1998 Boxer 1.9TD Grey smoke and rough idle - checked fuel lines for air, air intake for leaks... still no solution

[mcpop]

So, it's a Peugeot Boxer 1.9 TD 1998 Autosleeper Pollensa motorhome, on 64000 miles, with bad idle and smoke. I've owned it since 2015, since when it's had regular oil, air and fuel filter changes and literally never missed a beat until Nov 2023 at around 63690 miles when lumpy idle and white/grey smoke began to be a problem, even when fully warmed up, but only at idle, accompanied by noisy engine. When this first began it was just very slightly noisier than usual, just a bit more of a diesel rattle than before (as it always ran very quiet for a diesel of this type). At that stage it was difficult to say if there was anything wrong or if I was being over-sensitive but over the months since then it has become obvious that something is wrong. At start-up it has been blowing out clouds of white to grey smoke, so much so that I do not start it if the neighbours are around as it's rather antisocial. The smoke is only really there at idle and gets progressively worse the longer it idles. I've taken to switching it off at traffic lights to avoid a smokescreen and possible attention from the authorities. Once it's at driving speed the smoke goes away almost entirely. Power is down a bit - perhaps 20% down on normal, a struggle up hills it used to take in its stride - but it's driveable, and runs seemingly normally and smoothly.

Fitted new intercooler and radiator in April 2021. Replaced all four glow plugs in 2019 at 51980 miles, so they're not old.

Some background details:
Did the timing belt (DIY) for scheduled maintenance in September 2022 at 62420 miles as well as an oil change. However, unable at the time to get correct oil (Total Quartz 5000, 15w-40), used Valvoline SynPower 10w-40 instead. At 62774 miles, in May 2023, noticed small leak from front crankshaft oil seal. In August 2023 (62933 miles) added 125ml Forte seal conditioner to engine oil to combat this and then a further 125ml Forte Seal Conditioner in October 2023. A bit later, thinking the oil leak might be due to inadequate oil viscosity, did an early oil change in October 2023 (63590 miles) to Total Quartz 5000, 15w-40. Just after this was the point (63690 miles, Nov 2023) when I first identified the lumpy idle as a problem. Added 400ml Forte Specialist Diesel Injector Cleaner.

Shortly after that, the idle became very bad, with intermittent puffs from exhaust and engine wobble - suspected timing belt off one tooth. Took it to garage who said it was not timing as that would be much worse and regular, whereas these puffs occurred every 10 seconds or so.

Nov 2023, suspecting air in fuel line due to white smoke and intermittency, changed fuel filter and bled fuel system using hand primer pump. (Fuel filter was previously done March 2022 so very new). Made no difference.

Dec 2023 - still idling badly. Replaced injector spill-off pipes with new ones.

Jan 2024 - suspecting leaks from fuel filter housing, replaced fuel filter AGAIN. Unchanged. Still suspecting air in fuel line, fitted an electric pump in fuel pipe close to tank to try to create an automatic bleeding system. Suspecting water in old(-ish) fuel, drained and discarded all diesel in tank using electric pump and put in 3 gals new.

Electric pump caused leaks from filter housing so removed it, re-joined fuel pipe and re-bled using hand primer pump. Refitted fuel filter and rechecked seals - OK. Bled and primer pump firm after this.

Feb 2024 - now suspecting air leaks in intake system/duff turbo, removed, checked and replaced all accessible air intake pipes - all tight, no splits/problems found. Checked turbo by turning vanes by hand - rotating smoothly with no wear apparent.

Today - checked crankcase breather - can blow through either way - and dipstick hole for blow-by. A bit of blowing from there but not dramatic - I think it's normal.
Added 250ml Mannol Diesel Jet cleaner and topped tank up to about half full. Took it for drive up hill, half-way up which it blew the connector hose off the turbo, proving at least that the turbo works! (And that I didn't tighten the clip enough). Awaiting new jubilee clip to refit that tomorrow.

So... any ideas what could be wrong? I long suspected air in the fuel system but think I've done that to death now. Then leaks in air intake system, which as far as I can tell there aren't. Don't think it's the timing belt off as that would make more noise, be more regular, and would quite probably have killed the engine by now (1500 miles since timing belt change). No particular reason to suspect head/head gasket trouble as it has never overheated since I've had it and there's no evidence of oil in the coolant or coolant in the oil. Could it be the possibly unwise use of two lots of Forte Seal Conditioner, actually damaging the valve stem seals rather than improving them? Not sure, even if they were damaged, that this would cause these symptoms as a diesel doesn't suck the way a petrol does.

Next step is to buy a compression tester and see if all the cylinders/valves are healthy, but I wonder if anyone has any ideas based on all these woes and attempted remedies, 'cos I love my bus, it were a great old bus and now it ain't!

[CitroJim]

Gosh, you've checked most of the suspect areas...

As it will have an EGR valve, check its operation. It can be temporarily closed off with a plate. Do not leave it in this condition as it is part of the vehicle's emission control equipment and must be operational. An EGR stuck wide open may account for the puffs and so on.

If not that, a leakdown test to check compressions will be a good plan but just before you do, check the valve clearances.

They can close up in these engines and cause poor running through low compression.

