I’ve had zero problems with my LR4 for the first 7 years of ownership.

Then it went in for a $2200 service at 72000 miles.

Now it’s becoming a major headache.

I noticed steam coming out of the hood. The dreaded plastic cooling pipe cracking at the block, behind the water pump. I replaced all the plastic pipes with some nice cast aluminium aftermarket pipes.

whilst I had everything torn down I thought I would replace the coolant, spark plugs and drive belts. That’s right, a $2200 service doesn’t include any of this.

i fitted the nice NGK iridium plugs.

after hours of bleeding the engine, and replacing more ‘rotten’ plastic coolant parts, I have the engine up and running

At first the engine ran well but I got a noticeable misfire under load around 3000 rpm. No codes though.

So I figured I should have replaced the gasket on the supercharger lid (I did replace the inlet gasket and torqued to 25Nm)

I just replaced that gasket and it’s running much better. Until I get to 80mph and accelerate hard. I get what feels like high frequency misfires, shaking the car., but still no codes. I am using the BlueDriver diagnostics tool.

i know the logical thing to do is to swap the ignition coils but they are super expensive and I’m not getting at codes to suggest this is an issue

Anyone come across something similar? Any advice welcomed

 

I suspect your code reader is not exposing LR specific codes.

 

Can anyone recommend a good diagnostics tool for a 2016 LR4?

 

GAP diagnostics is the one most people use. LR specific tool.

 

The saga continues.

The car continues to misfire but doesn’t set a diagnostic code. I’ve had it scanned by 3 different code readers so far. OBD is supposed to detect misfires.

i guess I’ll bit the bullet and buy 6 new ignition packs 🤞

 

might not be misfiring. if you had coilpack problems, you’d probably have issues other than at high speed when flooring it. could be fuel supply. could be drive train or engine mounts. if the car overheated when you had that coolant leak, could be a little head gasket leak showing up under extreme load.

if you have a diagnostic tool, might check with monitoring fuel pressure/fuel trims.

 

I fitted new coil packs

it drives differently but still misfires or hesitates around 3000 rpm

I went from standing start to 70mph under hard throttle. Hesitation around 3000 rpm, but once it got to 4000 rpm it was smooth all the way up to 6000 rpm

i’ve also noticed my fuel consumption went from 17mpg to 13 mpg after the dealer refitted the fuel cassette in the fuel tank (recall) back in December. But, the car has driven fine since then, just uses a lot more fuel

I can monitor fuel pressure/fuel trims. Not sure what I am looking for though?

 

To check fuel trims, you need to set your diagnostic tool to monitor short and long term fuel trims on each bank. In park, take readings at idle and while holding throttle steady at a couple of higher rpm readings…maybe 1500 and 2500. Add short and long term trims together to get total fuel trim on each bank. Ideally, fuel trim will be zero, but anything +/- 10% is within a “normal range.” If you are running lean, the fuel trim will be positive (ecm is adding fuel by keeping injectors open slightly longer to compensate for lean condition). If you are running rich, fuel trim will be negative (ecm subtracting fuel to compensate for rich condition). Changes in fuel trim at the different rpms can tell you something about what’s going on. For instance, high positive fuel trim at idle that trends closer to zero as rpms increase points to a vacuum leak. Fuel trims that get more positive as rpms increase might suggest a fuel supply issue.

To check fuel pressure, track (graph) the actual fuel rail pressure and demanded fuel pressure at various rpms and under load. Then look back at the graphs and see if actual fuel pressure is tracking pretty well with demanded. If it’s not keeping up, might be a weak fuel pump or fuel rail pressure sensor/regulator.

 

I’ll get on it in the morning. Thanks

 

Interesting LT1 is consistently higher than LT2

617 rpm. ST1 -2.5 LT1 7.8. ST2 0.3. LT2. 6.2
1900 rpm. -0.5. 7.8. 0.6. 6.2
2600 rpm. -0.5. 7.8. 0. 6.2


i did see one reading with ST1 4.2. LT 7.8. Tot 12, but this was when I was increasing speed