Yep...Newb here...to the Forum, not the Brand.

So here's the deal. Picked up another XJR the other day for short money. Currently own as a daily a 2000 XJR. 154k on the clock and running strong. Anyway, just grabbed up this 99' with 87k and it wouldn't start let alone crank/turn over.

The dash display shows Traction Control Fail and Stability Control Fail

Check Engine Codes p1646 and p1797

Now, after replacing the starter and battery respectively, the car actually turned over. It successfully turned over 6 or 7 key cycles but did not fire. Then out of nowhere it just stopped cranking period.

I diagnosed zero fuel pressure at the rail with a gauge with the key in the On position.

Removed EVERY fuse in the car and checked it. Found cigarette lighter blown thats it.

Removed EVERY brown relay I could find...both sides engine compartment as well as the trunk. Switched them all around. Still no crank.

Jumped relay's 1 & 4 in trunk...fuel pump relay's. Then checked for 12V at pump harness. Tested 12.36v so my guess is the pumps are bad as I have 0psi at the rail.

However, that still does not explain the complete lack of desire to crank. I have 12.36 at the starter, 12.36 at the connection by the ECM, full function of All accessories...windows, stereo, climate control, lights, blinkers etc. Everything works but the damn thing just will not crank. I dont understand why.

So here I am...one good XJR and one bad.

Any help would be most appreciated.









So, I diagnosed a bad battery and bad starter. Replaced both with new.

 

You will only get voltage to one fuel pump for a few seconds when the key is turned to ON in a XJR. So by the time you get back to the trunk to check the relay it has turned off. You should check out my fuel pump video in my signature.

 

Thanks for your response mustangtyson. Cool video regarding the fuel pumps. I will watch the tensioner one next as I will need to perform this on my 2000 XJR here soon.

In my haste I may have left out a couple of things I did. For both relay 1 and 4, I jumped terminals 30 & 87 and then checked for voltage at the harness. Good to go at 12.36 volts with the key in the On position. With the harness plugged in and the main pump relay jumped, still no fuel pressure at the rail and further No Cranking. I read also that in a pinch the 2nd pump can be used temporarily to get you home. I jumped that relay also and Still no fuel pressure at the rail. Further, still no cranking. This is how I came to the assumption that both pumps were bad.

Everything lights up and does what it should when the key is in the On position...even the ECM cooling fan fires up but I still get ZERO cranking...not even a hint.

Perplexed...yes.

 

Hi 1FASTJAG,

Welcome to the Jaguar Forums!

It definitely sounds like you may have multiple problems, but I'm thinking you need to figure out the cranking problem first. Lots of possibilities: gear shift lever not fully seated in Park, ignition switch, ignition positive relay, starter relay, battery power connections, ground/earth points, Body Processor Module (BPM) connector corrosion or water ingress, engine ground strap corroded or loose, etc.

You can download the 1999 X308 Electrical Guide here:

http://www.jagrepair.com/images/Auto.../jagxj1999.pdf


Have you scanned the car for any stored Diagnostic Trouble Codes (DTCs)? The DTC Summaries manual can be downloaded here:

http://www.jagrepair.com/images/Auto...J27%201999.pdf


Also, since we're a friendly group, please visit the https://www.jaguarforums.com/forum/n...-intro-must-5/ and post an introduction so we can learn something about you and your Jags and give you a proper welcome.

Cheers,

Don







https://www.jaguarforums.com/forum/x...ngines-120221/

 

Thanks Don B for the info. I made the proper introduction via your link.

Stored codes: P1646 & P1797

Code link does not go up to P1797 but I was able to locate P1646 and identified it as a bad O2 sensor

So I figure I'll start with pulling the ECM connectors and checking for corrosion there as well as at the points under the hood feeding the various relay and fuse spots. Ill also jump the ignition and starter relays to see if there is any change.

I guess 1 out of 6 Jags I own is bound to create an issue. Would just hate to part this one out but there also comes a time to cut the cord if its going to continue to drain time and money.

 

Hold the show. All these things probably did not fail on the car at the same time. Can you bench test the old starter?

We need to do some voltage drop tests on things. I think you have a bad ground. Check out scannerdanner on youtube.

 

Codes like P1646 (which looks to be a bad O2 sensor) won't stop it cranking so concentrate on the no-crank.

On the later cars, P1797 is a CAN issue (and might not recur) but again I don't see it causing no crank.

 

P1797 seems to show up when there is a battery problem, so it may be a poor/corroded connection in the power circuit or grounds is causing a large voltage drop by the time it gets to the starter. That is if the solenoid is okay.

