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Discussion Starter #1
Hi Fellow Range Rover Owners,

I've used this site many times to help me diagnose issues and have used the various user guides on common services items.

To that end, yesterday I replaced the PCV valve with 89,000 miles on the clock. On inspection the two breather hoses connected to the oil separator were shot, spongy with holes at the points where the pipes were not straight. The additional small pipe at the bottom of the separator was shot along with the 4mm inner diameter vacuum pipe connected to the PCV valve.

This is, I understand, pretty normal. Pipes replaced marked with red arrows on the attached image.

All went well - it was tight back there with myself looking like a beached whale lying on the engine but all the pipes were eventually replaced. I also replaced the air filter, changed the oil and filter and the coolant, since I didn't do it when I replaced the radiator last month (I have had 3 rads in 6 years).

The engine started, and ran fine and then it switches over to LPG after it was warmed up. I approached a junction, braked as usual and it stalled. I repeated the process and I noted the revs dropped to 250 or so and then it stalls. I switched it back to petrol and it dropped to ~250 rpm but didn't stall.

Umm, I thought, this used to happen when I first had the LPG system fitted 6 years ago. Just after the system was fitted the car used to stall when approaching left hand bends while braking (typically roundabouts - I am in the UK and the system was fitted in Winter)

Back to the LPG installer it went - alternator it be, alternator it was not after having it serviced. The diagnosis of the alternator was that, if the voltage output dropped below a threshold the LPG system shut down. All made sense but now in light of yesterday's happening it was simply due to very low revs and thus lower voltage. The low revs happen on LPG and on Gas / Petrol but only the LPG system shuts down on low revs to close the LPG valve.

Over the years the stalling issue disappeared. No doubt due to perforated pipes on the PCV valve? Additionally on petrol if I blip the accelerator I can get it to stall.

So fellow owners, I am at a loss, what could this be? In summary:


  • 2003 L322 - 4.4 V8 BMW M62 engine - 89,000 miles on the clock
  • Perforated PCV valve breather pipes
  • Replace PCV valve, associated breather pipes, air filter and oil
  • When braking at junctions revs drop to ~250rpm and on LPG the engine stalls, on Petrol / Gas revs recover - no stall.
Links to simialr question:

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/41057-stalling.html

Answer from gyrogypsy quoted below:

"Mine is also LPG, and if you switch over to LPG when the car has just warmed up, at idle it runs quite rough (only when it has been running for some time does the idle roughness disappear). Never drops below 500rpm though.
The increase in revs after the drop is normal, as the engine management can see a stall coming and will increase the throttle to compensate. This can only be one of two things causing this... air or fuel. As it is happening on both fuels, you can look at:


  • The throttle position control (pedal)
  • Air intake (filter clean?)
  • MAF sensor failing (should throw up some other errors also)
  • Fuel pressure (as it happens on both fuels then look at injectors, but unlikely).
  • Other possibilities are output speed sensor problem giving intermittent bad RPM data to the ECU.
Charlie
 

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Discussion Starter #3
Additional info:

So to add to my fun I now seem to have a minor oil leak and coolant leak - I didn't want to start another thread as the oil leak could be be related...

Oil leak

The oil seemed to be dripping down the larger pipe from the cyclonic oil separator. It's not enough to drip on the road but the gremlin should not be there. I shone a light and tried to see if it was actually dripping down the outside of the pipe as I replaced the rubber pipe that connected the metal pipe to the separator with 13mm ID tubing. I struggled with smaller ID tubing so resorted to larger tubing and a more fully tightened jubilee clip.

I couldn't see any oil dripping down the pipe but I did see a small drip on the underside of the block casing below the half moon of the outer valve gasket (that is my next job). It was only a small drip, could this drip work its way down onto the oil separator pipe? I could have had this leak for a while?


Coolant leak (should really be in a different thread but I made one video)

This is the one that I don't like. I've had significant coolant loss before and the car is not driven by me but my better half and checking the water before a drive does not happen - fair enough as things should just work.

I've seen the usual leaks from the underside of the rad and have yet to see a valley pan leak - I'm waiting for that one, this one is just plain odd!

I spied a drip on the underside of the front tubular sub frame (I assume it is a regular sub frame) - left hand side if looking at the car from the front (driver's side in the UK, passengers side in the US). Up it went on the ramps (I had to find the oil leak anyway) ...this drip was a puzzler. I've made a terrible video but to those with more knowledge than I it will hopefully make sense (I'd just done my back in so please excuse my grumpy tone)

Any ideas where this leak might be coming from?


n.b. the rad/block was filled with water before as I had to do a quick rad change before driving 1000 miles and the shop was closed to buy coolant so 100% water it was. The result was that the coolant leak had probably been around before but the water simply evaporated.

Charlie
 

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Discussion Starter #4
...I mentioned in my first post that if I blipped the accelerator a noise resulted and I could get it to stall...video below..

 

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Silly me, two pages of post back on this forum I found

http://www.rangerovers.net/forum/6-range-rover-mark-iii-l322/129306-revs-dropping-really-low-when-coming-stop.html

Which is exactly what my original reported issue was? The question for me is why would the the new pcv valve and hoses reinstate the issue that I had 40,000 miles ago and what is the odd noise on blipping the throttle...strange...

I will investigate the throttle body this coming Thursday - day job takes me away from home...

Charlie
 

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Personal thought is that it's not the throttle body but there would be no harm in giving it a thorough clean before anything else.. The sound your hearing I think is the throttle body slapping open fast, putting massive suction on the upstream air intake pipe work. The sound is the sook of the engine.

The symptoms are similar to issues I had. Turned out to be the mass airflow sensor. It's extremely sensitive, and the ecu system around it is extremely sensitive to itworking correctly. If it can't sense the flow correctly then the engine gets a false reading about how much air going in ... So fuels for the wrong amount of air and so the idle is affected. Symptoms show at lower revs cause the air flow is much less, so errors in the reading are more influential.

The LPG system piggy backs the petrol system for its readings, and LPG is more sensitive to wrong fuel ratio, often just dying as soon as it gets too rich. ( from my experience of tuning an old carb LPG system).

If you're considering getting a new mass air flow sensor, then only get a genuine one from the dealer ... Nowhere else. The aftermarket stuff is just not accurate enough is my experience.

Now, why would the PVC valve change make this appear again? Perhaps the old pipes were letting air in from somewhere which was allowing the engine to self balance errors with the air flow sensor.

Just my thoughts .. It's been a few years since I had my rangie.
 

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Hi Charlie, Hope you are still watching this one, did you ever get sorted with this as although i don't have LPG I have similar issues.
Andy (I think i know you from another forum)
 
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