Scuby,
the fact that you managed to get the car running smoothly on brake cleaner is an important step forward, and considerably narrows the range of possibilities.
The hissing sound and the fact pinching the return pipe causes a slight improvement all point the finger at the fuel pressure regulator. Given they are easy to replace and not too expensive, I would replace it. In truth I dont think it is the problem, but I feel sure it is a contributor.
A theory which is taking shape with me is that the diaphram in your fuel pressure regulator is burst, allowing fuel to pass through it and back to the tank without ever building up sufficient pressure to allow the injectors to operate. That would be the hissing you are hearing, and why blocking the return pipe helps a little. The fact you are hearing a hissing tells me that the fuel pump is doing something, and I wonder if it too has a burst diaphram or seals (I dont know what design of pump it is, but there must be seals of some sort which wear/perish), such that it operates, but cannot sustain the pressures needed to operate the injectors.
Can you remind us how you know the pump is capable of pumping at pressure,
and how you know it isnt operating at all? (remember, it isnt supposed to operate continuously with the ignition on; it only comes fully to life once the engine has fired.)
I wonder whether modern high ethanol fuel has done for the seals in your fuel system: the pump weakens progressively and has to work overtime to maintain pressure, then your regulator gives up, game over?

 

I'm back.

Had a crack at the jag again. Here's the developments:

replaced the crank sensor with one off a running car. No change.

Hot wired the pump. No change.

Replaced the FPR AND added 10 litres of fresh gasoline at the same time. It has since sputtered to life. When I don't start it for a while the negative terminal goes off wiping the memory.

Here's the behaviour now:

It wil run, very roughly. It behaves as follows almost every time I start it up again after a week of giving up

* crank crank crank crank sputter crank crank until it comes to life on 2 or 3 cylinders at most. Give it any throttle and it dies out right.
* sometimes the first two times it fires up it wil fire up SMOOTH, rev up to 1500 rpm and DIE. Then repeats behaviour listed first
* Once it runs it's REALLY smoky. White smoke, but not coolant (just trust me), not oil (trust me). It REAKS of unburnt fuel which makes sense as it's running on a few cylinders not all
*leave it to bumble for a few minutes and slowly apply throttle, it will very roughly pull up through the power band, sputtering and protesting.
*after about 4 minutes it will go in gear and not die. Running on about 4 to5 cylinders by now on and off
*NEVER runs smoothly. I drove it about 15 miles likes this. It missed power, bogged, coughed, missed. Ran like absolute rubbish.
* I've checked the CTS wiring, gauge shows temp rising etc.
*Put more fresh gas in it and it's more consistent in starting but still runs like a pig.



In conclusion: It runs really rough, the idle is ok once warm, randomly will be smooth for a second on startup. Lacks power, does keep running once warmed up.

As a side note which still baffles me: it STILL doesn't switch the fuel pump on via ignition/ECU. I'm suspecting a terminal/plug somewhere as offered up before that also involves info fed to the ECU from other sensors perhaps?

Still hissing loudly from the fuel rail

 

I dont want to drone on about it, but water in the fuel?
Petrol sits on top of water, so you can add all the fresh fuel you like, but if there is water at the bottom of the tank, that will be what you are ingesting.
The fact she will now run is a big step forward, and I would be tempted to let her sit and run for a good long time to see if your new fuel starts to make a difference. That is what worked for me when I had a bad fill of fuel during a period of interruption to fuel supplies due to industrial action. Within minutes of filling her up, she started to run pretty much as you describe, and didnt improve until I had consumed about a quarter of a tank. Thereafter symptoms quickly disappeared.

 

If you split the issues into 2 parts one being rough idle and the other being fuel pump turn on the common item between the 2 is the Crankshaft Position Sensor as this turns the pump back on after the initial key to " run " position priming sequence .

I personally would leave the pump alone for now and focus on the engine regulation ( and it may resolve the pump control ) .

Have you inspected and cleaned the CKPS connector and inspected the short wiring run as it is in a bad environment ?

