XJ XJ8 / XJR ( X308 ) 1997 - 2003

2000 XJ8 turns over but won’t start

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Old Mar 27, 2024 | 11:53 AM
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Default 2000 XJ8 turns over but won’t start

It just won’t seem to catch but it has spark and as far as I’m concerned fuel, if I hold it for a while it really starts to sap the battery too.
 
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Old Mar 28, 2024 | 07:39 AM
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Did you start it & turn off within a couple of mins previously? They are well known for flooding if you do as they run mega rich initially to warm the cats up. The general theory to avoid it again is don't turn it off till the idle has dropped to it's normal 600rpm.
The normal fix is to floor it, & hold the pedal down then spin it on the starter for sodding ages. Stopping every 30secs or so to let the starter cool. I did it once with my previous 4.0 Sov, must have taken 7-8 goes before it even spluttered.

People will suggest taking the plugs out & a few drops of oil in each hole as the excess fuel can cause bore wash so there's no compression till it clears but I've never needed to do that.
 
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Old Mar 28, 2024 | 08:01 AM
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I have had to "kick" an engine off using a small shot of starting fluid.
As posted above it could be bore wash and as soon as you can get the engine started the heat and combustion forces will fix it.

I won't bring up Nikasil but with a 2000 model I think it's still a possibility? Any idea?
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Old Mar 28, 2024 | 08:16 AM
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Originally Posted by clubairth1

I won't bring up Nikasil but with a 2000 model I think it's still a possibility? Any idea?
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I believe high sulphur fuels were phased out years ago so that's not an issue now.
 
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Old Mar 28, 2024 | 11:48 AM
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I tried to floor it while starting and did that for around 15 times with no sputters. So put some starter in now and try it out or look elsewhere?
 
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Old Mar 28, 2024 | 12:33 PM
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Whats the recent history on this car? Is it just a regualr working car, ran yesterday or last week sort of thing and today it won't start or has it been in storage and this is just getting out for the spring or something?

What makes you say as far as you're concerned that its getting fuel. What have you done to test that?

How does it sound when it cranks? Like is it the normal starting sound or does it seem like its cranking fast or anything?

Have you checked the computer for codes? There may be info in there that will help.
 
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Old Mar 28, 2024 | 05:10 PM
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Yeah, Mayhem is spot on. We could use a little history and how you
determined it has fuel delivery. (as far as you are concerned)
 
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Old Mar 28, 2024 | 06:49 PM
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It was getting fuel fine until now, it was running before and now it’s just quit, I had fixed it like a month back and hadn’t taken it out until 3 days ago where I ran it pretty good, just tried to start it again yesterday and had the crank but won’t start.
 
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Old Mar 28, 2024 | 06:51 PM
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Originally Posted by mayhem
Whats the recent history on this car? Is it just a regualr working car, ran yesterday or last week sort of thing and today it won't start or has it been in storage and this is just getting out for the spring or something?

What makes you say as far as you're concerned that its getting fuel. What have you done to test that?

How does it sound when it cranks? Like is it the normal starting sound or does it seem like its cranking fast or anything?

Have you checked the computer for codes? There may be info in there that will help.
all codes I had I’ve fixed, it still has a drive cycle code that arrived after I replaced the battery but I don’t think that has anything to do with it, the cranking sounds fine it just won’t start.
 
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Old Mar 28, 2024 | 07:59 PM
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Have you checked the Schreader valve on the fuel rail for pressure?
 
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Old Mar 30, 2024 | 10:46 AM
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I bought some stater fluid and it responds to it pretty immediately but it gets dragged back into cranking after a second. I haven’t checked the shrader valve yet either.
 
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Old Mar 30, 2024 | 11:33 AM
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Sounds like you're not getting fuel to me. Thats where I'd be looking if it were my car. Jump the fuel pump relay with the car off to see if you hear the pump run, pop the schrader valve at the fuel rail to see if you have pressure at the engine. Maybe a bad relay or fuse, failed pump, clogged filter or something like that.
 
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Old Mar 30, 2024 | 12:42 PM
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Yes...the no fuel from the fuel pump situation. It's not a terrible job,
but it does consume some time.
 
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Old Mar 30, 2024 | 03:31 PM
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What does this fuel pump project entail?
 
