E90 320i rough idle

[Bmwed]

Hi Gents

Is it possible for a coil pack to malfunction intermittently or is it like a light, it either works or i doesn’t reason for asking is my car went in for valve stem seals and ever since i got it back the car seems to idle rough when the engine is hot.

 

[Lizzard]

Can you elaborate a little more when you mean idle rough?

Does the car go from high to low rpms when standing at a robot/stop street, or when the car is started. Does the car sound funny when idling, like it is almost misfiring. What exactly is the car doing.

Can tell you mine idles at around 600 - 700 rpm and when I just come to a stop the car will dip sometimes to below 500rpm and then back up to 600rpm.

Maybe get a code reader and see if there is an error stored in the cars memory. Maybe also look at the intake solenoid or google it as it also can contribute to the idling.

 

[Bmwed]

its when i stop at a robot the cars idling jumps from 500 to 800 and the whole car shakes. there is no engine light.

 

[Bandile]

Sounds to me like a misfire, and yes, a coil does cause those symptoms. Had the same issue on cylinder 2 about 2-3 months back. As said above, have the codes read... Or test your coils manually to see if it's indeed the coils.

 

[Dewald_Bark]

I had the exactly the same issues. Definitely coil and in my case added engine sludge wich stuffed the inyake intake vanos solenoid around. How is you overall power and fuel consumption?

 

[Bmwed]

How would i test the coils? I bought a new one and placed it in the 1st slot went for a drive and then same thing. With the car running and shaking i disconnect each coil one by one. Whn disconecting each coil the engine runs worst

 

[Dewald_Bark]

How would i test the coils? I bought a new one and placed it in the 1st slot went for a drive and then same thing. With the car running and shaking i disconnect each coil one by one. Whn disconecting each coil the engine runs worst

How os the overall power and fuel consumption. If it is bad and sluggish clean the vanos solenoids.

 

[Bandile]

How would i test the coils? I bought a new one and placed it in the 1st slot went for a drive and then same thing. With the car running and shaking i disconnect each coil one by one. Whn disconecting each coil the engine runs worst

With the car idling, you remove the coils one by one... And for each coil, if the car becomes worse when you remove the coil, that coil is still in good nick. And if nothing changes when you remove the coil, that's your suspect... Replace that coil and test drive.

 

[Bmwed]

Thank gents.. I have now tested the coils and they all seem fine. I bought a new one and swopping it to a new cylinder every day.. so its safe to say its not the coil packs. I have cleaned the valve solenoids and replaced the o-rings. still the same... any other ideas?

 

[Lizzard]

Well a car can misfire for 2 reasons, Fuel and spark. you just diagnosed the spark part by removing the coil packs and reinsert them. Maybe go to the fuel supply and look at the fuel lines etc. See if that is having an issue.

But you can see this fuel info in INPA, cant you get someone with this software to drive co passenger and monitor the car to see which cylinder is perhaps going of balance and making the car shake?

 

[Bmwed]

Sounds like a plan. I was thinking it could be the injectors.