What would you do with my JK if you were me???

[Turismo07]

Originally Posted by Slickturtle

TURISMO 07 Hi Turismo. You touch on the nub of the problem. Everything in the car is in perfect working order. Or at least it was when the problem first came up. Only in the last six months after its final stint with the dealer did other problems come up. And these are no doubt related to the original prob. Now the electrical battery charging systems don’t work. When I last drove it home (45 minutes) the battery was audibly boiling when I got there. Was a good battery – now a dead battery. The ESP light won’t go off, the ABS light won’t go off, the hand brake light won’t go off – even though the handbrake is fine.

Sorry I didn't read all of your replies to everyone else, so I could be off. But based on your replay to me, it sounds like you either had a bad batt or might have a alternator issue, or at least wiring/sensor issue to do with the alt.

The alt on the CRD's is a smart unit, it charges the batt as required, if the ECU is not getting the right batt info then it'll run the alt at full power and overcharge and kill the batt.

Modern vehicles (that are full of sensors and elecs everywhere), and even more so modern diesels need good strong current to run properly. If the batt/alt start to die even the slightest drop in voltage will cause all sorts of probs throughout the vehicle. ABS/TC warning lights etc are some of the first things to send faults when voltage to their ECU drops.

I have heard of vehicles with malfunction auto trans and fault codes etc and after a new batt was fitted the trans worked perfectly.

[StuieG]

Hi Slick,

As I was reading your first post I was immediately thinking it could be a wiring issue. Unfortunately there's a lot of "dartboard-diagnosis" that goes in the motor industry these days. After 15 years in the industry for more than one prestige brand and providing technical support to a network of 65 dealers across Australia, I had simply had enough of people not wanting to do their jobs properly and simply just replace parts until they had fixed it.

The turbo's in these are VGT (VNT/VVT, depends who you ask). They have the ability to vary where the exhaust gases hit the turbine by using an actuator which changes the position of the vanes. This actuator is run off a Pulse Width Modulated signal from the ECU and with a standard multimeter it can be difficult to monitor the signals, especially when the vehicle is stationary. The best thing to use to detect these signals is an oscilloscope and someone to watch it whilst you drive it.

If the turbo actuator isn't getting the correct signals, it will not move the vanes into the correct position and therefore you won't reach the desired driving characteristics, ergo your vehicle goes into a limp home mode.

Knowing that the ECU and the turbo has been replaced (I assume a new actuator comes with a new turbo?) the wiring is likely at fault (providing that your fault codes relate to turbo faults). Wiring can be easily checked with a multimeter by unplugging both ends of loom, from the ECU and the component, and checking the resistance along the wire. A healthy wire usually has between 0.3-0.6 Ohms. Any higher and there is more resistance and any lower and it could be short or open circuit.

Your best bet would be to trace along the wiring loom from either the ECU outwards or from the turbo back to the ECU and check for damages.

Not in the same location, but also a concern to many diesel Jeepers, is the boost pipe that comes out of the intercooler and into the inlet manifold. You haven't mentioned any noises, but they don't always make loud enough sounds to easily distinguish the pipe being split. I would recommend checking it for splits and tears whilst you're in the engine bay.

Hope that helps some way?

All the best in your diagnosis

[Vinnie]

Just to be clear, the problem you are having is that the car is still going into limp mode?

Before buying my JK, I had a 79 cruiser that was basically one big electrical fault. Not having to do anything much to my JK yet, I don't really know how well the following work with the JKs, but this is what I would do.

Step 1 - Check your battery and alternator.

When I last drove it home (45 minutes) the battery was audibly boiling when I got there. Was a good battery – now a dead battery.

I'd buy a cheap multimeter from Jaycar and test the charging voltage of the battery. It should be around 14 - 15V (ideally 14.4V which about what mine sits at too). Higher than that and your battery will "boil". When the charging voltage is too high the water in the battery is split into hydrogen and oxygen giving the appearance of boiling though the battery is not actually at boiling temperature. The voltage at which this happens is called the gassing voltage of the battery and is generally lower on hot days ~14V at 40°C, and higher on cold days ~14.5V at 20°C.

It should be noted that car batteries consist of multiple cells each at approximately 2V that add up to give you the 12V required. (A bit like how you put two 1.5V D-Cells in your torch to give you the 3V battery required.) Thus it is also possible for it to fail in such a manner that one of the cells short circuits causing the power that would normally be dissipated during charging across this cell to be dissipated across the other cells. In this case it will also cause the battery to "boil" by over volting the individual cells that have not failed.

Some googling suggest that the JKs do not have smart charging circuits for the batteries. Thus you should be able to use a cheap Jaycar multimeter to measure the voltage across the batter at different engine revs and check if it's in the range above. (A meter like this should do the job: https://www.jaycar.com.au/low-cost-d...r-dmm/p/QM1500) Most battery places can actually do this test for free too.

The ESP light won’t go off, the ABS light won’t go off, the hand brake light won’t go off – even though the handbrake is fine.