Have you inspected the ECU connectors as you remove the ECU and look down into the connectors . The CKPS wire into the ECU is Black 23 ( White wire ) and Black 26 ( Orange wire ) marked as a connector view as the black ones in the below pic . I have the replacement individual socket part number and source if needed . The sockets are 2 pinching halves to bite the blades on the ECU side and can be sprung out not biting the blades .

Have you cleaned the ECU grounds along the upper portion of the firewall or bulkhead as these are sensitive wires ? The ECU also " case " grounds on the aft lower mounting bolt .


Editing

 

Well, you're self described droning doesn't fall on deaf ears. As far as rough running goes it makes a lot of sense. I'll drain the fuel out and refill and try again. Can't hurt. One more thing off the checklist at that point too. I've only put about 15-20 clean litres in which didn't register quarter of a tank and only driven 15 miles.


Can't mult-quote somehow so Lady Penelope: I have cleaned ECU terminals, cleaned grounds, checked ECU connectors for water ingress. I haven't yet checked the CKPS wiring loom with more than a quick look, nor the connector other than a quick spray of electrical connector cleaner, so I've had a quick look but nothing there called for further inspection. It's well worth it though as the issue of fuel pump not switching on needs fixing AND if they're related, well...

The question I have though is: how could it run at all in this case (with CKPS failure)? I also have 250RPM showing, and I've driven it about 15 to 20 miles on a short trip to it's new storage. Surely CKPS is ruled out then no? Also the CKPS itself has been swapped with my 4.0 Sport back and forth and gives that x300 no issues...

Not disagreeing with you just trying to fully get the line of thinking. Obviously some fault somewhere isn't letting the pump go on. Regardless of how it runs, hotwiring the fuel pump isn't a good permanent solution.

Cheers guys, thanks for sticking with me and getting back on this so quickly. I'll be able to drain fuel and check a few things tomorrow while I'm in the shop. Lot's of work to do though.

This engine needs to run right so I can stop putting of it's transplant!!! 1978 XJR time!

 

The CKPS can fail partially and not fully by wire , connectors , or the sensor .

The fuel pump relay control circuit runs through the CKPS , ECU and connectors Papa Indy 1 ( White / Pink wire ) and RS3 ( Pink / Brown wire # 22 ) connector and can go through that as mine was incorrectly wired on the control circuit to get around a connector problem as I received M'Lady P .

I agree with the fuel quality aspect to freshen up . You have 2 fuel pumps on the S/C engine but the # 2 doesn't come on until 4000 RPM by that same CKPS

A note on the CKPS , as it fails from 100 % good the ECU may not see it at a certain point in it's degradation of signal . May be good enough for the car you sourced it from but not the car you put it into . To complicate maters that CKPS signal is looked at by different things like the spark timing , tachometer , fuel pump control , ECU map shifting , and others . These sub - systems may require a higher then others signal quality to function . The tachometer is the last sub - system to fail from what I have read . Might have to try a new sensor .

 

Some time back, I had an engine which would start but idle badly on few cylinders and would not pull away at all. Towed it home and examined the crankshaft position sensor. There was a bright wire showing on the electrical lead where the insulation had rubbed away on something. Repositioned the lead, wrapped some insulating tape around it and we were away. Changed it for a new one later. May help!

 

Might try a slight tug on the wires in the sensor connector as I have changed alot of them , not in this field .

 

Hello Scuby,

I'm sorry to hear of all these troubles, but I admire your will to keep poking at it until you get some results! I am very late coming to this thread, and I see it has been over six months from the onset of trouble. After finally reading through the whole thread, two items came to mind as related to the quoted items above:

1. When you checked or replaced the spark plugs, were you sure to get the correct ignition wires back on to coils 5 and 6? It has happened before where the coil wires for 5 and 6 get reversed. This causes terrible running, smells of unburnt fuel, and a cat converter that glows red-hot! At this point, it would be advisable to check the plugs again. They may be getting fouled because of the rough running with improper ignition.

