My wonderful 2000 XJ8 won't start every time. I've been stuck out in it more times than I can tell you. We replaced the transponder yesterday; just tried to start it and it won't start.

We've checked the power studs under the hood and near the megafuse, I've tried both keys, I've read all I can read. Last Friday it cost me $362 for a mechanic just to tell me he doesn't know what's wrong w/ it, if in fact he checked it at all or just played computer games. The Jag dealership said 90% of the time it's the transponder and that should take care of it. It didn't.

We have to unplug the battery, wait 10 minutes or so, hook it back up, wait another 10 minutes or so and pray that it starts. I was stuck in a parking lot the other day for over 3 hours. In reading the owners manual it stressed never to use a voltage meter on that car. Is it possible that the first idiot who worked on it used a voltage meter and did some permanent damage?

Can anyone please help me?? This is the second thread I've posted on this problem. I think we have done all that we replied in the last post and I gave printouts of it to three different mechanics. I'm worn out from this and I want my car to work. I've waited a long time for that little beauty out there.

Thank you.

 

Monkamah, sorry to read of your continued misfortune with your Jag.
Lets try again to nail this problem down. When you say it won't start every time. Does this always happen when the motor is hot, or has it also happened on the first start of the day? Has the starter been taken out of the car and tested? It sounds like your starter armature may have a dead spot in it, this can cause this exact problem. If this is the problem it would be just as likely to happen on a cold start as a hot start.
Also the starter solenoid may be the issue, if it always starts cold, but sometimes gives problems when hot. Worn starter brushes may be the issue, although less likely. Is a hot start on a hot day more likely to fail, than a hot start on a cool evening or morning? Don't despair you will find the problem.

 

Hi Monk,

You need to look around in the box for a sharper pencil...the people who are looking at your car are a bit dull.

Right side of engine bay, false bulkhead, pull off the rubber boot. This is the battery cable stud that you have been warned about. If you follow that cable back about a foot, there is a grey wiring connector with a single wire. That's the power feed to the starter solenoid.

So you turn the ignition key to position two, and hook a jumper wire from the battery cable stud to the solenoid feed wire and your engine cranks and starts. That eliminates everything in the starter circuit before the solenoid and starter, and will probably get you going every time the intermittant failure occurs. If you can't crank the car this way, then you will have to repair/ replace the starter (rare).

That won't be necessary, but finding a good tech with a wiring diagram and working knowledge of your car will be. Good hunting.

 

Thank you both so much for your responses. They give me hope.

The car starting is random. Sometimes in the morning, after sitting all night (cold), the car won't start. Sometimes when I have done errands all over town and end up in a bigbox store parking lotthe car won't start. If it's been sitting all day and I make a quick run to the store sometimes it won't start to make the return trip, usually when I have the best parking space right in front of the store for the world to see.

Also, I neglected to mention that when this occurs the locks don't work properly. Not just with the use of the fob but using the key, as well.The keywill lock the driver's door but no others.

It seems like it is in kill mode when I try to start it. I get dash lights and the seat adjuster will work.

At the suggestion of the female, non-mechanic service writer at the Jag dealership yesterday (Tuesday)she said the the battery might be bad. Went and had it tested, 12.5 volts and 2+ amps. They said that was a good battery...it's only a year old.

Will a bad solenoid cause the the security system problems, too? I just want to double check every avenue before I spend another dime on another deadend.

I will take this information to the smartest guy I can find. The mechanic from last week has been working on Jags,Lotus, Rolls, Aston Martin, etc.for 25 years and has a pretty good reputation in town so I thought I was in good hands. Apparently not.

Once again, thank you so very much.

 

Is it cranking over continuously, but not firing up?, or is it not even cranking sometimes? If it always cranks, but doesn't always start, you may want to have your fuel pressure checked.

 

When it does this, it doesn't crank at all. It does nothing. It's dead. Doesn't even think about starting.

So, I have to reset the computer by removing the battery cable and the wait begins. Any more thoughts? All are welcome.

Thanks. (Please see addendum below)

 

Okay, just tried to start for the first time today (Wed)and it did not start. I used the keyand not the fob to open the door. The security light was blinking in the center by the gear selector, I got in, turned the key, and nothing happened. Got back out, relocked the car w/ the key and the security light started blinking again like nothing is wrong.

I'm stumped.

 

Sporadic problems usually indicate bad contacts. I would start by replacing the starter relay and the main ECU relay or trading another relay for them temporarily. Old relays can get sporadic. I am guessing the security problem is not related. Look at the security module harness first.