As the other guys suggested, reliable power is very important. Most of my previous cars illuminated random dash lights when the battery or alternator died. This is usually due to the electronics entering a funny state due to incorrect voltage levels. I.e. some logic gates not fully switched on or off, etc.

If you have a new battery installed and are achieving those charging voltages over a rev range of idel - 3000rpm, then you can confidently say that your battery and alternator is good.

Step 2 - Check the engine codes with a cheap OBD reader.
The fact that so much time and attention has been spend on the turbo to no-avail suggest to me that the turbo is not the problem.

I think if you reach this stage you need a more/new information and the only real way of getting it would be to read ODB interface. This should give you a list of error codes (if any) and hopefully give you clues as to where to look. Your problem may perhaps not be electrical, perhaps rats crawled up the air intake or exhaust, etc? Granted that would be weird, but it seems like at this stage anything goes. I've recently been given a reader similar to the one linked below and have not had time to test it out. I have the same engine in my JK (2008, 2.8L TD) so can let you know if it's worth getting.

https://www.kogan.com/au/buy/mini-bl...nostic-scanner

Step 3 - Hunt for loose / broken / chewed wires.
If things are still buggered at this point, I would do what the other guys suggest and start hunting around for loose, broken or chewed wires. This is just an annoying time intensive job and would only do it as the last resort before sending it to the auto electrician. With any luck the ODB reader may have given you a hint as to where to start looking. A large portion of the auto electrician's time will likely be spend stripping the dash and various panels to inspect the cable harness. For most part the cable harness is usually well wrapped up with tape and plastic. So it should be relatively easy to spot obvious rat attack zones if you can see the cable harness. I would personally not fork out more money without doing a thorough visual inspection first. (Make sure to check that the connectors are seated properly too, i.e. wiggle the wires and press the connectors together etc.)

Step 4 - *MAYBE* take it to an auto electrician.
This would be my last resort since this is the most expensive method. In steps 1 - 3 you will know if you need to take to an auto electrician or not. If steps 1 - 3 does not give you anything to work with and everything looks fine, it would be hard to make a case for something electrical. Of course it's not impossible, for example the feedback path to the computer is reporting "all good" while the drive path has been chewed through by rats. This is generally very unlikely since these automated systems rely very heavily on the relationship between the drive and feedback signals and generally have self tests build in to verify these paths, so if you don't get any error codes through the ODB reader, I would be skeptical of an electrical fault. (Fundamentally the computer causes it to go into limp mode and if can't tell you the reason, I would skeptical that it's electrical.)

If none of the above pan out, I would look at more primitive mechanical functions in this order:

1. Check the color of the exhaust while reving the engine under both cold and hot start. It should not be black for long and definitely should not be white or blue.
2. Check and maybe change the air filter and hoses leading into and out of the air filter box.
3. Unbolt the muffler and take it off. If you have a blockage this is most likely where it would be.( I'm not entirely sure if it's legal to drive without one since the Jeep dealership around here has been telling people to take them off to get extra power out of the diesel engines. But it should be ok to drive like that on your property for testing.)
4. Check the fuel lines, make sure the fuel hoses are not compressed or kinked, check and maybe change the fuel filter.
5. Get a compression test done on the cylinders. They should generally be within about a 10% of the maximum cylinder compression. Mine sits at about 6%.

Step 5 - Kill it with fire?
If by this stage you have not found an answer, I would be incline to take the whole vehicle apart (you seem to have a shed to do it in). This way:

1. You will either find the problem.
2. You can sell the individual parts which will probably fetch more than selling the whole vehicle.

If you are at wits end, you can always make it into a nice bon fire. Not entire sure if it's illegal to set your own car alight on your own property, but it may make you feel better about the whole situation.

[Banshee]

Originally Posted by Slickturtle

My bet is that a well established and experienced, independent sparky is likely to be better than those in a dealership. I will probably get a caning for saying that!!

I will keep you posted.

Slick

Not around here you won't! Most of us have had learning experiences with what is sometimes referred to as the stealership network. There are a few good ones, but most seem to have 'mechanics' that couldn't pour piss out of a boot with the instructions printed on the heel.

Add onto that an often 500% markup on parts costs compared to importing the same part yourself from the U.S., and you start to get the idea. (Local dealer quoted me $1179 for a clockspring several years ago, but you have to wait for us to get it in, then come & pick it up. I got the same genuine part from the U.S. on my doorstep within a week by courier for $240.)

The only time mine sees a dealer is for recall work, and even then they fscked that up last time!

[StuieG]

Originally Posted by Banshee

....There are a few good ones, but most seem to have 'mechanics' that couldn't pour piss out of a boot with the instructions printed on the heel.....

That absolutely cracked me up!!! And I totally agree with you

[Banshee]

An oldie, but a goodie! And oh so useful!

[bagnkat]

I haven't seen anywhere in your replies, what the fault codes were? You really need to get a list of them, and start working through them, otherwise, it's just guessing. Also, that FB link i gave you is really helpful. I know you said you don't use FB, but your wife does. There's a couple of good JK diesel mechanics in that group. If you give them the codes, and ask them what they think, I'm sure you'll get positive direction from them. Good luck.