Something curious and maybe nothing to do with the driving issue but not sure. I started the car up yesterday after work and the radio came on but no sound all the way home.

Just wondering if my driving issues could be electrically related? I did replace the alternator a couple years ago and did not go with the OEM part. Used a cheaper one around $300.

Thoughts?

 

So I finally have time to start working on my LR3. I did clean the MAF yesterday and will be driving about 30 miles today. I assume it will take a little bit for the system to reset itself if this was the problem. One side of the MAF was pretty black in color. Other a shade of deep red.

I am going to perform a BG treatment. Not really familiar with this so can somebody just elaborate to make sure I am doing the correct thing. I see a BG oil treatment BG RF-7, is this correct?

I will also be cleaning the TB today.

I may have asked this before but when the adaptive memory is reset on the pcm the car runs fine. Is there a way to lock in these setting and not have the sensors override things? At least until I get the problem fixed.

Thanks.

 

Took my first ride after cleaning the MAF sensor. Just like before the first mile or so was really rough, as a mater of fact much worse than before I cleaned it. Straightened out after that an ran fine at higher speeds.

Drove about 15 miles and then drove home about 90 minutes later. Not really any issues with this trip even at startup.

Cleaning the TB next.

Thanks.

 

Still have serious issues with my LR3. Cleaned MAF sensor, cleaned TB, Replaced Air filter, put in fuel treatment, spark plugs replaced recently.

Issue is getting pretty consistent. Starts up and idle is a little rough bouncing between 300-1100. No mater if I let in run a while or not, runs very rough for about 1/4-1/2 mile and then revs up to 4000 as I accelerate, coughs and then runs fine. During the first 1/4 mile or so I can push down the gas pedal and car will run at 3-5 mph then a little faster but I feel like I am riding a bull. Not that I would know but you get the point.

I have had a few strange electrical issues, radio not working a couple times, bonnet open message several times, engine light on (but plenty of codes in previous post), tire pressure light on.

Reminder that when the car is reset to factory settings it runs fine for 20-30 miles.

Could this be a electrical issue?

I have been driving about 50 miles daily now for 3 months with the issue.

Thoughts?

I guess it is going to a mechanic soon.

 

What is likely happening is that when the reset it being done - the PCM deletes all of its recent learned history about fuel/air mappings and falls back to the factory map. Then as you drive it - it is listening to the sensors (what's coming into the motor and what's leaving the motor) and then it starts adjusting the fuel(short and long term trims) based on the data its getting from the sensors as you continue to drive. So, something is causing the information coming into the PCM to be such that the PCM is changing those trims trying to correct for it but it's not doing too well. You really need to see your fuel trims (short and long term) to gage what the heck is going on in there.

It could be un-metered air (cracks/leaks) in the intake assembly (the plastics do get brittle), bad sensors(mass air flow), leaks in the exhaust, bad sensors there too. Approach it pragmatically. But the fact that it runs well after the reset says that the engine can run OK with what the factory thought was a good starting point. So that's a good thing I believe.

 

Also - it is a CANBUS system - so if any wiring is screwed up, that can cause erroneous information to the PCM and then it makes crappy decisions based on crappy data. And LR wiring in the LR3 can be a problem. Any water leaks lately?

 

I am seriously leaning toward electrical but not sure if wiring or the PCM itself. Any significance to the Bonet Open light coming on? Also, just curious if all my codes could be a result of electrical and PCM.

Thanks.

 

I may have asked this previously, damn old age, but what symptoms would occur with a bad TPS?

Reminder of codes;

P0506-24, P0016-00, P0018-00, P0622-00, P0171, P0172, P0174, P0175, P0316, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0101

Thanks

 

Hi bhermes. I'm new to the LR3 platform, but not to diagnosing issues with vehicles. After reading your thread and looking over your list of DTC's, I think you may be correct about it being an electrical issue. The question, then, is what part of the system is causing the issue.

My BMW is very sensitive to electrical system voltage, and it will wreak havoc when voltage is low. I see that one of your codes is P0622, which indicates you may have a grounding problem, or a bad alternator altogether. You can cross this off the list by checking voltage at the alternator with a multimeter while the engine is running.

I don't ever advocate throwing parts at a problem without making sure that's the issue, but if you can't do datalogging with realtime data while the car is running it is difficult to really narrow down the issue (though a competent mechanic should be able to)

You have both lean and rich AFR codes, along with multiple misfires and codes for camshaft position sensors. So we have three issues indicated by your DTC's.

1. Timing
2. Air
3. Fuel

For timing, you have the camshaft sensor position sensor and the variable valve timing solenoid that could be the culprit. The camshaft position sensor is cheap and easy to swap out, so maybe throw a part at that? Check for leaking oil around the VVT solenoid. Because it uses engine oil to actuate the valve timing changes it might get gunked up if you run longer between oil changes. See this thread for more info.

For air you should check for vacuum leaks anywhere between the MAF and the throttle body. Also check around the intake manifold and any hoses that come out of them.

For fuel, you may have an issue with your fuel delivery. If you've never done it you should consider changing out your fuel filter just because. Have you haver had your fuel rails and injectors cleaned with a pressurized system?

For both fuel and air you have already addressed two parts of the system by cleaning the MAF and the TB. It could also be your O2 sensors. You have four of them, and the PCM uses input from them to adjust your fuel trim. It's not really cheap, but you might need to swap out your O2 sensors, particularly the pre-cat ones.

All that said, if I were making a diagnostic plan for your problem without the ability to track live data on the running vehicle, I would go in the following order:

1. Check the voltage at the alternator while the engine is idling.
2. Check the VVT solenoids on the valve covers. Is there oil weeping out of them? It could be sludge buildup causing your issues. A low budget way to try and fix this is running seafoam through the car or using an engine flush method like described here. I've not done either of these, and would only consider it as a last resort. Do some internet research and weigh your risk tolerance.
3. The engine runs ok when you reset adaptations, but quickly goes back to the same state as you drive. That indicates that it is not likely anything in the fuel system. The PCM uses data from a variety of sensors to adapt over time. I would think you have a problem with intermittent signal from any of the sensors (MAF, MAP, O2, CPS, etc.) or a faulty sensor itself. You can only completely rule that out by measuring voltage and signal during operation. Since you don't have a scan tool that can do that, it's hard to not say to replace those sensors one by one until the problem goes away.
4. Get a new mechanic.

 

srey, what a great post.

Any chance this could be all related or mostly related to a bad ECU?

I do have access to a scan tool but not sure what to look for? Or for that matter could take it to a "new" mechanic and have them do it.

Good or bad I did try the seafoam with no improvement.

In regards to alternator I will check today. Not sure if you noticed in one of the post I did replace the alternator a couple years ago and did not go with the $1100 OEM part. Maybe over time this has caused a problem.

Thanks.