02 KJ CRD 2.5L running poorly and no acceleration or power.

[Rob.fer07]

Hi guys first time posting here. I was referred here by Billybob who's been helping me in the Lost Jeeps Forum. He told me that export KJs are somewhat different from the US libertys.

The story is I bought this jeep a couple of weeks ago as a project and have been playing automotive investigator ever since.

The timing belt broke, so it was replaced and the top end rebuilt (rockers) by previous owner.

Here's what the motor sounds like from the engine bay and the exhaust.

https://youtu.be/JR0sySCXXbE

https://photos.app.goo.gl/S96YtBwYqZLTxnpq7

As it is it'll idle for a couple of minutes then stalls eventually. I'm able to drive it once I let it build up revs which it does with great effort but it'll only crawl. Before digging in to check that the timing belt was done properly I thought I'd exhaust any other possibility for this issue.

Apart from the timing being a major suspect here's what I've checked out so far following the error codes.


Sir Sam also from Lost Jeeps Forum who I consider as extremely knowledgeable since he has a YouTube series performing a timing belt replacement on a liberty replied to my question as to whether it was possible that the injection pump was timed incorrectly.

"The injection pump cannot really be timed, and if its running its seems like its timed correct.

Its worth checking the timing of the engine, but I would look in a different direction.

Check the mechanicals, timing, compression, etc, but this seems like a electronic control issue to me."

__________________________

I ran the dashboard error codes display and this is what I got together with their corresponding meanings found in the manual.


- P0110 - Intake Air Temperature Circuit Signal Too High/Low

- P0201 - Cylinder 1 Injector Current Decrease
- Cylinder 1 Injector Circuit Load Drop
- Cylinder 1 Injector Overcurrent High Side/Low Side

- P0204 - Cylinder 4 Injector Current Decrease
- Cylinder 4 Injector Circuit Load Drop
- Cylinder 4 Injector Overcurrent High Side/Low Side

- P0235 - Boost Pressure Sensor Plausibility
- Boost Pressure Sensor Signal Voltage Too High/Low

- P1130 - Fuel Rail Malfunction Small Leak Detected (Fixed this)

I couldn't find codes P0460 and P0836 in the manual, so I did a google search and got this

P0460 Fuel Level Circuit Malfunction
P0836 Four Wheel Drive Switch Circuit Range/Performance
__________________

The codes that interested me the most were

P0110 - Intake Air Temperature Circuit Signal Too High/Low.

And

- P0235 - Boost Pressure Sensor Plausibility
- Boost Pressure Sensor Signal Voltage Too High/Low

Both of these codes I assumed relate to the Boost pressure sensor since it doubles as an air temperate sensor as well. I compared the ohm readings from all the pins of this sensor compared to Billybob's from Lost Jeep Forum and they're comparable

Measuring pin to pin resistance from Pin 4 Dark Blue/Yellow Stripe facing front of Jeep.

Pin 4 to pin 1 5.505 k Ohm
4 to pin 3 10 k Ohm
4 to pin 2 6.65 k Ohm


My Results are comparable.**
4 - 1 ... 4.773 Ohm
4 - 2 ... 6.82 Ohm
4 - 3 ... 10.03 Ohm

_______________________

I also cleaned all the chassis grounds and can now confirm that pin 1 on the connector is properly ground.**
https://drive.google.com/file/d/1ngJ_HZ ... sp=sharing
I checked pin 3 which is supposed to be the sensor reference voltage which from my research and understanding is supposed to be 5 volts but I get a reading of 6.91 Volts with the ignition on.**

So my questions are .....**
1. What could be causing this high voltage reference
2. What are the potential symptoms**
3. Where do I start in fixing it?

I also checked the ECM ground using the manual procedure and all the tests were satisfactory.

That's the story so far. Anyways if this proves to difficult for me I wouldn't mind some advice or a good Jeep mechanic that won't spend as much time in looking for the problem as I have. I'm in Southeast Victoria.

Thanks in advance.

[TR Laredo]

I’d be checking for bent valves & correct camshaft/valve timing.

[Rob.fer07]

Thanks for the suggestion. How would I go about checking correct valve timing.

Also on a suggestion I disconnected the CAC hose which goes from the intercooler to the turbo and there's no suction but instead blowing.

Sent from my Nexus 6 using Tapatalk

[TR Laredo]

You’ll need the workshop manual info which details the positions of the timing alignment marks for the crankshaft & camshaft(s).
Air inlet from air cleaner to turbo will have normal air pressure.
Air outlet from turbo to intercooler/engine will have positive pressure provided the turbo is working ok & there are no holes/ air leaks in the hoses/piping

[Rob.fer07]

I do have the manual. I'll have a look at that.

Sent from my Nexus 6 using Tapatalk

[layback40]

You may wish to do a compression test & check the 2 injectors that are faulting. If the timing is out, chances are you have bigger issues that will need the head off. I think you have an injector issue. would not hurt to clean the MAP sensor.

[Rob.fer07]

I'll do a compression test next. I have cleaned the map sensor. As a test, I disconnected the map sensor (boost pressure sensor) while the car was running and found it made no difference whatsoever, which lead me to believe that it wasn't working but on checking it out against Billybob's it seemed fine.

Sent from my Nexus 6 using Tapatalk