Hi everyone... new x308 - 2000 XJ8 VP owner here... fighting my first issue and I was wondering if anyone out there could give me more insight.

The car has an issue where all the electrical items - interior/exterior lights, etc are all flickering. The voltage seems pretty high to me as well...jumping to the upper 14.8 range when running. The alternator is new and I took it to a couple shops that did a bench test and it passed. I tried grounding the alternator housing to the battery and nothing changed. I pulled every fuse and relay across the 5 different fuse locations to see if it influenced the issue...it did not. I've been cleaning grounds...didn't get to all of them... but wondering if I need to be chasing grounds, or if there is anything else in the electronics system that may be influencing the charging. It's tripping up every module out there, but i cleared all the odbii entries and looked at a few data streams.... Noticed:

Battery Voltage: 216
Battery resets: 254
Battery Positive: Central processor unit 1 - fluctuates between 1.23v and 315.75v


I thought these were some strange data streams, but i'll be looking into these a bit more. Is there something in the car management that would be misreading this data and influencing this constant electronic flickering?

Any info is appreciated...thanks!
Pete

 

I know it's going to sound silly and way too simple, but I would test it with a replacement battery, even just temporarily, and see if it levels out. The systems in these cars in regards to the electrics are so, so sensitive, that it could be something that simple. After that, I got nothing tho.

 

I agree with the possibility of the battery.
Since its located in the trunk in such a confined area, the ventilation isn't great in that area.
Try cleaning the battery terminals.
They try and test a new battery.

When they did the bench test on the alt, did they get the same readings you did?
Did they test it with a load/stress?

I doubt it's the ECM considering your getting readings at all.
It's all or nothing with these units..

 

I found a nice 'electrical troubleshooting v2.2' guide floating around the web, which was a huge help in verifying all the points to test, etc. I literally went through the vehicle cleaning the battery terminals, replacing the battery ground lead, replacing the engine ground strap, cleaning all these mating points (starter, alternator, psuedo firewall/bulkhead connector, the power distribution next to the tire)...cleaning all of this stuff until it was shiny and such. I even pulled the ecu connectors and reseated. Still..it's all strobing away.

So that leaves me with at least two areas to target - the alternator and alternator mount itself and battery, as it would seem like I have 'taken care of' any potential grounding problem...unless there's some other component in the chain that is causing a grounding issue - or something internal to the alternator.

I'm going to take the battery in for a load test...but haven't always been convinced that these 'local auto store' tests really validate 100% success.

Similar to the alternator, the 'local auto store' bench tests says it's 'good', but with no real data beyond that. I have another alternator en route as well... obviously it's easier to pull the battery than the alternator, but I'm not quite sure what else to look at.

This XJ8 has the 3 pin alternator connector (2 of which are actually used), and then the B+...there's no supression connection or anything else. I notice on the bench test they hook up a grounding wire to another point...they're not relying on the casing to be the ground. I wonder if that is influencing anything..or just how thorough the bench test is.

Pete

 

When you say "new". Where did it come from? Make?

It's not unusual for the mass market units to be bad out of the box. Do you still have the OE unit?

 

Do you mean the Alternator? It's a month old Ultima Alternator from OReilly's.. Evidently the past owner was chasing something down and had this put in and then lost interest... I don't necessarily trust this thing, but the OReilly and AutoZone bench tests both said this was good. Well, the OReilly one did crash 3 times and need the 'computer' restarted and that didn't do much to confirm much of my doubt...but after a couple passes and having the old lecture about it being bought at another store and another owner and 'corporate is cracking down on returns', and a few more excuses out of the book of excuses, I decided to spend my time in another direction.

Right now I'm thinking I'm either having a voltage regulator issue or the Feed going INTO the Alternator isn't holding 12v and if that is flakey or bouncing, then it's throwing off the voltage regulator (and regulating to an unstable signal). Not sure how to really test that without pulling the connector off the back of the alternator and testing...(not sure I can even get to that without pulling the alt....so I may wait until the new 'bosch rebuilt' alt shows up.

Pete

 

Can you call the previous owner and ask if he was having the same problem? Why did he replace the alternator? When he replaced the alternator -- was the OE still in the car?

Unless the OE was having the exact same problem prior to replacing the alternator -- you have a bad alternator. The charging system is simple - not much to it. Not knowing the condition of your car -- unless it's been sitting by the ocean what you are describing is not a corrosion or bad contact problem. The regulator is part of the alternator.

Alternators fail .. nothing unusual about that. My preferred way is to get the OE rebuilt -- if that can't be done .. I hunt for the proper OEM unit. The vast majority of new and rebuilt alternators available aftermarket are junk .. same with starters.