2. Through my own diligence and lots of input from forum members, I was able to solve a fuel pump problem on my old VDP a few years ago. The pump would only run intermittently. It took several months of testing, checking and frustration, but I eventually stumbled upon the solution. Lady P mentions this idea briefly in his post here last August 30th:

The fuel pump has a series of two relays. The fuel pump relay in the trunk is switched on by the ignition-on relay in the right-hand heelboard fuse box. The RHH relay in my car was intermittent. After replacing it, I never had a problem again! Have you checked that relay? Also check fuse 10 (5A) in the right-hand heelboard. That is the path, when switched on by that relay, to activate the fuel pump relay. Hope this makes sense.

The fuel pump relay in the trunk has a green socket. Green for go!

Keep in mind that for all five fuse box locations, any electric items connected to fuses 10, 12, 14, and 16 are powered on only when the ignition is on. The ignition-on relay in each box switches those 4 locations "on".

An important piece of evidence in my investigation was that when the fuel pump wouldn't run (car wouldn't start), the brake lights and reverse lights also would not work! What do you know, the rear lighting control module is switched on by fuse 14 in the right-hand heelboard.

Round of applause to Mr. Lady Penelope, for his tireless efforts to assist those in need!! Also to the other contributors. It's a team effort. Let's get that engine running. Smoothly.

 

Back at this mystery XJR not running.

It will start and run now fine.... on three cylinders.

I drained the fuel. Fitted all new champion plugs.

Starts, a little hard, but fires up.

Runs poorly and will smooth out a little if you rev it up but pops and bangs along the way.

Long story short:

When running the front three coils (is that bank 1 or 2?) or injectors when disconnected make no difference.

The car is running on 3 cylinders. The 3 cylinders closest to the radiator are not firing.

I know ignition is sequential not wasted spark.

Have checked compression. All even and 180 psi per. Spark is present. Swapping coils all three running cylinders will run just fine on the the three not running. So coils are good. Plugs are new. Compression is good.

changing out fuel rail and pump but I think it's wiring or relay.

How are bank 1 & 2 controlled?

 

The AJ16 engine has the # 1 cylinder on the front of the engine as well as the # 1 bank . All the oils get their power from the same wire from the fuse . And each coil gets it's controlled ground from the 6 individual wires from the coils to the ECU . The same with the injectors .

I'm looking for a possible bad wiring splice between the 123 and 456 halves , Yep there is on both coils and injectors . Probably under the fuel rail cover for the injectors , don't know for the coils

Have you looked at the condition of the ECU connectors and the 3 ECU grounds

 

I was careful with my wording as the XK's have the opposite numbering.

So I can then say that 123 aren't firing. Both coils and injectors have 12v with ignition on. I'll test now with the engine running. There quite a lot of fuel in the oil so I have to change that first.

I'm going to rig up a "noid" light to check each plug and injector for actual pulsing.

After going through some threads on JagLovers, I found one, that was never solved after three years, where he had very similar issues. 3 cylinders that wouldn't keep running.

I'm wondering if a common ground of some sort for Bank 1, the fuel pump feed can be found? Remember my fuel pump isn't getting switched on by the ECU, I still have to jump the relay... but that's 12v, and my injectors and coils ARE getting 12v.

I might just pull the engine and box and redo the entire loom for the car it's going in anyway. At this point it's taking so long and I'd have an easier time of it on the workbench then in the car... I'm starting to give up.

Any thoughts?

thanks again.

 

The XK was a series of the inline 6 engines in earlier years

The AJ16 is opposite the AJ6 of the XK series

The V8 series of engines have a change in the cylinder numbering during the years off the top of my head around 2002.5

I'm no expert on this mater so I can be wrong

Since you have power on all 6 points on both coils and injectors , suggest look at the control grounds provided by the ECU . Suggest look at all grounds that the ECU requires , in red squares .

Since you have fuel in the oil it points to no ignition and the correctly working fuel injectors are overfueling the suspect cylinders and pushing fuel past the piston rings during compression .


