Hi,

About a month ago, I bought a '98 XJ8 VP, put the 100000th mile on it a couple weeks ago. It has been running well, the only issues being the "battery not charging" light and a slight rumble at idle and low RPMs, that a mechanic told me not to worry about.

Today after I got gas (91 at Shell, as always) I tried to start it and it didn't turn over or anything, just a loud grinding noise. Tried it again a little bit later and same thing. Had it towed back to my house, we tried to jump start it and that didn't help either.

The RPMs jump way up when I try it, the first time it did it there was a "stability control fail" message that flashed briefly, but not since then. There was no check engine light or anything preceding this.

The tow truck driver said that it's probably the starter and/or solenoid. Could it be something worse, like timing chains or some compression issue?

 

 

Sounds like dead battery and possibly charging circuit issues, since it is saying "battery not charging". The stability failure is also a sign of low battery. When the ecu is reset, the first time it starts will run the engine at very high idle for a few seconds until it returns to baseline. If the battery is nearly dead it can cause the ecu to reset and do that. As well as many other odd glitches.

 

 

Charge battery up to full 12.75 volts . Alternator voltage regulator test first . Look for around 14 volts on the B + terminal ( this is higher then the 12,75 meaning it is working ) as it is running or remove it and spin test the alternator on a machine if they have one . Low voltage will cause many issues . Later look into the battery . Starter and solenoid will probably work out after that

 

These cars are very temperamental w/ a less than optimal battery.

 

New Battery is definitely needed and I suspect a new alternator is on the horizon too.

If your mechanic is telling you your issues are nothing to worry about, then you should find a new one. Battery not charging warning means there is a problem somewhere, the whine from your speakers also suggests alternator problem. There is a built in suppressor which may not be functioning because of the possible fault with the alternator. Your rumble could be a ruined bearing on the alternator, AC, PAS or Water pumps or it could be something in the transmission.

 

Take the car to a guy that rebuilds alternators: he will test it and rebuild it. Cheaper than a new one. Took my guy less than 20 minutes to pull the alternator, rebuild it and reinstall. Was almost home when he called and said come get your car.

Same guy rebuilds starters, too.

 

This is your suppression module that smooths out the slight ripple in the voltage as it comes out of the rectifier diodes which may be also at fault . A test will determain if the diodes are bad . The alternator produces AC voltage which must be converted to a smooth DC voltage . Without this smooth DC things will act up , speaker whine is a important clue and tool to observe .

The first thing you need is high enough voltage ( the 14 or so at B + ) out of the alternator into a good battery ( to be determained if good second step in my opinion ).

Then I would look into the suppression module ( a capacitor in reality ). Simple test is to watch with a meter a climbing resistance as the capacitor charges it up . You can short out the pins and watch it climb again .

 

Thanks everyone for the responses.

I put a new battery in this morning, but that did not help. I don't have anything to test the alternator with, so I'll see what the shop says.

 

With the battery , was it fully charged as it may not have been as it came off the shelf , or may have been someones return . Today's batteries are junk even new ones so keep that in mind . Have you swapped starter relays ?

Even with a bad ( or not bad ) alternator the starter should rotate with a good battery .

 

ALL OVER THE MAP...
1. With the new battery does it CRANK?
2. If not first a starter issue
3. If cranks and no other codes like fuel pump pressure and all AND
YOUR catholic, SAY A HAIL MARY, YOU SAID IT HAS 100,000 MILES.
ITS A GOOD CHANCE TO BE THE TENSIONERS AND TIMING CHAINS!
The killer of the 308 engine.
I loved my 300 so much better.
100 grand on a 308 is the limit, if your luckY 125.
Good luck, Don't keep cranking it, youll be sorry.
Good luck
GTJOEY1314

 

Might have to remove the spark plugs and see if it will turn over by hand , or a valve cover visual check .

 

It doesn't crank, just the loud grinding noise when I turn the key.

 

Yeah I thought so......
Well it could be the starter gear grinding into the fly wheel, OR everything else crashing into itself with the chains popped or loose.
Safely tell the shop to remove the starter and bench test it and look at the flywheel.
If that's okay, you know the drill, Jag recommends tensioners at 75,000 I did mine EVERY 50,000.
Its a huge job.
Don't crank it till you do the above.
I could be wrong but call your vin into jag and give them the vin for the service reords to see if it was done.
Good luck
GTJOEY1314

 

I don't know if the timing chains have ever been done, the last owner did not do them so it has been at least 4-5 years. My plan was to get them done with the upgraded metal kit, in a month or so, when my tax return gets in. So I really hope that it's not that. The "low oil pressure" warning used to come on, I read that that's one of the warning signs, but that stopped when I got an oil change. I haven't heard any rattle or anything else.

The noise doesn't sound like it's coming from the block, it's more high-pitched and much closer, either the starter or something right by it.

The noise sounds exactly like the noise in this video, the differences being that I get a rev when I try to start it, and the only messages showing are the "stability control fail" (only once) and "battery not charging". I also have had the same buzzing noise (that plays through the speakers)

 

Can't tell from the video - is it actually turning the motor over or is the starter spinning by itself? From the video, it sounds like the starter is spinning on its own without engaging the flywheel.

The buzzing I believe is coming from the TB motor - I wouldn't worry about it if that's what it is.

If the tensioners had come apart you'd probably hear bad rattling as the pistons were crashing into the valves... If you take a 24mm socket and stick it on a ratchet, try turning the engine over by hand by using that on the crankshaft pulley bolt. Turn it clockwise (as if you're trying to tighten the crank pulley bolt) and see how it feels. Or take a valve cover off - not too much time needed, and you can easily inspect tensioners and guides.

 

you need your starter rebuilt.

 

You have no RPM on the tachometer . That would point to the starter not engaging if the tachometer is properly working . Is the front engine stuff turning , you can mark a belt with something and see it change positions if working solo ( a harmless piece of tape ) . Did you swap the starter relay ? May not be carrying enough current . Location unknown to me .

https://www.ebay.com/itm/STARTER-REP...haR3e2&vxp=mtr

 

That video isn't mine, I just posted it because the noise is similar.

I do get RPM on mine, goes up to around 2-3k.

It's in the shop right now, I didn't swap the relay or anything else. I'll see if they can rebuild the starter or if I should just order a new one.