 | Home > Puma (Tdci) > Help! Surging power in 2.2 |
 
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20355  
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Failed clutch switch, VCV or EGR are the typical culprits.
EGR typically flags DTC's or MIL aka amber dash light. VCV flags not DTC's up at all. Clutch switch should flag DTC's, but I found that on mine it didn't as it was operating but not as it should. If you find its after bringing the clutch up in gear, under light acceleration. The clutch switch is likely. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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2nd May 2020 4:35pm |
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| The Fox Member Since: 24 Mar 2014 Location: Shrewsbury Posts: 94 
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I thought VCV issues were exclusive to the 2.4 and weren’t a problem on the 2.2. Will do some reading.
I wasn’t aware of a clutch switch! Is this the actuator in the clutch pedal which holds the revs during gear changes? Any other tell-tale signs of egr failure? |
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2nd May 2020 5:16pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20355
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Yes, the clutch switch can cause a rev hang and a sporadic revving without driver input. Usually after gear changes. On a 2007 onwards you can bridge it just to test that it maybe at fault. It’s a simple 2 pin connector that requires a closed circuit. Unlike a TD5 you can’t just unplug it.
EGR issues seem more sporadic, clutch switch problems I found would show in seconds after being in-gear. Any of these things really mess with the fuelling and performance. I would take a look at the cheapest options first. I’ve bridged my clutch switch permanently but if there is a problem with it you can replace it. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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2nd May 2020 5:43pm |
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| The Fox Member Since: 24 Mar 2014 Location: Shrewsbury Posts: 94
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Update on diagnostics today - surging MUCH worse and happening on load (climbing hilly road). I was careful to see if the problem was happening exclusively after gear changes/clutch use - this isn't the case. It happens at any time, sometimes minutes after being in a gear and at any point in the rev range. Interestingly it doesn't happen at idle - during a period where it was happening really badly, I went around a car park at tickover and not a single hiccup - apply some throttle and it was surging/shunting almost immediately.
Connected OBD reader - FRP looks fine at tickover and with revs, so don't think its a high-pressure fuel pump issue. No fault codes found.  Click image to enlarge Throttle position sensor wasn't all over the shop and seemed to stay static when I held the petal still. The 2.2 has a lifter-pump in the tank, could that be causing the issue? It definitely 'feels' like a fuel/ignition problem, air in the line sort of surge. EGR seemed to open/close - self-cleaning cycle working fine on shutdown. Bad fuel? Tank lifter pump? EGR? Other? This is my first engine problem with my defender and I'm used to old english motorcycles/cars so forgive my ignorance! |
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3rd May 2020 2:17pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20355
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Turbo actuator and injector performance maybe worth looking at. A bit behind my scope of knowledge really.
If you have equipment capable of live view diagnostics that it appears you may have. It may be worth asking tuners such as BAS or Alive what specs you should be seeing. Fuel filter maybe worth changing as a possibility too, as there could be a fuel supply issue. MAF and MAP sensors are also worth checking. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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3rd May 2020 2:30pm |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 484  
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Yes, the renewal of all filters (air intake, diesel) would be most important. Is there any water in the diesel filter box ? That's an easy job to be done within 10 min Do you use your van often on short distance trips ? If so, I'd unmount the EGR and take a look inside ... P.S. You could also check with a Nanocom, if this issue only appears while the EGR is open ... Good luck |
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3rd May 2020 5:53pm |
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| The Fox Member Since: 24 Mar 2014 Location: Shrewsbury Posts: 94
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Today I fitted a new fuel filter and cycled the low-pressure system to flush any air though - no fix (also the previous filter didn't have anything nasty in it - good news)
I also tried Custom90Steve's clutch switch mod to test if it was that - no joy (but I did find out just how much slack there is in my drivetrain  , and kudos to him for his superb PM telling me how to do it! )
I ran my test reader while test driving and noticed the following readings when the power cut during a surge: Throttle Application sensor: no change (not the sensor on the pedal, then!) EGR: 'blip' closed Fuel Rail Pressure: 'blip' low ... Question: if the VCV/EGR were faulty - would that fault also affect the other... ie: if the VCV was broken, would the ECU automatically actuate the EGR when the FRP blipped due to the faulty VCV? |
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4th May 2020 5:20pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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I can't categorically answer your question but my instinct is 'no' as they're at opposite ends of the combustion process.
I see that you have some live data but do you actually have any fault codes logged? If not then the VCV is very likely to be the culprit as it's not monitored. The EGR valve, on the other hand, is and faults typically make themselves known by illuminating the MIL light. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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5th May 2020 1:57pm |
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| The Fox Member Since: 24 Mar 2014 Location: Shrewsbury Posts: 94
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No MIL and no DTC codes found with my (albeit £12-special) reader.
I'm also wondering about air in the fuel supply, but that would surely trigger injector codes or something... wouldn't it? And where would air be getting in?! |
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5th May 2020 2:09pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20355
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Has it been serviced recently at all before this started?
Although a long shot, maybe worth checking your battery clamps are tight. Voltages are correct both at rest and with alternator charging current and also that transfer box ground points are clean, dry and not loose. Long shot, but they can have serious affect on performance due to electrical activity and fluctuating voltages. All of these things inc what you have mention usually are created after works has been completed incorrectly and not because of general degeneration. If nothing else it’s free to check. When the VCV was going in mine, I found it was down on power but not greatly and I tended to notice it was drinking more fuel. Fairly subtle but it was there. As mentioned the VCV doesn’t flag up any data either if it’s at fault. Rev hunting when cold sporadically is another thing that would happen on days below 5.C as a rough benchmark. MAF and MAP sensors would flag up DTC’s if there was any, but they can still get dirty and lack performance. $W33T $0U7H3RN $UG4R 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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5th May 2020 2:56pm |
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| Marks Landy Member Since: 09 Feb 2015 Location: Cheshire Posts: 299 
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Are both accelerator pedal position sensors reading the same values ?
Check through the pedal range while monitoring the values. |
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5th May 2020 3:15pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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Unlikely to be the EGR then and air getting in usually manifests itself as poor starting rather than surging. Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia Last edited by LandRoverAnorak on 29th Dec 2020 10:36pm. Edited 1 time in total |
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5th May 2020 4:22pm |
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| The Fox Member Since: 24 Mar 2014 Location: Shrewsbury Posts: 94
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There are 2? 😂 I’ll connect up and have a check. Should both sensors read identical values, or are they inverted or something? |
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5th May 2020 5:06pm |
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| Marks Landy Member Since: 09 Feb 2015 Location: Cheshire Posts: 299
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Yes mate, dual rotary potentiometers.
They should be the same. |
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5th May 2020 5:19pm |
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