Erratic Idling !!!

Hi,

I recently bought a 2005 Freelander TD4 Adventurer. Over the past couple of weeks, when the engine is warmed up, the idle speed is erratic (surging), to the point of near engine stall. A good rev of the engine temporarily cures the problem. I suspected dirty fuel but. several refills and a good dose of fuel additive hasn't cured it. Just as i think its cured it starts again.
I read on other sites about a 'MAP Sensor'??????????
Can anyone help solve this mystery please

Thank you

Ian

try yer fuel filter, i duno about the freelander but my disco idles like a bastard when the fuel filter is dirty

yella disco said:

try yer fuel filter, i duno about the freelander but my disco idles like a bastard when the fuel filter is dirty

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HAHAHA!!!

Cheers ...i'll give it a try

as its 05 i cant see the filter being the problem they last 60k before it needs changing,

sounds like a fuel pressure issue in the high pressure side, you may have a poor connection to the fuel rail pressure sensor, thus giving the ecu a false reading.
best pop it in to your dealer for a fault code read its probs something really simple

LR GUY said:

as its 05 i cant see the filter being the problem they last 60k before it needs changing,

sounds like a fuel pressure issue in the high pressure side, you may have a poor connection to the fuel rail pressure sensor, thus giving the ecu a false reading.
best pop it in to your dealer for a fault code read its probs something really simple

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Thanks mate. It seemed strange to me too because its only done 8000 miles! Its due a service soon anyway so i'll book it in now. I'm not a motor whizz and don't really understand what you mean but i'll quote it to the mechanic.
Thanks for your help

Ian

Has anyone got to the bottom of this erratic idling problem. My 04 TD4 is doing the same. 36k on clock - tried new air filter, fuel filter etc. Has roverron box but appears to do the same whether this is on/off. It's out of warranty so reluctant to take it to the steelers before I try all (fairly) simple fixes.

Ideas anyone?

have yu tried pm'ing Roverron - I gather he is quite helpful.

Will do...
Ta

try pulling the connectors off each injector in turn , see if its a bad injector, it was on my td4 70k, injector cleaner eventually sorted it ,,, good luck

john t said:

try pulling the connectors off each injector in turn , see if its a bad injector, it was on my td4 70k, injector cleaner eventually sorted it ,,, good luck

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Thanks john t - will try that at the weekend and through some inj cleaner in the tank. Given that it's only got 36k on the clock and having replaced fuel filter I'm not confident this will be the fix. I'll also try the connections on the fuel rail pressure sensor (I'm assuming this is the one roverron's box goes into?)

it took two full tanks with injector cleaner in and several blasts down the motorway to clear my duff injector problem,
now its running great it thinks its a ferrari not a BMW,,,,

john t said:

it took two full tanks with injector cleaner in and several blasts down the motorway to clear my duff injector problem,
now its running great it thinks its a ferrari not a BMW,,,,

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Hi ,can you name the cleaner you used
no probs with mine
but still like to know

Ta rich

john t, If I were you I would still pop out the fuel pump and check the screen at the bottom of the pump body. I got hold of some lousy gas a few months ago and it gave me fits until I pulled the fuel pump apart and washed the screen out.

Its a 2 hour job, and I think it is worth the effort.

the injector cleaner i used was redex diesel cleaner, about £15 a bottle, i put the full 0.5L bottle in a full tank of fuel, the results can only be described as a total transformation, engine now idles very smooth and accelerates crisply, money well spent,
i am now following mings advice putting in a litre of cooking oil,
john t

I did the litre of cooking oil bit and its improved the bouncy idle no end. Plus it pulls better.

I still appear to have this problem runs ok, perhaps a bit lumpy during normal driving no probs on acceleration, when idiling it stutters almost to the point of stall - it's intermittent (although seems more frequent recently) so I'm stumped.
I think my MAF may have some degradation, so I've switched MAF compensator on TU3 (Roverron Unit) on - performance and economy is better since doing so, but erratic idling has got worse.
Have tried injector cleaner (Millers and Redex) have tried the cooking oil additive etc. Next step is to unplug ronbox altogtether and see if problem is still there. (might identify poor connection somewhere)
I'm also going to try unplugging injectors in turn - hopefully this won't be an injector problem as that'll be costly. This fuel rail pressure sensor that's been mentioned how can I tell if it's faulty -if faulty is this a part that can be replaced DIY (and where can they be obtained)?

have you checked all the vacuum pipes ?you only need one to be worn and it will give you problems , also check that the turbo boost control is not stuck

john t said:

have you checked all the vacuum pipes ?you only need one to be worn and it will give you problems , also check that the turbo boost control is not stuck

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Thanks JT - will check the pipes although I'm probably going to replace as I understand even the tiniest of leaks can give trouble (smokin etc). Turbo boost control - how do I check?

This is probably one to run past Ron, but here's the latest findings..

Switched MAFAM (TU3 Synergy) off and idling while not perfect improved. Next I unplugged MAFAM compensator wiring plug and replaced with orignal, kept TU3 lead (that goes to the fuel rail) in place and idling problem is no more. Also replaced air filter today (old one wasn't bad but had done around 7k on it) also and runs like a dream again. So while I'm happy I'm still confused - why would the MAF compensator cause the eratic idling?
Not checked fuel consumption yet, but no smokin and it pulls well again.
Should I be looking to replace the MAF? - I have the TU3 so can opt for Ron's Pierburgh.
Any advice appreciated.

Have exactly this problem with a 2005 Td4 Adventurer with 80K miles. Never fails to start and can run ok every day for weeks but will then start idling erratically to the point of stalling and run roughly at cruise speeds.
Two LR specialist garages have failed to diagnose the problem with Autologic. Injector leak off test ok and diesel system cleaner added.
Question is, if the problem is the high pressure sensor wiring loom, would that show on diagnostics ?