Hello,
I've had my '89 XJ6 for about two years now. All the while, it's had this same issue. If starting and shutting down the car too often, if driving long periods of time, and especially when it's 100+ degrees outside - the car will just shut off. The only warning I get is a semi-high pitched, relatively loud, humming from the car. I can't pin-point where from, but the sound is the loudest towards the back. No shop has been able to tell me what was wrong with it...

Anyone have ideas...?

 

It appears that you are NEW, so welcome and enjoy.

Your XJ6 is commonly known as an XJ40, and hopefully one of our every reliable Mods will move this to the correct area to maximise responses.

Your car has a fuel pump, it is mounted "outside" the fuel tank, commonly known as an "external pump", and is somewhere near the rear suspension cradle, and the "humming " you are hearing is the pump failing, they do that, and as the load gets higher, such as a restricted filter, and just plain old age it gets louder. Hot fuel causes noise also.

Place the rear of the car up on ramps, or support it on STRONG safety stands, coz you are going to be under the car, run the engine, slide under the car and locate the fuel pump, it will be humming away there and be quite easy to locate.

Someone will come in and tell you "exactly" where it is, coz I dont know.

 

Ah, apologies on the mis-post. Perhaps that's why there wasn't an '89 option in the xj6 forum :P

So, the pump failing is what's causing the car to shut off while driving? Or is that just the answer to the humming?

If that's the case, how pricey can that be to fix?

 

It may be worth mentioning that when the car shuts off, it's not an immediate shut-off. It starts with a 'give' in the gas. If I pump the peddle a bit, I can squeeze out a little more drive-time to get to safety - until it shuts off. I can sometimes start it up again right after, but not always. After about 10 minutes of sitting, I can then drive it about another mile or two - and it'll quit again.

 

Hello, since you're an XJ40 Owner, I am moving your thread off to the proper forum

 

Hi Stubbyxj6 and welcome to the Forum.

Same symptoms with my Mom's Tempo last year. Towards the end, it began to squeal, too. I replaced the fuel pump and it cured the problem.

I find it hard to believe a shop couldn't tell you what the problem was. A squirt of starting fluid into the air box while you're on the road after it quits would tell you it's fuel related when the engine starts to run again.

A quick internet search reveals you're gonna pay about $135 for a new external pump.

Click here for a Google Search for XJ40 fuel pump

Good Luck.

 

YEP, the humming, pump failure, engine stopping are all related.

A new pump, AND fuel filter, another 20+ years of pleasure.

As said $200 tops for parts and quite do-able by any reasonably competent DIY person.

Old age is all down hill, for cars also.

 

Check first, whether it's just the fuel filter, with mine it was. Take it off and see if it's clogged.....Roger.

 

All good advice, and be thankful that you have the earlier external pump.

 

Thanks everyone. I got a new fuel pump and filter - but I haven't really stress-tested it due to old nerves. Driving it to school, though it still made the humming noise - kind of loudly. It's the Arizona Summer, so the fuel is bound to get hot. Is the sound nothing to worry about? Is there anything else that could have possibly made my car shut off?

 

So, to update... on the drive home it started to do the same dying routine: slowing down with less responsive gas output... Unlike before, I was able to pump the gas a few times and keep it going until I got home. I'm incredibly nervous now to drive to or from school, as I don't always have a clear exit to safety- and I haven't even had to deal with traffic yet...

What else can it be? What can I do? I'm a wreck right now :/

 

Unfortunately, with a problem like yours, you have to drive the car in the heat of the day to see if you fixed it.

When (if) the car breaks down, you're going to have to determine then and there if the problem is fuel or fire.

Does the humming noise still occur when the car is stopped, but engine is idling?

If it is indeed a fuel problem, you may be suffering from fuel vaporization since the pump is external.

I believe I read somewhere that Jaguar installed two fuel pumps to counter this vaporization problem. I'll have to look for my source.

I think an easier on the wallet solution is thermal insulation. I would at least give this a go.

