Hi Daim

Neither one of them fitted my Car and as the cost of efans was cheaper than a new clutch, I went for those.

 

Hi Guys

XJS 'Cherry Blossom' Won't Start!

(1) Have Started her up a couple of times during Winter to keep her fresh and to make sure the Injectors don't get gummed up again!

(2) Went to Start her up today No Start.

(3) No Fuel coming through to the Fuel Rail

(4) Wired the Fuel Pump direct to the Battery (Just touched the leads on) Fuel comes through to the Fuel Rail.

(5) Put a Test Light on the Wires that I took off the Fuel Pump to do the 3 Second Test on the Fuel Pump Relay. (The Test Light didn't light)

(6) Conclusion: No Power going to the Fuel Pump, (Although the fuel pump works when Wired direct)

(7) Checked the Brown Spade Connectors on the Positive Battery Lead (All Look OK)

(8) I'm thinking a Fuel Pump Relay problem but that is just a guess.

Any ideas Guys

During the Winter She Started no problem at all.



No Fuel going into the Fuel Rail
Fuel Pump Not Running



Fuel Pump Runs When Wired Direct to Battery



Test Light connected to the Wires that I took off the Fuel Pump.
Test Light doesn't come on for 3 Seconds when Ignition is Turned On.
No Power going to the Fuel Pump.

 

Fuel pump relais sticking? Would be the next step...

 

Hi Daim

Any idea how I fix that?

 

Locate it first. Might just be some bad contacts...

 

Buy a new one OB. The fuel pump normal-looking square relay is the nearest one to you up on the RHS buttress behind the trim. It is the one with the black socket in this photo. But first read Grant's recently posted "My car won't start" which explains what to do to test it, and mentions various ECU-related earth faults that can affect it's working.
Greg

 

Hi Greg

Cheers!

I'll have a read, although I haven't touched anything since She started last time.

The only thing I've done is to put on a battery and wonder if I may have blown a fuse on the fusible Link, except I don't know where that fuse is.

 

Don't forget the inertia switch, this removes power from the main relay disabling the ECU, injectors and fuel pump.

The main relay is the other relay next to the pump relay it powers up the pump and ECU via pin 87. Check for 12v on pin 86 of pump relay and 86 of the main relay.

 

Hi Warrjon

The Inertia Switch was the first thing I checked and when I tried to push it down it felt solid with no springy movement.

So I am guessing that it is engaged in the 'lockdown' position, as I have never yet had to re-set one.

I'm also not sure how you go about checking the Relays.

Do I take the Relay out of its socket and then put the Volt Meter probe into the Socket where Pin 87 came out of and then do the same with the

Socket where Pin 86 came out of?

 

The first check for relay is whacking it real good.

 

Hi Jig Jag

Believe it or not that's the first thing I did!

 

Short Re-Cap:

XJS V12 Wouldn't Start.

No Power to the Fuel Pump, although the Fuel Pump did run when connected direct to a Battery (Just touched on quickly to test it)

Suspected a Fuel Pump Relay Failure and so I swapped the Fuel Pump Relay for another one off my Parts Car.

Still no dice, Relay not working!

So what could it be?

Made many Cups of Tea and had a think!

During the Winter I Started Her up a couple of times just to keep Her Fresh and also to hopefully try and prevent the Injectors from Sticking again!

Apart from that I didn't alter anything.

Or did I As I suddenly had a 'Light Bulb Moment!'

As one of the things I did do, was to remove the Redundant Immobilizer Horn, which was taking up valuable Space underneath the Bonnet/Hood.

No idea how that could make a difference and so I reconnected it just so that I could be sure and then once having done so I Tested the Relay again.

And 'This Time It Worked!' Doh! And so now I'm back in the Game!

So while I was about it decided to make a short Video of how to Test the Fuel Pump Relay.

In a 1990 XJS the Main Relay and the Fuel Pump Relay are located behind a Plastic Cover just behind the Wheel Arch in the Boot/Trunk on the Right Hand Side (UK Car)

The Red Relay is The Main Relay and The Black Relay is the Fuel Pump Relay.

You don't need to be able to see the Fuel Pump Relay in order to Test it, so you can leave the Plastic Cover in place unless you are planning to change one.



The Red Relay is the Main Relay and the Black Relay is the Fuel Pump Relay.
You can leave the Plastic Cover in place unless you are planning to change one.

In order to do 'The Three Second Test' to make sure that the Fuel Pump Relay and its Timer is Working.

