Freelander 2 (LR2) Rough idle

Ok, thanks....so seems like an (undetermined) intermittent fault causing the EGR valve to open excessively.
Maybe related to the throttle pedal position sensor fault?..(scratching head)..scanner is not showing faults for the o2 sensor, but no live readings either.....

coltron1 said:

Ok, thanks....so seems like an (undetermined) intermittent fault causing the EGR valve to open excessively.
Maybe related to the throttle pedal position sensor fault?..(scratching head)..scanner is not showing faults for the o2 sensor, but no live readings either.....

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That would be strange as you wouldn't have thought they would build an EGR valve that could pass more gasses than the engine could handle, and the most it can handle is at idle.

Maybe they do though, maybe it enables an easier 'cleaner' flow of gases in the range that it should be allowed to open. Or maybe it just comes from a parts bin that's shared with bigger engines.

Thanks (Grumpygel) I think the EGR module may be intermittently getting wrong instructions from the ECU when the engine is idling, as the smog/smoke created out of the exhaust is definitely more than the CAT can handle when the phenomena occurs.Maybe the egr valve doesn't know where its at before the signal changes again...EGR valve is opening and closing bout every 7 seconds...

GrumpyGel said:

That would be strange as you wouldn't have thought they would build an EGR valve that could pass more gasses than the engine could handle, and the most it can handle is at idle.

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The EGR valve is sized to flow enough for correct operation at high engine speeds, so it closes at lower speeds, to maintain the correct ratio.
The ECM controls how much the valve opens and when.

coltron1 said:

Thanks (Grumpygel) I think the EGR module may be intermittently getting wrong instructions from the ECU when the engine is idling, as the smog/smoke created out of the exhaust is definitely more than the CAT can handle when the phenomena occurs.Maybe the egr valve doesn't know where its at before the signal changes again...EGR valve is opening and closing bout every 7 seconds..

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I'm wondering if the engine needs an air path calibration.
It seems something has gone out of spec, which needs bringing back into spec.

Hi Nodge, sorry bout late reply. I,m certainly ruling nothin out..how expensive is the software needed??

coltron1 said:

Hi Nodge, sorry bout late reply. I,m certainly ruling nothin out..how expensive is the software needed??

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The software is available for free, but you also need a special cable to connect it to the vehicle.

I started a thread on SDD as it's going to be more relevant as these vehicles start to be repaired by the home mechanic.

https://www.landyzone.co.uk/land-ro...-experiences-help.365631/page-14#post-5514844

cheers, I will check your thread out thanks.
The fault is definitely intermittent, which is leading me to think this could be an electrical issue, bad connection somewhere on the loom, ecu, egr , o2 sensor, throttle body maybe?

Ying yang (idle) balance has been restored...

figured if ebay crank sensors can have slightly thinner contact pins, (read that in another post) causing intermittent signal, may be the ebay MAF i had installed has too?........so got my scanner out and watched the egr position values on live wave function while simultaneously moving the MAF connector plug around a tad.....this action made the egr spike at 90 percent at idle...

Putting my old MAF back on and scanning again, I noticed the egr live wave values were (especially the wave form), was less erratic with no spikes....The ebay MAF appeared to work fine when I bought it i.e. decent g/s readings, but the effect on the egr valve can be a different story........Thanks again to Nodge, (you were in the right ball park from the off of this post) and Grumpy gel comments, all good stuff.

I've concluded that the ECU - EGR , depends heavily on the MAF for correct idling and other functions.

Hope this post helps others with idling issues (check MAF - plug contacts - wiring)