Primitivesmith
Member
Hi all!
My 2nd post here ever, however I wanted to share my findings on the journey so far of owning a non running (sadly still not quite running perfectly) z4. While this will be a long tale, it has a simple lesson at the end if you can bear to get to it, but its been a long road to get even this far and I wanted tk try to give something back as I've been lurking on the forums for advice for quite some time now, and this car has been taking me for a ride for a long time
Anyway, I got this car as a poor, sluggish runner a good few, maybe 6 months ago, for a very good price. I know my work was cut out for me, but I'm no stranger to a spanner, having done a novice to intermediate amount of tinkering, and this seems like a nice couple of weekends of getting the hands dirty to get her on the road. It's only a NA petrol, how much could be wrong with it? (insert regret just about here)
So, she runs, but very lumpy idle and she's not willing to go beyond about 2500 revs. Limp home mode I thought, and rightly so as there were several lights upon the dash, but mechanically she sounded fine and was pretty rust free for the age.
After a white knuckle ride home (not due to speed, mostly hoping she doesn't give up) and subsequent unpuckering of my behind from the much worn leather, I decided to plug in ista( ill try and add photos as I go, but to be honest it's largely an album at this point, slightly larger than my wedding) to which I found the famous codes-vanos vanos vanos with a touch of eccentric shaft sensor, and some bits about an sim module and eps. Not too bad I thought, I'll take a look online... So vanos (not to be confused with phanos, the popular character from the comic books, though about 347% more frustrating and difficult to deal with) consists of enough symptomatic tenancies that it might be better off to start at the other end of the car and work your way back to where it lives
So the list begins :
Eccentric shaft sensor check - no improvement, code for it gone
X2 vanos solenoids - no improvement, still one code remains for vanos
Spark plugs and coils - no improvement
Ccv assembly - no improvement
Throttle body and maf sensor - no improvement
Intake vanos unit (code came for it intermittently, no other codes after this)
Injectors - no improvement
O2 sensors - no improvement
Battery - no improvement
Being left somewhat defeated and feeling as though there was no way back from a certain level of cost, and having no codes to go by, I was at a loss. While it was never my intention to throw parts at it, I had run diagnostics on it multiple times and cross checked my findings online and to no avail, nothing seemed to pop up as a huge issue from which, let's be honest, there are thousands of to be found. From my previous years of working on cars, vans, motorbikes etc, I had never seen an engine so unwilling to run, with so few clues as to why she refused to every time
Taking a last stance on it, I decided finally to do the remaining tests, using a pressure test set I picked up on online as I hadn't had a good one before, I thiught I'd check the last thins that possibly remain compression again (did it before she's fine) then fuel rail pressure, then finally.... The exhaust...
I plugged it up, turn the key, and pow... 10 psi at idle, the needle could've bent round the stop point. I turned it upside down and felt suddenly like I might just be the dumbest guy to trawl the forums or even attempt to fix a car, or that I must have broken the tester. Tested it again on the 2nd bank, same result. Tested on the 3rd point down the pipe, same again... Either the central secondary cat was blocked, or the tester was broken
Being at such a loss at this point anyway, and somewhat hopeless, I went for the exhaust, lowering it, with much frustration and annoyance at the rubber bungs that hold it up at the rear... I mean seriously, these used to fall off old cars, however I can happily say I placed 80kgs of pent-up-broken-down-bmw rage upon them and they wouldn't budge... So I grabbed a hacksaw, and went kill Bill coffin punch hacking away at the stop until I had the whole thing off
I then tried to blow a compressed down them, nothing... I had a thought which worked quite nicely, I poured some boiling water down the end and followed the hot patches as the metal warmed up. Nothing past the central box! The grinder came out 2 mins later, and lo and behold, the amount of junk and debris that fell out of the box was liken to the bottom of the cooled down bbq in the summer, just carbon carbon carbon and bits of what used to be carbon. Pretty sure at 10 psi with that much It mightve been spitting diamonds on the drive home.
Anyway, X2 exhaust clamps and a piece of scaffold tube later (long flexis are hard to get in my area apparently) and I now have a car that can rev beyond 2500rpm. Albeit noisily and of course with the emmisions of a Boeing 747.
HOWEVER. - I do still have an issue with the rough idle/dying idle when trying to start up, but much cleaner now. If any of the bmw geniuses are about that know how to discipline these n46 engines, I'd be much obliged if you could tell me the secret of the rough idle, that might be something I haven't already changed
So, three things to conclude this post.
