Lumpy running at constant speed...

mjrimmer said:

Another thought....try running it with the synergy disconnected and also unplug your maf. It should then run on default maf values and will prove if the maf is ok.

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I've got a bit of a run to do tonight so I'm going to turn the box off and see if that makes a difference.

I have the standard MAF, not the pierburg one.

After that I'll remove totally and then if still ****ing about I'll find somewhere (challenger 4x4 in Tongham perhaps?) with a computer and get it plugged in.

bsa77 said:

I've got a bit of a run to do tonight so I'm going to turn the box off and see if that makes a difference.

I have the standard MAF, not the pierburg one.

After that I'll remove totally and then if still ****ing about I'll find somewhere (challenger 4x4 in Tongham perhaps?) with a computer and get it plugged in.

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Yes.. But running it all put back to standard and your maf left disconnected, forces the ecu to run on default maf settings........all this will do is prove that you maf is ok and you would be able to cross tis off the check list.
When plugged in to a test rig it is very rare for them to pick up problems with a maf. I think roveron has a big write up on maf problems on the tuning diesels website.

I had similar (but not exactly the same rough running problems). The local Land Rover dealer found no faults logged but thought the injectors might be faulty. They wanted £700+ to change them. I took it to a diesel injector specialist, he tested the injectors and found nothing wrong with them. However he did find a fault logged regarding the fuel pressure sensor. The lead from this back to the ECU had been replaced in the past and the terminals looked OK so he replaced the sensor (not cheap, but a lot less than £700) and the car has run perfectly since :lvfingerscrossed: and :lvtouchwood:

bsa77 said:

It idles at around 700-800 and sometimes bounces around a bit between the two, then the worst bit is just over 2000 RPM at constant throttle.

No EGR valve, was removed but I had this problem before and after!

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As far I have read, the turbo kicks in at 1750rpm after which there is excess air being forced into the intake, so the MAF is not as important.

Did you clean the MAP sensor? I'm just clutching at straws to be honest.

Another thought after having a few drinks..........
Don't know if they would cause the problem.....but has the turbo vent filter and Pcv (crank case breather ) been changed at the last service........oh well I'll just pour another large nightcap.

With Synergy turned off it made no difference, apart from being a bit slower. Still randomly rough however I have noticed, now I have the windows down that it sounds weird - not quite a pinking sound but not far from it, at the same time as the roughness hits.

Not changed the breather filter although I have just ordered one - didn't know about the turbo vent filter - will look into that.

This weekend the synergy unit is coming out so will be able to eliminate that.

If you give it a rev with the clutch dipped does it clear the rough running and maybe blow a bit of smoke from the rear.
Its sounding a bit more like an injector may be on it's way.

no load (clutch dipped or in neutral) you wouldn't know there was anything wrong!

mjrimmer said:

If you give it a rev with the clutch dipped does it clear the rough running and maybe blow a bit of smoke from the rear.
Its sounding a bit more like an injector may be on it's way.

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bsa77 said:

no load (clutch dipped or in neutral) you wouldn't know there was anything wrong!

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Any update on this? Having similar problems

I had a similar problem and it was an injector, got my local independent garage to check the cylinder balance with a plugin gadget and straight away it showed a failing injector, so I bought one and fitted it today, now like a new engine.

I'm pretty certain I need to get a new injector, new crankcase breather has been fitted and didn't have an effect on this problem. Last chance check over this weekend and if nothing comes up then I will order a new injector.

It has been getting worse and I've noticed the idle becoming lumpier too.

Reading Mr K's experience, how can I find out if an specific injector is faulty or not myself? It isn't a case of not working all the time, much more intermittent.

Find a garage that has a land rover diags system as this will tell you if there is a faulty injector and which one it is, it's called a 'cylinder balance test'.

Last weekend I decided to have a last ditch effort at fixing the running issues with my car - firstly I removed all the Synergy stuff again and started the engine, a bit less lumpy but still not great. Replaced fuel filter and the oil breather and started again.

No noticeable difference so pretty much concluded it was an injector. Just thought I'd check all the connectors from where the Synergy unit had been, two of them had quite a lot of corrosion on the non-synergy side (so the Land Rover connectors), cleaned this up with some contact cleaner and a toothbrush, reassembled without the Synergy - perfect!

Went for a run, perfect still so decided to reconnect the Synergy box - ECU light came on and throttle didn't work, but perfect idle so rechecked all the synergy connections and recleaned them.

The result is perfect running, smooth idle and cruising and now I'm back to setting four, lots of umph!

Thanks for all the help with this!