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XJ40 1986 - 1994

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Old 04-27-2008, 05:29 PM
 
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Default 1994 jaguar 4.0 hard start help please

hey all new to the site just a few questions took car to the dealer they said
$2000.00 to do a fuel pump ouch so i took home and did it my self $200 in
parts walbro pump any ways got it all done same problem hard start cold
will crank and crank but finally will start after a wile from cycling the key
then runs perfect 1994 vanden plas 4.0 also where is the odb connector
so i can scan it thinking its a sensor problem i have a odb 2 scan tool but
i think 94 is to old thanx for the help....... jeff
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Old 04-27-2008, 09:27 PM
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Default RE: 1994 jaguar 4.0 hard start help please

No OBD socket on a '94. The Jaguar dealer probably quoted you for the complete fuel pump module, not just the pump: the module (pump housing) has supply and return one-way check valves to maintain residual pressure. Your fuel pressure may be bleeding off when you shut the engine off. Best to check with a fuel pressure gauge to see if cycling the key is indeed what is allowing the engine to start.
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Old 04-28-2008, 07:50 PM
 
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Default RE: 1994 jaguar 4.0 hard start help please

isnt the fuel pump on the rear axle.. i believe there is a check valve you buy that screws to the fuel pump.. to maintain pressure.
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Old 04-29-2008, 12:14 PM
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Default RE: 1994 jaguar 4.0 hard start help please

Here's the catch with the Walbro pumps. If the squared off o-ring in the bottom of the white plastic fuel pump canister has any nick, tear, gouge, etc. the pump will not pick up fuel. See if you have fuel pressure first. That way you know whether or not you are wasting your time pulling the pump again. If the o-ring is shoot, so are you.

The o-ring does not come separately. My purchasing department has cased all over the US and Europe and cannot find it. Jaguar is selling you the complete housing with new o-ring. We carry the complete housing for $665.50. (Yikes!)
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Old 04-29-2008, 12:17 PM
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Default RE: 1994 jaguar 4.0 hard start help please

Just FYI. We carry the Walbro pump for $132.71 and I beg people not to buy it for exactly this reason. If the o-ring is torn, Walbro will not warranty the pump since it works just fine.
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Old 04-29-2008, 10:12 PM
 
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Default RE: 1994 jaguar 4.0 hard start help please

thank you ken for that info yes the ruber fitting ring on the bottom of the pump had small tear but from looking at that i thought it was for centering or vibration cause the pick up screen was on bottem of that... i need figure out a way to put on a pressure gauge since there is no shradder valve will post more info soon when it starts and runs its perfect dosent miss a beat does not run out of fuel under full throttle thank ...jeffrey
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Old 05-19-2008, 05:20 PM
 
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Default RE: 1994 jaguar 4.0 hard start help please

heres the deal loosened fuel line to check pressure and flow no fuel to make
it run every time you need to activate the fuel pump relay my question is
what activates the relay blue wire w red stripe when it runs it doesnt miss a
beat or after it runs you can pretty mutch start it evey time thank you ..jeff
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Old 05-19-2008, 08:17 PM
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Default RE: 1994 jaguar 4.0 hard start help please

On a 1994 XJ6, there are four terminals on the pump relay socket. Blue/ red wire is the feed from the relay to the fuel pump: if that wire is hot, the pump is running. Brown/ yellow is the power feed, it originates at the right forward fuse box, C6, 25 amp. If you jump across Brown/ yellow to Blue/ red, the pump will run, key off.

The black wire in the fuel pump relay socket is a ground, that connects to a ground point below the right rear bulb failure module. The fourth wire to the fuel pump relay socket is Blue/ purple: that's the ingition feed that closes the relay and enables power to the pump. Power to this wire is supplied via the oxygen sensor heater relay. This relay is mounted on the right bulkhead relay panel, under the hood and back at the firewall. There are six relays in this location, they were all originally blue but should be uprgaded to the black (sealed) relay. The oxygen sensor relay is plugged into the yellow relay socket.