Denso is the supplier -- I believe the XJ8/XJR have different part numbers. I did an XJR -- I think it was a 150amp. If you go to a place like Rockauto -- you have to be careful. You will see a part labeled as "Denso" rebuilt ... it may not have been rebuilt by Denso. Many are rebuilt in China -- with all manner of parts. A proper part is remanufactured -- not just rebuilt. It started out as a Denso.

 

All sorted out... I swapped in a rebuilt Bosch unit and the flickering is gone. What a headache doing this twice...but glad it's working. Not quite sure what i'm going to do with a 'rebuilt' OReilly's alternator that they said was good, and Autozone said was good, but wasn't holding up. I saw another post in internet-land with someone who bought an Ultima (Denso rebuilt) alt from OReillys and they had a similar issue on another jag...ended up needing the HD version of the alternator, I believe... Regardless... It's going to be lonely watching a dash that isn't setting off every alarm out there! I'm sure something else will arrive to work on, soon enough

Pete
p.s.If it helps anyone down the road, the 'bad' alternator has a Rand Tek RT1446 voltage regulator on it (Also marked 7460-251)

 

As I said above -- The vast majority of rebuilds are done with cheap components. When you purchase a rebuilt Denso alternator -- it comes in a Denso box from Denso .. and it started life as a Denso alternator. The parts used to rebuild it are Denso.

Your "Denso" alternator may have started life as a Denso unit, been a true Denso alternator that failed and came in for rebuilding -- but it was not rebuilt by Denso .. they don't use Rand aftermarket. I have seen new units built in China with Denso look stickers and part numbers.

Unfortunately the same is true for Bosch .. in fact it's more of a problem with Bosch. Bosch license their name ..... Have to be very careful and understand what you are buying when buy products branded as Bosch. The $150 parts are junk.

 

I get that the 'aftermarket' can be a cloudy area, but I wouldn't necessarily say that buying a new $500 alternator from Bosch or waiting a week for an alternator rebuild is the only option. In 16 years, who knows if the alternator that's on the car is even the original anymore. This $220 alternator from the local shop is what most people are going to default to... and if it doesn't work, they bring it back...my issue was that I couldn't bring it back. The alt I went with was a $100 ebay Bosch reman unit that was a Bosch reman (bosch box/warranty registration) and looked like it just rolled off the assembly line. Did I get lucky? Probably a bit... but I'm pretty sure if I bought a new voltage reg for this Denso unit, I'd probably be back in action. Unfortunately I'd be paying $60 for the HD regulator and waiting around a week for that to arrive, too...if it didn't fix the issue, there was $60 gone. The Bosch was marked as an XJ8 replacement unit - so if THAT didn't work, I either had another issue, or it would be returnable. Just glad to have this sorted so I can figure out things...like why the bulbs for the AC controls cost $14 each but I can buy the AC controls with all the bulbs and have a backup unit for $8

Pete

 

Don't believe Bosch ever supplied Jaguar with alternators for the X308 .. or the S type for that matter. Ford used Denso -- same with Land Rover. Bosch would not be your answer.

Sadly, Bosch is licensing .... It's only a box with a name. I'm sure it did roll off an assembly line -- in China. The case is most likely new -- that's how they get the fitment. The internals are interchangeable over many makes within the same manufacturer. I have seen MB's that came with Bosch OE alternators -- the Bosch aftermarket is not a Bosch case. If, six months from now you have an issue that points to the alternator .. that's what it is. I'm only trying to explain -- not attack. The big box stores can make more money selling junk w/ lifetime warranty (No Labor) vs a quality part .. sad ...but true.

I recently had to get an alternator for an e320 MB -- Valeo OE unit. The dealers want $700.00 ... various rebuilt ones around ... best price was around $350.00. I called Valeo technical in VA .. the guy gave me the Valeo cross reference. I was able to order it from rock auto -- $250 -- new made in France. Rockauto did not list the part as fitting the car. I had the same problem with my Nissan Pathfinder last year. Unfortunately, the OE supplier (Hitchai) only supplies them to the dealers. I was still able to find one for around $350.00 at an online dealer that had a few. It's a very difficult R&R on that vehicle.

I'm just trying to explain to those who don't understand how all this works. Even if labor is free -- having a part go is problematic ... especially if it's not an easy swap. With manufacturing cost today -- most of the OE stuff is new.

 

The X308 only ever came with Denso alternators.

It's never cost me more than $30 to rebuild an alternator
as diy using parts from local rebuilders.