After getting the car taxed and insured (the thieving.....)
I finally managed to get it out for a run around, mainly to make sure that the work that's been done on the cooling side of things is working properly, and it is I'm glad to say.

Then I found that I may have a problem.

For example:

Stop at a 'T' junction, turn left and you start to go up a hill.
Nothing major in terms of a hill, wouldn't really bother a cyclist type of hill really.
And the car has no power to pull itself up the hill.
And I mean no power. Like 25mph power. Stays in 2nd gear.
It won't accelerate, or at least gathers speed very slowly indeed.
If I mash my foot into the carpet on the other hand, it'll drop through the box, spin the wheels and we're away like a scalded cat.

On the flats, absolutely no problems whatsoever. Smooth gear changes, nice and quiet, no thumps or bangs.
It did feel like it had gone into limp mode with the lack of power, but I had the diagnostics running as I was monitoring the coolant temps while driving, and it threw no codes at all.
The only pending codes I had were for the Bank 1 cam sensor that I haven't traced yet, (it's got 2 new sensors and I removed the bolts near them to rule those out) and I'm wondering if that may be the cause?
But then I remembered reading that the cam sensors were only for starting then the igniton PIP took over for the timing, or something like that.
But I could be totally wrong of course.

I'm also thinking while I'm out today that it doesn't feel like an engine with nearly 300BHP, doesn't seem like it's got much get up and go like a V8 should have, until you mash your foot that is. Then it goes.

I just spent the last 2 hours using the search option but can't seem to find anything that matches.

I'm going to pull the plugs tomorrow and see if any of them are not firing, but without codes being thrown for a mis-fire? I'm not hopeful.

Any thoughts or ideas would be most welcome.

P.S.
I'm off to the pub now so will pick this up later or tomorrow and post anything I find.

 

While monitoring the coolant temps the readings are getting stupid.
They are bouncing around all over the place, 424*F, 300*F, then to normal 190 to 216 and back up again and so on.
Found on the XK threads a member with something similar to mine, lack of power, restricted performance, no codes thrown, but their problem occurred at higher outside air temperatures, started to correct itself at lower outside temps.
Got me wondering if it could be something as simple as the ECTS gone bad.

 

You'd hope for a code but things need to be fairly consistently bad for it to flag.

ECT is one of the vital sensors.

 

Thanks for the reply.
I'm going to order and replace the ECTS just to rule out if it is going wonky on me. It's only a very small cost so no harm there
Those temp read-outs are ridiculous.
I had a thought that maybe it could also be my obd tool itself so I'm probably going to order a new one of those as well. Again it won't hurt any and it'll be good to have a spare around.
The reason I got to thinking about the obd tool itself is because when I looked at the fuel trims, they were also bouncing around, as was the intake temperature readings. They dropped down to -19*F. Then up again they go.
The engine timing read-outs were a bit iffy too.

 

Suppose ECT was doing weird things - a new fault on here but I guess not impossible - then the fuelling will be changed to cope. It will be wrong if the ECT is wrong and the trims would also be wrong.

ECT doing that sounds unlikely but yes they're cheap. Wiring might also be a suspect.

 

Please god no, not a wiring fault

 

Changed the ECTS today, no real change when monitoring the temps while driving, except that it no longer hits the 400*+ F mark.
Although I did see a 353*F reading pop up.
So I might be looking at a wiring fault somewhere. Dropping out to earth might be the culprit I think.
So about an hour ago (22:00 hrs GMT) I went out for a little spin.
Was out for about 35 - 40 minutes total.
Maybe my foot was a little heavier than normal, it seemed to go a bit better, but still showed the previous signs of lack of power until I knocked it down through the J gate to manually select lower gears to get it up to speed.
I had a flick through the trip meter on the dash while driving about and came across my average speed reading.
I thought "that's going to change shortly", but strangely enough, it didn't.
And the only time I got down to this reported speed was at junctions or traffic islands.
Now it's got me thinking that maybe my lack of power could be associated with a wheel speed sensor problem thats not showing up because my OBD reader won't read 'C' coded faults. Which is what a speed sensor would show up as, if I recall correctly.
Took this photo when I got back home

 

I would try not to drive it at all until you get these vital sensors working because it will fuel very badly and may destroy the cats.

 

The erratic ECTS signal - Shouldn't that also be driving the dash gauge all over the place? Or are you just seeing quick spikes on your scanner? I realize the gauge is deliberately dumbed down, so maybe quick excursions don't register.

The inaccurate AVG speed - A little more research may be in order. My hunch is that figure is based on transmission output speed, not wheel speed. The transmission output speed is already fed to the ECM for its calculations. Wheel speed primarily goes to the antiskid system. The two systems probably crosstalk to some extent, but I bet each computer is biased towards its own respective inputs. Strictly conjecture on my part, so take it with a giant grain of salt...

 

At the moment I'm using Scan XL Pro to do the diagnostics and live monitoring with the ELM327.
The readings are indeed spikes as you say, I think the readings refresh every 5 seconds or so, but after last nights little drive I'm starting to wonder if they really are anything to worry about.
I am judging that by listening to the speed of the radiator fan when I stop.
If it's going hell for leather then I know it's getting to the top of it's temperature range, but when I returned home last night and stopped on the drive, the fan speed could be described as moderate.
I'll see if I can get a mate to sit in the passenger side and video the read-outs and post them here so anyone can get a good look at what I mean.
Pictures and videos always speak a thousand words and all that.
As for the average speed read-out, been looking around today on the net and haven't found anything significant at all.
From what I've read so far, and not currently being able to read any 'C' codes, the ony thing that may indicate a wheel sensor problem is if the traction control flagged a fault, but I've nothing in that department.

