Poor running

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redwood said:
I have read a lot of stuff on TD4 engine fuel management and how it all comes together, but still this engine smoke when cold and a blip, misfire or shudder at 2000rpm still baffles me how lots of you are still getting this after changing just about everything and then it hit me, the TD4 will open the EGR valve in temperatures below 4 degrees so the engine will breath hot exhaust gasses for it to warm up quickly, if you have a out of spec ambient temperature sensor that is showing colder than what it really is, hence opening the EGR valve this might be the cause.... well you never know ? Please correct me if I'm wrong but clutching at straws for you lot.
you will need to plug your FL into a diagnostic machine and check the temperature that is being read by the freelander sensor and compare it with a thermometer placed in the engine bay close to the one on the FL
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Interesting, and could be true. Unfortunately most other us would have to stick the EGR back on to try it. Weirdly, I'd been considering putting it back on recently, as I'm tracking down an electrical gremlin, and wondered whether the ecu was getting confused due to no feed back from the EGR. I also would like to know whether any BMW cars fitted with the m47 have this fault, or if it's bad coding from Landrover. Mike
 
They do, if the ECU is picking up a wrong signal from the ambient temp sensor then the engine will over fuel anyway on cold start and if the ECU does not get the correct signal when its warm it still could be over fueling slightly,
I really don't think it's an injector dribbling as my mate who has the same problem is fine starting in the summer when left overnight but as soon as winter comes it has clouds of white smoke when left overnight. Next week I'll plug in my ethos and read the dater coming from his sensors although he's not in the slightest bothered by it but me being a mechanic it bugs the hell out of me.
 
Another thing that sprung to mind is the throttle position sensors and the clutch switch but not too sure if Land rover use the clutch switch for engine fuelling management if you don't have cruise control, if they don't why is it fitted to mine ? Mission on lol
 
redwood said:
Another thing that sprung to mind is the throttle position sensors and the clutch switch but not too sure if Land rover use the clutch switch for engine fuelling management if you don't have cruise control, if they don't why is it fitted to mine ? Mission on lol
Click to expand...
Well keep us informed. Interestingly alot of the things you talk about are on the check list for the electrical gremlin(far to complicated and drawn out for this thread). But it would make sense that the EGR throwing an error(the only code mine shows, from a full diagnostic) would knock on to other systems, hence, over/under fueling, blips and hesitations. Funny thing though, 99% of the time mine runs great, but throws a major wobble 1% off the time. But I will not be defeated. Mike
 
I had the shudder/ misfire on the way to work this morning and on my way home tonight. It's mostly on down hill sections on a trailing throttle. I had my I930 plugged on for the homeward journey. The displayed values were intake temperature, MAP value and fuel rail pressure. The intake temperature didn't drop below 12°C the whole way so was definitely above 4° C when it messed about. The fuel pressure and MAP gave no indication of a fault while it manifested itself. Investigation will continue. But I'm going to reinstate the EGR valve tonight, if I get a chance.
 
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Just a little update on my misfire at 2K Rome. I recen disabled the EGR valve and only noticed the misfire after I'd done it. Well I re-enabled the EGR valve on Thursday evening and the engine has been running perfectly ever since. So the cure for me appears to have a functional EGR valve. I suspect this is something that will surprise many, but it worked for me. The engine is more responsive and doesn't miss on a trailing throttle. Hopefully that's the end of my problems at 2K Rpm
 
Nodge68 said:
Just a little update on my misfire at 2K Rome. I recen disabled the EGR valve and only noticed the misfire after I'd done it. Well I re-enabled the EGR valve on Thursday evening and the engine has been running perfectly ever since. So the cure for me appears to have a functional EGR valve. I suspect this is something that will surprise many, but it worked for me. The engine is more responsive and doesn't miss on a trailing throttle. Hopefully that's the end of my problems at 2K Rpm
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As I understand it, the EGR is closed at idle and WOT, and variously open inbetween. Do you think your misfire at trailing throttle was because the engine was expecting less oxygen, therefore reducing fuelling, and you were getting a lean misfire?
 
