406 HDi engine running fault

Hi,

At first, my english is not perfect, Im sorry. But I try: I have 3 years old 406 HDi (66Kw with chip), mileage is 196000km and it has a serious fault. When I drive slowly with 1st or 2nd gear, car/engine not drives smoothly. It "jumps" like somebody kicks to back about every 1 sec., and when I try to accelerate speed, engine sleeps few seconds and then it starts to work correctly. With cold engine problems are more seriously than with hot engine. accelerate-effect with cold engine is like old diesel-mercedes with caravan. In highway HOT engine works well. But when I slow down speed and engine is running idlespeed, something accelerates engine smoothly +500rpm every

1 sec. Has anybody have same problem in HDi-engine? What could be damaged part? When problems starts, car`s fueltank was pretty empty, and I just thought that could it be damaged fuelfilter, if fuelpump pushed water to the filter? Filter is just renewed. I thought that some possible faultpoints could be (...could it?):

- Fuelfilter

- Air mass meter (Is it so sensitive in HDI than in TDI?)

- Turbo pressure sensor

- Gaspedal potentiometer (beside air mass meter)

- Fuel pump (in the tank)

Z Bremer

Reply to
Z Bremer
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So,have you removed the chip and tried the car without it. Sometimes the chips put more fuel into the engine at low speeds(my brother's car, VW Passat, chipped, jumps about a bit at low speed as well, the kangaroo effect depends on how far he has turned the HP control knob on the chip unit.)

Reply to
ML

In matter of fact, I have three different "power"-chip (whom I`m testing just now) and fault-effect is same with every chip. I havent tested car with its own original chip, because I havent codeadapter for that (yet). Anyway, I have driven thousands of kilometres with every three chips without any kind of problems => So I think that fault is not chip (bacause chip is only digital controlmap for engine working).

But now after few days fault is not so bad/pronounced than one week ago. Engine works about correctly, especially in highway above

1700rpm. But idle-speed is not stabile enough. Before fault, idle was exactly 920rpm, but now it bumps between 900-1000rpm. I have booked time to dealer for fault-code reading, but Im afraid that anything wont found. Im just thinking what kind of sesnsors relates to idle-speed? If some sensor is just unclean?

ZB

Reply to
Z Bremer

Hello,

It could well be an inductive sensor, placed above the flywheel. Output voltage should be interresting to view using a scope.

Regards, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :
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Reply to
G.T

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