need help on M40 engine vibration at low rev

[markus_74]

hello, Friend

I have bad issue on my engine and become worse.

when my engine is still cold it vibrate like old diesel engine, all car's body shake and when I drive the car is like kangaroo move, it will be disappear when engine temperature is hot.

but sometimes, when I drive the issue suddently come, it is like 1 of my spark plug die or because of pump relay ?

I have clean my ICV, change all spark plugs, and it still like that.

what does cause it?

Thank you

[soul4t]

How long have you had this problem?

Is it typically at low revs? - The engine vibration and kangarooing? Or is it shaking at higher revs too?

[markus_74]

I had this for a long time, but not as bad as this 2 weeks, since I'm not use my car for a week and it happened

as alsways at low rev when engine not hot, like 1 of my spark plug die, but I have check and replaced all it still.

engine vibration when car stop and idle, but when I force it to run, it like kangarooing the car move but jump like it will stall but not.

and I see if I try to shut my window, the engine is also response like a but stall.

I know that I have electrical wiring short in my car recntly, and my mechanic has cut it and make a new route for front extra fan AC, so 91 degree and 99 degree switch is not function also he make new connection for ICV that take the new earth from new cable.

but I have this issue before this.

[soul4t]

Have you checked the blue temp sensor? The best way to check it is at the ecu pins using a multimeter, by checking at the ecu, you also check the wiring at the same time.

When you first start the car and you have low revs, without driving it, you put you foot on the accelerator pedal, does it make it worse then it sorts itself out a bit, or does it rev smoothly? Could you take a video?

[soul4t]

Does your car behave like the video's half way down the page:
http://www.e30zone.net/modules.php?name ... c&start=50

[Billwill]

I had this for a long time, but not as bad as this 2 weeks, since I'm not use my car for a week and it happened

as alsways at low rev when engine not hot, like 1 of my spark plug die, but I have check and replaced all it still.

engine vibration when car stop and idle, but when I force it to run, it like kangarooing the car move but jump like it will stall but not.

and I see if I try to shut my window, the engine is also response like a but stall.

I know that I have electrical wiring short in my car recntly, and my mechanic has cut it and make a new route for front extra fan AC, so 91 degree and 99 degree switch is not function also he make new connection for ICV that take the new earth from new cable.

but I have this issue before this.

What do you mean when you say your mechanic made a new earth for the ICV?

The ICV is not supposed to have an earth....the one lead has +12 volts on it when ignition is on while the other lead goes to the ECU, pin 22 I think, which switches to ground in variable pulses....not constant ground.

If he has simply replaced a bad lead with a new one then fine but this new wire must not be at solid ground all the time....you probably have burnt out the ICV by now as the ICV would have been powered on at all times.

I also do not see why he disconnected the 90 and 99 degree switches from your fans...these are definitely need.....I think your mechanic is destroying more things than he is fixing.

[markus_74]

I had this for a long time, but not as bad as this 2 weeks, since I'm not use my car for a week and it happened

as alsways at low rev when engine not hot, like 1 of my spark plug die, but I have check and replaced all it still.

engine vibration when car stop and idle, but when I force it to run, it like kangarooing the car move but jump like it will stall but not.

and I see if I try to shut my window, the engine is also response like a but stall.

I know that I have electrical wiring short in my car recntly, and my mechanic has cut it and make a new route for front extra fan AC, so 91 degree and 99 degree switch is not function also he make new connection for ICV that take the new earth from new cable.

but I have this issue before this.

What do you mean when you say your mechanic made a new earth for the ICV?

The ICV is not supposed to have an earth....the one lead has +12 volts on it when ignition is on while the other lead goes to the ECU, pin 22 I think, which switches to ground in variable pulses....not constant ground.

If he has simply replaced a bad lead with a new one then fine but this new wire must not be at solid ground all the time....you probably have burnt out the ICV by now as the ICV would have been powered on at all times.

I also do not see why he disconnected the 90 and 99 degree switches from your fans...these are definitely need.....I think your mechanic is destroying more things than he is fixing.

I think I will go back to original wire for 90 and 99 degree switch.

as for ICV I will check again he has connect it to correct pin 22 or not? it is difficult to check the cable to ecu as it has a lot of cables there.

but it is reasonable my icv be the problem, because the issue is power loss repeatly when I accelerate the car.

it is like when you accelerate in carburetor car but the carburetor flood or fuel, I think you will be understand

the reason my mechanic make new route because of when I switch on my air conditioning the fuse number 20 always blown.

[markus_74]

Have you checked the blue temp sensor? The best way to check it is at the ecu pins using a multimeter, by checking at the ecu, you also check the wiring at the same time.

When you first start the car and you have low revs, without driving it, you put you foot on the accelerator pedal, does it make it worse then it sorts itself out a bit, or does it rev smoothly? Could you take a video?

hello. soul4t

i have read all your thread before, mine behave like your, it smell rich, hesitate and lumpy when cold, but not when hot, but sometimes it is appear when in hot condition.

when I drive it and the temperature at the half it drive good.

but the different it has steady rpm no hunting.

[soul4t]

Yup, sounds pretty much the same!

Is yours a 316i M40 with ECU ending 174?

It will be interesting if it is the same!

[markus_74]

soul4t
mine is 318i M40 with ecu ending 157