Ahoy. My 93 Jag won't start. Engine turns but no catch. Had fuel pump changed 2 years ago. Is there a fuse or relay to check? Thank you.

 

Paul,

I've moved your question from General Tech Help to XJS forum. Members here with the same model will be able to help.

Graham

 

Hi Graham. I had the question there for about two weeks with no replies. Any tips on getting a reply? Only views.

 

Paul,

It's an absence of fuel or sparks. Pull a plug and then you'll know which one of the two is causing the problem.

Cheers

Paul

 

Is it a I6 or a V12?

 

6 cyl 4.0 liter. 5 speed manual. Is that I6 or A6? Not an A12.


I imagine I should crank the engine first, then remove the plug to see if there is gas on it? Or there another way to determine once I pull a plug?

 

Yes, just crank it then pull a plug. You'll smell if there's petrol. Then hold the plug and lead with insulated pliers agsinst the head or similar and crank again to see if there are sparks at the plug.

Good luck

Paul

 

OK. So I did that, smelled fuel. Then saw the spark and the car almost started. I shut it off cause didn't know if that was ok. I reinserted the plug and wire and then she wouldn't start. Hmm!?

 

Tried it again, disconnected that wire from distributor cap so don't have spark there while cranking, she didn't start this time. Spark and fuel smell present, no start. Ready to flatbed to shop. Or, what next? A friend loaned me a fuel pressure gauge, but I didn't find a port and another thread here said there is no port and have to rig it. True?

 

Hi Paul

It looks to me like you are almost there!

But you need to know 100% whether or not the Fuel Pump is working and just because you had it changed a Couple of years ago, is no guarantee it still

works now.

So what you really need to do is push her out of the Garage into the open Air and then with the ignition off and the Battery disconnected

(for the time being) pull the King Wire out of the Distro.

So the Engine cannot fire (thanks to 'Grant' for that tip)

Then disconnect the Main Fuel line under the Bonnet/Hood and push a piece of tubing over that pipe and then drape the pipe over the Front

Wing/Fender.

Where the end of this can go into a container (ie an old saucepan) Also the Tube does not have to be a perfect fit, almost any piece of Tube will do.

Then reconnect the Battery and Turn on the Ignition (Do NOT Try And Start The Engine) and while you are doing this, have a 'mate' watching to see if

any fuel comes out of the Tube.

The Pump only runs for 3 Seconds with every Key Actuation, so you may have to do this Half a dozen times before you see (or do not see!) any Fuel

coming out of the Pipe hanging over the Wing/Fender.

This little Test will let you know one way or the other, if the Fuel Pump is Working or Not.

If Yes! then the Fuel Pump and Relay will be both OK and then we can eliminate those two from the mix.

If No! then things get a little bit more complicated, as they thoughtfully put the Fuel Pump in the worst possible place.

Obviously while doing this Take Sensible Precautions and have a Fire Extinguisher Standing by just in case.

If you get Fuel coming through, disconnect the Battery then reconnect the Fuel Pipe and then we can go from there.

 

I'd rather not assume anything so... the King wire is the one in the center of the distributor cap?
Does disconnecting the fuel line and trying this process require me to bleed the fuel line later? Is that a simple process? I don't mind trying things, I am handy and inquisitive, but limited with tools, etc. I have a repair CD I bought online so that should show me the main fuel line location. I didn't find a port to attach the pressure tester as I said in the previous post.


Just turning the key from off to on without cranking is "Actuation" right?

 

Hi Paul

That is Correct, 'The King Lead' is in the center of the distributor cap and is disconnected for reasons of Safety as you don't want any Sparks with either

Fuel or Fuel Vapor anywhere around.

Disconnecting the Fuel Line, does not require you to Bleed the Fuel line later.

You don't need any CD's or Manuals, all you need is a couple of Spanners to disconnect the Fuel Line under the Bonnet/Hood.

Use Two Spanners to undo the Fuel Line: One to Hold the Fitting (To Prevent Straining it) and then use the other Spanner to undo it.

(Technical Name for this is Counter Torquing)

Then put a Tube over the Fuel Pipe and Hang the Pipe over the Front Wing/Fender and have a Tin or Similar to Catch the fuel in.

Because the Pump only Runs for about 3 Seconds at a Time, you may need to Turn the Ignition, On and Off about a half a dozen times (aka Key Activations)

A Key Actuation, is no more than Turning the Ignition ON and OFF (But don't turn the Engine over)

If any Fuel comes out of the Pipe, then you can stop and reconnect the Fuel Pipe and put it all back together, how it was before as it will self bleed.

Then at least you will know the Fuel Pump is Working which also means the Fuel Pump Relay is Working.

Then we can eliminate a duff Fuel Pump as being the cause of your No-Start problem.

So all you need would be a Couple of Spanners together with precautions just in case of a Fire, ie Fire Extinguisher/Fire Blanket.

But with a Common Sense approach, you shouldn't have any problems.

Don't do this in your Garage, do it outside in the Fresh Air, as Petrol Fumes can be dangerous, as I'm sure that you already know.

 

Got it. Thanks. Will do when I get home tonight. Hopefully there won't be any fireworks!

 

I apologize for falling off the planet here on this. I had some difficult family stuff came up and then I was not able to check on the fuel pump any further. I had spark and smell of fuel in the cylinders. I could not find the rail to check for fuel pressure. So I had the car flat bedded to a shop. This guy is a lot more reasonable than my past shop. He checked the pump and found it good. I had it changed only22 months ago. He suggested a possible short and found one. He did also find a floating short with the crank shaft timing relay. Hoping to get the car back this weekend. I will send another update with all the details. I just couldn't go any further on this. I've been missing driving the car in this beautiful Autumn we're having. Thanks.

 

In addition my driveway slopes down very fast from the garage, so I wasn't able to roll her out since I'd never be able to get her back in the garage. I chickened out on trying the fuel pump check any further while she was layed up in the garage. No fireworks! I like that car!