just asked the Jaguar Daimler Heritage trust yesterday
more pics of engine in car, it has just been removed completely for change of the motor starter ; what a job just for this , I suppose it is not accessible otherwise ?
of course changes of engine mounts, cooling hoses, plugs, oil, filters, and camshaft bronze bearings done “while you’re at it”
the engine starts with “Start Pilot” spray, but then stalls, no idle; so a bit of a gamble to purchase ?
many things could go wrong, but on the other hand the engine seems fine, so only peripherals can be faulty ? 2 ECUs are joined as “spare” , but are they faulty or not is difficult to assess
and 2 spare ECUs in the boot , DAC3062 (6CU) and DAC4478 (16CU), wich seem according to the list above provided by Aristides, possible right ones for a High compression engine without O2 sensors (respectively 1981 and 1985); although for a 1989 engine (if confirmed) DAC6336 would be 100% period
The list I posted is from Roger Bywater so it’s definitely correct.
The fact that there are two spare ECUs for a 12.5:1 CR and NO Cats sounds like a strong indication.
Hope the Jaguar Daimler Heritage trust will give a definite answer.
Difficult job, but many, if not all, have done it in situ.
Many things that could be wrong, ECU, injectors wiring, ignition amp etc etc, but most probably all peripheral.
Did you measure compression ?
It’s the one and most important thing in your case.
Any weird noises?
There are very robust and over engineered engines, so if compression is good and no weird noises, most likely everything else is easy, especially with the engine out of the car.
And add to the list:
Sandwich gasket, oil pan gasket, cam cover gaskets, all banjo bolts, front main seal.
thanks Aristides !
this book…call it a bible !
I do not have a measure of the compression alas, and as the engine is not properly running (due to wrong ECU, now I am certain thanks to the pics sent by the seller), I cannot witness any noise at all, wether weird or normal !
the engine is now back in the car (see first pic above), all new belts, also
When it starts; how does it run, Orlando - you used ‘start pilot’ on both banks’ intakes…?
If the ‘running quality’ was smooth; it implies that the engine itself is OK and that ignition is working - though start gases generally ignites easier than petrol. Have you checked spark quality with a triple gapped spark plug - strong and blue?
It certainly looks as if the engine is not getting fuel; have you checked that the injectors a ‘clicking’ while cranking? And/or used an injector test lamp (noid) to verify ECU is triggering the injectors? No injector action means no fueling - start gas bypasses injection problems. And do you have the same behaviour on either ECU?
Also; the fuel pump should operate for 2 seconds when ign is turned ‘on’ - does it? And does the fuel pump actually run while cranking? The confirmation of proper fuel pressure requires a fuel pressure test, of course.
I quite agree with Aristides; a compression test is good practice with a misbehaving engine - it verifies that the engine itself is OK. Even if compression testing a V12 is a bit awkward. A compression tester is a cheap addition to diagnostic tools.
It’s difficult to assess engine running with the brief run on start gas - and it is very difficult to portion the application of gas for smooth continuous running.
All told; I think pursing fuel delivery - the ECUs’ sole purpose…
the fact is that I live 600 km from the car, which is currently at a mechanic, who is not a specialist of injection at all; so I can only very partially answer your questions, forgive me for this
you used ‘start pilot’ on both banks’ intakes…? YES
you used ‘start pilot’ on both banks’ intakes…? NO ( spark plugs are new though but it does not mean they get a spark)
And do you have the same behaviour on either ECU? it seems the mechanic has mounted the ECU version for D-Jetronic, not the one for P-Digital ! that would probably explain a lot of the issue but I can’t try the “right” ECU now
he fuel pump should operate for 2 seconds when ign is turned ‘on’ - does it? YES
And does the fuel pump actually run while cranking? Not sure
no compression tests carried out and I am away from car now;
If I buy the car, which is very likely now, I will perform all your suggestions right away !
thanks again for present - and surely future - help !
I think the trigger systems are very different.
On Lucas cars the ECU gets the signal from the Ignition Amp via the infamous coax wire.
On Marelli cars there is a Crank Position Sensor.
it seems the mechanic has mounted the ECU version for D-Jetronic, not the one for P-Digital ! that would probably explain a lot of the issue but I can’t try the “right” ECU now
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There is a possible snag here, Rolando…?
The car’s(!) wiring to the ECU connector(!) is fitted to serve the specific ECU with the original engine. So the connector may not be wired, ‘from’ the various sensors and ‘to’ the engine, to fit the new engine…?
In addition, as others have said; the ‘signal forms’ to the ECUs may not be understood by a ‘wrong’ ECU. Which explains the number of ECU variants; while an engine’s demands for fuel is fairly identical - the way the ECUs deal with inputs vary…
While I agree with Aristides and others is at the bottom of your problems - the fix may not be straight forward? tThe ECU designed for your engine may be incompatible for the car wiring - and some rewiring may be required?
All that said; the pictures show an engine that seems to be well cared for - and worth while having. However, once the engine is in your domain; the tests suggested are still valid - but will be inconclusive for a malfunctioning engine if there is a wiring mismatch to and from the ECU…
You have a good point there Frank.
The XJC, being a series II car would originally have the D-Jetronic system, (therefore the AEU1121E (15415) ECU fitted in the boot).
Being triggered very differently I would suspect that the wiring would also be somewhat different from the later 6CU and 16CU.
@rolando38, will have some homework to do… but as long one has the wiring diagram, it’s just cables.
I wonder if this engine ever worked on that car?
