I used the car yesterday visiting various places so the car was started, stopped, started again etc. had no problems what-so-ever and it ran like a dream as usual. Went to it this morning, it fired once (I think) but absolutely dead as far as starting is concerned? Now it just flings over with no signs of firing

The car turns over fast, there's a 120amp battery in there, and appears to have compression, I say 'appears' as I remember what it sounded like when I suffered Bore-Wash and it was flinging over on the starter.

I have absolutely no idea where to start, it was low on fuel so I put some in from a can, though it has been lower and started no problem.

Apart from the Bore-Wash problem some months ago the car has always started 1st time, so I am wondering where to start and look. After checking there's fuel pressure, I am guessing I start with electrics?

Thanks in advance for any help/advice.

Paul

 

It could be the MAF, easy way to find out is to uncouple the MAF and the ECU will go into Default and allow you to drive it, if it starts. Fuel mileage will suck, but at least you'll know the issue if that's it.
Before doing that, do you have any codes? Because this will give you a code and I want you to know the others beforehand so it doesn't create confusion for the setting off of this code.
Other possibilities, fuel filter, fuel pump or CPS (crank positioning sensor) just off the top of my head.

 

Highhorse, thanks again for coming to my rescue.

I did look for any codes, but only using the small device connected and linked up with Torque Pro on my phone, it just read "No DTC's Found". I intend to check again tomorrow with the iCarSoft i930 device, see if that will tell me anything.

CPS was replaced not that long ago, maybe 1.5k miles, I will also try disconnecting the MAF and see if starts (didn't know you can do that!), if it does start I may be in luck as I have a spare?

I will also check if there's any fuel pressure, that should tell me if it's the pump I guess? Then after that, should I take out a Coil and make sure it's sparking using an old spark plug, maybe put some oil down the bores just in case it's the dreaded BW? What do you think?

Can you tell me where the fuel filter is, I have recently (week ago) under-sealed the car spraying it on from front to back, could I have clogged something up under the car? There was the 'device' on the left side rear, (UK passenger side) just in front of the rear wheel, I disconnected that to under-seal behind it but connected back up and it has ran fine for the week since? Obviously I didn't spray over the device with under-seal?

 

First thing: when you turn the key to II, does the pump make a sound? If no, dead pump. It should be hearable. That can go over night.

Obvious things to do: check for fuel, spark and air. Air is always there, but fuel and spark aren't.

 

You can put your finger on the fuel pump relay as you key to on it will click once for 3 seconds and click the second time to turn back off . This on / off can throw you off in troubleshooting The fuse is after the relay in this example

If no click swap relays and look at the fuse under the rear seat

 

Sorry Daim, I just had to...

 

Greetings Mr Euphonium.

Let's check the obvious before lunging for the unlikely. Did you bump car? Check inertia switch? Don't just check the button; check its electrical continuity. Next obvious candidate is bore wash after all that stop/start driving and I guess you know the "pedal to the metal" fix? Despite appearances to the contrary, very few Jaguars celebrate a good drive in the open at normal operating temp, by returning to garage and failing overnight while you are asleep.

Only then, proceed to fuel and there is a simple test that requires no spanners, no assistant, no pain, and bypasses every possible failure up to and including the injectors. Lift the air filter, inject a 3-5second burst of ether based starter spray (ours is called "Start Ya Ba$tard") and immediately close and crank. If engine lunges into a 2-3 second start, then dies, you have a fuel delivery problem; if there is still no attempt to start, then problem lies elsewhere.

Next comes the ignition system . . . and that starts with checking all interlocks, fuses and relays . . . all far more likely suspects than plugs or coils that have died in your sleep. Not being flippant; just emphasizing that you must adopt a logical approach to this problem solving and that is where the SDS/IDS process helps.

There's more, much more if the incident becomes more complex, but forum life is full of maladjusted shift cables and other interlocks that many owners tolerate until the car is stopped in its tracks . . . I know, I have just bought an XJ8 Sport with a duff shift selector that originally couldn't start, but now can't engage either Park or the entire LH manual side of the gate . . . has Reverse, Neutral and all 5 Drive gears. Drives fine but the PO was quoted a fortune to fix, so baled out.

Best wishes, and please keep us posted with progress,

Ken

 

Hi to all :-). I think I've made a little progress?

I tried disconnecting the MAF and starting the car as suggested by Highhorse, apart from a message on the dash saying Limited/Reduced Performance, there was no change (still didn't start).

I checked the fuel lines under the bonnet then checked the fuel pressure by pressing in the valve near the left bank cam cover... absolutely nothing, no pressure what-so-ever, checking this in the past produced a small jet of fuel, so something wrong here! It seems it is likely the pump, again suggested by most, though it had got dark when I found no pressure so haven't made anymore checks yet. So the "little progress" made is that I have no fuel pressure!

