Hi Someday

I'll put one on my wish list, although I've got a Mirror on a Stick

 

Well, it looks like I might have managed to fix the problem. Unless posting here saying I fixed it jinxes it and it happens again. You never know.
Anyway, after reading various hints here from helpful people (thank you, Helpful People), I decided to start off with cleaning the starboard (RH) bulkhead grounds. Pried off the cover, which has gone hard and doesn't cover that well, and removed the nut. Slid the eyelets off, and took a look. Not too grotty, but a bit blackish, so carefully cleaned them all to shiny metal with some fine sandpaper. Slipped them back on, tightened the nut back on, and...
...no CHECK ENGINE warnings for three days now. Could it really have been that simple? Seems so, so far....

Starboard Bulkhead Ground

Anyway, I need to think about something to apply to the grounds to keep them clean. The port bulkhead grounds are a lot harder to access, and the rubber cover still covers them well--they look quite shiny. The two front grounds show signs of oxidation, so I'm going to clean those next, with proper contact cleaner if I can find it. Cleaning the engine ground will be harder. I've located the subframe connection, but will need to get underneath.

So once again, my thanks to this forum and its members.

 

No, it's not that simple. Of course not.

After remaining off for about a fortnight, the CHECK ENGINE thing came on again. So I bought some CRC contact cleaner and did the job properly, getting all the metal nice and shiny. That worked... intermittently. More worked that didn't, but I still got a few warnings, only once per day. None for the last couple of days.
And today I was at the lights after driving for about ten minutes, and over the space of about five seconds, maybe ten, the car started vibrating a bit more, the engine shaking or something, then the revs wobbled up and down, up as far as nearly 1,000 and down as far as nearly 500 before settling back to normal, and the annoying CHECK ENGINE warning on the trip computer came back on. Still FF44.
This strongly suggests a physical, mechanical issue, not a mere bad earth.

Also, the last couple of days, it's been colder and when the car is starting out, I've noticed a groan or whine, not that high-pitched (not a squeal) that can vary in intensity, but goes away once the engine is fully up to temperature. I wonder if this is connected, or is an entirely different issue...
Aside from those, the car drives perfectly fine. I'm checking fuel consumption on the trip computer and it seems normal.

 

How old are the O2 sensors? Replacing mine and adding the extra earth cured the light from coming on for me. The NTK sensors (Japanese made) are excellent quality. Part number 25040, you should need 2 for Japanese spec I think.

It's not that bad to change them, remove the air filter housings and the filter and you should see them on the downpipe. Unscrew (sometimes easier said than done) and unplug the old ones and screw in the new one.

 

Does it happen when the car is moving or not? I'm trying got work out if it's engine related or something in the driveline. If engine, perhaps a pulley bearing on the belt drive? Does it change with engine speed?

 

Thanks very much for your comments and advice, Jagboi. I honestly hadn't even considered trying to access them from the top. I had visions of crawling under the car and reaching up.
The whine is mainly heard at idle, but at its loudest is heard when driving at around-town speeds. This morning I opened the bonnet and turned the engine on to hear what I could hear, but nothing. It didn't actually become noticeable today until she'd been driving for a couple of minutes. I do think it might be related to engine speed--one possible suspect is the air pump bearing, which my garage suggested as a cause before we tracked down the original screeches to failing harmonic damper rubber.

After posting, I decided to put the car into my usual indie garage, as I want to take her on a road trip next week, and will almost certainly not have time between now and then to do any work myself. My schedule's pretty full work-wise, including weekends. Normally I would have left it, and fiddled with it as you suggest once I got time, but today's rev fluctuations were not something that the car had ever done, not like that, and I don't want it cutting out on me a hundred miles from home.

However, once she's back, I do intend to see about those extra earths. I was reading up on them more today, trying to work out just where they connect to the engine--when I looked earlier, I couldn't see anything on my intake manifold that looked right.

 

That can go anywhere convenient. My car is put away for the winter, but I believe I found a bolt at the rear end of the intake manifold and slipped a wire with a ring end under a bolt. It's not critical where, just provides a good earth across the (sometimes) rusty exhaust pipe to manifold joint.

 

Thanks again, Jagboi. Am I correct in assuming you're referring to the extra earths outlined in the TSB for the 6.0 litre V12, or are these entirely different extra earths?

 

They are the ones in the TSB.

