Poor Starting XKR

[steve.pritchard146]

Hi all,
My MY2001 XKR cab has become extremely difficult to start hot or cold, it cranks well as the battery is brand new.
Once started it runs perfectly.
Looking at the AJ26 diagnostic flow chart it suggests starting with the Rochester valve. I thought I had found it yesterday as I was dismantlling and investigating but it turned out that was the purge valve! - also on the list of possible culprits.

My question is, where exactly is the Rochester valve? I’m probably being dim but have struggled to work out exactly where it is.

I’ve also ordered a fuel pressure test gauge so I can check the Rail pressure.

Does anyone have any advice or direction to give?

Regards

Steve
2008 XJ 2.7
2001 XKR Cab
1968 3.8S - a longer term project

[Andy P]

Hi Steve,
Found this thread on JaguarForums which mentions the Rochester Valve and might be of interest to you.
https://www.jaguarforums.com/forum/xk8- ... er-233478/
Hope you get it sorted.
Take care.
Andy

[steve.pritchard146]

Thanks Andy, just what I needed.
…and it looks to be easily accessible.
Fingers crossed

[steve.pritchard146]

Ok further developments on the poor starting journey….
I swapped the canister purge valve in the wheel arch - no difference, and as a reminder we are talking of 20-30 secs of cranking to get a start.

So I decided to check the fuel pumps. The XKR has two pumps, the secondary pump used for starting the car and additional fuel under load (I believe) and the primary one for when the engine is running and normal use. I decided prior to any pressure testing of the fuel rail, the quickest test was to pop open the relay box in the boot, pull out the relay for each pump, jumper it’s switch pin to live and listen for a pump.
If you want to try this it’s pin 5 on the relay slot and there is a large live terminal at the corner of the relay box. I did take a picture but it seems to have vanished!
Anyway the primary pump sprang into into life with a whining from the tank, but the secondary was dead as a dead thing - time to read about fuel pump changing……

….<wind forward about 2 hours>

I have to admit that after having read various write-ups and watched a few YouTube videos I was feeling a little demotivated and a little intimidated as:
-the pumps are submerged in the fuel tank
-You have to remove the fuel tank to access them
-There are two inaccessible fuel pipes that have to be detached from beneath the car buried up above the diff.
- I had over half a tank of fuel on board

I pulled myself together, ordered a pair of fuel pumps for next day delivery , (as why would you only change one after going through the dismantling pain?) and set off to find my set of unused quick-release fuel pipe tools.

I took the decision to back the car up on ramps for the safest and easiest access both putting the boot at a good-ish working height and allowing easy access to the area around the diff.

I won’t put too much detail about the boot area it’s pretty easy to do:
-Remove the battery! (Sparks, fuel etc etc scary thoughts)
-Remove the rear light covers, interior boot linings, left, right, rear
-Remove the large metal bulkhead that runs across the rear of the boot (5 bolts)
-Remove the pipe work around the fuel filler cap.
-Disconnect a few cables

That leaves you with the fuel tank ready to remove - apart from the pipes at the bottom…….

I was definitely delaying climbing underneath!

I got out my inspection lamp and made my way underneath.

FIRST MISTAKE and learning point for all.
As you move order the car you will quickly see two fuel lines high up above the diff vanishing under some heat shield, I didn’t remember reading about it but set about unbolting it.
After much cursing, bending attempts and general failure to see how I could remove the heat sink I was inclined to think I was going to have to retire hurt for the day, Then I remembered reading one of the Jaguar bulletins which had mentioned you needed to look behind the UJ on the prop shaft (or something like that) so I crawled further back and with my head at the front of the diff around the prop-shaf connection point I saw it!
Deep behind the diff through an incredible tight gap we’re the two pipes connected into the bottom of the tank - it didn’t look particularly accessible but I could get fingers hooked around the pipes before they bent up to the tank, so If I could release the ‘quick-release’ connector I could definitely pull on the pipe.

But could I find my set of quick release connectors? Purchased a few years back for disconnecting a fuel line on an S-Type I’d actually not used them as they had not been required. They were nowhere to be found.

SECOND MISTAKE
I then set about wasting 3-4 hours fabricating quick release tools which didn’t work.
The quick release tool works by sliding between the fuel pipe and the connector releasing 4 spring clips allowing the pipe to be pulled clear.
I figured that a 15mm upvc push-fit plumbing connector could be slit, narrowed, chamfered and would do the job.
I also figured that to push it home I could use a long straight tube that was slotted to fit over the pipe and would push my makeshift release tool home. I was wrong!