I will first check Lady P's suggestions regarding Relays and Fuse(s) tomorrow.

Highhorse/Daim, seems you were both right from with the fuel problem, I wasn't aware the pump could "go overnight" as Daim put it, what can cause that to happen? Thanks Highhorse for the filter location info, is it an 'inline' filter i'm looking for or?

cat_as_trophy, I know about 'bumping' the car, did that a few times with it jacked up and hammering when doing some welding, and also the dreaded BW problem, had both those in the past but this was different, won't ever forget the sound of a Jaguar engine whizzing over when it has a BW problem!

The only thing left for me to get concerned over, is if I have created this problem when under-sealing the car and clogged something up, I should imagine testing the Pump, Relays, and Fuse(s) will tell me.

Any further advice/check/procedure is most welcome.

 

A couple of things, the fuel rail valve pressure is a pretty sure sign the pump is out.

But, it can show no pressure when the engine temp sensor doesn't supply a signal to the ECU. ECU cuts fuel.

I suspected a bad fuel pump, did the relay check, traced a momentary feed to the fuel tank connector, a blip on the test meter, which wasn't normal behavior. So then looked into the signals that would cut fuel - ETS was the number one suspect at this point. Like the CPS and CSPS they kill fuel requests.

A quick removal and contact cleaner on both sensor and connector with a touch of dielectric grease and it fired up. A 2 minute job that took me almost all f__king day to diagnose.

Hope this helps

 

Thanks Sean B. After the BW problem I had a few k miles ago, I got the engine started putting a little oil down the bores, usual fix! On first start it popped and banged a bit, I think blowing out one of the knock sensors? I replaced both, put in new CPS and CSPS sensors at the same time. While I had the inlet manifold off to do the Knock sensors I also changed the cooling tower to a metal one, new thermostat, and a new temp sensor.

Since all that it's run beautiful until a few days ago, so in a sense, I'm hoping it is a Relay, Fuse, and/or Pump (if you understand what I mean?). But thanks for the info, if the Relay/Fuse/Pump seem Ok, then I know where else to look, hell these cars can be frustrating at times, good job we love 'em!

 

The filter is behind the differential just above it and its inline.

 

Hi again to all.

I think i'm 99.99% certain what all answers will be, but here's what I've done so far:

Checked the power/earth to the fuel pump Relay with a test lamp -- OK
Checked the resistance between pins 86+ & 85- on the Relay -- OK (82 Ohms)
Powered Pins 86+ & 85- and the Relay clicked -- OK
While still powered, checked the resistance between pins 30+ & 87 -- OK (2 Ohms)
Put the Relay back in and turned the ignition to II, Relay clicked -- OK
Got some 'Easy Start' and sprayed some into the Air Intake -- Car started for a few seconds then stopped.
Tried this 3 times, the car started each time.

I guess I have a Fuel Pump to change?

Few more questions:
Read somewhere about making a tool that helps with disconnecting the Fuel Pipes, has anyone had experience of this or know how it's done?

If anyone has suggestions of a 'better' Fuel Pump than the original (hopefully that fits without any, or too much, alteration and faffing about) I would like to find out if they are available in the UK and where from?

Thumbs up to those who went with Fuel Pump problem from the beginning

Paul

 

There is a check valve in the fuel pump to keep the fuel line charged for days . If this check valve is inop it may take more then the single 3 - 5 second precharge as you turn the key to the on before starting position . This precharge can also be lost through the fuel pressure regulator .

You can hotwire the fuel pump and bypass the relay control circuit . This will also overcome a defective check valve . With blade connector and a short piece of wire put the jumper wire in the relay socket between 30 - 87 or 3 - 5 depending on the relay manufacture . Look for the Blue / Red wire e to verify you or on the correct socket location . The power side of the relay is high current and arcing hazard so remove the B+ battery terminal . The supercharged engine has 2 fuel pumps and can jumper either 1 .

Keep in mind a relay may still click as it is commanded correctly but still have damaged power contacts inside limiting the current to the pumps so it is suggested to swap relays even though it clicks .

With the engine rotating the ECU should see this through the crankshaft sensor and give you the 3rd click to turn back on for the duration of your drive .

Something to keep in mind with the engine off and a flow restricting clogged filter you can still see the correct fuel pressure on the other side of the filter and pump but not enough volume .

Don't forget to change the fuel filter as this is a foundation item in scheduled maintenance often neglected .

 

Before attempting to make this device, please try the A/C-Fuel line quick disconnects. Yes many will argue they don't work, but those are from those they didn't work for. They are a much better item to try using first and aren't that expensive, just a few quid in your case Paul.