• You may want to mount an aluminum flat plate or extruded U-shape around the fuel pump in order to shield the pump from the heat from the road. You may want to mount some high-R insulation between it and the pump it's shielding.
  
  You do NOT want to restrict or block fore and aft air flow across the pump, though.

• You may want to try wrapping insulation around the fuel lines, too.

• You may wish to keep as much gas as is possible in your tank. I realize you have an external pump, but more gas takes more heat in order to rise in temperature.

Sure, lots ... these come to mind:

• fuel pump relay contacts are worn and chewed. A bad relay will turn off the pump prematurely. Does your pump run after the engine dies?

• coil going bad ("when the car cuts out, if you pour some cold water over the coil and it restarts again and runs ok, chances are the coil is gone/going and breaking down" - XJ40-MARK )

• distributor rotor arm could be going. Replace cap, too.

• ignition amplifier beginning to go. The signal can be checked at the engine management ECU with probably a good multimeter set on AC voltage.

• loose electrical connections and/or bad grounds.

⚡

 

Yes. Before the new pump and filter, it was a singular hum. Now it's kinda... flickery? If that makes sense..

And how would one go about this? Consider me a novice.

I don't know if the engine is actually dying anymore. As I mentioned earlier, it started to go while I was driving today, but as I pumped the gas a couple times I was able to keep it running. Before, I could only do this enough to pull over somewhere safe. I was able to get five miles out of it today.


Thanks for bearing with me.

 

I agree with all advised as far as insulation etc is concerned.

Your reponse to the humming being "flakey" tends to point to the fuel pump relay having burnt contacts, which is a fairly common XJ40 issue. I am not sure where the relay is located on your model, but the ID charts on the various electrical covers should give you a good steer. Someone more up to it with the XJ40 will give you exact location I am sure.

My XJ-S went through a number of fuel pump relays in the early days, and I finally replaced it with a Bosch 40amp relay, and 10 years later it is still OK.

A second thought, I do that, stay with me a moment longer hahaha.

Maybe the fuel tank venting system is NOT working, and the tank is vacuuming and causing the pump to "starve" for supply fuel. A simple "novice" test is to remove the fuel filler cap (dont lose it), go for your normal drive and observe any changes, IF any. I may not be on the track in your case, but I have had it on numerous cars, Jaguar and others over all my years.

 

Stubbyxj6,

Grant and I both agree you should check out how good your fuel pump relay is.

It is possible the fuel tank venting system is NOT working, as he writes.

Since this has become an intermittent problem, my advice is:

• Check all vacuum hoses for leaks, cracks or breaks.

• Check fuel pressure regulator. Pull off vacuum hose to it and see if fuel squirts out of the thing. If so, replace it. While you're at it, check the fuel pressure for 38 psi at the rail.

• Follow what Haynes has written on troubleshooting in Chapter 4 (Fuel and exhaust systems) and Chapter 6 (Emissions and engine control systems). I would pay particular attention to the TPS and MAF.
  
  There is also some MAF troubleshooting here, Testing the XJ40's Air Flow meter

• Don't have a Haynes? Get one from eBaY or an internet book seller.

Happy Hunting! at least it's not snowing.
⚡

 

Something that came up with another member on the XJ6 area, who also has an XJ40 with fuel issues, and the Mods have NOT moved him here as yet.

He believes that after his pump and filter change he has Ethanol rust/scale in the tank. This is blocking the supply of fuel TO the pump. This may be the case with yours also. This blockage would definately "overload" the pump, which would increase the amperage draw and overload the relay, domino effect actually. Of course the engine will run like crap when this happens. Stop the car, the crud falls away from the outlet, you drive again, and it collects again, etc etc.

We dont have much Ethanol fuel down here, but we hear the horror issues people are having with steel tanks etc when using this fuel.

The only proper way of cleaning the tank is to remove it, and flush it thoroughly and ensure it is all clean.