 | Home > Puma (Tdci) > Puma 2.4 Overboost on Motorway |
 
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628  
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You have the ability to monitor some live data..that's where I'd start..
What is you actually boost pressure when in fault.. How does the manifold pressure react to accelerator..you could observe when its driving normally and then have an idea of what's going on when in fault.. Without shutting down have a look at the actuator movement when someone is using the accelerator when it goes to fault.. It may well confirm a turbo fault but that's better than just replacing and hoping.. |
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7th Feb 2025 4:26pm |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17 
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Cheers Andy, will do some more diagnostics
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7th Feb 2025 9:30pm |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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I will try some turbo cleaner, to see if that helps, at this stage I’ll try anything !
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7th Feb 2025 10:30pm |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 553  
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You've replaced the turbo, the intercooler, the air sensors and now the hoses, too. Now it's most probable that one of these (except the hoses) is faulty.
I'd start with the sensors. Why ? Because they're easier to replace. And check if there are electric issues (mesure also cables, check contacts like it bas been said above). And I'd take original JLR parts (that you may return. If the ECU "thinks" that the air flow is low (air sensor fault) you won't have enough juice in your engine. If the air flow was low in reality (turbo fault), your engine would really lack of air (and some smoke should then be visible, shouldn't it ? Last edited by Julie on 8th Feb 2025 6:58pm. Edited 1 time in total |
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8th Feb 2025 5:45am |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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Thanks for all the answers and suggestions so far.
I’ve eliminated temperate as yesterday the temp was only 77degC when it went into limp mode. I’ve also ordered another MAP sensor, the original one was part number 6C11-SF479-AA and the one that I received as a puma 2.4 MAP sensor was part number 6C11-SF479-AB, I can’t find much info on the internet so don’t know the difference but for the cost thought it would be worth having the correct one. I need to check the MAF sensor part number today. I’ve watched the actuator with the engine both cold and hot when the engine is revved and it moves what looks like a full stroke. When the engine is running it’s running clean even under hard acceleration. I’ve checked the wiring to the connectors but will do another check just to make sure I haven’t missed anything. |
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8th Feb 2025 10:56am |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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Hopefully the link below works of the turbo actuator in action.
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8th Feb 2025 12:02pm |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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One of the actuator wires (one closet to the drivers wing) on the back of the connector
, although not showing signs of being broken is bent at almost 90 deg so I’m wondering if I’m getting a intermittent signal from/to it which might explain that when driving with constant acceleration/deceleration I’m not getting limp mode but when cruising this is causing the issue ? |
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8th Feb 2025 12:19pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628
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the connector if its like mine on a 2.2 will be numbered 1 to 5...5 closest to wing is a 5v reference signal..4 will be the signal, and with a multimeter on it with ign on you will see around 2.4 volts which should rise as you use the accelerator... 3 is the ground ie 0v and 1 and 2 are the actuator motor wires as described in my post above
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8th Feb 2025 12:30pm |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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Thanks Andy, that’s really useful info. I’ll do some investigation
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8th Feb 2025 2:11pm |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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So just checked, numbering from 1-5 is as you say. With the ignition on, I’m getting 5V across pin 3&5, 0V across pin 3&4 no matter where the accelerator is and 5V across pin 4&5.
Need to make up some wires to see what the voltages are with it running so I can have the plug connected to the actuator. |
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8th Feb 2025 3:00pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 628
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Find a good ground for the negative multimeter lead and then with engine running probe no 5..should be 5 volts..next probe 4, I think you should see about 2.4 volts.. which if you have someone operates the accelerator you should see that voltage change as the actuator arm moves
And finally check pin3 by probing that.. should be close enough to 0v if its got a good ground.. I dont think you need to worry about pins 1 and 2.. if you can see the actuator working.. Now if you don't get a varying voltage on pin4 as you use the accelerator then that will be an issue..possibly faulty actuator signal circut.. |
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8th Feb 2025 8:23pm |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 553
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If there weren't these low values from MAF sensor, I'd also check the duel line (+ filtrer is probably clogged from summer diesel + low températures) |
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9th Feb 2025 9:18am |
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| PipsterP10 Member Since: 31 Jan 2025 Location: South West Posts: 17
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So just checked the voltages, ground and reference are ok, the voltage on pin 4 with the engine ticking over is 3.3 volts, it does vary slightly with the engine revved but only by about .3 of a volt. What was interesting when revved hard the voltage on pin 4 suddenly dropped to 0V. Turned the engine off, checked the test wire which as far as I could tell was still properly connected, when the engine was restarted had 3.3V on pin 4 again, but I’m wondering if the test wire had come out slightly and when I removed the plug to check it I reseated it.
I’m not convinced it’s a fuelling issue but could be wrong, it doesn’t get very cold in Cornwall where I live and it’s always run on premium diesel. If it was fuelling then surely it would show up on normal road driving and not just when cruising at 60-70mph? |
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9th Feb 2025 10:16am |
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| Julie Member Since: 07 Oct 2017 Location: Nantes Posts: 553
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If you look in the Technical section, you'll notice somebody experiencing exactly the same issues (on a 300 tdi).
For him it's just 50 mph and not 60 ... Could be inspiring for you. Both trucks are turbo diesel after all. And even here in France, on the coast, we're having snow + temps below 0 in the night. Could be similar in Cornwall  |
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9th Feb 2025 10:49am |
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