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Rust issues, especially bulkhead

XJ4081
Posts: 162
Joined: Fri Oct 23, 2015 12:12 am
Location: Germany (South-West)

Re: Rust issues, especially bulkhead

Postby XJ4081 » Wed Aug 30, 2017 10:08 am

What is CPS? Surprisingly it started yesterday as if nothing had happened.
1993 XJ12

pimgmx
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Re: Rust issues, especially bulkhead

Postby pimgmx » Wed Aug 30, 2017 11:26 am

Crankshaft position sensor.
Crucial for ECU-governed engines to fire up.

Fuel could be a good hunch, though: check the pump relay and the fuel harness wiring/connectors.
You may want to apply 12V directly to the pump wires to rule out any intermediate electronics gremlins...

the daily: 01 S8 http://bit.ly/2kIwP4m
the tractor: 77 LaRo LW https://bit.ly/2Hr9n6y
the eyecatcher: 93 Insignia http://bit.ly/1iGrmsU
the GT: 89 XJS http://bit.ly/1WQGpC5
the project: 95 X306 http://bit.ly/1cW11DN
the pocket rocket: 97 Z3 http://bit.ly/12IfE7B
the ex: 93 3.2 http://bit.ly/14GTNrq

XJ4081
Posts: 162
Joined: Fri Oct 23, 2015 12:12 am
Location: Germany (South-West)

Re: Rust issues, especially bulkhead

Postby XJ4081 » Fri Sep 01, 2017 11:11 pm

I will check these. The last days it just started fine, but that does not really relieve me - that's rather an indicator for the gremlin theory.

Let's talk again about sounds and noises: I once again noticed a kind of fizzling noise, especially when accelerating. First I thought it were wind noises, but it is definitely rather related to throttle/rev than to speed, though it becomes more apparent above 80-100 km/h. Does this indicate something special? Initially I thought about the fuel pump, but from other cars I know these sound rather whimpering or howling.
1993 XJ12

katar83
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Re: Rust issues, especially bulkhead

Postby katar83 » Fri Sep 01, 2017 11:29 pm

Always, I mean always have a spare CPS with you, this is pretty much the only part that can fail anytime and recovery is the only option.

Read here

viewtopic.php?f=9&t=997965

for further details and the importance of having a spare CPS. As soon as it gives you trouble - replace it.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

XJ4081
Posts: 162
Joined: Fri Oct 23, 2015 12:12 am
Location: Germany (South-West)

Re: Rust issues, especially bulkhead

Postby XJ4081 » Sat Sep 02, 2017 12:37 am

Can anybody tell me where I can get a new CPS? Or at least the part number? I searched the internet but only found one for X308 and newer.
1993 XJ12

naki_k
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Re: Rust issues, especially bulkhead

Postby naki_k » Fri Sep 08, 2017 1:10 am

XJ4081 wrote:Can anybody tell me where I can get a new CPS? Or at least the part number? I searched the internet but only found one for X308 and newer.



https://www.jaguarclassicparts.com/uk/part/DBC12507

Bargain price, but IMO these don't fail so often on the 6.0 models


The Honey moon period is over already? Have you checked all the ignition parts, especially the rotor arm? Notorious fail on the XJ81.
You can try starting on easy start as a quick test, but also its easy to open the fuel rail and see if you have fuel pressure.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 3.2 XJ6 SportPack Manual
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 4.0 X306 XJR
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97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

XJ4081
Posts: 162
Joined: Fri Oct 23, 2015 12:12 am
Location: Germany (South-West)

Re: Rust issues, especially bulkhead

Postby XJ4081 » Mon Sep 11, 2017 10:50 pm

Thank you for the link. In the meantime I had found a sensor for X300, but that seems to be a completely different thing.

Well, I must say honeymoon has not begun yet - there were obstacles right from the start and continue to be. Had no starting problems the last few times, but then it died down waiting at a cross-way (on the way to the garage). Could be started again but died out immediately again. First diagnosis is dirt and water in the fuel tank, but the garage where it was towed to has no time to clean it, so I'll have to wait until it can be towed to the other garage.
1993 XJ12

Starbuck
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Re: Rust issues, especially bulkhead

Postby Starbuck » Tue Sep 12, 2017 1:28 am

Hi XJ4081,

Before getting onto anything else like the CPS. Have you thoroughly checked the primary ignition components on your car to ensure they are all new, or very recently replaced? I may have missed it, but I've not seen anything to suggest this has been done?