Parker , The Rock n' Roll Jaguar fixer

 

Hi scuby,

If you are referring to the X300 Mystery thread by Steve Swallow (Jags_on_gas), he ultimately did resolve that issue by installing a new CKPS. Of course, he had tried many other things as well, so the resolution may have been due to a combination of actions. See posts #623 and #640 in this thread:

https://forums.jag-lovers.com/t/x300...ery/240719/623

Cheers,

Don

 

interesting... one wouldn't think the CKPS wouldn't create 1 bank running the other not. but who knows!

I'll keep at it. Thanks again Penelope

 

Having read those posts you reference there are a few differences in my scenario:

the car DOESN'T start normally and then start to run rough. It just runs poorly from startup..

Also, so far, I have not witnessed any "flipping" of the offending bank. Bank 1 simply doesn't fire.

I haven't had a chance to have a dig yet. Probably next week. What I will take from the mystery thread is to check my CKPS wiring. I have a good one in the car and another jag to be able to trade parts with back and forth. Only difference is that it isn't an XJR so the ECU isn't an option.

I thinking wiring is the issue somewhere or a bad relay. Finding that needle however...

 

As the signal degrades down from 100 % ( CKPS ) and the receiving device ( ECU ) has a window of acceptance that is out of range to see a signal that can be worked with . The ECU probably has 2 sections of 4 cylinders ( same ECU is used on other V8s with some pinout changes ) to process and command the ignition . Since you have 6 cylinders the 1 section handles 123 and the other 456 . Easier and cheaper to work on the CKPS signal quality and those grounds including the large ground by the starter . In the wiring guide there is no split on the 123 and 456 sections . The 456 section window could also be degragrated below that of the 123 . Just spitballing without a schematic inside the ECU .



My mom says I need to take a nap now .

 

It's been awhile since I read the entire Mystery thread, but if I recall correctly, it was only one of the banks that kept shutting off for quite awhile. It was after much testing and head-scratching that Steve observed the malfunction flipping to the other bank. Given how odd and inexplicable the behavior is, I certainly wouldn't rule out the CKPS and its wiring.

One other thing to think about. The original CKPS had grounded shielding around its wiring harness. A few of the replacement CKPS's I've purchased had no shielding. One even had signs that the harness cable had been shielded originally, but the shield had been cut off prior to fitting the connector plug! The shielding braid is obviously there to protect the CKPS signal from EMI/RFI, much of which is generated by nearby components such as the alternator, ignition coils, electric cooling fans, etc. If your CKPS wiring harness is not shielded that might be a suspect.

Cheers,

Don

 

The current state of affairs is as follows:

After checking compression I pulled the fuel rail, visually inspected all the injectors. Nothing to see there.

I replaced all the plugs for the second time in this process. I used factory spec Champion plugs as Jaguar did.
Out everything back and added 10 liters of fresh fuel. Gauge reeds 1/4th tank full.

the XJR runs. Sort of: facepalm.

It's a little hard to start. It idles almost smoothly but does run on all 6 cylinders. Insepersted the wiring loom to be able to inspect it. Nothing to see there. Also gives me easy access to pull injector plugs one by one.

So it idles ok.

It will rev up in P smoothly if done very lightly .Blip the throttle or five it the beans and stumbles skips and hesitates. This is, as you would expect, a lot worse in gear under load. It will stall under load. Once warm it will accelerate pretty smoothly under very very light throttle.

Fuel pump?

Ideas?

This car...driving me barry!

 

Shot two vids.

Also changed the oil as there was fuel in the old oil.

In summary: ok idle. Misses/hesitates/dies under load.

Light acceleration it can handle.

New oil, plugs, fuel ckps. All wiring advised looked at, cleaned, and inspected again.

​​​​​​Never mind the dash and all the warning lights. It's a donor car and always ran fine as it is now. Just missing a few modules. Never effected it before.

idle and throttle in P:

​​​​​​
https://youtu.be/puhITfyNNNc

Under load:

https://youtu.be/ji-vnjiw_Qw