Hello everyone. I just got a bmw z4 e85 3.0 (m54b30) with manual gearbox and 114000 km. The problem is that the car doesn't have the power it should have. Let me explain better, in the first gear up to the limiter, the car has a constant and not high power even after 4000/4500 rpm. Every now and then I feel that in this threshold there is a greater push. Furthermore, by sinking the gas pedal, the car makes more noise from the exhaust but without really pushing. I have connected the machine to inpa and the only codes I receive are on the o2 post cat sensor of the first bank, blocked at 0.42v, but I have read that the o2 post cat sensors do not affect the performance, and a code for the engine oil sensor . however, this also does not affect performance.
I checked the disa that I fixed, I checked for leaks from the suction circuit and there are none. I tested ccv and everything is ok.
I know it could be some of these VANOS, injectors, filter and fuel pump but having no codes I wouldn't want to change working parts. Any idea why I don't get more boost after 4500 rpm? Thanks
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I forgot, I disconnected the maf and no change.
On the other hand, no problem at the minimum, nor an anomalous increase in the number of rpm
I have heard of the vanos seals needing a refresh causing this problem. Since it's a oil pressure issue in the vanos you won't get any codes.
Thanks this in an idea. I’m also thinking about cats, but with both the o2 pre cat sensors removed from the exhaust manifold, I’ve the same performance.
With only 114000 km on it the cats should still be fine.
Thanks
The problem is that I don't feel the kick when I reach 3500/4000 rpm. I'm thinking due to Vanos seals, anyone know something?
I’ve done my Vano’s on a ‘04...
I just pulled through 5+K rpm a few times in first gear today and it pulled evenly from stop til I shifted.
So not sure what you are looking for as the engine performed as It should...
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Last edited by Clearancediver; 08-10-2020 at 08:57 PM.
it's like something that should happen doesn't happen
I'll suggest the inlet cam shaft sensor. It sometimes soft fails and does not bring up a code. The Engine DME does not know where the camshaft is and turns off the VANOS control giving you low power.
To test the sensor https://www.youtube.com/watch?v=jUZAiHpuF0s
1999 2.8L Z3 Roadster,
2000 3.0L Z3 Roadster,
There is only one thing more pleasurable than working on a Z3, that's driving it top down on a fine day.
Thanks, I’ve tested the sensor like you suggested and it seems working
Hello everyone, sorry for the absence but I was waiting for the spare parts that took a very long time in this covid period.
Problems persist despite the following interventions:
- rebuilt vanos: improved lower torque
- catalysts replaced, one of them had broken and with a hammer I could hear the sound of pebbles banging inside.
But now I know better what I mean, under strong acceleration at any rpm, the chirp needle jolts, the car hesitates, and then pushes well. I think this may be due to bad coils (but I have already inspected them and tested the resistance and everything is ok), spark plugs, injectors or fuel pump, and finally bad o2 sensors.
I will proceed to test everything, meanwhile the machine does not show codes.
Anyone with any ideas or could you tell me where to start?
thank you
I am worried about the soft failures that are not shown in the diagnosis and I would not want to take things at random.
thanks again
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