By primary ignition components I mean the spark plugs, the leads, the distributor cap and rotor, the coils, the coil trigger modules, and the underbonnet wiring for the coils? The Marelli ignition V12s have what are effectively two ignition systems and all sorts of rough running maladies are caused when one or both starts to play up (including the infamous 'Marelli fire'). When the engine is hot and resistance of some components increase, the problems are more noticeable. When cold the problems often disappear for a while. Make absolutely sure all the primary ignition components are either new or very near new before trying to diagnose other problems.

There are two fuel pumps for the V12 and a module that controls them. If the car has been sitting for a long time the second pump (which only operates under 'full load' conditions) will often seize because it doesn't get much use anyway. The control module can also fail, but this is rare. If your mechanic is going to take the tank out to clean it, get them to check both fuel pumps for operation as well.

The V12 has two, almost identical, crankshaft reference sensors - one is crank angle and one is crankshaft speed. One reads off a three pointed 'star' bolted to the back of the crankshaft pulley, the other reads off the torque converter drive plate. They were interchangeable on the 5.3 with Marelli ignition, for some reason on the 6.0 they are slightly different (plug, cable length, whatever). That said, Naki is spot on when he says these rarely fail on the V12.

Like many cars, the crankshaft pulley on the V12 is a harmonic balancer. There is an inner and outer part of the pulley which has a bonded rubber section between the two parts. Over many years the outer section of the pulley can slip in relation to the part bolted to the crank, and since the 'star' is bolted to the outer section of the pulley the two reference sensors are then 'out of synch'. This also causes ignition problems.

The pulley can be checked by either doing a top dead centre (TDC) alignment using the number one piston (PITA), or by setting the engine to TDC using the engine speed sensor teeth on the drive plate (slightly easier PITA). Once the engine is at TDC, if one tip of the star on the pulley isn't in alignment with the crank angle sensor - the outer section of the pulley has slipped.

As mentioned at the start though. Make sure your primary ignition components are all absolutely spot on before doing anything else.

Good hunting,

Starbuck
'94 XJ12 (and other toys)

pimgmx
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Re: Rust issues, especially bulkhead

Postby pimgmx » Tue Sep 12, 2017 7:43 am

Starbuck wrote:...If your mechanic is going to take the tank out to clean it, get them to check both fuel pumps for operation...

IF you go down the tank-out route, I would it one step further and preventatively replace both pumps.
They're a known weakness on V12s (especially the secondary pump as Starbuck mentioned) and getting the tank out is a PITA for the DIYer.
Pumps are <100EUR each, and pretty easy to replace with the tank out.

the daily: 01 S8 http://bit.ly/2kIwP4m
the tractor: 77 LaRo LW https://bit.ly/2Hr9n6y
the eyecatcher: 93 Insignia http://bit.ly/1iGrmsU
the GT: 89 XJS http://bit.ly/1WQGpC5
the project: 95 X306 http://bit.ly/1cW11DN
the pocket rocket: 97 Z3 http://bit.ly/12IfE7B
the ex: 93 3.2 http://bit.ly/14GTNrq

XJ4081
Posts: 162
Joined: Fri Oct 23, 2015 12:12 am
Location: Germany (South-West)

Re: Rust issues, especially bulkhead

Postby XJ4081 » Sat Sep 16, 2017 3:19 pm

Well, we're getting closer to honeymoon ;) .

Just coming back from a Jaguar specialist (the one I originally intended to visit, but could not due to schedule problems) and we got rid of a lot of issues. He cleaned the fuel tank (according to him it it was not necessary to remove it) and he replaced the fuel pump relay which was the second cause for the starting problems, both fuel pumps are running fine. Besides that he replaced many connections and wires which were broken/corroded and caused miscellaneous issues. A/C is working now, too. He also found the reason for the battery/alternator control lamp: though the alternator was almost new, someone managed to 'kill' it by installing the battery unworkmanlikely, so it needed to be overhauled again. Steering has been adjusted, too, the steering wheel now is (almost) straight.

What's still remaining from technical side is that whistling noise above 100km/h and the cooler radiator running even some minutes after engine has been stopped. But both may be normal :?: .

Next will be optical improvement and rust removal/conservation.

So today, for the first time, I felt confident enough to use sport mode - and wow, that was even more impressive - that feeling made up for a lot 8-) .
1993 XJ12


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