My 95 6L v12 is blowing white smoke out of the B exhaust.

Let me explain how I got here and it may help illuminate what I need to do next.

A few weeks ago I had the AC compressor replaced. When I got the car back everything was running great. About a week later I changed the spark plugs, wires, and distributor rotor then took her for a @30 mile test, no problems (no traffic cool weather) running better than ever. The next morning she had a little trouble starting and blew a little white smoke out of the B exhaust. I foolishly started to drive her to work only for her to overheat as soon as I hit traffic. I bailed on work drove back home (she cooled considerably on the way) and popped the hood to let her cool faster. As soon as I opened the hood I noticed the aux fan was not on.

The next day I checked the aux fan, fuse, and relay, and eventually found that the aux fan sensor/switch was not working. The wire running to it was very lose but in any event it was not switching. I have ordered a replacement aux fan switch/sensor and will install that as soon as it arrives. In the interim, I am systematically checking the rest of the cooling system. It all seems to be in order, hoses were replaced about 3 months ago when 1 sprung a leak. I am going to make Kirby's modification to the Banjo Bolt. What else should I do/look for?

But here's the real nightmare, I have started the car only once since I discovered the aux fan problem and it blew copious amounts of white smoke out of the B bank and had a very hard time starting (the starter would sometimes fail to even turn the engine over). When this happened before it took a few mins but the smoke eventually stopped. I don't want to try that until the aux fan is fixed and will kick in.

Am I now in a worst case scenario? Have blown the head gasket? If I have, is the only recourse an engine rebuild? That is beyond my capabilities. How much will that set me back in the US? While I'm having the head gasket fixed what else should I have done? Could head gasket sealer help?

Nightmare!

 

White smoke is a classic sign of totally unburnt fuel going through the V12. It is far, far more likely that you have either:

(i) a B bank ignition system failing to ignite the mixture (the Marelli failure mode) - see the Great palm's book; or

(ii) an injector loom that is failing and earthing, thus holding open the B bank injectors permanently and flooding the engine on that bank.

Either way do not drive it until you find out, and if it is one of these, change the oil which will have a goodly amount of fuel in it!

Greg

 

Also, check your coolant levels. If they are low and drain fast when the car runs...well, maybe head gasket. You may also find oil in the coolant and/or coolant in the oil, another sign.

Hopefully it isn't a blown head, just unspent fuel. A blown head isn't the end of the world, though. Difficult to fix, yes, but not impossible.

 

Coolant usually smells when its burning. Out of curiosity where did you get the rotor and cap?
I had a rotor and cap go bad on me and I couldn't for the life of me figure out what it was cus I got no spark.
Throw a timing ligjt on a b bank spark plug wire and see.

 

@Greg in France I went back over the Palm book checked all the witing and did the "silicone squirt" fix last night. Anything else you would advise?

@calvindoesntknow I got the cap and rotor from rockauto. Both are Standard Motor Products. The cap is a "made in Italy" aluminum contact version.

@eskr It does not lose coolant quickly and when it does only a little. When I replace the aux fan temp sensor/switch I will check the coolant for oil and when I change the oil I'll check for coolant. Hopefully this weekend.

 

Probably not relevant in this case but maybe worth a thought; had a Porsche 911s a few years ago and it started bunging out enormous quantities of white smoke (I was in Normandy at the time and I'm pretty sure that some of the older locals were having flash backs!), turned out to be the brake servo seals had gone and it was ingesting brake fluid.
Quite spectacular.

 

I am not familiar with the 95 model, but if it was on my 86, I would start by looking at the wiring harness around the compressor, to see what could have messed up when changing the compressor. Pretty easy to pinch wires in that area, and vibration would take it's toll very shortly. I always start with the last thing done before the problem occurs.

 

This would be consistent with a damaged injector harness earthing and holding open the injectors on one side. Or some sort of damage to the wires from the units on the rad top (guessing here, I have no experience of Marelli cars!)

Greg

 

If the starter cannot turn over the engine. That could indicate some fluid in cylinders. Water, oil or fuel. Could also pull the plugs and see if any one looks poor or washed. Since they are new they should all be similarly used.
I thought white smoke was an indication of water. I hope it is not though.

 

This forum is sooo helpful. I retraced my steps and indeed it appears that I damaged the wires leading into the B bank ignition coil. I have so far been unable to find a source for a replacement boot with pigtails. I will likely try to splice it today.

Is there anything special I need to consider when splicing a wire that will get HOT?

Anyone know where I can source a new boot with pigtails? One of the cracks in the wiring is very close to the boot.

 

Bummer, I started to splice the wires coming from the B ignition coil only to find that the wire is crumbling all the way into the B bank ignition loom. I think I will need to remove the protective covering before I find a solid wire from which to splice. I was planning on building a complete new loom for both banks this winter. Anyone know where I can find a good schematic for this project? All the ones I see are for earlier v12s and do not include wiring to the A + B ignition coils.

 

I'm sure one of the guys can get you a schematic. I will tell you that I rebuilt/built a new ignition harness for my 89 V12 car, and even though it took some time, it wasn't that bad. Looks like I need to build a new FI harness now too. My car had been at the hands of some notorious parts changers. Had new harness built, then cut on them trying to get the car running. It was a real mess. It really isn't that bad. Feel free to contact me for some moral support. I had two or three guys give me advice via cell phone, and it turned out great.

 

So I redid the ignition harness and am now getting a steady spark on the B bank. But ...... its still pouring out white smoke.

Do I have to run it for a while to "clear" the cylinders of any residual fuel? Or do I now need to look into the fuel injection harness? How can I test the FI harness?

Alternatively should I start by ruling out a blown/leaking head gasket. Is there a easy definitive test? I don't see anything unusual in the coolant.

 

Are u getting spark on B bank?

 

Yes spark on both banks now.

 

Do a leak down test on B bank and that will determine if you have a blown head gasket.

 

That, and or a compression test. Only takes about another 20-30 minutes more than changing plugs. Pull all the plugs, open the throttles, and check one cylinder at a time. A compression gauge is a pretty inexpensive thing to invest in, to get a better idea of what you are looking at. The leakdown test even moreso I would imagine.

 

Spark or no spark, it still sounds to me as though a short to earth in the injector loom is holding open all the B bank injectors. This is a very common fault on the V12 and the symptoms you describe are exactly those I would expect. Also, as some of the loom in the area has crumbled there is a good chnace other bits have too. If you pull a plug it will be wet if this is the problem. Or, pull all the injector connectors off the B bank side and see if the white smoke stops.

Greg

 

Pulled all the injector connectors off the B bank, no white smoke! Good news I suppose.

Can I confirm the injector short diagnosis using a multi-meter?

 

No need. it is definitely the injector harness. The white smoke is pressurised then depressurised evaporated fuel droplets being blasted out of the exhaust. There is so much fuel in the cylinder it cannot ignite. No naked lights !

You can buy a new injector harness from Jaguar, or you can make one. Meanwhile, if you CAREFULLY remove it (I do not know if the B bank injector harness on your model is separate from A bank, or if they are in one) first Make note of where each plug goes and second if you carefully unwrap it you may be able to insulate it up so it does not short to earth any more (it is shorting to the engine). A bit like the repair you did on the amplifier unit harness, first insulate each wire and then reinsulate the bundle with a new outer. But new is better, obviously.

Great that you have found it. Congrats. And what do you mean "I suppose" ?? !!
Greg