Is it difficult to start and does it smoke excessively when first started? If so, what colour?

[mcpop]

Many thanks, Jim! Those suggestions certainly make sense. The reason I haven't looked at the EGR valve yet is that I have always thought it didn't have one - I'll have to search for that.

Starting is good, as it always was, and the smoke is the same - heavy clouds of white-to-grey, never black. It's strange that the smoke doesn't get any less when the engine is hot, and that it's only on idle, clearing up once the engine is warmed up and running at driving speed, coming back every time it's at idle and getting progressively worse the longer it idles. There's no extra smoke/no black smoke on heavy acceleration.

I've never done a leakdown test before so that will be a new experience - I'll have to buy a compressor to do that. More money I can't really afford, but less than taking it to a garage.

It's raining today so I'll leave it until he weather's better and then report back...

[CitroJim]

Ahh, white/grey smoke is an indicator that nil or very little combustion is taking place and that really does point to a loss of compression, likely only on one cylinder. White smoke is just an aerosol of finely atomised unburned fuel...

Check those valve clearances before you do anything else... That may save you the need of a leakdown test...

[mcpop]

OK - thanks, Jim! I'll have to dig out my long-lost feeler gauge!

Forgot to mention that as part of my work so far I have (repeatedly) loosened off the union pipes at the injectors to clear any air lock there and am getting a good spray of diesel from each, and apparently equal reduction of revs at each cylinder, indicating that all four cylinders are firing equally. But I'll check the valves next anyway.

[RichardW]

Has this got the No 3 injector with the lift sensor? Failure of this is not unknown, and throws the timing out which can lead to the symptoms you have. I'd have thought valve recession was unlikely at this mileage, but never say never. It could have done its head gasket, that is not exactly unknown on the TD engine (although more prevalent on the 1.7s) - is there pressure in the cooling system when it's cold?

[mcpop]

I don't think there's any sensor on No 3 injector - no wires on any of them, just the fuel union and spill-off pipes. I have uploaded a couple of pictures of the injectors: https://www.dropbox.com/scl/fi/lp6ynl5y ... yrtba&dl=0 and https://www.dropbox.com/scl/fi/118awz2r ... 1vcca&dl=0.

No pressure when I removed the top of the expansion tank https://www.dropbox.com/scl/fi/7i0t1f10 ... 0bb7k&dl=0 this morning - but I'm not sure there ever is. It looks like the red outlet pipe is open to the world. Ran my finger inside the expansion tank and it came out clean (at least, as clean as it was when it went in!) - i.e. no oil in there. Also, the oil filler has no mayo sludge, so I'm optimistic that the HG is OK. Never been overheated in the 8 years I've owned it.

[mcpop]

I think what I'll do next is fit a length of clear fuel into the pipe line as a final check that no air bubbles are getting into the system, 'cos to me it points to air more than anything else. Buying now on eBay...

Also, do you happen to know if these have a primary filter in the tank (which might be blocked - the fuel sender gauge sometimes drops to zero and then comes back to life later, indicating something less than healthy there)?

[mcpop]

Many thanks, Jim and Richard, for your excellent suggestions. Now I have inserted a length of clear pipe in the fuel line and see no air bubbles, so I have (unfortunately) ruled out air in the fuel line. My prime suspect now (as I see no reason for anything to have gone wrong with what has always been an excellent engine, and which hasn't really been used since it was last OK) is the EGR valve, as crud resulting in this sticking open could certainly cause the problems I've been having --- assuming it's actually got one.

The Russek Manual says it should have one but I have scrutinised it from above and below and looked all around the exhaust manifold, the turbo, and the exhaust at the turbo end and see nothing which looks like this: https://www.ebay.co.uk/itm/315024418978.

I wonder, has anyone on the forum actually FOUND the EGR on a 1998 1.9TD Peugeot Boxer with the XUD9TE engine, and if so, could they tell me where it is?!

[CitroJim]

Gosh, I'm surprised that a fairly late 1.9TD won't have an EGR valve. 1.9TDs in Xantias and other cars fitted with this engine after 1996'ish had them. They are usually fairly easily seen at the right-end end of the exhaust manifold although they are somewhat underneath...

If you don't have one, it's no bad thing!!!

[mcpop]

No, they're a sh*tty piece of technology. As I can't see one, I don't think it's got one, which is very surprising. Anyway, now I've bought some EGR cleaner anyway as £7.99 and 15 minutes spraying is much easier than what comes next and may clean out any yuck.

I'll keep you posted!!

[RichardW]

Post up the VIN (it will hide itself) and I'll have a look. TBH I think something has broken the pump and upset the timing....

[mcpop]

Hi Richard - Many thanks!! The VIN is VF3**************[VIN obfuscated, can be read by forum staff].

[RichardW]

LH end of the exhaust manifold, vac operated

Don't know what the item at 8 is, seems to be an atmospheric pressure sensor, but don't know what it does.

[mcpop]

Thanks very much for that, Richard. It definitely hasn't got an EGR valve (designed without one, not just removed and the various holes blanked off) as there is only one pipe from the vacuum pump, for the brake servo. So the mystery deepens. I'll give it a go with EGR cleaner when that arrives anyway, more because it's cheap and easy than anything else, and see if that has any effect.