Hi Everyone,

I'm new to the Jag Forum and have posted on new member page,
My car is a 1990 XJ40 4ltr Sovereign RHD in Solent Blue, it is close to concours condition and I have owned it for 19 years.

Since retirement and moving home some 7 years ago our dear car has been weather protected in an outdoor Carcoon. When last started 18 months ago it went first go, since then its been safely tucked up in the Carcoon, I removed it two days ago and sadly it would not start.

Investigation has shown that no fuel is reaching the rail during cranking with the feed slackened off, maybe it's a pump fault or something else.

I've added 4 gallons of top grade petrol and still no fuel reaches the rail.

Checking the VCM I've had various and seemingly random indications as follows:
1st check: 'Fuse 1,2,3,5,PRO, FAIL'. 2nd check:'Fuse 6; 3rd check: 'Fuse 5 Fail'; 4th check: 'Fuse 5';

All fuses that I can find in both 'A' posts are not relevant - so I'm stumped as to the problem. I have yet to check the pump using a separate power supply - this means jacking and crawling about which at 75 might try my coronary stents a little.
I've done over 50,000 miles during ownership and the car has never given cause for complaint - even when towing our caravan.

I have the official Service Manual on CD and looking at Fault Descriptions (Engine Management - 4.0) page 18.2-11 codes start at 11 through to 89 none of which are relevant to the VCM indications shown.

If anyone can shed some light on this I would be more than grateful.

Jim

 

Jim,

I would do the simple stuff first. Your fuel pump is driven by a relay, and I believe on your model the relay is in the engine bay, on a yellow base. On LHD's it is located next to the brake pedal housing, I would assume the same on RHD.

Pull it and clean the connectors on it and the base connectors with an electronics aerosol cleaner. Also, if you are able to do so yourself, or with the help of another set of ears, ensure the relay is engaging, you should here it click when the ignition in put in position II (not cranking the engine).

Next, and this may be a challenge for you, get the fuel filter changed out. It's not hard to get to, but you will need to put the car up to access it, but not have to get completely under the vehicle. Since the car sat for so long, the filter may have failed and/or clogged up to prohibit flow of petrol. Additionally, when you remove it, you'll see whether fuel is getting from the pump to the filter.

If the petrol is not getting to the filter, then you have pump issues and fortunately for you, the pump is external (they put the pump in the tank starting with the '91), but the vehicle will need to be put up on jacks. Once up, the pump is easy to see and access. If you look over the fuel pump, you can visually track the feed line back to the pump and see it's location.

I would eliminate the above items first, which will narrow down the direction(s) to get the vehicle running. I would think that if you had no issues with performance prior to parking the vehicle, the fix you're looking for will be simple.

BTW, what components are on the Fuse 5 circuit for you vehicle?

 

Hi Rob,
Thanks for the info - some I've done already, the relay on this car is under the left passenger glove locker, a small unit about 1-1/4" cubed, there are four others like it so I removed one of these and replaced it into the pump relay socket and vice versa, it made no difference.

Fuel filter? Haven't checked that yet but with fuel at the rail regulated to 45 psi (what the manual says) it would be a very blocked filter to stop such pressure. I've been to the pump area where it is nestled within the axle carrier frame on the left side - not at all easy to get to, so to apply alternate power I would like to find the other end of the pump wiring and apply power from there....
All I want to find at the moment is a working pump squirting petrol all over the place....!
And of course, the meaning of those VCM faults.

I'll keep you informed of progress rob.

Jim

 

Hi Jim:
It could obviously be a failed fuel pump if you are certain that there is no pressure at the rail (did you confirm that with a proper fuel pressure check) and you have already swapped out the relay. It is possible to jump the relay to get the pump to run continuously. I don't know that procedure offhand and would need to do some digging to find out. You might do the same. If when you jump the pins on the relay base and the pump doesn't run, I would strongly suspect the pump itself.

Cheers,
Scott
PS- very nice looking car!!