 

do the lights come on the inst pack? any change when you go to start? We have had more than a few ignition switches fail(the electrical part behind the key cylinder) and way to eliminate an issue with the starte is turn the key to on and jump the starter wire to the starter as previously noted on the side of the cool box for the ecu, other issues are a broken starter solenoid wire connector under the boot on the starter that intermittently contact or not since the boot is holding it, pull the boot back on this small wire and check it. The starter rarely ever fails which is why theyre about a grand. If when turning the key to start is there power at the terminal on the firewall?. These are all quicks checks for a decent tech, but the bigger issue is getting it to ffail when diagnosing if something obvious is not apparant

 

This is a follow-up to several posting we have made in the past. We have had some good advice but so far nothing hasd fixed the problem. We have a 2000 XJ8 that is perfect condition, 78,000 miles and everything works perfectly except that it does not want to start everytime. This means that when we try to start it, nothing happens. The starter does not turn, the locks on the doors do not work properly. If we try to use the key to lock or unlock the door only the drivers side will work but the other doors do not. We have taken the hot lead off the battery and waited about 10 mintues then put it back on and waited another 10 minutes then put it back on then it starts. Most of the time. Sometimes we have to do this a couple of times to get it to start. Seems like the security system is shutting down the car and it acts like we ar not using the correct key. We have replaced the transponder in the ignition but this has had no positive effect, still wont start sometimes. It does not seem to matter if the car is hot or cold. Sometimes it happens after it has sat all night and wont start in the morning and sometimes it happens after we have been driving it around and the next time we try to start it just wont. We have checked every connection, haave had three different mechanics look at it to the tune of about $1,000 so far and all they do is scratch their heads say they don't know what to do. We have tried both keys to see if maybe one of the keys is not working properly but neither key helps. We have tried locking and unlocking the door. nothing. All the electrical connections have been checked and or replaced and the battery is fully charged - only one year old. This is really getting to us and now my wife does not want to drive the car because she has been caught at the store for hours trying to get it started and just does not want to go anywhere in it. Any help will be greatly appreciated.

 

Please see latest posting. If their is a problem with the starter relay or the ECU relaywhould this effect the proper functioning of the door locks when this occurs? The key will work only the drivers side door but not the others and the key fob will not operate any of the locks when it has failed to allow us to start the car. It really seems like it has something to do with the security system as it acts like it does not recognize the key but we have replace the ignitiontransponder and it did not do anything. Each time we take the hot battery lead off, wait 10 minutes or longer then reconnect and wait an addional 10 minutes or so it seems to start. This does not always work but most of the time it does.

Thank you

 

You may have a body processor problem where the immobilizer module part of itis concerned.
Since you have had little luck with pro's, you may have to get in there and do some sleuthing. Get an Alldata subscription and look at the circuit diagram for the locks and body processor. It is very complex and there are a lot of parts, but something is haywire there and it may be immobilizing your car. The doors have locking modules in the front two and there is another module in the trunk. The body processor is behind the front passenger airbag cover.

Another thing that will cause this is a tranny rotary switch or a tranny neutral safety switch out of adjustment. Get them adjusted to be sure. Does wiggling the shift help any?

 

I bought a 1998 xj8 with the same problem. I got it home and replaced the 2crank sensor. It is locatedon the front of the engine and I have not had a problem.

 

^^^crank sensor wont keep it from cranking but no door locks when it does it means body processor fault of which i just had a 98 doing it intermittently and wouldnt crank, operated doors etc, and with it failing traced to the BPM(body processor) Ill have to check tommorrow at work to see if you start function goes throught the BPM too on a 2000, pm me and remind me

 

I think I had the same intermittent starting problem that you are reporting and also posted here for help. (In fact I just logged on today so I could update my post).The only difference was that I didn't have all theadditional stuff going on.My experience was thatevery so oftenI would turn the key andall the lights in dash would comeon as normal, but thecar would not turn over. I could hear a faint clicking sound, but that was all. Then if I kept trying eventually it would start. In the end it was taking 7 - 12 attempts before it started. Sometimes I would also have to wait a few minutes.

Anyway, I just took it into a Jaguar mechanicI have used in the past and it failed to start the morning they were going to work on it. They replaced the starter motor and it has been fine ever since.

So I am wondering if it's possible thatyou havemultiple problems that aren't actually connected? Could it be a horrible coincidence that you have a bad starter motor and some other problem/problems? I also have about the same number of miles on my'98.

Gary

 

sorry sgivhan, the original poster hasn't been online since 10/2008, so likely he either fixed it and never returned to inform us, that's typical, or he has a big paper weight in the garage. Follow the advice above, maybe start you're own thread with loads of symptoms and list what you've already done as part of your diagnosis, and see if you can resolve it yourself.