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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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| 4.4 V8 engine surging & reduced engine performance |
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Chaps
Done a quick search here as well as on rrsport but nothing's come up, so I'm wondering if anyone's had anything similar. My 4.4 V8's having a little episode and the LR dealer have been stumped by the ecu download (not surprising really).
I'm getting the reduced engine performance indicator on the dash and an occasional EML (although not always) , always when it's coasting along or stuck in stop/start traffic. To be honest the performance isn't reduced, it's just not right. The engine surges up / down about 100rpm when on a constant throttle between tickover & 800rpm, then also between 1200 & 1600 rpm so it makes driving it quite uncomfortable, it's like driving a ship ! They downloaded the fault codes last week and came up with MAF sensor issues, lambda issues, running lean & running rich on a couple of cylinders. They've blamed it on the LPG system & the K&N airfilter so consequently wont touch it, which is fair enough and something I've always accepted.
Trouble is, all these issues are when it's running on petrol, I'm rarely on LPG at the moment and haven't been for a while, so although I know the lean /rich fault is due to the LPG, in my view the MAF & lambda aren't, so I'm wondering if anyone here has had MAF or lambda sensor issues on a petrol V8 ? All help / ideas greatly appreciated. Does anyone know if the MAF sensor is self cleaning or if the oiled filter screws them up ??
Thanks for reading what is a bit of a long post, but although I've got some ideas I'm a bit stumped with this one.
Cheers
Mike. BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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 1st Feb 2011 3:25 pm |
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PaulP
Member Since: 04 May 2007
Location: Barcelona
Posts: 4317
  
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Just a thought....can't you get them to clear all of the fault codes and then "promise" to run only on petrol until the next time if fails (or maybe disable the LPG system in some way)?
At least this way the errors can't really be attributed to the LPG system unless they try and pin it on the installation 
As I said, just an idea. You're right in accepting the responsibility for any problems caused by the use of LPG, but if you can prove it's nothing to do with it, then they should at least try and help you fix it....
Cheers,
Paul 2006 Discovery 3 TDV6 SE Auto Buckingham Blue
2007 Golf GT DSG
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| 1st Feb 2011 3:55 pm |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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Yeah, it's been cleared and only run on petrol since, took it about 50 miles before I got stuck in slow traffic and the warning came up again. Sadly disabling the LPG system isn't that easy, although it's switched off and I could pull the fuse on it as well, it's still physically connected to the injectors so LR wont touch it as they don't understand how they operate (or need to). For them to be interested I'd have to remove the system entirely.
I'm going to try cleaning the MAF sensor, I've got it in my head that K&N's don't mix too well with hot wire MAF's, but I'm not sure whether the LR MAF is likely to be affected in that way, some are and some aren't. BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 1st Feb 2011 4:22 pm |
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dtest
Member Since: 02 Jan 2011
Location: Weybridge
Posts: 140
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I guess your LPG system is a sequential system that takes the LPG injector opening and closing signals from the original petrol injectors??
This should present no problem to LR diagnostics when the system is switched off and isolated!! They are fobbing you off as they really dont know the answer.
I had a similar problem on a DAF truck that was stalling, 'coughing and spluttering' when either coming to a halt or creeping along in traffic. Had injectors changed, inlet manifold pressure sensor and even engine speed sensor and still no better!!!!
Until we changed the alternator and all the symptoms disappeared!!!
Apparently the ECU requires a very good stable current and when the alternator was running above 850rpm ( engine speed) it was happily supplying the correct current but anything below this and the current quality (or lack of it) was causing the ecu to 'switch on and off'....
Check your alternator 
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| 1st Feb 2011 6:19 pm |
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vnitos
Member Since: 17 Oct 2010
Location: ZA
Posts: 61
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MikeS, the battery and/or alternator can also play a role in the symptoms you described - had similar symptoms on my platkar. Also, it could be that there is oil on the MAF sensor resulting in the erratic idling/ poor performance.
hope you get it sorted out
trevor
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| 1st Feb 2011 8:38 pm |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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Thanks for that. The battery's almost new and is from a TDV8, so certainly has enough beans in it. I'd not thought of the alternator though and it's worth me getting it checked, I think the bearings on it have been rumbling for a while after I dunked it in some deep water last year.
I've cleaned the MAF sensor tonight and it was quite grubby, a dark grey dusty colour and the orange 'bulb' on the bottom of the wire was black, so will see how it runs tomorrow. I'm thinking a MAF and lambda's might be worth investing in... BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 1st Feb 2011 10:17 pm |
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nags
Member Since: 14 Jan 2009
Location: in the hills
Posts: 71
 
