Does the engine feel like 98° ?
What pending codes do you have?
Are the LTFTs also zero?
I imagine the OBD temperature must be what the ECM uses to decide when the engine's hot.
I think you should get a P0125 if the problem is real.

I've just been out and cranked up with Torque running.
I get the Open Loop low coolant temp and STFTs of 0 for about 20 seconds then closed loop with STFTs of -5% both banks.
Can you try your dongle in another car to see if it works on STFTs?
I would think, though, that it would either pick up everything or nothing.

ps I don't think being stuck in open loop will much affect performance, just petrol consumption.

 

The engine certainly seems to be getting hot. The fans have cut in a couple of times when trying to read the FTs but both the ST and FT have still been reading 0%.

The pending faults showing are exactly as before i.e. P. 0202, 0203, 0205, 0208, and P1647.

It's strange that the RP has just suddenly gone when the pending fault codes are still there, and I suppose I will never know for sure if the fuel system ever did go into closed loop before this RP came up.

Fuel consumption wise the car has always averaged around 22 mpg but obviously drops when you gun it.

My other two vehicles don't appear to have OBD but I will see if I can find another car somewhere to try it on and at least eliminate a fault with the reader, but as you say this seems unlikely with all the other readings available.

So who knows perhaps RP has gone for good or perhaps it is just lurking around the corner, waiting to bite me in the butt.

I had forgotten how quick the standard XK8 was, so I really can't imagine how quick the XKR must feel, perhaps one day someone can take me for a drive in one, and I can get really jealous! As an XKR owner (Steve in France) perhaps you can tell me how they compare!

 

XKR's are quick enough for me!
I get a bit upset by folk who seem to exist only to get more power out of them.
A bit like the jogger puffing away in his Lycra keeping fit for what exactly?

If ever you make it to central France you're welcome to have a go.

I'm still at a loss.
The Torque app automatically translates P0125 to the ' Insufficient Coolant Temperature for Closed Loop' message so either the dongle is bad or there is something wrong with the temperature sensing.
Before you were getting
P0202, P0203, P0205, P0208, P0327, and P1647.
now (via Torque) you have
P0202, 0203, 0205, 0208, and P1647
so you've lost the P0327, KS problem.
I'm out of my depth here.
I guess the Torque app is working correctly but something is screwing up the CAN BUS and corrupting the ECM.
If you can check the dongle against another car we can at least eliminate that.

I'm determined to sort this so watch out!!

 

I had forgotten about good old P0327, but that has never come up on the Torque reader, only on the original Autologic diagnostics at the garage.

It does rather get under your skin, this problem and thanks for sticking with it.

I will let you know when I have checked out the reader on another car, does anyone near Newmaket want a free diagnostic check so I can test it?

 

At this stage with this mix of problems I'd avoid a dealer.
Unless they're exceptional you may find they start replacing things according to the codes and I don't think that's the problem.
Can you also check that you do have +12V at the HO2S connector - between Red/Blue and white/green on bank1 or blue/yellow and white/green bank 2

 

Don't have an answer other then to check all cabling from the ECU to the injectors. The codes do default the ECU to stay in open loop. Have you already checked the O2 heater relay?

 

He swapped it but hasn't checked the volts on the heater cable.
Any ideas on the other codes? I'm stumped but have a feeling they're spurious.
His battery is good.

 

As he is able to drive, it does seem intermitted; still I would check all cabling/connectors to have that tick in the box. As I also don't think that several injectors go bad, and if the cabling is good, it may be a ECU issue, but that should be saved for last as it could (doesn't have to) be expensive.

If all cabling is checked (not sure what sort of resistance must be there), then swap a injector and see if the code will folow or not.

The O2 sensor might just be bad, but good to check 1st if it gets the voltage needed (and also amps if you have a meter), and in worst case if all works out, it could be related to the ECU (but that is last, there is enough to check 1st)

 

Haven't had a chance to check out the O2 sensor voltages yet. I have got a multimeter but am not sure what sort of resistance readings I should expect on the injectors etc. Will try the car again tomorrow and see what's happening on the RP front. There must still be something wrong for it still to be showing the pending codes, but it is strange the car runs so well.

It's hard to follow exactly where all the cabling goes, have you any idea which connector plug it is on the ECU that goes to the injectors?