This relay socket has four wires: Blue/ purple is the feed out to the pump relay. The brown/ pink wire is a constant power feed from the right fusebox, C4, 10 amps. Pink/ brown to the O2 heater relay socket goes back to the engine control module, that would be a ground with the key on. The fourth wire is white/ brown, that's a power feed from the EMS main relay which will be hot with the key on.

The six relays on the bulkhead are notorius for corrosion problems. Try pulling the relay from the red socket (air pump clutch relay) and swapping it with the O2 heater relay (yellow socket). I'd suspect your problem is here, so long as your pump relay is working.

I agree with you, the O ringat the base of the pump is designed to provide a seal to the pickupfilter at the bottom of the fuel pump module. All of this is submerged, unless the tank is virtually empty. The worst that can happen is that fuel will be drawn directly through the pump screen, instead of through the pickup filter. If you have enough crud in your fuel tank to damage the pump this way, then you didn't bother to make sure the tank was clean and don't deserve to blame the pump's manufacturer.

To test fuel pressure, you have to make up your own rig and "T" it in at the inlet fitting on the fuel rail. That means scrounging up fittings to join both the fuel rail and the fuel feed pipe: mine are from a LH fuel pressure regulator hose from an XJS V12,cut in half and connected to the "T".
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Old 05-23-2008, 10:02 PM
 
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Default RE: 1994 jaguar 4.0 hard start help please

jagtechohio you hit it on the spot i had a new relay so i swapped it like
you said works perfect shoud i replace the 02 sensor and or whitch one
i owe you many thank yous for fixing my problem thanx again..... jeffrey
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Old 05-23-2008, 10:48 PM
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Default RE: 1994 jaguar 4.0 hard start help please

I'm glad you got it figured out, thank you very much for reporting back with the cause of the problem. So many times people neglect to do this, and the result is that nobody else learns anything. Now I know that it happens more than the one time I got stumped on this problem.

There isn't anything else wrong that caused the problem, it wasn't caused by the oxygen sensor. The bulkhead relays are all subject to corrosion and failure: that's why they were superceded with the waterproof black relays. You may want to replace the others, or at least make sure they are not corroded. The ECM relay will shut the car down, the A/C clutch relay is often the cause of A/C faults, and the transmission ECU fails and turns the trans warning light on and puts the trans into limp home mode. Those are the other relays adjacent to the Oxygen sensor heater relay an all '93 and '94 XJ40.
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Old 05-27-2008, 04:37 PM
 
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Default RE: 1994 jaguar 4.0 hard start help please

thank you once again ......jeff
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Old 02-07-2013, 12:47 AM
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Default 1994 Vanden Plas

Help.. Does someone know how to change the fuel filter?
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Old 02-07-2013, 09:36 AM
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Welcome,

How to change it, or where it's located?

It's located on the driver's side, under the car, and if I recall correctly, in line with the pillar separating the front/rear door. You'll need to put the car up on the drivers side at the least to r/r the filter. I don't recall the size wrench you'll need, but you will need two.

You will need to de-pressurize the fuel delivery system. Remove the fuel pump relay located in your trunk (boot), right rear corner, above the Bulb Failure Module. Then crank the engine until your confident there is no pressure (won't start). You can now r/r the filter. Slowly back out the bolts, you will still have some pressure in the lines, have some towels handy. When your done replacing, put the relay back in and turn the ignition key to the ON position, (con't start the engine) to energize the relay and pressurize the system. Check for leaks at the filter before you take the car down or start it.

Also, do yourself a favor and purchase only OEM filter with proper fittings. If yo need a source, post up or PM me or someone else.


Quote:
Originally Posted by Sheilalussier View Post
Help.. Does someone know how to change the fuel filter?
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Last edited by Rob Evenson; 02-07-2013 at 10:07 AM.
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Old 02-07-2013, 09:36 AM
 
 
 
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1994, difficult, firewall, fuel, hard, jaguar, location, module, perfect, pump, relays, runs, start, started, starting, v12, xjs



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