 

The FF44 or 45 iss the bete noire of codes. I had one for several years and was only able to clear it when I read somewhere that an exhaust leak code, could cause it. Sure enough, when I checked, there was a leak between the manifold and down pipe. Replaced the gasket, reset the code and all was fine.

 

Thanks for your suggestion. Definitely something to keep in mind. I got a call from the garage last night and they said it was the O2 sensor, so we'll see if they're right--probably due for replacement soon anyway. If that doesn't work, we'll look at other things like the exhaust (I patched a couple of small rust holes in the right rear muffler a while back, but doubt there are sensor readings from way back there). I really only put the car in for a professional check as (a) I had that weird rev hunting, which has never happened before, and I don't want it to be the precursor to something worse somewhere worse, and (b) I'm taking a short road trip next month as it's a long weekend, so (a) applies doubly.

 

Annoyances pile upon annoyances. The garage replaced the O2 sensor, and the car ran fine that evening and all next day on an extended run for a couple of hundred km, several hours, on a road trip. No check engine warnings at all. Then that evening, after having dinner in our hotel, I took the car out again, and less than a minute later the damned FF44 warning came on again. Though it stayed off on the way back to the hotel. This morning, on a tour of temples, it came on twice, both times very soon after starting the engine, and both times, it seemed, the engine didn't catch immediately--like last night--but sort of coughed and then caught. So I turned it off, cleared the thing by checking it was FF44, then started again (fired right up) and no Check Engine. Stayed off until the next time the engine was started and didn't fire immediately (and I mean within a second). Then this evening it stayed off for an hour after a normal start and then came on again for some reason. And came on again pretty fast after the engine was started again after dinner (when it took about two seconds to catch).

Now, it seems to me that replacing the O2 sensor did something, as the FF44 remained off for a couple of hundred kms, and now when it comes on, it's coming on in a different pattern to before. At times today driving around, window open, I smelled fuel (which is not that unusual; garage said in older cars like ours it's more or less standard to smell it from time to time). I wonder if the fuel filter could be causing it? The pump's new, but the filter hasn't been touched. I should add that if it wasn't for the Check Engine warning I wouldn't think anything's amiss: the car's driving perfectly well.

Anyway, I'm going to report this to my garage, and make sure they did actually test the O2 sensor....

 

Smelling fuel is not normal. I know it's difficult to track down, but can you determine at least a general area where the smell is coming from? Engine bay, boot or?? Have the fuel lines ever been replaced? I can't remember if your engine has the short pieces of hose from the fuel rail to the injectors or not. My 92 Daimler did, but it also had Lucas ignition and you have Marelli.

You have had the ignition overhauled haven't you? Plugs, wires etc? I wonder if the car is running rich. Does the exhaust sell normal, or a bit acrid and stings your eyes?. I usually put my hand near the pipe end for 30s or so and then smell when the engine is up to normal temp.

I'll have to do some research on what trips the code.

 

Thanks again, Jagboi. It's hard to determine where the smell is from--yesterday I opened the bonnet, but only smelled hot engine, and the boot smelled normal as well--nothing noticeable there. Mine's a Marelli, without those short hoses to each injector, but it does have the two cross hoses, which were replaced at the the start of the year. The car could be running rich, though this would be a recent thing as it passed inspection in July and emissions is one of the things they check. Nor does she appear to use more fuel than normal, at least going by the trip computer.

Ignition-wise, the leads, plugs, dizzy and cap, and both coils are new (all within the last two years; second coil within the last few days). I have noticed once or twice recently after starting that the battery warning light takes a couple of seconds to fade out (and I do mean fade out, not just go out). Battery issue? Alternator issue?

I'll do the exhaust smell test as soon as I can. Today, if I remember after getting home.

That reminds me, actually--one thing I noticed a couple of days ago, starting the car up for this road trip, is that the cold-morning exhaust cloud from the right (port) pipe seemed less dense than the cloud from the left (starboard) pipe. And putting my hand there, the port pipe did seem more of a putt-putt than the starboard pipe. A missfire? Or just a cold engine? The engine's running as smoothly as ever, however. Might want to keep an eye on it, however.

