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Discussion Starter #1 (Edited)
Hello!

Engine 120hp 2.0HDI.
I have a difficult issue where the car is jerking at low load, especially in the range 1500-2000rpm on gear 5 and 6 (it is not related to the gear, but it is most noticable on gear 5&6 in range 1500-2000rpm).
If accelerate to much or to much load then jerking is stopping and the car will run smoothly again until deaccelerate and then low load again.
The jerking will go on forever if not accelerate to much.

I have tried to disconnect MAF, EGR, air intake connector and also one vaccum magnetic valve without any change to the jerking.

When connecting the ODB I notice that many values go up and down with the jerking including
MAF values, Fuel pressure, fuel injection values.
There are no error codes except for glow plug (?) relay, but that error code seems to be very common as I have seen it on several HDI engines.
Also clutch pedal switch is alarming as the connector to the switch is disconnected.

The jerking is very continous on/off every ~1second.
No difference on the behaviour cold or warm.

Anyone that has any ideas?
 

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Discussion Starter #3 (Edited)
The clutch switch is removed to be able to start with the caravan when it is very much upwards (better burn the tires than burn the clutch). :)
The clutch switch connected prevents the burnouts

Im not sure if I have changed the fuel filter after the jerking started, but the fuel filter was new within 5000km when Jerking started.
But I have a strong feeling that it is not related due to the behaviour of the Jerking.
Constant ~1 second jerking, it occur under low load only and it is fully controllable to get rid of the behaviour by shortly accelerate.
Also the behaviour when accelerate to get rid of the behaviour then what happens is that engine get "stuck" in the higher power level (high power level of the jerking). So it then increase the speed 10-20km/h and as long as you do not decrease the speed the jerking is gone.

But I should of course change the fuel filter to be 100% sure.
Meanwhile, any other ideas?
 

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Check the engine mounts? (Grab the top of the engine and use all your weight to to rock it hard backwards and forwards. If it moves at all then you need new mounts.)
 

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Discussion Starter #6
1. I have doubble checked the service log and the Fuel filter has recently been replaced without any improvement (the jerking was the same before and after the fuel filter change).

2. The problem is not related to engine mounts.
It is defenately the engingine that once every ~1second change the power output level and by that cause the jerking.
Note: When reading values via ODB, then both expected and measured values (like fuel injection level , MAF and so on...) do jump up and down (about 10%) and this is follwoing the jerking. The question is what is causing the engine power level to continously jump up and down. See the initial message, I have tried to disconnect a lot of sensors without improvement to the jerking.
 

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Get it on Peugeot planet and check the Fuel Pressure Regulator status as it could be the fuel pump / pressure regulator. Had a similar thing on the 90bhp 2.0 HDi.
 

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Discussion Starter #8
Problem seems to be solved!
reliable406: It seems like you were correct...

I noticed in Peugeot planet that gearbox gear was continously changing between indicating "5th" and "???".
So then I reconnected the clutch switch and the jerking seems to be gone (and the gear is indicating correct gear "5th")! :thumb:

So there seems to be some jerking in the Frenc logic in the firmware when the clutch switch is not attached properly.... :eek:

But now I need another way to fool the French logic to be able to get more than 2750rpm when start in the hills (2750 rpm is not enough to get started with the caravan).
Question: Is there any way to turnoff the 2750rpm limitation when the clutch pedal is pressed?
Maybe I have to attach a separate switch where I can enable/disable the clutch switch when needed...
 

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Max torque is around 1700 rpm so I would have thought anything above that would not have much affect on pull away unless it not fully boosting off load

Sent from my SM-T310 using Tapatalk
 

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Discussion Starter #11 (Edited)
Total weight of caravan + peg is around 4500kg and combined with Norwegian +10% cerpentine (single lane, two way) natonal tourist roads then you have two options, either you burn rubber or you burn the clutch!
2750 rpm is good to burn the clutch while burn rubber need more!
😀
 

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Sounds to me like the caravan is simply too heavy but as has been said max torque is much lower than the limited rev amount so i cant see why you would want more revs you may need a different car :)
 

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Think that 4500kg might actually be illegal for the Expert. Isn't the recommended braked towing weight 85% of vehicle weight?
 

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Discussion Starter #15
4900kg is allowed in totalweight.
Max torque is likely below 2750rpm, but that does not help if the horsepower is to little to get started when it is 10% uppwards in average.
It is likely possible to start at 2750rpm but clutch would likely not survive many times.
You need to have power enough to spinn wheels a few meters until you got some speed forward to not burn the clutch.
Even more people burn the breaks when it goes downwards... 🙂
(Low gear and 4000rpm downwards (on 2nd gear) then you avoid burn the breaks as well). 🙂
 

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I tow a lot and IF i was struggling to get going i would not do it i would use a different tow vehicle.

As for 85% bollox that is exactly what it is bollox its not law its a rule dreamed up by caravan club or whatever there is NO LAW in the uk that states you cannot tow more than your own vehicle weights its all recomendations and best practice etc there is very little law regarding towing except for commercial towing.

I do realise you seem to be in a different country and rules may be different but facts dont change the van cannot manage the load safely.
 
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