1969 Jaguar XJ6 Won’t Start

[DaimlerJ]

I’ve recently bought a 1969 Jaguar XJ6, but it’s been a love-hate relationship so far.

It has been converted to fuel injection.

Always a brilliant starter until it landed on my drive. It wouldn’t start when I first got it, turned out the fuel pump had become disconnected from the relay. Reconnected the cable and it fired up instantly - great!

That was about 2 weeks ago. Today I put in about 15 litres of fuel from a petrol can, went to start it and it quickly fired up, went to about 2k revs and then spluttered and died. I started it again but it died right away again. Now it just cranks and won’t start.

I don’t know why it suddenly won’t start after sitting for a couple of weeks. Battery is brand new. The only thing I notice is the fuel pump is significantly louder than normal and seems to prime for longer. I put in a good amount of fuel today as it’s been run on empty for short journeys all the time for the past few months. A fuel pressure gauge says it goes up to 60 psi on priming, so it seems the fuel pump is doing something.

I’m wondering if it’s another fuelling issue, possibly a clogged filter (hasn’t been serviced for a while I imagine), or if it could be something else? Any ideas much appreciated, thanks!

[GreenV8S]

DaimlerJ said:

Today I put in about 15 litres of fuel from a petrol can

Why?

[DaimlerJ]

GreenV8S said:

DaimlerJ said:

Today I put in about 15 litres of fuel from a petrol can

Why?

As I said, it’s been run near empty for quite a while every time it’s been used, so I wanted to start it with a decent amount in for the benefit of the fuel pump.

I should add, it’s not yet UK registered so can’t go anywhere, but is having an inspection soon so I wanted it in a good drivable condition with some fuel in it.

[Auntieroll]

Has it got twin tanks ?
Could be feeding from an empty one .

[DaimlerJ]

Auntieroll said:

Has it got twin tanks ?
Could be feeding from an empty one .

It has. That was my initial thought so I put a few litres in the other tank (knowing both were basically totally empty before today), but it made no difference.

One thing I forgot to say is when the fuel pump makes a loud noise (and it's very loud, not like normal where it's very quiet), it comes up at 60 psi fuel pressure measuring from the FPR. As soon as the noise stops, it drops right down to 0 psi. I haven't looked at fuel pressure when priming before so I don't know what's normal for this car and how long it should hold, but that seems possibly suspect to me?

[Auntieroll]

The old XJs used to have a LH and RH pump / tank selector switch on the dash ?

[DaimlerJ]

Auntieroll said:

The old XJs used to have a LH and RH pump / tank selector switch on the dash ?

It does, I've tried it set to both tanks and it makes no difference sadly.

So far this car has been a lot of head scratching! Add to that, the driver's door handle conveniently decided to break today.... For some reason, I still love it!

[Wacky Racer]

DaimlerJ said:

It does, I've tried it set to both tanks and it makes no difference sadly.

So far this car has been a lot of head scratching! Add to that, the driver's door handle conveniently decided to break today.... For some reason, I still love it!

My Dad had one of the first 4.2 XJ6's in the country in January 1969.

People crowded around it everywhere he parked up looking through the windows. Notes were left on the windscreen offering him 20% over list.

Beautiful car.

[DaimlerJ]

Wacky Racer said:

DaimlerJ said:

It does, I've tried it set to both tanks and it makes no difference sadly.

So far this car has been a lot of head scratching! Add to that, the driver's door handle conveniently decided to break today.... For some reason, I still love it!

My Dad had one of the first 4.2 XJ6's in the country in January 1969.

People crowded around it everywhere he parked up looking through the windows. Notes were left on the windscreen offering him 20% over list.

Beautiful car.

That’s a very early one - to have one of the first of such a groundbreaking car must’ve been an experience!

Unfortunately (or fortunately for them), they’re so beautiful that you can’t help but forgive them every time they go wrong.

[Wacky Racer]

DaimlerJ said:

Wacky Racer said:

DaimlerJ said:

It does, I've tried it set to both tanks and it makes no difference sadly.

So far this car has been a lot of head scratching! Add to that, the driver's door handle conveniently decided to break today.... For some reason, I still love it!

My Dad had one of the first 4.2 XJ6's in the country in January 1969.

People crowded around it everywhere he parked up looking through the windows. Notes were left on the windscreen offering him 20% over list.

Beautiful car.

That’s a very early one - to have one of the first of such a groundbreaking car must’ve been an experience!

Unfortunately (or fortunately for them), they’re so beautiful that you can’t help but forgive them every time they go wrong.

Yes, he even managed to get 7.5% discount on it, the salesman got a rollocking from his bosses when they found out, as there was an eighteen month waiting list a few weeks later. Pale Blue. KEN 142G.

He sold it in 1971 for virtually what he paid for it and bought a 4.2 Daimler Sovereign in Maroon, which was the same car but a bit plusher.

He used to let me drive them both often, which was a bit brave (daft) of him as I was seventeen and had only just passed my test

Good luck getting yours sorted....

[imagineifyeswill]

XJs used to be known for the drains round the tak fillers getting blocked and filling the tanks with water, I would pull the supply pipe of the injection and make sure your not pumping water.

[Peter3442]

Is it converted to a complete series 3 XJ injection system or something else?

