I’ve got a 1994 Daimler XJ40 that is probably only really good as a parts car and I’m about to list it for sale so that someone can make use of it. I’d like to satisfy myself before I list it that there’s nothing wrong with the engine because recently, about 5 to 10 seconds after starting, it’s producing clouds and clouds of acrid white smoke.
I’ve read that this is possibly brake fluid leaking from the master cylinder in to the inlet manifold, but I can’t find a post here that deals specifically with this problem. It seems fairly likely as the problem occurs as the brake system gets pressurised. Short of pulling the fuse for the brake pump, is there a reliable test I can do to verify that this is the problem?
The car doesn’t seem to be losing coolant and it seems to be smoke rather than steam that I’m getting. However, I don’t see that the brake fluid level going down either - I’m working on the theory that a little oil in the combustion chamber creates a lot of smoke.
Hi Rog - thanks for your question! It’s difficult to describe exactly, except to say that it smells smoky rather than steamy. It’s kind of acrid - like something’s on fire, lodges in the back of the throat a bit.
Anti freeze “smoke” might have a sweetness to its smell. Your description doesn’t seem to line up with that. And, you stated the coolant level holds steady.
I don’t see how brake fluid could get into a combustion chamber.
The smoke from oil getting past a valve seal or piston rings could be considered to have an acrid odor. Cars I’ve had that burned oil emitted clouds that had kind of a very light bueish gray hue. Is the car very high mileage? And does you oil level decrease over time?
I agree that getting BF into the combustion chamber on a non vacuum brake system is a non starter, assuming this car still has its original brake booster system.
Thanks gents - ah, so it’s a different brake system that causes BF to get into the fuel mixture. Looks like I can rule that out.
The smoke definitely doesn’t smell sweet either.
I don’t see any blueness to the smoke to suggest it’s engine oil - I know what that looks like.
If anything, its appearance is most Iike over-fuelling, but I’ve never seen fuel smoke in such copious amounts
Thinking about it (I’ll verify this) the check engine light may be on, on the dash, too.
I’m going to start and move the car in the next little while so I’ll get a pic or video of it. I must admit that the last few times I’ve run the engine, I’ve done so in the dark because the smoke quickly fills my driveway and then goes over the fence to smoke-screen next-door’s garden, too!
Overfueling is light grey to black, if unburned it smells like fuel so another dead end I‘m afraid.
It’s not loads and loads of condensation in the exhaust boiling off from the smoke screen description.
Thanks again folks - yeah, I’d not thought of the fuel smell with over-fuelling - that’s rules out then.
To be honest, I guess it could be condensation in the exhaust system, that would account for the volume of ‘smoke’, and the fact that none of the car’s fluids seem to be going down.
Who knows what steam that’s been forced through an exhaust system would smell like - possibly a bit acrid and burnt.
So far I’ve not had the courage to just run the engine and see if it goes away. Maybe I’ll wait until next door go out before I start it up again.
I’ll keep you posted with more information when possible!
You need to idle it for quite a bit if you think it could be lots of water in the exhaust. I was thinking of that because you said it’s a parts car.
If it smells like fireworks or sulfur your catalyst could be burning lots of fuel.
I remember a 7 series that had a horrible smell to it but emissions etc. were all in order. Maybe that adds to it.
When i first went looking for an XJ40, I test drove one that started right up but had been sitting for some time -months, maybe. This car filled the entire cul-de-sac of the owner’s neighborhood with smoke and opaque god knows what for several minutes, but eventually cleared up and then it seemed fine.
I took it for about an hour’s worth of driving and the smoke issue didn’t return other than the puff of oil smoke they all do.
Have you given the car a good hot run and then checked the startup condition? Could just be a load of built up crap in the exhaust system.
I got round to moving the '40 yesterday and got this brief video:
The smoke smells different to how I remember it - definitely reasonably strongly of fuel.
It started perfectly after about 4 months standing and seems to idle smoothly.
I’ve advertised the car for sale as a parts car, but I’d like to get it running properly first, partly to satisfy my curiosity about what’s wrong with it, but also so it’s more attractive to a potential buyer.
When I get time tomorrow I’ll check all the plugs to see if they can tell me anything and also have a good look at the oil / coolant to see if there’s anything there.
How old is the fuel in the tank ? IF none of the other related fluid levels are dropping ie oil, coolant and brake fluid, and there’s no sign of them mixing anywhere it could be a combination of moisture in the exhaust system and fuel that is past it’s best. What is the longest time you have let it run for ? I’d put some fresh fuel in and then try running it for at least half an hour.
One time when I started my XJ40 after an 11 week lay up it took about twenty minutes for all the steam to clear and there was water actually trickling from both tail pipes !
I had time this afternoon to do a bit of diagnostic work on the car, and think I may have made a bit of a discovery.
I took all 6 plugs out - they were all black and showed signs of over-fuelling. I didn’t find any loss of coolant or oil, and no evidence that they were mixing. The distributor cap was showing corrosion on the contacts so I cleaned it up with some wire wool and checked the rotor arm was fine.
A quick check of the engine bay revealed that the multi-plug that connects to the air flow meter was unplugged - not completely, but withdrawn enough so that it wasn’t making contact. After I’d shut down and plugged it back in, the engine re-started and the CHECK ENG light went off on the dash.
I ran the engine for 10 minutes from there and gradually the smoke on idle cleared to the point where it seemed to be normal, but water was still evident from the exhausts.
Revving the engine results in the smoke returning, however, hopefully this will clear as well.
The fuel is about 3 years old so it could easily be contributing to the problem - there ain’t a lot left in the tank so I think the addition of a bit of fresh super unleaded (97 RON E5) will help matters further.
I’ve currently put the car up for sale for £850 as a source of parts for someone, so it will hopefully be gone soon - I have a feeling it won’t be the last big old-fashioned Jag saloon I’ll own as they’re addictively good fun. Funny thing is I just never got to love this car as I did my first '40- I shall choose more carefully next time and find something I’ll really enjoy owning and driving.
Drive it if you can, without real load nothing gets hot enough to really clear out, you need to have the tailpipe hot enough to burn yourself. It won’t completely clear out if you just let it idle. It needs load!
Add low octane fuel if you think that matters as octane will go up when the light components of the fuel evaporate. I don‘t think it makes much of a difference.
That particular colour seems to suffer from laquer peel more than the others. I noticed this when I was searching for a replacement for my first XJ40, I went to see more than a dozen different cars and that problem was present on three cars all with that same colour. I have seen it on other colours but it seems more prevalent with that colour.
I think the engine in your car sounds and looks like it just needs fresh fuel and a mega service, I think the remaining smoke would probably clear with fresh fuel and an oil, spark plug and filter change, maybe some injector cleaner followed by a long run would help too, although I realise that is impossible seeing as it is currently not legally roadworthy.
Good luck with the sale, I hope it goes well for you.
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