Now in fairness, it would have worked if I had made it properly as the tools you buy work using exactly that principle but in the end it was 4 hours wasted, skinned knuckles and general grumpiness before I gave up and shelled our £12 for an Amazon next day delivery for a set of 5

In the picture of the set I ordered you will see the one learning point from my attempts to make a tool and that was to attach wire to the release tool as dropping it happened quite regularly and I lost two before attaching tethers and that would have been disaster if it had happened with the tool I purchased as there is only one of each size.

So wind forward 24 hours and with fuel pumps, quick release tool and a nice car crawler from SGS ( I’ve been meaning to get one for years)
I rolled under the car with my head on foam - how nice is that!
Reached up with the 5/16 pipe release clip with tether attached and clipped it on the part of the pipe I could reach and then using a long thin screwdriver (a good 30cm long and very thin ) I gently pushed the release tool around and up into the connector in the tank where to my surprise it clicked in place. I reached up and was even more amazed when the pipe came straight out!
The second pipe (on the left from where I was )was slightly more difficult but not much.
Be prepared for some petrol to come out but really just a glug (as Jamie Oliver would say)
So that was it everything disconnected!

Time to move the tank.
I was quite nervous about this as it had a lot of fuel in and sharp edges close to lots of wires.
I wasn’t sure what to expect so placed some angled bits of wood in the wheel well to stop it suddenly dropping into the well.

You need to grasp the filler pipe and gently easy that side towards you, the tank actually moves quite easily and I quickly discovered that I didn’t need to pull it too far out before I could get at the access panel in the top.

The access cover is held in by a retaining ring which needs to be knocked around by it’s tabs to release, best probably to alternate which tab you hit so as not to wreck any.

You will see the two (if you have an XKR) pumps submerged in the tank. You need to get a socket in to release the two 7mm nuts securing the pumps. If you are doing this in the car with a tank full of fuel you don’t want to drop the bolts! I had a magnet next to each bolt to avoid upset.

One the bolts are released the pumps can be lifted up. You need to disconnect the flexible fuel line and wiring connector from each one.

THIRD MISTAKE
When looking for replacement pumps I saw many places selling lots of different versions with hugely varying prices from £18!!! Each.
I opted for some at around £70 but shied away from the £230+ oe ones.
The issues with the pumps I got are :
-the new pumps came with a different wiring harness connector which means you need to do cutting and splicing
-The filter bags with the pumps I purchased are fitted 180 degrees out (I;ve included a picture) this gives you a problem as it prevents refitting, I had to mount the filter bag reversed which meant I didn’t connect it;s retaining lug which is hopefully not a problem
The actual shape of the pump is subtly different to the original which means the anti-vibration rubbers don’t fit perfectly which means the retaining bracket is difficult to refit.

In reality for me the wiring connector was the biggest concern as I had to cut off the original connector and make a new loom section that was secure and safe. You don’t want to rush this I removed the cables to the garage (away from petrol fumes ) and attached the new connector with soldered on spade clips protected by shrink-wrap covers. You really don’t want live wires floating around in the fuel tank…

Re-assembly is as the say the reverse of disassembly!

The fuel tank pushed easily back into place.

With my new car crawler I quickly slid under the axle and with the long narrow screwdriver managed to quickly reconnect the pipes.


I quickly tested both pumps using the relay method mentioned earlier

With some trepidation I started the car or rather tried to - still took inordinate cranking before it fired - I’m hoping it might be borewash we shall see later.

In the bright side, I’m back to 2 fuel pumps!

[steve.pritchard146]

Seemed to only attach 3 pics on the last post
You see on the picture of old pump and new pump side by side how the filter on the new pump is different and sticks out behind the pump

[mike020150]

Some good lessons there for many members. Thanks for taking the trouble to provide such a comprehensive write-up. I hope the pump change proves successful in providing a cure for the starting problem. Mike.

[steve.pritchard146]

so the journey goes on as two working fuel pumps made little or no difference to my starting woes..

So number three in the list of things to check on TSB 303-55 (difficult/non starting) is the the throttle body. Now I know that the TSB is for the AJ26 versioned engines but I'm assuming that it is fairly sound as a basis for diagnosis.

YOU SHOULD REALLY GET A NEW THROTTLE BODY GASKET in advance of this as you may tear the existing one and it is not good practice to re-use gaskets!

