 | Home > Puma (Tdci) > Lack of Power |
 
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17602   
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Sounds like that old favourite, the VCV.
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11th Mar 2024 6:42pm |
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| Ianh Member Since: 17 Sep 2018 Location: Essex Posts: 2137
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As per BW in this topic and nicolas0505 and custom90steve highlighted in the other topic you raised, https://www.defender2.net/forum/topic90678.html the VCV is the likely culprit if you have a 2.4
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11th Mar 2024 7:10pm |
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| TheBigHess Member Since: 07 Jan 2024 Location: Oxford Posts: 7 
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This previous issue was solved and car was running well for about a month or 2 and then recelenty had this new issue arise are we still thinking the VCV?
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11th Mar 2024 7:25pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20613
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It could be that the VCV isn’t any good, unfortunately some of them are re-worked / refurb but passed off as new.
Where did yours come from? Chillin In The Backwoods🇬🇧🇺🇸 ⛽️🛢️⚙️🧰💪 |
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11th Mar 2024 7:39pm |
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| Ianh Member Since: 17 Sep 2018 Location: Essex Posts: 2137
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The lack of DTC’s would indicate it’s a VCV if it’s a 2.4. Noting the 2.2 does not have the VCV issues the 2.4 has.
Did you change your VCV on the last fault ? I ask as there are a lot of fake VCV’s being sold and you do need a genuine Denso one else they likely fail again. |
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11th Mar 2024 7:42pm |
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| TheBigHess Member Since: 07 Jan 2024 Location: Oxford Posts: 7
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Unfortunately not sure what was replaced to fix the issue before as was with the dealership I purchased off and they still 2 months down the line have not sent me the work that was carried out. Is Denis or OEM better to go for for the VCV?
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11th Mar 2024 8:21pm |
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| TheBigHess Member Since: 07 Jan 2024 Location: Oxford Posts: 7
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VCV replaced issue the same struggle to get over 50mph on the cruise and hills are a struggle still. Any ideas?
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17th Mar 2024 9:40am |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8168  
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whats it boosting too? Cheers
James 110 2010 XS Utility 130 2011 M57 bespoke Camper 90 2010 Hardtop 90 M57 1988 Hardtop |
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17th Mar 2024 10:14am |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628
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not experienced your symptoms but from reading bits and pieces , I believe the accelerator pedal position sensors can cause a loss of power beyond the first quarter or so of the accelerator pedal movement if one of the tracks fails...so would be worth checking that..
and if the fuel temp sensor was faulty that would also restrict power as it might be spilling more fuel into the return line rather than feeding the hp pump.. have you checked the fuel rail pressures to see what they are doing as you operate the accelerator ... |
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17th Mar 2024 1:06pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20613
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Throttle or turbo actuation issues, likely the latter. Mine was way better after freeing up the vanes manually and regular light lube.
DTC’s often give clues, with the exception of the VCV. Chillin In The Backwoods🇬🇧🇺🇸 ⛽️🛢️⚙️🧰💪 Last edited by custom90 on 17th Mar 2024 4:01pm. Edited 1 time in total |
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17th Mar 2024 2:03pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628
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Been meaning to ask before and this thread seems as good a place as any given the subject...
Everyone is saying vcv valves can play up and cause issues.. Has anyone put a scope across one and run it in conjunction with a fuel rail pressure trace.. Or does anyone know what sort of trace to expect. Ie analogue or digital.. Voltage etc.. I have thought about it and will get round to it, but someone may have good examples they can share.. |
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17th Mar 2024 3:38pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20613
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I believe it’s usually mechanical failure with the VCV rather than electrical issues, such as wear and scoring.
I would imagine electrical parameters are fine, so possibly difficult to tell based upon that. As Blackwolf on here has mentioned before, water traces in fuel can do a lot of damage and kill a VCV. Something like the CHT Sensor is easy to tell though and that’s resistance tests in KOhms. (kΩ). On a table along with ambient temp. When I took my old one (VCV) off, Blackwolf was correct there was wear in the bore IIRC and some scuffing and scoring. The signs were more fuel used (less pronounced issue) and a rough idle (hardly noticed but noticed a lot more in temps below 5.C.) Lack of top end power, and harder acceleration required than normal. Having to drop down from 6th to 5th on a light incline with no load I.e. no trailer is a common factor. Lack of power much more pronounced in 5th and 6th gear. Then eventually randomly stalling on idle or when cold, less likely when cold but randomly stalling but restarting again. Eventually the stalling becomes much more common, and any signs of that replace VCV as it can cut out in a dangerous situation such as just pulling out of s junction or joining a roundabout. The lack of power in higher gears can go on for a while and poor idle etc, but the stalling is a more immediate impeding sign which was when I changed mine. I would imagine good tuners can spot the signs via their diagnostics systems, this is something Pete @ BAS or Gary @ Alive would know more of. I’d imagine there is parameters in the ECU live diagnostics that show this and is easier to look at than testing with say a multimeter in this instance. A drop on torque and hp probably is a sign anyway in higher speeds on a rollling road, especially when looking at the torque and hp curve on a graph vs standard parameters. Chillin In The Backwoods🇬🇧🇺🇸 ⛽️🛢️⚙️🧰💪 |
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17th Mar 2024 4:15pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628
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I get what you are saying, but the symptoms you refer to like loss of power / torque etc would be down to a fueling issue as we are talking about a vcv..or thats the way I see it... so the vcv mechanical issues are causing that... it may well be responding to demand in terms of the expected electrical response , but its mechanical inability to do its job has to have an effect and produce said symptoms, so if you have a good example as a scope trace of the vcv and the fuel rail pressure , then if its faulty mechanically it should be evident on the trace when compared to one that is known to be good, if you follow what im trying to get at.... bit like the mass air flow meter... a known good trace should be capable of showing up a failure in the sensor if it malfunctions electrically or the air flow is impeded mechanically..
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17th Mar 2024 4:38pm |
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| TheBigHess Member Since: 07 Jan 2024 Location: Oxford Posts: 7
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For anyone interested, nothing fixed the issue so ended up taking to a specialist. Contaminated fuel tank which led to damage to the HP pump and injectors. Both replaced and hoping has solved the issue
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26th Apr 2024 11:30pm |
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