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hi mike my v8s been doing exact same local indy said im the first v8 hes worked on when he looked at faults came up with only air flow meter running rich on left bank and running rich on rigth bank he cleared faults and told me to call next week and he would check faults again,has done the same thing since faults being cleared and he i pretty convinced i need a new air flow meter,was going to put up a post for any other sujestion but you beat me to it by the way i dont have lpg but sympotoms are the same if it aint broke dont fix it
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| 5th Feb 2011 7:51 pm |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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I'll be interested to see how you get on then. We found a knackered breather valve on mine that was leaking air & causing the lean / rich mixture on each bank, so replaced it, making a huge difference and in fact thought it was fixed. Sadly the fault came back 200 miles later so I'm off to see my indy again tomorrow night. Feels like the valve has gone again or another airleak somwhere.
Faults when downloaded last week were MAF sensor, lean & rich on each bank. Ran it whilst hooked up the laptop and watched the readouts for the MAF and all the O2 sensors both up & downstream, which is how we identified the broken breather valve. The MAF readouts when running were fine, so we suspect the air leak is then screwing up the MAF at some point. Have to admit I'm gutted that the repair didn't last, it ran better than it has for ages and fuel economy shot up. BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 6th Feb 2011 9:30 pm |
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thorgal
Member Since: 26 Nov 2008
Location: on the east side
Posts: 541
 
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Mike....If you have a code PO 101 within all those codes with banks rich and lean on both sides, you might want to check a THROTTLE BODY .Po 101 is usually associated with a MAF sensor fault, but my mechanic told me , that in LR3, is calling for a throttle body check up.I exhausted every possible scenario, replacing spark plugs, MAF, air filter, checked oxygen sensors, looked for leaks, but finally, went to dealers and after further diagnostics they told me , that throttle body sensor is shot, cousing all the symptoms, that you described and later even stalling, when turning and stopped at lights.Since sensor is a part of entire throttle body, I had to replace whole unit, but dealer was right on the money on this call. No problems ever since.Hope that helps. 
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| 7th Feb 2011 12:07 am |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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Will look out for that code tonight, cheers BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 7th Feb 2011 1:41 pm |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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PO101 was present and the new inline valve on the breather system is broken, with the characteristic whistling of an air leak again. Had a good look through GTR last night and there's no mention anywhere of issues with the throttle body, but we did get a breakdown of the breather system which was useful.
Cleaned up both the part idle and full throttle breather pipes to check them for leaks and none were found. Had a good look at the throttle body and to be fair, the butterfly was gummed up to hell and wasn't seating properly when closed / partly open so we gave it a good clean. It's made things slightly better and there's now less of an air leak on the valve, so I'm replacing that again and seeing how it goes, with a view to changing the throttle body if it goes again. My indy's view on it is the throttle butterfly being gummed up has put strain on the operating motor and probably knackered it, he's seen it on several other vehicles (not Land Rovers) and a new TB has been the cure.
Can't recommend the independant chap I'm using more highly, we spent from 6pm to 9pm last night working through it all, looking at GTR, cleaning bits up and trying different things and I can't see any other indy doing that ! If you're near Leicester (or even not near Leicester to be honest) then look him up, Stu Armson of Armson Automotive.
Thanks to thoral for this one, that may have just saved me the pain of replacing everything else and still having the same fault. BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 8th Feb 2011 10:24 am |
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thorgal
Member Since: 26 Nov 2008
Location: on the east side
Posts: 541
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| 8th Feb 2011 5:34 pm |
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MikeS
Member Since: 27 Jul 2007
Location: Melbourne, Oztralia
Posts: 81
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Just to boing this back up, after popping yet another breather valve I had a new TB fitted under warranty last week. Took some explaining at Stratstones as to how we'd come to the conclusion on the TB being knackered, but they agreed with me and put it through the LR warranty. The result is after 300 miles I appear to have no more faults and a properly working car, throttle response and even the gear changes are improved so I guess there's a link in the ecu from the throttle body motor position & the gearbox.
So, thanks to thorgal again for the heads up, the forum & Stu Armson for his patience. 8) BV55 YZE, ex G4 Challenge RRS. So not a Disco 3. Well, not quite.
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| 28th Feb 2011 10:45 pm |
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