I have finally given up with the wifi OBD2 reader for the iPad, could never get it to connect despite trying all the suggested fixes from the sellers. It has gone back for a refund, shame as it would have been nice to have a larger screen to view all my faults on.

Thanks for your input Avos, I must admit I am beginning to wonder if it is the ECU itself. This all seems to stem from when the battery voltage went low and has been there since, despite fitting a new battery. What are the options regarding the ECU, second hand ones seem fairly reasonable, but I presume they need to be the specific part number i.e. LNF etc. Still I will try and check the wiring etc first, before going down that road.

What is the normal mpg to expect from an XK8? I am wondering if the car ever did go into closed loop. I think 22mpg is around what is expected although I must admit it has been closer to 19 mpg recently but then I was driving it quite hard.

Will hopefully have a free day soon to check out the rest of your suggestions.

 

Steve, that guy in France , put a bug in my ear a couple days ago about this. Seems like a weird one for sure.

First thing, with odd ones like this, with inexplicable codes seemingly off in left field, you have to remember that the order in which faults are set can cause the faults to 'come and go' and make you scratch your head. You clear the codes, drive and see what resets, and one time you get a P1647, and the next time you get a P0327 but not the P1647. Those are arbitrary for this example just because they both have been mentioned in this thread. My point is, once some codes are stored, P1647 for instance, the ECM stops checking or storing other faults. In that case, the ECM will never check for a dead catalyst once P1647 is stored. So you likely will never see P0430 and P1647 at the same time. If it thinks there is a bad O2 sensor, why check the catalyst if it can't believe the O2 sensor. Get it?

So that could explain the first one code and then the other business. Because you have to have some pretty detailed OBDII information to know when a code will disable some other test.

The consistency here seems to be the Injector codes, and those are odd-***** for sure, very rarely see them. I'm inclined to think they are wiring related somehow. In particular I'm concerned about two connectors and a splice in the engine harness. I would suggest taking apart that big connector on the bracket at the firewall, the one bolted together that has the 13mm nut to separate. The second one is usually below and a bit toward the driver side and I think clipped to the bracket bolted to the transmission. It has 13 wires in it, the big one has 52 or some such connections. These connectors and all the wiring in the area should be inspected for any moisture, corrosion or rodent damage etc. Then hunt down the splice is in the engine harness on the engine side of the smaller connector, the wire should be Black with a Red trace. That circuit is the injector supply from the Fuel Injection relay in the ECM box. I have seen that splice get funky and some injectors get marginal power........at times. Of course I have to add that. All the injector return circuits go through the big connector, so it needs to be looked over, too.

That is a couple things that I don't think have been touched on as yet. Time to put on our detective hat!

Good luck!

 

Had a little spare time this morning so looked at the wiring issues. Checked the left bank O2 connector but could only get a reading of 8.3v. However when I put the negative probe from the multimeter to a good earth I got a reading of 12.2v, which does rather point to a bad earth somewhere in the circuit. Does anyone know where the earthing point is for this circuit. I have already cleaned and tightened several earths that I have found but may have missed this specific one.

However I then checked the right bank sensor and this also gave a reading of 8.3v also, which is rather strange as this bank doesn't even show as a fault.

I then ran the engine without the O2 sensors connected and it ran fine without the RP coming up. When I checked it on the reader it came up with P1646 as well as P1647 but P 1646 went as soon as I reconnected the sensors, whereas P1647 remained.

I found the firewall connector with the 13mm nut, it seems really difficult to get at, especially when you have got big hands.

I have run the engine many times now and the warning lights all stay off and there is still no sign of RP. If I didn't have the reader I would be oblivious to these faults! Perhaps I should lose the reader and become Mr. Oblivious.

Who was it who said ignorance is bliss?

 

I presumed that I had checked the O2 heater relay , but now I am not so sure. I thought it was the innermost relay in the LH enclosure box. However when I look at the relay and fuse box location in the Jag manual for a 2000 XK8 it is showing 4 relays in a line. 3 together and 1 on its own. The one on its own is the innermost and is shown as the O2 heater relay.

The problem is that on my vehicle this does not exist, I only have the 3 relays together and no 4th one! So where is the heater relay? There doesn't even seem to be a space for it. There are four other relays which are exactly as shown in the manual, one is in the engine management fuse box and the other 3 are together on the inner wing side.

Did they have a different location for this relay on earlier or later cars?

Would be grateful if anyone knows!

