aja540i 1906 Report post Posted October 26, 2015 Sooo, went to move the M5 this morning and when i started it the dash and hud lit up some some kind of demented christmas tree of doom! Engine in limp mode, reduced power, dsc, start assist, everything with a 3 letter name not working!! Had to move it onto the lawn so i could get the trusty old e39 out, and it felt like the brakes were on, no power, didnt want to rev etc. After i had a little cry i did some internetting and plugged in the bluetooth dongle to read any fault codes, and it looks like probably a dead throttle body actuator, so i am going to have to pull them both out and perform autopsies on them. Has anyone on here done this? Quote Share this post Link to post Share on other sites
Breaker 980 Report post Posted October 26, 2015 Oh crap me thinks Quote Share this post Link to post Share on other sites
gjm 3258 Report post Posted October 26, 2015 I can imagine just how frustrating and disappointing that is. Hopefully the autopsies can be forensic and not clinical. Quote Share this post Link to post Share on other sites
andrewm 236 Report post Posted October 26, 2015 (edited) You probably already found this but If you google search s85 throttle actuator teardown there are some good threads on it. Theory seemed to be the plastic gears wear causing the electrics to continue to hunt for positioning and eventually burns out the board. People were rotating the black gear round 180 degrees to a less worn section to confirm gear wear as the failure. Edited October 26, 2015 by andrewm 1 Quote Share this post Link to post Share on other sites
KwS 2425 Report post Posted October 26, 2015 before digging too far, hows the battery condition and voltage? Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted October 26, 2015 It's probably upset about not being in M mode. Can you put some tape on the lights? Should only cover 1/3 of the windscreen. 1 Quote Share this post Link to post Share on other sites
BreakMyWindow 1874 Report post Posted October 26, 2015 Clear the codes, see if it returns then take course of action? Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 26, 2015 before digging too far, hows the battery condition and voltage? Have to disconnect the battery to get actuators out so will probably do at the same time. Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 26, 2015 It's probably upset about not being in M mode. Can you put some tape on the lights? Should only cover 1/3 of the windscreen. Not sure I have enough tape! 1 Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 So, i can get a set of replacement gears for about $250US, or a replacement actuator for about $1500NZ new from BMW. Problem is replacing the gears only seems to fix about 75% of failed units, the rest die electrically, and there doesnt seem to be a reliable way to test the circuit outside of the car, so the replacement gears is a bit of a gamble. I think i will order 1 new actuator and a set of gears so i know i can get back on the road. On the plus side it looks fairly easy to get the units out so i have a good excuse to get elbows deep in my V10!! 1 Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 Update, got the offending actuator out this afternoon, and opened it up....gears are worn as expected, but it also looks like one of the semiconductors on the board has gotten a bit hot under the collar so i will be buying at least one brand new unit. Quote Share this post Link to post Share on other sites
dkonsta1 109 Report post Posted October 28, 2015 What is BMW opinion about the issue? Common failure? Expected in this milleage range and age? Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 (edited) I dont think BMW have much of an opinion about this, the unit has worked far longer than the warranty period of the car so its hard to see why they would care...they are in it to make money after all. They did seem quite happy to sell me 2 new units Edited October 28, 2015 by aja540i 2 Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 I have been thinking and i have a theory about why these units fail like they do.... In my old school e36 (with an accelerator cable) as the throttle butterfly starts to gather a bit of oil and scum it starts to bind slightly when fully closed and it takes a bit of a kick on the go pedal to free it up and get it moving... Now imagine 5 sticking butterflies and you can see why the motor trying to move them starts to draw more current than the driver board was designed to handle and poof the magic smoke gets out!!! It is my intention to remove and thorougly clean all 10 ITBs, i believe this will extend the lifespan of the actuators quite considerably.(at least i hope it will) Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 Side note: turns out the battery in my car is the original from 07, so i was on borrowed time with that as well!! 1 Quote Share this post Link to post Share on other sites
gjm 3258 Report post Posted October 28, 2015 Side note: turns out the battery in my car is the original from 07, so i was on borrowed time with that as well!! The battery in our 320d is original too. I keep thinking I ought to change it, but it shows no signs of any problem so... Cleaning 10 ITBs sounds like a fun way to spend a couple of evenings! Quote Share this post Link to post Share on other sites
turbolizard 38 Report post Posted October 28, 2015 The battery in my e39 M5 lasted 12 years! Reading this thread does make me thankful my car is at least a little bit simpler but it can be really interesting digging into the engineering - it sure helps if you have time and dont need the car every day. Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted October 28, 2015 Most BMW (Varta) batteries last 10 yrs +, often 12 & more, ours did 11. Replaced one at work a couple of years back in an E36 - 17 yrs Back on topic - good luck with resurrecting the M5. From what you describe - sounds like a not very well thought out/ designed unit for the requirements of it. Not that ITB's was new technology when it was designed for this car. Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted October 28, 2015 Side note: turns out the battery in my car is the original from 07, so i was on borrowed time with that as well!! Moes is a warranty replacement from 2003 :-) Shall I get you 3 cases of Wurth system cleaner to get all the crap out of the intake??? Do it just rpior to each oil change :-) Quote Share this post Link to post Share on other sites
Ahmedsinc 414 Report post Posted October 28, 2015 Sounds like it's an expensive week! 1 Quote Share this post Link to post Share on other sites
aja540i 1906 Report post Posted October 28, 2015 Moes is a warranty replacement from 2003 :-) Shall I get you 3 cases of Wurth system cleaner to get all the crap out of the intake??? Do it just rpior to each oil change :-) Intake in general is very clean, and that Wurth stuff works a lot better if the car is running when you use it! I will probably go a bit OCD with this and get all the injectors cleaned and tested while im at it, why not tempt fate! I just have to sell the 540i to pay for it all! Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted October 28, 2015 I will probably go a bit OCD with this and get all the injectors cleaned and tested while im at it Gee, that doesn't sound like you at all. I seem to recall the supercharger was on it's way out too - best you put that on the list for the accountant too Quote Share this post Link to post Share on other sites
Matth5 471 Report post Posted October 28, 2015 So, i can get a set of replacement gears for about $250US, or a replacement actuator for about $1500NZ new from BMW. Problem is replacing the gears only seems to fix about 75% of failed units, the rest die electrically, and there doesnt seem to be a reliable way to test the circuit outside of the car, so the replacement gears is a bit of a gamble. I think i will order 1 new actuator and a set of gears so i know i can get back on the road. On the plus side it looks fairly easy to get the units out so i have a good excuse to get elbows deep in my V10!! Look online in Ebay, ecstuning, Fcpeupro ect.. Might be far cheaper to import one yourself. It's not uncommon for BMW NZ to sell things at double the price of US/Euro retailers so even with shipping, customs ect you save money. If you have a second car maybe you can afford to wait for the delivery. Quote Share this post Link to post Share on other sites
WYZEUP 283 Report post Posted October 28, 2015 your not really going to save any money if your paying 1500 each for them with the exchange rate unless you go ith an aftermarket version. only option is if you possibly have someone in the automotive trade that can purchase them at a trade price for you Quote Share this post Link to post Share on other sites
polley 916 Report post Posted October 28, 2015 Can you take a picture of said board and semiconductor that got a bit hot? Quote Share this post Link to post Share on other sites
