RPM Drop
09-30-2010, 07:55 PM
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2004 530i E60 M54 automatic
115k miles
1.) When I let off the gas and the car is coasting (at almost any speed, but always happens above 40 mph) and I don't apply any brakes; when the RPM reaches ~1100-1400 the motor will bounce/hit a harmonic, jumping 200 RPM up and down always between the ~1100-1400 RPM. If I apply brakes or a small amount of accelerator the engine stops bouncing around RPM. This has been happening for about 6months.
2.) About 2 months ago I began having acceleration issues. At about 2500 RPM the motor will hesitate and bounce RPM when applying moderate gas. If I give it more gas the hesitation disappears and the motor accelerates strong. I have noticed some decrease in mpg.
For problem (2) I have found that this can be caused by the vanos (variable valve timing) seals can cause this problem and there is a fix for this: http://www.beisansystems.com/index.html
The computer isn't throwing a code causing a check engine signal.
- I've cleaned the ICV (idle control valve) and it seems to move very freely when shaken back and forth.
- Changed the CCV (crank case ventilation valve) and all associated hoses.
- Replaced the DISA valve.
- I've looked for vacuum leaks by spraying carb cleaner near hoses, no fluctuation in RPM
- Spark plugs have been changed.
- Air filter is free of debris and clean.
- Looked at MAF (mass air flow sensor), it was not clean but cleaned it anyway
- Don't seem to be any crack in rubber hoses
Please help before I spend way to much money to have it diagnosed and not find the real problem.
115k miles
1.) When I let off the gas and the car is coasting (at almost any speed, but always happens above 40 mph) and I don't apply any brakes; when the RPM reaches ~1100-1400 the motor will bounce/hit a harmonic, jumping 200 RPM up and down always between the ~1100-1400 RPM. If I apply brakes or a small amount of accelerator the engine stops bouncing around RPM. This has been happening for about 6months.
2.) About 2 months ago I began having acceleration issues. At about 2500 RPM the motor will hesitate and bounce RPM when applying moderate gas. If I give it more gas the hesitation disappears and the motor accelerates strong. I have noticed some decrease in mpg.
For problem (2) I have found that this can be caused by the vanos (variable valve timing) seals can cause this problem and there is a fix for this: http://www.beisansystems.com/index.html
The computer isn't throwing a code causing a check engine signal.
- I've cleaned the ICV (idle control valve) and it seems to move very freely when shaken back and forth.
- Changed the CCV (crank case ventilation valve) and all associated hoses.
- Replaced the DISA valve.
- I've looked for vacuum leaks by spraying carb cleaner near hoses, no fluctuation in RPM
- Spark plugs have been changed.
- Air filter is free of debris and clean.
- Looked at MAF (mass air flow sensor), it was not clean but cleaned it anyway
- Don't seem to be any crack in rubber hoses
Please help before I spend way to much money to have it diagnosed and not find the real problem.
10-01-2010, 06:09 AM
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My Ride: 2008 535i:
(8/07 Build) Metallic Bronze, Beige NASCA Leather, Ventilated Seats, Sport Pkg, Cold Wxr Pkg, Logic-7 Sound, HUD, Night Vision, PDC, Split Rear Seats, NAV, Premium Pkg, Comfort Access, HD Radio, Sport Auto Trans
Current mods: M-Aero Kit, JB4, Motorcepts 6000k HID Foglamps
Umnitza ICE-Lite 10w LED 6000k AE's
1992 Camaro RS:
Fully Restored w/Custom Interior, 5.0L V8, T-tops, OEM Z28 Foglamps, Inst Cluster, & Spoiler, Custom Sound, Too many engine mods to list
I'd look into replacing the MAF sensor - hopefully its not too expensive.
10-01-2010, 12:04 PM
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My Ride: 2008 535i:
(8/07 Build) Metallic Bronze, Beige NASCA Leather, Ventilated Seats, Sport Pkg, Cold Wxr Pkg, Logic-7 Sound, HUD, Night Vision, PDC, Split Rear Seats, NAV, Premium Pkg, Comfort Access, HD Radio, Sport Auto Trans
Current mods: M-Aero Kit, JB4, Motorcepts 6000k HID Foglamps
Umnitza ICE-Lite 10w LED 6000k AE's
1992 Camaro RS:
Fully Restored w/Custom Interior, 5.0L V8, T-tops, OEM Z28 Foglamps, Inst Cluster, & Spoiler, Custom Sound, Too many engine mods to list
10-02-2010, 12:46 AM
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Have you ever changed the gearbox oil?
My bet is that the mechatronic module is busted. It is not able to keep up the preassure in the box and its slipping thats why the revs are jumping up and down. You will soon smell burning every once and a while which is making the problem even worse because resedu will get into the oil and into the mechatronic, making the problem worse by clogging up the parts inside.
You better start saving for a gearbox revision with a new mechatronics module and then the entire computer upgrade else it won't understand the new mechatronic (hard downshifts etc)
It has set me back a good 6000 usd.
My bet is that the mechatronic module is busted. It is not able to keep up the preassure in the box and its slipping thats why the revs are jumping up and down. You will soon smell burning every once and a while which is making the problem even worse because resedu will get into the oil and into the mechatronic, making the problem worse by clogging up the parts inside.
You better start saving for a gearbox revision with a new mechatronics module and then the entire computer upgrade else it won't understand the new mechatronic (hard downshifts etc)
It has set me back a good 6000 usd.
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