All you need is a 12 volt Test Light or a DVM (Volt Meter)

(1) Remove the Two Wires from the Fuel Pump and Connect them to your Test Light, either way round.

(2) Put something in between the Wires, to make sure that they can't touch together.
For the purpose of the Video, I have left the Test Light in the Boot/Trunk.

But its best to have the Test Light, somewhere you can see it when you Turn on the Ignition.

(3) Keep an eye on the Test Light while you 'Turn on the ignition' to the position the Dash Warning Lights all come on. But DON'T START THE CAR!

(4) If the Fuel Pump Relay is Working, then the Test Light will come ON for about 3 Seconds and then it will go OFF again of its own accord.

You could repeat this a couple of times to be sure.

Some Timers might be a bit laggy, so the Test Light might be on for a little bit longer ie maybe 5 Seconds (But this is no big deal)

(5) Disconnect the Battery, Reconnect the Wires to the Fuel Pump, Reconnect the Battery and all should be OK.

Just make sure there is no Raw Fuel or any Petrol/Gas Fumes in the Boot/Trunk while you are doing the Test.

Thanks to Greg and Grant for their invaluable help.

 

So, the horn you removed was wired in series in the fuel pump circuit?


Merely curious, as those "immobilizer" circuits are not amongst my favorites.
help, little if any, trouble, oh yeah !!!


Carl

 

Wouldn't surprise me... My car has some kind of alarm system (no immobilizer) installed and that will fly out asap!

 

I'm lost. What is a redundant immobilizer horn?

edit: ah I see additional comments now. Yes those '80s alarms seem very effective. Even prevent taking it if you own the car.

 

Hi Carl@Daim@JigJag

When my Car wouldn't Start the First Time round after a 16 year layup, the immobilizer wouldn't answer to the Key Fob to disarm it, even though I put New Batteries in.

This immobilizer had an integrated wiring loom 'to die for' and so it seemed impossible to try and Start the Car, unless I had a bit of expert help.

When I dropped the Dashboard under tray, I saw so many wires that it looked like a great big bowl of Spaghetti and not being what you would call an Auto Electrician.

I just got the cutters out, in a sort of shall I cut the Red Wire or the Black Wire sort of way and just got lucky when I touched a couple of bare wires together which disarmed it!

Which sort of goes to show that a Car Thief could have stolen it in Seconds.

So seeing how I didn't really want it anymore, this Winter I decided to remove the Siren Horn, as all it did was bleep so quietly that no one could have heard it even if they had a deaf aid in.

So that turned out to be the reason why She didn't want to Start this time.

 

There is obviously wiring still in the car cutting power to most likely the main relay.

Let me know when you're ready and we'll have a go at tracing the wiring remotely.

 

Hi Warrjon

Now the Car is running again, I'm really scared to touch it and would rather leave well alone.

The Previous owner paid £450 to have this alarm immobilizer fitted and I accidentally managed to disarm it in just a few Seconds.

So I don't think that a Car Thief would have had a problem.

There are much better ways to disable an XJS for Free, so any potential Car Thief would also need to be a Jaguar Expert.

But there is something you could help me with if you wouldn't mind.

I've still got to wire the Electric Fans and have found a couple of 'Live Feeds' under the Bonnet/Hood.

These are always on Live Feeds, as long as the Battery is connected, which were originally put in there for the now redundant Car Alarm.

These wires don't look very thick but wonder if they would carry the current if the Fans were fitted with a Relay.

This is just a guess on my part, as I don't know anything about Auto Electrics.



Could I use these Always ON Live Feeds to Power my efans, if I fitted them with a Manual On/Off Switch?

Both those Spade Connectors are Always ON Live, if I could use those to Power the efans, would it be better to connect One Fan to One Spade Connector.

To reduce the load on each wire.

 

They are not heavy enough to carry the current for the distance you need to run them. A good rule of thumb with wire BIGGER is BETTER.

You need to use 15amp wire, I used 240V 15A extension cord wire, you could buy a small roll of wire from an Auto Parts store, could be listed as 26 x 0.3mm or 3.3mm.

A big heavy duty eyelet crimped on and then connect it to the power feed on the firewall.

Wiring to turn the relay on can be that size.

 

Hi Warrjon

Cheers!

I've got plenty of Heavy Duty Wire ideal for the Fans but I haven't got a Clue where to find the Power Feed on the Firewall.

Maybe someone has a Photo of where that is as I don't seem to be able to find it, on description alone.