 

Lovely sunny day, thought I'd take the XK8 for a nice leisurely drive, what could be finer?

I got about two miles down the road and guess what back came good old RP.
Not to be deterred I continued on my journey and we had a very pleasant Sunday lunch at The George in Cavendish, which I can highly recommend if anyone is ever going that way.

We carried on for another 10 miles or more the car driving superbly smoothly except for the RP that cuts in about 2800rpm. The ave fuel consumption was showing 23 mpg so to all extent and purposes the engine was running to spec. Then for no reason the NO ASC warning came on the dash along with the NO TRAC available and the ABS warning light on to make up the hat trick.

Through all this the car just drove as nothing had happened and if it hadn't been for all the warnings I could have easily been Mr. oblivious again.

I put the car on the OBD reader when I got home, and all it showed was the usual injector and O2 sensor faults. So I have no idea about the other warnings, I presume that perhaps this reader only sees engine codes?

Will try and get to the big wiring connector on the bulkhead and see if I can find anything there, but it getting to the point where I am losing the will to go on especially with all these new faults raising their heads.

Never mind worse things happen at sea and at least I had a nice lunch!

If you see a cheap XK8 in Autotrader you'll know who it belongs to.

 

Where have all the experts gone? I have got my car in lots of pieces all over the garage floor and was eagerly waiting for the next instalment.

Will my car ever run properly again?

Will I be able to use it again before it becomes a classic?

 

That is correct, your OBD will only read the standard Powertrain codes (engine/transmission). All others are 'manufacturer specific', thus not required by law.

Have you explored the wiring from your injectors to the ECM as xjrguy suggested above? You're treading in very unfamiliar and uncommon waters, this isn't like an airbag light or headrest diagnosis.

 

Thanks H2Oboy,
Used to run a car workshop so have stripped down a few motors in my day. I must admit that I am not really up to speed on modern electronic systems but have got my teeth into this now and don't want to let go.

I will just have to slowly plod through the wiring but there seem to be quite a few variations and relays that don't seem to exist on my vehicle. I am sure it must be a bad connection somewhere all I have got to do is find it!

Will start with that connection on the firewall if I can get to it and see where that gets me.

Best regards

 

1st check what has been suggested, so wiring, swapping injector etc. You haven’t given any feedback on the results, so am surprised you react now like this.

The jtis has all the details; with that you can follow precisely each individual cable, but you must select the electrical diagram for your year (it’s a pdf file on the cd). If your car is a 2000 model then you can find the pdf in \DATA\jyk2000en

If the diagrams there are wrong, than your car is not from that year.

 

A little patience, my friend, we all have things to tend to that takes our time.....


First, the big connector you asked about, the 13mm nut holds it to the bracket; once that is loose, the 10mm bolt head on the opposite side is what separates the connector itself. Then you can look it over.

Second, I think you have a compound issue going on here. I'm thinking the ASC, ABS & Tracs warnings are one thing, and the P1647 and injector business is another. I suspect the ABS has a fault like a wheel sensor or the C1095 Pump Motor fault stored that your reader can't read. That will need some better equipment to prove. Then the sensor and injector codes and RP are another cause, probably wiring or poor grounding somewhere. So, I guess in your predicament, I'd suggest concentrating on the latter and save the ABS etc. for later; those won't cause any running problem with the engine.

Good luck!

 

Sorry to appear a little impatient, it's just that I thought I was going in the right direction and then matters got even worse with all the ABS, ASC & TRAC faults suddenly appearing from nowhere.

Have been slowly trying to work through the suggestions but was a little thrown by the fact that I don't seem to have an HO2s heater relay and the innermost relay that I swapped must have been for something else. also the voltage I am getting across both of the HO2 sensors is only 8.3 volts although only one is showing as a fault code. Both are showing 12.2 volts if I use the engine as an earth.

I have checked all the wheel sensor leads at the main connector and all are reading a very similar resistance so don't think this can be the problem.

When the fault first occurred I did have the car put on an Autologic which apparently could read all the Jag specific codes, but it only came up with the same injector etc codes as my Bluetooth reader is now showing.

Thanks for the info regarding the bulkhead connector, it makes it so much easier when you know what to expect, I didn't know that there was a 10mm nut as well.

Apologies once again for seeming impatient, I do appreciate your input but have been rather frustrated by my lack of progress, which certainly isn't you fault!

 

Duplicate Entry Doh!