 

mustangtyson...Thanks. Old starter tested bad, hence replacement with a fresh reman unit...that top bolt is a b*^th to get into place.

rj237...battery is fresh and I show 12.36v at the starter with the key in the On position. Starter is a reman unit 3 days old. It cranked the car 6 or 7 times before this issue arose which was about 5 minutes after I finished installing it. Can a solenoid go bad that fast?

I will check grounds tomorrow. I do recall seeing the engine to chassis braided ground close to the starter colored quite green. I will start by replacing this.

carefully removed shifter cover and stereo. someone has been in there before as there were some broken tabs and 2 poorly repaired stereo harness wires. Thought maybe neutral safety or shifter was misaligned. Shifter light illuminates at all gear settings.

 

I think you're making progress. Bad connections and faulty work by previous owners/ mechanics are hard to chase down.

 

The white connector on the shifter illumination module can break loose from the board, partially, and cause the P1797. This can cause the No Crank.
Since previous owners have worked with the stereo they could have stressed that connector and be the root of your problem.
You may be able to put gentle pressure on the connector toward the board and get the car to crank. I was able to do that with my XJR.
If the connector is beginning to break from the PC board, then the only fix is to replace the board or solder the wires directly to the PC board.

 

So I had my wife turn the key for me while I was underneath with a test light.

The trigger wire lights up which tells me the solenoid is getting power but it still doesnt engage the actual starter.

 

I should further mention, when attempted again, this time with a meter, under load (key held in crank position) I registered 12.10V continuously.

Frustration ensues...

 

RELAYS...

Uugghhhhhhhhhh So with the key in the ON position I recheck my relays under the hood and notice the I ignition relay on the drivers side is Very warm. I then check on the relays in front of the ECU. Ignition coil, Starter solenoid and throttle motor relays are all Very warm...borderline HOT.


The heck is going on here??? They should Not be hot like that...

Any thoughts?

 

On the diagnostics:
Where did you have the multimeter grounded when conducting this test? To the engine or to the frame? It would be good to know the voltage drop to the engine and to the frame when cranking.

Conduct another test while having wife turn key. This time measure voltage from engine block to frame. See if we have a bad ground strap.

From the non diagnostic (just grasp for things camp):
Clean ground straps on battery and to engine. Take them off, wire brush, try to pull then ends off to make sure they are well attached still and not corroded in the crimped area.
On the right hand side of the car take off the engine well cover (the one that has the little compartment in it) and there will be a terminal under there that connects the battery feed from the trunk to the starter harness. Remove this terminal and clean both sides and wires.


Some things to make life easier:
Get a battery load tester to make sure the battery is good:

Get a battery tender so it you don't kill the battery in the car. You can try to start the car some each night and this will have the battery ready to go the next night for more trial and error:

 

Now, if I am understanding this thread correctly?


You have one perfectly good running XJR, and one that will not even crank, Why do you not measure the values of the starting circuit etc... on the good one, and see if they are the same on the broken one?


You are in a lot better position than most of us on this forum, who only have the one car, and have to rely on the superior knowledge of others, or their goodwill to go and check!


Please do not forget, that 12v on the meter at any wire is not proof of a good circuit.


12v, but at 0.2 amp will not even light a bulb, let alone trip a solenoid or turn a starter motor!


To put it another way, If your garden hose has a kink in it between the tap and the nozzle, it is still full of water (12v electrikery ) but because of the kink in the hose ( bad ground, frayed wire etc.. ) no matter how much you turn the tap on, it cannot pass the kink!


If you transpose water pressure for amps, until you sort the kink you have no, or not enough water ( electricity ) where you need it.

 

So...replaced the engine to chassis ground cable with a nice new encase version with copper tabs. Guess the old one Could have cause a little resistance.

However, after replacing, the problem still persists





@mustangtyson:

*Pulled both terminals up front. They were clean but I cleaned them again anyway. Jumped to drivers side and repeated the process. Trunk connections are Mint...clean and new looking.

*Wifey not home today but will grab her tomorrow for the voltage drop testing.

*When we first tested...with OLD strap in place...I grounded to the chassis side of the strap.

@andrewlowe:

Yes I am lucky to have 2 of these cars but humbled by the fact that my Running car has been so good to me. Further, thankful for those that have taken the time to help me get this other ones problems sorted.

I guess when you buy a 1999 XJR with only 88k miles on it for the mere sum of $900 there are bound to be some hidden issues. Silly of me to have assumed it would be an easy quick fix. Better to be in my hands than the crushers as thats where it was headed.

 

Just read the first post again, missed the bit about no fuel pressure!


Try resetting the inertia switch, it shuts the fuel pumps off in an accident or if it gets knocked.

 

Inertia switch is fine.

Relays still getting very warm.

I suspect this car went for a swim. The under padding is quite wet.

Looking more and more like a parts car.

 

That could be due to clogged A/C drains, but it might be worth checking the ECM and BPM for signs of water ingress.

Don