E39 M5 losing power at ~5000rpm
Discussion
I just got my 2001 M5 a week ago and already I'm having some issues. I've noticed on a couple of occassions that when I drop from either 5th or 6th gear to 4th, when the rpm rises to around 5k it feels like I've hit the rev limiter. After this, the car has no power and runs rough, particularly in lower gears. However, if I stop the car, turn off the engine and restart, the problem goes and the car's got all it's power. The problem doesn't seem to arise (I don't think) if I run up through the gears, changing at 6k rpm; it only seems to do it if I down-change. One time after this had happened the 'check engine' light came on but this doesn't happen every time. Any ideas? Thanks.
Hi, would suggest getting the fault codes read at either a main stealer or independent that has the correct plug and play computor, could be a number of things but as you say check engine light has appeared then there "should" be a fault code stored in memory which will pinpoint the problem.
Gav
Gav
ViperScot said:
Im assuming that it's engine management related since the problem goes away once I've switched the car off and back on again. I'll make sure the next tank of fuel is V-Power and see if that solves the issue. Cheers.
Nice to see you've joined the dark side Hamish
Let us know how you get on.
ASBO said:
ViperScot said:
Im assuming that it's engine management related since the problem goes away once I've switched the car off and back on again. I'll make sure the next tank of fuel is V-Power and see if that solves the issue. Cheers.
Nice to see you've joined the dark side HamishLet us know how you get on.
I'm starting the rebuild now and have noticed that fitting a super-charger may be within my budget if I sell on the M5 
ViperScot said:
ASBO said:
ViperScot said:
Im assuming that it's engine management related since the problem goes away once I've switched the car off and back on again. I'll make sure the next tank of fuel is V-Power and see if that solves the issue. Cheers.
Nice to see you've joined the dark side HamishLet us know how you get on.
I'm starting the rebuild now and have noticed that fitting a super-charger may be within my budget if I sell on the M5 
Hope you get the problem sorted, let us know.
Neil.D said:
ViperScot said:
ASBO said:
ViperScot said:
Im assuming that it's engine management related since the problem goes away once I've switched the car off and back on again. I'll make sure the next tank of fuel is V-Power and see if that solves the issue. Cheers.
Nice to see you've joined the dark side HamishLet us know how you get on.
I'm starting the rebuild now and have noticed that fitting a super-charger may be within my budget if I sell on the M5 Hope you get the problem sorted, let us know.
Edited by ViperScot on Monday 5th May 12:55
Filled the tank from about 1/4 full with super/premium tonight. Still seem to have the problem though (although problem manifested itself within 5 miles of leaving petrol station - still influenced by regular fuel?). This time the 'check engine' light came on and stayed on until I stopped and restarted engine. However, when it did it this time, the rev counter in 5th and 6th spun way up to the red line with no extra power delivery. I sort of noticed this previous times too. Could a slipping clutch confuse the engine management and cause these problems? Or is there anyway some ECU issue could cause the racing engine without power? I'm confused!!!
On further driving, I notice a 'blip' in performance around 4000rpm prior to the more significant problem at around 5000rpm. Could this be a VANOS issue? I say that as the previous owner used a more viscous oil (a Silkolene product) than Mobil 1 in the last oil change - could that cause issues with the VANOS system at higher revs?
The M5 has a very advanced Engine diagnistic system, and before spending money, and before continuing to drive it with a fault, I'd try and find someone with a diagnostic tool, which will plug straight into the diagnostic port in the engine bay, and will tell you exactly what the problem is. I'd take a guess that it's one of the CPS's (Cam Position Sensors).....but a diagnostics tool would tell you if it is, and not only that, it'll tell you exactly which one of the four (Two Inlet, Two Exhaust) it is.
The M5 isn't a cheap car to maintain, but you can save alot of mis diagnosed faults by simply plugging in a diagnostic tool to get the exact faul identified.
If you were closer, I'd willingly help you out, but unfortunately I'm in Portsmouth.
The M5 isn't a cheap car to maintain, but you can save alot of mis diagnosed faults by simply plugging in a diagnostic tool to get the exact faul identified.
If you were closer, I'd willingly help you out, but unfortunately I'm in Portsmouth.
I just replaced mine.........went to the local VW Dealership and bought the VW equivelant, which is what most people do. Oh, and they're exchange, so you need to take the VW MAF out of the inlet pipe that you get with the VW kit, and put your old ones in, then return them and you get about £40 back when you take them in.
Had no problems at all with mine, car ran smooth with no lumpy idle or hesitation.
Perfect.
Had no problems at all with mine, car ran smooth with no lumpy idle or hesitation.
Perfect.
Jim Green said:
I just replaced mine.........went to the local VW Dealership and bought the VW equivelant, which is what most people do. Oh, and they're exchange, so you need to take the VW MAF out of the inlet pipe that you get with the VW kit, and put your old ones in, then return them and you get about £40 back when you take them in.
Had no problems at all with mine, car ran smooth with no lumpy idle or hesitation.
Perfect.
Is that right????Had no problems at all with mine, car ran smooth with no lumpy idle or hesitation.
Perfect.
That's worse than the AJP8 using throttle potentiometers off Fords that can't take the underbonnet temps. What's the BMW/VW price diff?
I put the car in for a diagnostic test this morning and have been told that it identified a 'misfire on cylinders 1 and 2 under partial load'. They suggested replacing the coils and plugs (at least for the 2 misfiring cylinders but ideally all 8). These are £60 plus VAT each (and more for the plugs obviously). However, from the advice I've got from others, I'm wondering if the root of the problem could be the MAFs causing the misfires and then putting the engine into 'safe' mode... Any thoughts? Don't want to change the coils if they're fine obviously...
ViperScot said:
The Viper will spin the wheels at 2000rpm (typically coming out of roundabouts) due to the massive torque. But it is very rewarding if you master how to drive it hard. I'm certainly enjoying the civility of the M5 right now!
Disengage DSC and hoof the throttle.I assure you it can leer with the best of 'em!
ViperScot said:
I put the car in for a diagnostic test this morning and have been told that it identified a 'misfire on cylinders 1 and 2 under partial load'. They suggested replacing the coils and plugs (at least for the 2 misfiring cylinders but ideally all 8). These are £60 plus VAT each (and more for the plugs obviously). However, from the advice I've got from others, I'm wondering if the root of the problem could be the MAFs causing the misfires and then putting the engine into 'safe' mode... Any thoughts? Don't want to change the coils if they're fine obviously...
I had the same prob with my 2001.Turned out to be bad cam sensors and the mafs were shot aswell.Would be suprised if the coils were at fault ,the mafs can induce a misfire code-aswell as the cam sensors.
Change the above and your beast will fly-mine did!
Gassing Station | M Power | Top of Page | What's New | My Stuff