 

Hi Scott,
A 'proper' pressure check at the rail? If you would call disconnecting the fuel feed pipe at the rail and finding not a dribble of petrol anywhere while cranking - that's a reasonable check,
The VCM read outs still bug me, there doesn't seem to be such creatures as fuses specifically marked 1,2,3,5,6, or information as to where to find them, even within the Service Manual. And what is the indication 'PRO' on the VCM ?

Also Fuses on both 'A' posts bear no relation to engine systems.

Jim

 

Jim:
I simply meant installing a fuel pressure gauge to determine the precise fuel pressure whilst cranking/running. But I suppose you're right; if there's no fuel to check the pressure of...!

Believe it or not, I've never changed a fuse in almost 5 years of ownership. So I consulted my manual (for my '91, which may be different from your '90) and I don't understand your VCM readings. Perhaps you could visually inspect all the fuses in all three fuseboxes? A couple of them, i.e. A3 and C8, seem to affect things relevant systems; but I have no idea whether they would actually prevent starting.

I think PAO actually is PAD - an indicator that a break pad is low somewhere on the car. Or, perhaps even more likely, the sensor indicating brake wear has gone bad.

Scott

 

Hi Scott,
With help from my local repair shop who will also carry out the annual roadworthiness test We've located the fault which turns out to be the fuel pump that has become gummed up with fuel sediment through standing unused for a long period.

With the repair technician under the car with hand on pump while I operated the ignition switch he felt the pump trying to move each time ign was switched, even mild blows with a hammer did not free it.

Today I ordered a new pump that will be with me tomorrow - then the kind technician (who has frequently come across the problem) will fit it for me saying it won't take long, I imagine at least 2 hours, which I could never do... It will be a small price worth every penny (cent).

I'll let you know how it goes, it will be so good to hear the dear old Jag purr again...

Jim

 

Your PRO is as Scott says PAD (digital hieroglyphics) seems it can also display when the sphere is faulty or uncharged. Which after 18 months of a no start yours certainly will be.

Clear the message when you have got her running again and driven it, to see what happens.

 

Hi Jim it may be worth alook at the inertia switch which could have been knocked or bumped'' Its purpose is to cut the fuel to engine in case of accident. On R/H drive cars it is in the footwell next to the accelerator. It is a small black box type switch with a 3 pin plug at the bottom. The trip switch is at the top when engine is running and every thing is fine the small round switch should be hard down; if tripped it will be up and showing the colour RED. Verry easy to access.
Cheers Ray

 

Ray,
What a collection you have! Very nice...

The inertia sw was one of my first checks, that's ok, the car hadn't moved since last started.
The new pump has arrived - and so have rain storms! So as soon as they clear we might be in business again.

SNG Barratt have been one of my chief suppliers for many years and very good they are too,
They have an outlet in the States also, I heartily recommend them.

Jim

 

Hi All,

With a new fuel pump fitted the car is now running but No 5 cyl is a bit recalcitrant to come in, all plugs checked and ok with gaps and cleanliness, after about 20 mins running all smooths out and 5 is running ok, first thought it might be the lifter filling with oil but when run on LPG the engine was instantly smooth during the time 5 was misbehaving.

As a point of interest the characteristics of the pump operation are interesting; with an empty fuel feed pipe as when fitting the pump, switching the ign ON causes the pump to operate for just two seconds before being shut down by the ECU, with the pump producing 6 Bar of pressure (circa 70 psi) the auto shutdown (A) insures that over pressure is not created when the engine is stationary with the Ign ON, and (B) that in the event of supply pipe rupture fuel will not continue flowing thereby causing a hazard.

To fill the system with fuel following the pump fitment is is necessary to repeatedly turn the ign on and off many times until the system has filled (detected by loosening the feed to the rail) as soon as fuel is seen the connection is tightened and the engine will start within a few seconds that it takes to fill the rail.

The car will go in for its mandatory annual test next week, if 5 Cyl behaves we will be on the road again after 6 years.

Thank you Chaps, for all advice which is most welcome.

Jim
Member: Jaguar Enthusiasts Club of UK

 

Best of luck with the MOT Jim.

Let us know how it goes.