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Old Mar 30, 2024 | 05:39 PM
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The hardest part is disconnecting the fuel lines from under the tank *prior to* sliding the tank back. If you think you feel sporty enough to pull the tank back before you remove the fuel lines from underneath, you’ll crush both of them then the real fun starts. Also you need lots of patience, WD40 and some small picks/flathead screwdriver (snub nose pliers for the clamps) to *carefully* remove the hoses from the evap flange on top of the tank. If you have more than a quarter tank of fuel, you’ll need to siphon the fuel out into another container.
 
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Old Oct 15, 2024 | 10:05 AM
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Originally Posted by Josh Nichol
It just won’t seem to catch but it has spark and as far as I’m concerned fuel, if I hold it for a while it really starts to sap the battery too.
i’m kind of having the same problem with my 2000 XJ8. I was cleaning the map sensor on the air filter box and then put it back on and then try to start it and it tries to start the first time you turn the key then dies and then then after that, it just cranks.
All I did was take off that sensor clean it with a Q-tip and put it back on. It ran good before that and would start right up every time since I’ve owned this thing for all five years. i’ve checked all the fuses. I believe I’ve checked all the relays. If I let it sit overnight and try to start it, it cranks and starts for a second and then dies and then it just cranks. I can’t believe it’s the fuel pump all of a sudden like that. How do you bypass the fuel pump relay because maybe I’m not getting power to it I’m just not sure what terminals to check on the plug-in. very frustrating
 
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Old Feb 11, 2025 | 12:08 PM
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Did you guys get this fixed I’m having same problem. JaH has been garaged for nine years, ran fine as it was put away neatly, replaced the battery checked that shraider valve or whatever got no fuel just a psst of air now nothing put ten liters of fresh fuel and tried to crank it on full throttle, jumped the relay and as far as I can tell I can’t hear it come on! Did anyone get there’s sorted? I told my dad fuel pump replacement but he says well if it was put away five it might not be it!? Any thoughts fellow jag fans!?
 
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Old Feb 11, 2025 | 06:31 PM
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The jumpering of the # 1 fuel pump relay from the hot at all times socket 3 to 5 to the pump is directly powering the pump

The battery voltage may not have enough umf to break loose a stuck pump

With a battery charger as you increase the amp setting the battery charger can have more umf with the 50 amp charger start setting the highest voltage

You would have to use medium gauge jumper wire with blade type connector ends for best results , A common auto parts store can make one for you with a toy box of tools and wire behind the counter

A failing pump motor will arc and burn the on the fuel pump motor connector sockets so check for damage , also change the fuel pump relay as the power contacts inside will also arc and burn limiting the current to properly run the pump

The fuel pump will run for 3 seconds only on initial key rotation , it will come on for the rest of your drive by the CKPS seeing engine rotation , safety design

There is a secret fuse ( at the rear seats as point 29 double hash circle ) and a relay must close ( rear seat also ) for the fuel pump relay to have " control , closing " power to close the power contacts , different big amp fuse # 7 in trunk

# 16 / 10 amp left heelboard fuse box , the king relay in the corner of this fuse box must click closed on key rotation , you can test this by yourself with key in run and rock the relay in and out of the socket and feel click

Notice the big fuse # 7 trunk is between the relay and the pump motor electrically so can be misleading

double click on images for cleaner view






 

Last edited by Parker 7; Feb 11, 2025 at 07:46 PM.
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Old Feb 12, 2025 | 11:31 AM
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So I assume the Schrader valve has been checked for pressure there.
If no pressure there, the most likely culprit is the fuel pump. That is not
to say there could be other issues, but in my experience, checking to see
if the pump is actually pumping is the first thing to check.
 
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Old Feb 12, 2025 | 12:26 PM
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Originally Posted by RandyS
So I assume the Schrader valve has been checked for pressure there.
If no pressure there, the most likely culprit is the fuel pump. That is not
to say there could be other issues, but in my experience, checking to see
if the pump is actually pumping is the first thing to check.

the pump is not pumping, I jumped the relay and still nothing. I have found a battery charger will I hook it up and try and give the battery a boost, it’s a brand new battery!? Other than that I don’t have the skill to replace the fuel pump, I’ve no ramp and I’d be worried about cutting a hole in the parcel shelf …
 
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