 

Back. Forgot to do the exhaust smell test, as we had a lot of luggage to deal with, but the boot/trunk does smell of petrol if you poke your head in and smell it. And you can smell it when the window is opened at around-town speeds.
This morning, the Check Engine warning came on a few minutes after leaving, then about ten minutes later I pulled into a carpark, switched the engine off, and switched it on again about a minute or so later. It remained off for rest of the 250 or so km trip, along surface routes and then along the expressway. Remained off after turning the engine back on following a 5-10 minute break at a rest area. Then after about an hour's break to do some shopping, it came back on pretty promptly.
This strongly suggests a correlation of some sort, though I'm not sure what. Basically, a cold or warm engine will cause it to come on, but a hot engine won't. Mostly....

 

There are 2 parts to an O2 sensor. One is the sensor itself, the other is a heater within it. The heater gets the O2 sensor up to temperature faster, as they need to be about 600C to operate. Usually, (but not always, like at idle) the exhaust heat is sufficient to keep the sensor hot. The plug for the sensor is actually 2 plugs. One for the sensor circuit, one for the heater circuit. I wonder if the heater side isn't plugged in, or there is a fault that it isn't getting power?

The heater circuit takes power from the fuel pump relay, and obviously you have power to the fuel pump, so that's not a concern. When you check codes is it just FF44, or is 45 there as well? 44 is the A bank (right) side, 45 is the left side sensor.

Here is what the manual says about FF44:

 

As a check one thing I find useful is to keep a logbook of my distance driven and litres of fuel I put in. Then I will calculate the mileage and compare to the trip computer. I don't expect an exact match, but it should be close. On my various Jags where I have compared the trip computer has been within 2%. Where there can be an error is the computer uses the commanded pulsewidth to the injectors to calculate the amount of fuel flowing through them. It's a a calculation of what should be flowing through them, not what actually does flow through. So a leaky/sticky injector that is allowing more fuel through than it should won't show up on the trip computer. Neither will a leaking hose or fuel pressure regulator.

However, since the emissions have been checked recently and are in spec, that bodes well that things are running as they should.

 

Thanks again, Jagboi. Very informative.
I only get FF44, assuming that the trip computer display will switch reasonably rapidly between faults if there are more than one (i.e. I don't have to wait for a minute or more, for example).
What confuses me about the whole situation is that it seems... well, not random as such, but odd. Before getting the O2 sensor replaced, FF44 would remain off until the engine was basically warm, so it certainly seemed like the sensor failing to respond to the hot engine fuel/air map. Then it was replaced, and it remained off for the next several hundred kms, albeit in one day. It stayed off after restarting the engine three times (three stops). One was only about 10 minutes, but one was for a quick meal and the other for some shopping, though neither for more than half an hour. Then there was a break of nearly two hours, and the FF44 popped up again. Engine colder, heater not working? Sounds logical.
But then it popped up the next day midway while driving in the evening, engine thoroughly warm. Which was an aberration, as it never did that at any other time.

Say the needle's reading about 1/4, and I add 50 litres. Then I see how far I've gone when the needle reads 1/4 again. What I've found is that the needle position can vary--coming back yesterday, for example, especially in the last quarter tank, it would sometimes read close to the red zone, sometimes closer to the 1/4 mark. Seemed to vary depending on how much I was demanding of the engine (speed, basically).

With the inspections here, they stick a probe up the pipe to measure the concentration of carbon monoxide and hydrocarbons. Pass rates are 1.0% for CO, and 300 ppm for hydrocarbons.

Anyway, I'm going to ring the garage today and say "oi mate". And "did you actually check the O2 sensor, or just assume?"
Although the fact that the behaviour is different suggests the replacement did have SOME effect. It just didn't cure it....

 

Which made me wonder if perhaps the heater wasn't plugged in! I forget exactly where the plug is, but with the air cleaner housing removed you should be able to see the sensor on the exhaust pipe and follow the wires back. Should be on the inner wing, roughly where the shock absorber bolts come through, i.e. about half way back in the engine bay.

The codes come up reasonably quickly, you don't have to wait around much.

Those emission limits are quite generous, I believe my (now sold) 1964 E Type could pass those with absolutely no emission controls.

 

So if the heater's not plugged in, it needs to warm up to 600 degrees purely from the exhaust temperature? Okay, I think I follow you. Not warming up fast enough = throws an error when the correct reading isn't reached by the fixed time, but if the exhaust is still hot, after a short break, it reads the correct figure. That makes sense. I'll see what I can see.
Hm. According to the ROM, the Big Green Book, for Air Cleaner Assembly, Renew (pp.472, 473), I need something called "arborsil sealant" and a new gasket when replacing the air cleaner. So for now, I'll use my trusty (?) Chinese probe....