leak off pipe meaning air is getting into the system when its left stood overnight, the reason it takes so long to start is that it has to drag the fuel all the way through from the tank as diesel engines (well older ones anyway) are not pressurised in the fuel system (i.e force fed from a pump), this will lead to eventual pump failure if you are not careful...

[andyiley]

You make a valid point, but surely the clouds of unburnt diesel mean that the fuel is getting through?

[geeks]

andyiley said:

You make a valid point, but surely the clouds of unburnt diesel mean that the fuel is getting through?

Smoke kicks out following start not other way round, so could still be air in the system, it would still be my first port of call, the symptoms are spot on for drain back!

[andyiley]

Sounds feasible, as I said I am no diesel expert, certainly worth checking then.

[Gerradi]

Unburnt fuel in diesel is black, white smoke usually indicates inlet valve problems.

[LeoZwalf]

Gerradi said:

Unburnt fuel in diesel is black, white smoke usually indicates inlet valve problems.

If the diesel pump timing is bad, there will be white smoke. I know this because I had a very similar problem on my Ducato 2.8 idTD (motorhome) - the cambelt (also drives diesel pump) tensioner bracket had come loose and the belt skipped a tooth or two, throwing the diesel pump timing out. (as an aside, I was lucky not to lose the engine - this happened about 3km from home after a 3000km holiday!)

Aeron, your Renault will have one of these engines: http://en.wikipedia.org/wiki/Sofim_8140_engine if it is a 2.5 as you say then it is basically the same as the later 2.8 litre version. As per that Wikipedia page, that engine is used in many vans and is very common. Your original message says it is a "D" so I assume no turbo and no common rail. These are very simple engines with little to go wrong so it shouldn't be too hard to figure out the problem. There are plenty out there with mega miles on too.

Maybe by the time you read this you already went to your diesel specialist so I, for one, will be interested in what the diagnosis was. I'm also interested in what you said about having the glow plugs replaced. This engine does not have a set of 4 electric glow plugs, but a single 'flame start' device in the inlet manifold. It does not operate over 5 or 7 Celsius (can't remember which). If you are having starting problems at temperatures above that, then there's certainly a different problem. For what it's worth, my Ducato starts very quickly even at sub zero temps without holding the flame starter on at all, it is amazing (but only has around 65,000 miles on it)

Very curious to know the outcome of this, so please do keep us updated

[andyiley]

Gerradi said:

Unburnt fuel in diesel is black, white smoke usually indicates inlet valve problems.

Over fuelling in a diesel can be a possible cause of black smoke, not the same thing at all.

Unburnt diesel looks like white smoke, it is actually atomised diesel rather than smoke, but looks like it.

[Aeron]

Hi,

Thanks All!

I have it booked in for the 6th May, so will let you know. I am now slightly thinking it could be the fuel line as further ho-humming has added these pieces of info...

There is no white smoke when I use easy start.
Once the engine has started I can switch it off almost immediately and it'll start again all day, so unlikely to have warmed up much

[Steve_D]

Does it park on a slope at night?
I had a drainback issue on a Pug but not if I parked it nose down on my sloping drive.

Steve

[Mr2Mike]

Gerradi said:

Unburnt fuel in diesel is black, white smoke usually indicates inlet valve problems.

That's not correct. Unburnt diesel forms white smoke, excess diesel or insufficient air (i.e. partially burnt diesel) produces black smoke.

If replacing the glow plugs has immediately made things worse, then clearly the plugs can't be working correctly.

Plugs aside, bad injectors will cause white smoke when cold due to insufficient atomisation. When they get really bad they inject a neat stream of diesel with almost no atomisation. The engine will still run when hot, but will be very hard to start and will produce clouds of white smoke.

Mechanical injectors can be reconditioned pretty easily, and for far less money than common rail injectors.

Edited by Mr2Mike on Thursday 23 April 16:39

[Denko]

[quote=Aeron]Hi,

Thanks All!

I have it booked in for the 6th May, so will let you know. I am now slightly thinking it could be the fuel line as further ho-humming has added these pieces of info...

There is no white smoke when I use easy start.
Once the engine has started I can switch it off almost immediately and it'll start again all day, so unlikely to have warm
So what was the problem?

[Denko]

Hi

I’m experiencing exactly the same problem on my Avensis.

Did you find out what is the problem?

Thanks