The series 3 has one fuel pump and a set of 3 valves that control which tank fuel comes from and where it returns to. If neglected, the valves can stick and cause problems. The drains block and the tanks fill with water as mentioned by Imagine above. Also empty tanks can corrode inside and the rust particles block the fuel filter and the injectors.

Series XJs are the most wonderful cars, a unique combination of quiet comfort and performance, but they need to be used regularly and treated kindly. Keep the tanks full and take them out for a good drive at least once in two weeks. And keep them in a garage, not outside.

[DaimlerJ]

Apologies for not keeping up with this thread, I’ve taken a bit of a break from this issue this week. The car was inspected by DVLA this week, who are very happy with it and I should have a registration number soon at least!

Me and a friend done some checks. Starts up very easily with carb cleaner sprayed in the intake, so it’s definitely a fuelling issue.

There’s fuel coming out of the pump, and fuel getting to the rail. He remarked the pressure felt a bit weak though, but the fuel also smelt very faint, almost like it’s diluted (by water perhaps?)

My concern is still the fuel pump doesn’t prime properly, only for a fraction of a second. The fuel pressure gauge still shows 0 psi after “priming” too.

I haven’t checked the fuel filler area for water, so will do that. At the moment, it’s been kept outside uncovered due to this DVLA inspection, but now that’s done I can cover it.

The fuel injection system is called Dicktator. It seems to be a popular system in South Africa. I have only one fuel pump, wired up to the left tank and placed in the boot, along with the inline filter. The right tank is connected to the left tank, so I imagine acts as an “overflow” tank. It seems the tank switch makes no difference to operation, as fuel will only effectively be supplied via the left tank.

[imagineifyeswill]

Is this a mechanical or electronic injection system. You say the fuel pressure whilst prming is 60lbs then drops to zero, you need a constant pressure of around 60lbs at the injectors for mechanical injectors to open.

[imagineifyeswill]

Is this a mechanical or electronic injection system. You say the fuel pressure whilst priming is 60lbs then drops to zero, you need a constant pressure of around 60lbs at the injectors for mechanical injectors to open.

It would be worth checking your getting a good earth at the fuel pump, a poor earth will cause the pump to work at low pressure. You also say the pump has got noisy, this could be a bad pump or it could be the pump struggling due to a blockage of dirt in either the filter or pump quite possibly a blocked gauze on the pick up pipe.

[DaimlerJ]

It’s an electric fuel injection system.

The big problem is fuel pressure is on 0 psi when priming. After cranking for a long time, it shoots up to 60 psi, but then falls away to 0 again in under 2 seconds when I stop cranking. While it’s on 60 psi, there’s a loud humming sound in the engine bay, sounds like it’s in the area of the fuel pressure regulator.

The fuel pump got very noisy the day this all started. Now it just makes a brief loud “priming” noise for less than a second on start up, and the fuel pump visibly jolts when it does this.

I’ve got a replacement filter here and have ordered a replacement fuel pump. I’m just going to bite the bullet and change them to see if it makes a difference. I will check the earth connector when I do this too.

[RobXjcoupe]

I would go with water in the tank. My own xj6 suffered exactly the same symptoms. Fuel that had no smell of petrol lol. I drained the tank and used that fuel to light a bonfire, well it didn’t it just made everything wet! Also I found once removing the tanks that the in tank fuel filter was also clogged with rust particals. So initially good fuel pressure then gradually reducing and starving the carbs. So that with water in the petrol it was a wonder it fired at all

[DaimlerJ]

RobXjcoupe said:

I would go with water in the tank. My own xj6 suffered exactly the same symptoms. Fuel that had no smell of petrol lol. I drained the tank and used that fuel to light a bonfire, well it didn’t it just made everything wet! Also I found once removing the tanks that the in tank fuel filter was also clogged with rust particals. So initially good fuel pressure then gradually reducing and starving the carbs. So that with water in the petrol it was a wonder it fired at all

I’ve ordered some tank drain plug washers, and will drain both tanks and fill with fresh fuel as I’ve been advised when they arrive (assuming new fuel pump doesn’t fix it). The tanks are incredibly easy to drain thankfully, just a bolt on the bottom of the car with nothing covering it. I know the washers will fall apart if I don’t order replacements though, as is Sod’s Law!

[DaimlerJ]

OK - I THINK I’VE FOUND THE PROBLEM!!
And a couple of you here were definitely right.

My left fuel tank cover has always been a bit stiff and doesn’t shut well. When the car was covered, I suppose it wasn’t a problem, but as it’s been left uncovered in the rain, water must’ve got in (and a LOT of it).

The tank is actually overflowing with what is about 10 litres petrol and 35 litres of water.....

I’ll drain that straight away. What I drain 45 litres into, I’ve got no idea. The drain hole isn’t blocked as that area is clear of water, I think I’ll need a new flap cover to fix the leak.

Could that water going through the system have damaged anything else I need to replace now? New fuel filter I suppose is a given?

[RobXjcoupe]

You can buy new the rubber seals on the petrol cap lids.
The thing I found on my car was the original fuel feed pipe between the tanks and hiding under the insulation on top of the rear axle had corroded through. It’s a rear axle off job to get to it unfortunately