guineafowl21 said:
As I understand it, the EGR is closed at idle and WOT, and variously open inbetween. Do you think your misfire at trailing throttle was because the engine was expecting less oxygen, therefore reducing fuelling, and you were getting a lean misfire?
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Yep. That's my exact thought. It's not technically a leaning of the mixture as a diesel doesn't work like that. However I do believe the ECU is altering the way the fuel is delivered and screwing it up. With a correctly working EGR, it's definitely running better.
I'm thinking that removing the EGR and resetting the ECU adaptations might solve this issue. I'm not going to try to fix something that isn't broken though. For the moment, I'm just going to enjoy using it!
 
finally had time to plug in my mates freelander, live dater was spot on, everything was performing well but held the throttle at 2000rpm and misfire and clouds of white/grey smoke, while the thing was ticking over I ran a few more tests, egr actuator on and off a few times and retested map maf and fuel pressures which took about 10 mins, tried the 2000rpm test and perfect not a misfire or an ounce of smoke:( Now the only thing on the readings that was different the second time was engine temperature was at 88 and air intake temperature was at 37 compared to 71 and 29. Now me thinking was this engine running at normal engine temperature or is the thermostat stuck open so I asked my mate what position is the needle on the temperature gauge when he's done a few miles and he said between cold and normal. Correct me if I'm wrong but could the exhaust gasses returning back to the engine via the egr are not being burnt correctly because the engine is too cold causing that misfire and smoke, also do you think the AIT readings are about right. I think I'll have a cup of tea now
 
the exhaust gasses returning back to the engine via the egr are not being burnt correctly because the engine is too cold
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??????????????????? ..
the only substance that will burn is fuel .. surely ..
( early exhaust gas recirculation was meant to burn any unburnt fuel present in the exhaust gases
( i.e. some early 1970's petrol engines ..
anyhow .. the td4 egr is supposed to allow the entry of pre-cooled exhaust gases ..
in order to cool down the combustion process ..
afaik .. it's heat that causes the formation of the NOX

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

" NOx is a generic term for the mono-nitrogen oxides NO and NO2 (nitric oxide and nitrogen dioxide). They are produced from the reaction among nitrogen, oxygen and even hydrocarbons (during combustion), especially at high temperatures."

  1. NOx - Wikipedia, the free encyclopedia
    https://en.wikipedia.org/wiki/NOx
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
You might be onto something with the temperature. My thermostat is dead so the engine sits at about 70°C. This might be over cooling the exhaust gas through the EGR system. Cool gas is dense gas. This might be causing an issue. I think it's more complex than that though. :(
 
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Whatever it is the lack of heat is causing it. Those who have this problem try leaving the engine run until the engine temperature is normal and try holding the throttle over 2000 rpm and below 3000 rpm and let us know the results. My thinking was that some have blanked the egr with results but there again the ECU might enrich the amount of fuel with a cold running engine, what I'll do next time is shove a gass analyser up the exhaust and monitor what's coming out hot and cold tests.
 
One of the biggest killers of egr valves in diesels is constant low mileage trips where the engine temperature never really warms up so they Coke up. Believe me I work on a fleet of vehicles that are constant stop start and it went to the stage when we told drivers to take it on the motorway and give it a good blast, this has now eliminated most of our egr valve problems.
 
A friend of a friend asked me to have a look at his FL with the same problem, easy I said, is reaching normal engine temp, yes came the answer so agreed to take a look, turned out that the vacuum pipe to the EGR h ad perished and the EGR was stuck solid so replaced all pipes, cleaned the EGR, and now holds at 2000 rpm with not an ounce of smoke and the stutter on a trailing throttle gone. The only other thing I done was clean the temp sensor.
The owner said on road test that the turbo boost is much better too so probably the turbo boost valve wasn't getting full vacuum because of the brake in the system. Hope this helps
 
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