E53 petrol fail safe again.

[X5smw]

Right… changed the throttle body, now goes like stink… 

didn’t start… new battery, now starts and goes like stink….

now drops into fail safe and says the idle valve is mechanically stuck open.

where is it, how much is it… can I kick it? 
 

 

[Greydog]

Morning Stu

Long time since I played with a straight six so the old memory might be wonky here so check realoem

From memory it is linked to the Air Pump and Vacuum control system. Find the Airpump and follow the Vac lines to the rear of the engine you should find a valve with a plug on top (or end) first make sure all lines are good no splits or cracks check the valve is operating, dont forget there is a non return vale in the system close to the inlet manifold. 

Hope this helps

Dave

[X5smw]

Right, changed it… it’s a bit of a faff, but basically remove the airbox and everything into the throttle body and there it is. 
took it for a run and all seems nice…

starts to come home and it suddenly goes into fail safe mode and loses all power again… 

gets it home and revs are all over the place. Computer says throttle position sensor Issue!.

I have already replaced the throttle body. 
I’ll take it for another run later. 🙄😩

[X5smw]

Update… took it for a run today and it did 30 miles without an issue… then the check engine light came on, no loss of power… got home and it’s telling me banks 1 and 2 running outside tolerances. 
put a new MAF sensor on which I bought this week. Let’s see what the next test run does! 

[X5smw]

Also noticed I have no headlight indicator on the dash now (blue high beam works) and the intermittent wipers have stopped! Lol

[Greydog]

Morning

Symptoms could point towards the Footwell Control Module or it's Earth point 

Dave

[X5smw]

Yet again, it’s dropping into fail safe mode.  Drives fine, then it’s like a misfire…. Then fail safe, the three yellow lights and no power and stuttering… 

Got home and the revs are all over on idle. Little scanner showing the throttle position controller jammed… 

it’s so far had a new throttle body, new idle control valve, new battery,  new maf… 

 

luckily I wasn’t on a motorway this time! 

 

[Greydog]

Looks like time to test the Warranty on the Throttle Body Stu

Was it a new one ?

Dave

[X5smw]

Hi matey. It was a recon one, so it has a warranty. 
to be honest, I’ll just get a refund and buy a new one… do you think a pedal could be faulty? Would you expect it? It seems to jump and choke if I’m lightly feathering the throttle. 
Idles fine without fail safe mode intervention and seems to be ok at full throttle. ( not that I can do this much before either speed limits or trees get in the way.) 

[Greydog]

Morning

All the Throttle issues I have seen (quite a few over the last 20 years) only 1 was pedal related all the others were Throttle Body issues

Just changed one on my neighbours 330i estate he brought it from the Bay £100 came with s 10 year warrnty, took longer to take all the engine covers off than to change it very smooth now. He had been having intermitent problems for the last few weeks but the recent weather convinced him to live with it untill it died on the M23 

Dave

[X5smw]

….. well, if you’re not busy Thursday….. 😂😂😂….

 

ill keep you posted! 
cheers.

 

[Greydog]

Out shooting Thursday got to keep my dogs busy 🤣🤣 

Good luck Stu

[X5smw]

I have a new one coming Saturday… I may need to borrow your gun Sunday! Lol

[X5smw]

Right! Quick update…. 
replaced the throttle body with a brand new one and took all the pipes and diss valve off for a thorough clean. 
I found some hairline cracks in the folds of the air intake boot of the idle valve intake pipe, coverered it with order tape then electrical waterproof tape as I couldn’t get another one today. 
started the car and it was banging and popping and wouldn’t run… 

then I remembered to plug the throttle body back in! 
reset all modules and adaptions and it calmed down. 
took it for a 20 mile run at pace and it’s off like a whippet again. 
 

thank you to @Greydog as usual for the advice. 
hopefully this has sorted the issue and on to the next one! 

[Greydog]

Yay just the pipes to replace now 🤣

Have a Great Christmas Stu

Dave

[X5smw]

Took it out yesterday and then shopping last night 4x20 mile runs and the car didn’t miss a beat. Still a few little nigly bits to sort, but hopefully the limp mode issue is solved! 
got a long run next week when I go on holiday so we shall see if I end up coming home via the RAC or not…

now to fill it with more petrol! 
 

[X5smw]

Well…. Took the car on a run out to holiday and back without any fault, so looks like mission accomplished on the failsafe issue. Thank you to @Greydog for valuable insights … 

now to tackle the next one!