I popped the air cover off the top of the throttle body (two bolts at the throttle body, a breather pipe to the RH engine bank and the large jubilee clip at the MAF)

The first diagnosis step suggest that you with the help of an assistant check that the throttle butterfly opens and closes when the ignition is turned on.

well I failed at the first hurdle here as my throttle just kind of twitched! However, I'm possibly led to believe that the AJ27 Throttle butterfly might not do this (personally I doubt I'm that lucky) Interestingly the throttle is humming continuously with the ignition on which I think is the butterfly being kept closed (there appear to be gaps in my understanding here)

I decided based on the level of carbon I could see inside that bench removal was called for. TSB 310-06 describes this process well although there were a couple of minor differences as it is for the AJ26

The removal process is pretty straight forward the key advice I would give is to ensure that you use a magnet tool at all times when removing the bolts as I suspect that 'dropped is lost'

Also, there is very little space at the rear of the throttle body to get your hand in to remove the hoses, particularly if they are stiff.
There may be disagreement here, but the method I use for 'stuck hose' removal is to gently grip the pipe in question and apply a slight twist aback and forth around the hose to effectively turn the hose a tiny amount on the pipe breaking any grip. The important thing here is gently, you do not want to be ripping and damaging pipes with pliers.

for the lower pipe it was too inaccessible so that although I could remove the clip I could not get anything in to grip and remove it so I left it in place and when I lifted the throttle body I was able to reach and pull it off.

You need to disconnect the throttle cable, something to consider at this point is whether there is too much slack in the throttle cable as you will need to remove the tie-wrap that locks the adjuster in place so if there is a lot of free slack in the cable you can remove some of this on reassembly (mine had loads of slack)

Once you've disconnected the pipes at the back, wiring connections, throttle cable , the air vent bracket and undone the 4 bolts securing the throttle you should find that it really easily lifts out.

I've added a couple of pictures so you can see the view in from the top of the throttle and also the view inside from the bottom with it on the bench.

I used carb cleaner and petrol to remove a lot of varnish and carbon deposits - you should not use any rough tools in the throttle body it will scratch easily and it you are using a paintbrush or toothbrush be really careful that no bristles are left in the body or butterfly mechanism as we are aiming for better butterfly movement not impeded!

So at this point I had some concerns as my butterfly is definitely not closing completely and wasn't before I started. There is no doubt that it is not sticking and it might have been before but there is probably a fraction of a mm of movement that it can be applied against the sprint to close it - now that may be idle adjustment related to the adjusters on the throttle sensor (more stuff to check!)

Anyway, reassembly is definitely the reverse of removal the only difference is that the two cooling pipes were much easier to refit. (remember to use a magnet to get the body bolts in place )

Also check out the free-play in the throttle cable as I mentioned previously - you do need to make sure that the cable is so tight its applying the throttle.

You should also refit the the throttle adjuster to its bracket with a new tie-wrap to secure - I think that the tie-wraps were main dealer applied retrofits to address issues of the adjusters coming out of their brackets.

With the body back in place and looking much cleaner I duly turned the ignition on and saw the flap give a little twitch - but it did not open and close - hmmm do I need to worry about that?

Cranking the engine without the airt cover back on yielded no engine start at all - surely it should start without the cover on.

Anyway, with everything back in place the engine roared into life almost immediately and restarted numerous times after turning off. I let it warm up, drove up to tesco, then went to get fuel. Each time it started as expected.

Hurrah!

Although I'm still not sure if that butterfly should open and close on ignition start.....

[mike020150]

The accelerator cable adjustment is meant to be carried out by measuring the voltages from the two pedal demand sensors to check the readings are equal and then following a mechanical process to set the cable. It goes like this.

Cut off the ratchet strap which retains the throttle cable.
Release the throttle cable adjustment nut to make sure there is no tension on the throttle cable.
Note the voltages for both the pedal demand sensors (simple if you're using Jaguar Diagnostics!)
Try inserting the cable adjustment nut into the bracket.
Recheck the voltages for both sensors.
Where the voltages are now higher than the voltages taken previously, continue to step 1 below.
Where the voltages are the same as the voltages taken previously, continue to step 2 below.
Step 1 Turn the adjustment nut clockwise (viewed from the front of the vehicle) until the same voltages are indicated. Continue to turn it until the sides of the nut are vertical. Turn a further 90 degrees, then fully engage the nut into the bracket.
Step 2 Turn the adjustment nut anti-clockwise until the voltage starts to increase. Turn the nut clockwise until the sides are vertical. Turn a further 90 degrees and insert the nut into the bracket.
Fit a new ratchet strap.
Move the throttle pedal 20 full cycles to settle the cable. Check the voltages remain the same.

Attempting to set the cable as Jaguar intended it to work but without measuring the voltages is a lottery of a task and could produce some strange throttle responses. Mike.

[steve.pritchard146]

Thanks for the steer on the voltages Mike - that is very useful.
Something else on the to-do list!