I think I may spend the weekend going over all that I've done so far, just to double check everything, more for my peace of mind and sanity than anything else.
I hate niggly problems like these, they make me lose sleep, and I get little enough of that as it is.
The OCD monkey is riding my back hard right now!

 

It might (perhaps) be glitchy software.

Bear in mind it could not change the fan speed at the same rate so it isn't a clue really.

Maybe watch fuel trims - see the many threads.

 

Glitchy software, a tiring 10" netbook for diagnostics, yes I suppose.
I understand about the fan not reacting quickly with the read-outs, that's why I mentioned about listening to it as well.
My ears sometimes tell me more than any machine can.
Being an old skool spanner, I always listen first, then look, then attack.
I did it to a bloke who just bought an old merc some years ago, in the car park of a clay shoot.
It was a nice looking car, and he had only bought it about 2 days earlier.
Very proud he was, and I complimented him on it.
Then told him that the valves needed doing and the exhaust was blowing on the manifold.
He couldn't hear it until he lifted the bonnet and I showed him where to listen and what for.
I heard it from 30 feet away.
That's the OCD in me.
Good job we were already friends, he had a shotgun over his shoulder!

 

Not to send you down a rabbit hole, but I'm wondering if an AC ripple from the alternator could be the cause of the oddball symptoms you're seeing.

Quick enough to eliminate. Some discussion here, specifically post #12, unfortunately sans resolution:

https://www.jaguarforums.com/forum/s...-start-183682/


Very interesting article, from a professional trade magazine, on the same subject:

https://www.motor.com/magazine-summa...tery-of-tests/

 

@KR98664
I can pick up an Ancel from china for around £30.
Might put it on the shopping list.
Strangely enough, after reading the links you posted, I spotted the analogue machines and kicked myself.
I threw one out last year, I can't remember why

@JagV8
Been looking at the fuel trims as well.
I'll show them when I get the video done in the next couple of days hopefully.

I'm going to put the battery on charge just to make sure it IS properly topped up before I do anything else. I have the Optimate 4 Can-Bus version that I use on the bikes, and can easily get another connector to keep on the battery for ease of 'maintaining' it when it's not being used.
In the meantime I'll keep scouting around amongst the threads for useful bits of information to keep the brain cells happy.

Thanks for the replies so far, most useful.

 

I wouldn't bother with a video. Overkill and confusion I expect.

 

With the 4.0L the only thing that matters is-Have the timing chain and tensioners been changed?

Unless they have I would not spend a dime on anything else until they were replaced.
.
.
.

 

+1

yes, vital to do that NOW.

 

Because the head gasket had gone on the right hand bank (UK side, passenger) ( see previous thread "Bought myself a new toy) it was necessary to have the breast plate off.
So while I was in there all the obvious stuff has been done.
New chains, tensioners, guides, plus new water pump, new thermostat and metal housing, new DCCV, serpentine belt, oils and all the filters, dropped the sump pan, checked and cleaned the oil pump and strainer for any stray parts, as well as every gasket and seal involved in doing the cylinder heads, including valve stem seals. I dropped the valves and cleaned and lapped them in. Yes I did both head gaskets, no point just doing one side.

 

I think I may have found the (or a) problem relating to my lack of power.
I decided to go over everything I have already done to the engine in the last few weeks, more for my peace of mind than anything.
Started yesterday morning 8 a.m.
Got interrupted more than a few times, but that goes with the territory.

Remember that the car was starting normally, driving normally on the flats, but had no power up hills unless you floored it.

Been turning things over in my head most of the week, looking for ideas on the forum's, found some stuff, all useful for the memory banks.

So I thought I would check all the timing first, just to be sure that everything was spot on.
Jacked the car, went to pull the crank sensor to fit the timing plug, damn thing snapped clean in half with the offending bit stuck in the hole in the bell housing.
Mad phone call to the Jag supplier for a new one, then a 20 mile drive to go get it. Then 2 hours to remove the piece that was stuck.
That job done, fitted the crank plug, got the valve covers off, only to see that the exhaust cam flats, on BOTH HEADS, didn't line up properly with the intake cam flats.
They were one tooth BACKWARDS, so, retarded exhaust cams.
Don't ask me how, I've no idea.

So I spent the rest of yesterday stripping out the front of the engine again so I could start today with putting everything right.

Had JTIS up on the screen as a reference

Started the whole timing procedure again this morning, started by removing the sprockets completely off all four cams, locked them in place, (so I had the crank and cams locked), then went from there.

Checked and checked and checked again to make sure I had done everything in sequence, VVT's fully retarded, every nut and bolt done up to spec, got all the timing done, turned the engine round (clockwise of course) to make sure that there is no valve contact and everything is moving freely as it should, and to make sure the cam flats are coming back in line with each other.

I'm glad to report that they are.

So now I have to re-fit the breast plate and all the ancillary parts and hopefully it should go better than it did before.

I shall report back as soon as I have news, good or bad.

 

Fingers crossed!