Power Loss at low rpm

[willy5]

Dear Sifus, Got a problem with power loss.2 days ago the check engine light came on and the engine would not rev at high rpm the max speed I could go up to was 100 kph. I stopped the car switched off the engine and the cel went off and the car seemed normal but lacking on power (some loss but could still go). A day later the cel came on again but would not go off, the car would still drive OK but lack of its normal response. Had the stored code checked today and it indicated cylinder misfiring and lean mixture. After swapping the coils around and clearing the codes, the cel does not come on anymore, and no fault codes show up. All the ignition coils are about 1 year old. Then it developed a new problem, now it won't accelerate normally between 1000 - 2000 rpm. Then the power comes in after 200 rpm. Idling is a little shaky but not very bad and it will rev up without load i.e. parked and in free gear. There are no fault codes. Did anyone have a similar experience? Please share what the solution was. TQ TQ.

 

[willy5]

A little more to add, I had the gear box repaired recently, gear changes in manual mode is smooth but D mode is not as smooth as when new, can the gearbox cause these symptoms?

 

[Herbert]

Check your camshalf sensors and airflow sensor.

 

[ezzo369]

my friend has idling problem when driving at low rpm. when he tried to use the kickdown mode, the gear changed to neutral. ending up that the gearbox was loose. does your ride provides the same symptom?

 

[bimmer73]

Check you torque convertor and gearbox lubricants level. Since you mention that you recently did your gearbox. you may have faulty Torque convertor

 

[moots]

Dear Sifus,

Got a problem with power loss.
2 days ago the check engine light came on and the engine would not rev at high rpm the max speed I could go up to was 100 kph. I stopped the car switched off the engine and the cel went off and the car seemed normal but lacking on power (some loss but could still go). A day later the cel came on again but would not go off, the car would still drive OK but lack of its normal response.

Had the stored code checked today and it indicated cylinder misfiring and lean mixture. After swapping the coils around and clearing the codes, the cel does not come on anymore, and no fault codes show up. All the ignition coils are about 1 year old.

Then it developed a new problem, now it won't accelerate normally between 1000 - 2000 rpm. Then the power comes in after 200 rpm. Idling is a little shaky but not very bad and it will rev up without load i.e. parked and in free gear. There are no fault codes.

Did anyone have a similar experience? Please share what the solution was. TQ TQ.

you may have a vauum leak.check your rubber boot from the maf to the throttle body and check the rest of the small air hoses....

 

[willy5]

THANKS everyone, mechanic still checking, so far
changed vanos seals - bogging down problem at low revs went away but misfire in cylinder 1 came back.
reprogrammed ECU
swapped cam shaft position sensors
swapped ignition coils
now checking throttle body...

this is a weird weird problem

 

[rpmnut]

Dear Sifus,

Got a problem with power loss.
2 days ago the check engine light came on and the engine would not rev at high rpm the max speed I could go up to was 100 kph. I stopped the car switched off the engine and the cel went off and the car seemed normal but lacking on power (some loss but could still go). A day later the cel came on again but would not go off, the car would still drive OK but lack of its normal response.

Had the stored code checked today and it indicated cylinder misfiring and lean mixture. After swapping the coils around and clearing the codes, the cel does not come on anymore, and no fault codes show up. All the ignition coils are about 1 year old.

Then it developed a new problem, now it won't accelerate normally between 1000 - 2000 rpm. Then the power comes in after 200 rpm. Idling is a little shaky but not very bad and it will rev up without load i.e. parked and in free gear. There are no fault codes.

Did anyone have a similar experience? Please share what the solution was. TQ TQ.

I had almost the same problem as you with my 2003 525i.
The car would hesitate to pull away from standstill, would sometimes jerk if the revs were below 1500rpm, and had no power till at least 2000rpm.
When fault codes were checked, the diagnosis showed cylinders 1,4 & 6 were misfiring.
Turned out to be a clogged fuel filter. Changed it and all the symptoms disappeared.
You might want to try checking that first....

 

[Herbert]

THANKS everyone, mechanic still checking, so far
changed vanos seals - bogging down problem at low revs went away but misfire in cylinder 1 came back.
reprogrammed ECU
swapped cam shaft position sensors
swapped ignition coils
now checking throttle body...

this is a weird weird problem

Why re-programmed the ECU? Looks like your mechanic is doing a trial & error basis which is not a good way to rectify a fault. Who is your mechanic by the way?

 

[bmyotaE36jz]

THANKS everyone, mechanic still checking, so far
changed vanos seals - bogging down problem at low revs went away but misfire in cylinder 1 came back.
reprogrammed ECU
swapped cam shaft position sensors
swapped ignition coils
now checking throttle body...

this is a weird weird problem

Wow!! How much the cost for all those?

 

[willy5]

Thanks All for the good advice.

The fuel filter was changed also, no improvements
Sensors for inlet and exhaust cams were also swapped and tested, no problems with these.
MAF checked out OK
ECU was reprogrammed as part of the elimination process. It is down to trial and error because the fault codes come on sometimes only but the problem is there regardless.
The problem is the fault code comes on sometimes and not always, but it will be misfiring in cylinder 1 or 2 if it comes on, but the engine bogging down on full throttle is always there.
Now checking to see if exhaust cat converter is clogged?? Otherwise might have to get another ECU to try, but these 525 ECUs are not so easy to come by, apparently.
Don't know how much it is gonna cost yet, keeping my finger crossed on that one.

Sigh....

 

[sewell]

i have my experience last time when i was studying abroad. E39 520i M52 engine. the cat converter stuck. it make the car loss of power. you can rev, but cant travel at high speed.

 

[willy5]

Finally solved, it was the cat converters, they were clogged. An interesting note, the 523 has 1 and the 525 has 2 and they are stuck on the manifolds. Both manifolds need to be changed together.

So in retrospect, the initial symptoms were loud induction roar (sounded like an Alfa) no power (lost a 'race' with an Avanza!!)

Thank You ALL.

 

[zib]

Finally solved, it was the cat converters, they were clogged. An interesting note, the 523 has 1 and the 525 has 2 and they are stuck on the manifolds. Both manifolds need to be changed together.

So in retrospect, the initial symptoms were loud induction roar (sounded like an Alfa) no power (lost a 'race' with an Avanza!!)

Thank You ALL.

so how much did it cost u all in?

 

[willy5]

All in 3k+ which included the 2 cats @ 800 each, vanos repair kit + gasket set, petrol filter, and labour for trouble shooting. Interestingly, the sensors are only fitted to one of the 2 manifolds, so if the one without sensors screws up first then no fault shows up on the diagnostics.

I am just wondering, the cat converters are probably plugged up with carbon gunk, anyone knows if it is possible to get a solvent of sorts to loosen it so that it can be back flushed to unclog?