Car barely runs - starts rough and then stalls - bad gas or bad fuel pump? Now car will not start at all. Please help, we are stranded 70 miles from home on a Sunday afternoon - is there a fuse we could check or other suggestion? 1993 xjs manual transmission.

 

I see your car is an XJS so I asked the Moderators to move your post there. You should be able to get more specialized help there.
Until then, yes you can check fuel pumps, filters. Good chance that if it was running well and then fouled up, it is fuel related.

The thing about electrical problems and blown fuses, etc., is when they come on then things don't just tease around, they go stone dead.

So, did you get gas recently? Go just a very few miles and then have problems? I had that happen once. Chances are if you went several miles, 10, or 20 or so, then had problems, it was probably not the quality of the fuel. I am thinking more like pump or filter.

 

I've moved your post to the XJS section, hopefully someone can help you get moving again soon.

 

Did you get home ok in the end?

 

I did get home. A nice person gave me a ride. We were at the same event. There are kuind people out there. good to see.

 

I will start with fuel pump rely and see if it runs when I turn the key and move from there. Is it realy that hard to get the fuel pump?

 

Not realy much to go on but I'll have a shot in the dark, you said it fires up but runs rough than dies. OK this points to fuel problem, open the boot and switch on the key do you here the pump working? makes like a purring sound and is located just to the right lower of the spare tyre.If no sound than chase the wires back look at fuses connections especially earth's and bad contacts, one way to check wiring is hot wire the pump straight to the battery. If yes (Its working) then I would replace your fuel filter, located behind your spare tyre, see how that goes. If still no start go I would get a friend to help and disconnect the return fuel line from your fuel injector rail back to the tank, place the line so it points into a bottle and turn the key, not as far as to engage the starter but so all is on, if fuel comes pouring out its not a basic fuel problem. If no fuel then look for another fuel pump or check the fuel regulator.
Ok if fuel comes poring out, look at the coil? distributor cap if cracked, rotor, if all Ok start chasing all the wires back looking for burouts or shorts or loose connections.
That should be enough to get you started, if still no you may have to dive in a little deeper. Oh before you go to far check all your fuse's but I'm putting my money on either fuel starvation or a cracked dizzy cap.
Good Luck!

 

this was very helpful.

 

It could be a number of things. I would start with the simplest.

1. Check your battery and connections. Our Jags are extremely sensitive to low battery voltage. Also is your check engine light on? If so what is the code?

2. It is hard to hear the fuel pump running as it only runs for a second or two if the engine is not running/cranking. Check the fuel pump fuse, if that is ok, pull the fuel pump relay and check that you have 12v present. Then using a short bit of wire, jump the relay. You should hear the pump running. If not then you may have a failed pump. It is fairly easy to change, you do not have to remove the tank.

3. Check spark as Katoh has mentioned above. I would also pull the plugs and look at their condition for clues.

4. If you have spark and can hear the pump whirring, check the fuel pressure at the rail. You should have around 32PSI at idle rising to 44PSI at WOT. It's a bit of a pain to check the pressure as you have to make up a fitting for the connection or cut the hose and 'tee' in a gauge. I don't like doing that so cobbled together a gauge like so.



5. If you don't have good pressure you may have a blocked fuel filter (when was the last time it was changed?) or defective fuel pressure regulator.

6. After that it becomes a chase. It could be defective crank sensor or bad earth or any of a myriad of other ailments.

 

This is very helpful. I heard you did have to drop the tank for the fuel pump. Maybe not the 93 xjs 4.0 coupe?


Also, What is bad earth I guess ground. dah and where is the fule pump fuse on a 93?


thanks


rich

 

Crikey I did not have my coffee this morning!!

There is no fuse for the fuel pump.

Yes you do have to remove the tank to change the pump, or at least move it forward enough to see what your doing and get your hand inside. Somehow I was thinking about the sender?

Sorry about that

 

Just a thought and a question for those who know more than I do. Would a faulty Inertia Cutout switch cause a similar problem?

Bill

 

Bill,

No if the inertia switch was defective or had been activated the car would not be able to start at all. The OP says his car starts but is rough and then stalls.

 

Allan,

Thank you. I had done a search here regarding the Inertia switch and the responses seemed inconclusive. Some say the engine still cranks and some say otherwise. I'm quite happy to go with your answer. If it could have been the switch, then it might have been an easy fix.

Bill

 

The inertia switch only cuts the fuel pump (in case you have a prang), the engine should still crank.

 

Bill,

I said the car would not be able to start if the inertia switch was defective or activated. The motor will still turn over but won't catch as the fuel would be cut-off. It is basically there to avoid a catastrophic explosion if the car is in a wreck and still running/pumping fuel that may be leaking out.

 

I'm definitely no expert! and maybe your model car is very different from mine being an 83, but my fuel pump is under the battery and easy to get to, you can hear it working a mile off. Sorry your model might be different and I didn't mean to put you on bump-steer.
One other place you could check and easiest way to check it is just buy a new one and replace, it is the coil, won't be the first time nor the last I've seen a coil gone bad.
Good Luck Again.

 

Unfortunately the fuel pump arrangement in the later 6 cyl cars is quite different. The pump is mounted inside the tank which sits behind the spare wheel and boot lining.

 

Learn something new every day, Cheers for the info.

 

my 93 you can turn the key to the on position without starting and wait and the trip computer will then display any fault codes it will say FF followed by a 2 digit number. if anything comes up you can punch jaguar aj16 fault code ffxx into Google and come up with what that fault code means.

a few things come to mind such as maybe the ecu temp sender. air flow meter, fuel pump. if you are able to retreave the code it might lead you to some direction of where to focus.

the fuel pump on my xjs is quite loud. with the radio and fan off i can hear it over the engine running and and very pronounced buzzing noise when you turn the key to the on position it should buzz for a few seconds and then shut off then it should come back on when you start the car.