This is the 1/2" electrical conduit (it measures 5/8) I used to get my lines out. If anything you can get an idea for making one.

 

Thank you to Highhorse and Lady P again, you guys could rewrite the book on these cars I'm sure!

The new pump is on the way, I decided to stick to original, after all, the one I have is likely to have been in there since 1998, so longevity doesn't seem to be too much of a problem? Also on the way is a new filter, thanks to Highhorse I now know where to look for it and get it done. With all the work I have done so far Lady P is right, I can't believe I haven't thought to change such an important item... we live and learn!

Away with work next week so hoping to try and tackle the job between now and the weekend, I will post progress and any relevant pictures... thanks to everyone.

 

May I jump in this conversation? I have a similar to the initial one.

After seven months of perfect starts and just a couple of small problems while driving, I started the XJ8L a few mornings ago and it started as normal, then after a few seconds ran rough and died. It started again, rough, then died and hasn't started since.

Checked FP fuses and switched relays, all fine. Checked for pressure in the fuel rail and got a squirt several times. Charged the battery overnight and did the ether trick, no joy. I really hoped it was fuel, but I think not at this point.

Next is pull a coil and check for spark - not today- but if there is or isn't, where to from there. This is my first OBDII car so I'm on the steep learning curve.

Any suggestions?

Actually, before someone else notices, it's not my first OBDII car, the XJ6 was, but after four years I still haven't had to do anything to it except change hoses.

Thanks for the suggestions you've already given.

 

Greetings CS. Best plan is . . . always, start a new thread . . . you may have a similar cause (or not) but jumping on another's is a sure fire way to cloud the issues. We like to see all issues fully resolved; each thread neatly bundled with solution.

Before you do so, observe the primary advice here . . . get and post any codes. Even if there are none, that is vital information.

Best wishes,

Ken

 

Put your finger on the # 1 fuel pump relay and see if it clicks 3 times on / off / on as these are 2 different sourced commands . The first 2 come from the key on switch but the 3rd comes from the crankshaft position sensor seeing engine rotation . The CKPS can go bad and not show a code . There is also a camshaft position sensor CMPS , code PO340 , that helps the car start faster but will start with the CKPS , just takes more revolutions . If your fuel pump relay clicks and you don't get results you can swap the relay and look at the fuse as this is sign the pump is on it's way out .

 

Thanks, again. I have a few things to check, all of which are difficult since it died in my front yard and my shop is and my tools are on the mainland.

Busy time of year.

I'll start a new thread with my next round of disappointments, if any.

 

To start off with, the car now runs and appears to be fine, quite how this happened is up for debate as my findings were not what I (and maybe others) expected. No need to go into the job of getting the tank out, that's been covered by many other posts, but having got the tank out I took out the pump.

I put the pump on the bench and connected it up, just the pump, not the wiring or the cover plate on top of the tank. Guess what... it worked! I began to think about what Lady P said, about the Relay clicking but maybe not passing current to the pump once the Relay kicked in, having checked that was all good, I decided to trace all wiring backwards from the pump. There were a couple of connections that are inside the tank, checking these I found dirty/rusting connections all the way back to the cover on top of the tank where the main connections is. I tested all from the cover to the last connection inside the tank... nothing, not even a blip of life. After cleaning all the connections, tried again and the pump worked. Tried it with my 'old' pump, and it worked, so it appears it was connections and not the actual pump.

Finally, I tested the white connections on the cover, and made sure they were good, then rewired all the way to the pump, new connections and all, everything seemed to work. Got it all back together, tank in and connected, I got instant pressure at the fuel rail, and car started first time. I know it's probably psychological, but the car seemed to run better with more power?

It appears in my case the popular belief that the pump was out was correct, but the reason for that seemed to be the power supply from inside the tank rather than the pump itself!

This made me happy of course, but set me thinking about a few posts I've read, the problem I found suggests it could very easily happen again, and again. That means the tank out again etc etc each time.

What if the rear shelf was cut out (as I've read on various other postings) to make access to the pump relatively easy? Cutting out a part of the rear parcel shelf carefully, then modifying it so it can be screwed/riveted back down with some sealer around it, would be a good idea. Certainly, there's already a 'big hole' there to accommodate a decent sized speaker, so it's not a question of structural integrity in my opinion, so why not?

I'm sure there will be some comments, but it is worth a thought as we are always looking for easier ways to do repairs, and as this could easily be a reoccurring issue, it does beg the question about making a removal/replaceable access panel! Maybe Jaguar would have done this themselves during production if was known then how much of a hassle it could be to fix this issue?