1. If you started and finished the whole post, you deserve a medal, unfortunately I can't provide it as I'm now broke after owning a z4 for 6 months
2. If you have a car with the same problems (scratch that, if it's a z4 it's a matter of when apparently) do the basics first, digital is fine but analogue has a way of not misinterpretating data like vacuum and compression
3. If you find yourself with any answers above I'd be eternally grateful, I feel like I'm nearing the end of much longer project that anticipated, and I'd love to be able to drive it at some point if the z4 gods will it. I just hope it drives as good as it looks being up on Jacks for 6 months
Happy motoring all
My 2nd post here ever, however I wanted to share my findings on the journey so far of owning a non running (sadly still not quite running perfectly) z4. While this will be a long tale, it has a simple lesson at the end if you can bear to get to it, but its been a long road to get even this far and I wanted tk try to give something back as I've been lurking on the forums for advice for quite some time now, and this car has been taking me for a ride for a long time
Anyway, I got this car as a poor, sluggish runner a good few, maybe 6 months ago, for a very good price. I know my work was cut out for me, but I'm no stranger to a spanner, having done a novice to intermediate amount of tinkering, and this seems like a nice couple of weekends of getting the hands dirty to get her on the road. It's only a NA petrol, how much could be wrong with it? (insert regret just about here)
So, she runs, but very lumpy idle and she's not willing to go beyond about 2500 revs. Limp home mode I thought, and rightly so as there were several lights upon the dash, but mechanically she sounded fine and was pretty rust free for the age.
After a white knuckle ride home (not due to speed, mostly hoping she doesn't give up) and subsequent unpuckering of my behind from the much worn leather, I decided to plug in ista( ill try and add photos as I go, but to be honest it's largely an album at this point, slightly larger than my wedding) to which I found the famous codes-vanos vanos vanos with a touch of eccentric shaft sensor, and some bits about an sim module and eps. Not too bad I thought, I'll take a look online... So vanos (not to be confused with phanos, the popular character from the comic books, though about 347% more frustrating and difficult to deal with) consists of enough symptomatic tenancies that it might be better off to start at the other end of the car and work your way back to where it lives
So the list begins :
Eccentric shaft sensor check - no improvement, code for it gone
X2 vanos solenoids - no improvement, still one code remains for vanos
Spark plugs and coils - no improvement
Ccv assembly - no improvement
Throttle body and maf sensor - no improvement
Intake vanos unit (code came for it intermittently, no other codes after this)
Injectors - no improvement
O2 sensors - no improvement
Battery - no improvement
Being left somewhat defeated and feeling as though there was no way back from a certain level of cost, and having no codes to go by, I was at a loss. While it was never my intention to throw parts at it, I had run diagnostics on it multiple times and cross checked my findings online and to no avail, nothing seemed to pop up as a huge issue from which, let's be honest, there are thousands of to be found. From my previous years of working on cars, vans, motorbikes etc, I had never seen an engine so unwilling to run, with so few clues as to why she refused to every time
Taking a last stance on it, I decided finally to do the remaining tests, using a pressure test set I picked up on online as I hadn't had a good one before, I thiught I'd check the last thins that possibly remain compression again (did it before she's fine) then fuel rail pressure, then finally.... The exhaust...
I plugged it up, turn the key, and pow... 10 psi at idle, the needle could've bent round the stop point. I turned it upside down and felt suddenly like I might just be the dumbest guy to trawl the forums or even attempt to fix a car, or that I must have broken the tester. Tested it again on the 2nd bank, same result. Tested on the 3rd point down the pipe, same again... Either the central secondary cat was blocked, or the tester was broken
Being at such a loss at this point anyway, and somewhat hopeless, I went for the exhaust, lowering it, with much frustration and annoyance at the rubber bungs that hold it up at the rear... I mean seriously, these used to fall off old cars, however I can happily say I placed 80kgs of pent-up-broken-down-bmw rage upon them and they wouldn't budge... So I grabbed a hacksaw, and went kill Bill coffin punch hacking away at the stop until I had the whole thing off
I then tried to blow a compressed down them, nothing... I had a thought which worked quite nicely, I poured some boiling water down the end and followed the hot patches as the metal warmed up. Nothing past the central box! The grinder came out 2 mins later, and lo and behold, the amount of junk and debris that fell out of the box was liken to the bottom of the cooled down bbq in the summer, just carbon carbon carbon and bits of what used to be carbon. Pretty sure at 10 psi with that much It mightve been spitting diamonds on the drive home.
Anyway, X2 exhaust clamps and a piece of scaffold tube later (long flexis are hard to get in my area apparently) and I now have a car that can rev beyond 2500rpm. Albeit noisily and of course with the emmisions of a Boeing 747.
HOWEVER. - I do still have an issue with the rough idle/dying idle when trying to start up, but much cleaner now. If any of the bmw geniuses are about that know how to discipline these n46 engines, I'd be much obliged if you could tell me the secret of the rough idle, that might be something I haven't already changed
So, three things to conclude this post.
1. If you started and finished the whole post, you deserve a medal, unfortunately I can't provide it as I'm now broke after owning a z4 for 6 months
2. If you have a car with the same problems (scratch that, if it's a z4 it's a matter of when apparently) do the basics first, digital is fine but analogue has a way of not misinterpretating data like vacuum and compression
3. If you find yourself with any answers above I'd be eternally grateful, I feel like I'm nearing the end of much longer project that anticipated, and I'd love to be able to drive it at some point if the z4 gods will it. I just hope it drives as good as it looks being up on Jacks for 6 months
Happy motoring all
Happy to take a detour through Medway though, the fuel is cheaper! :driving:
fingers crossed, and I'll keep the Updates coming hopefully to a positive conclusion!