Z4M misfire at 3500rpm

ph001 · Post by **ph001** » Tue Jun 12, 2018 11:16 am

Ah, yes sorry - I was replying from page 1! Anyway, sounds like you are on the right track.

samZ4M · Post by **samZ4M** » Wed Jun 13, 2018 10:23 pm

Last minute work before lemans tomorrow!

Think it’s fixed with the hidden throttle position sensor.

Will update once I’ve had a good drive.

Thanks all!

: QUl8oIy9.jpg (70.06 KiB) Viewed 902 times

ph001 · Post by **ph001** » Wed Jun 13, 2018 10:40 pm

Nice work! Did you enjoy getting those 6 throttle body clamps on and off as much as I did?

samZ4M · Post by **samZ4M** » Wed Jun 13, 2018 10:42 pm

Total job was 1hour 20 mins. I still need to do the clips back up, as I don’t have the tool, I’ll buy it tomorrow. But they weren’t that hard, with some bulky pliers.

1 of them was a bastard due to pipes in the way.

TomK · Post by **TomK** » Wed Jun 13, 2018 11:17 pm

Sounds like a result Sam, glad I mentioned getting a tps just in case after my initial diagnosis

Have a great trip to Le Mans, very jealous!

If any of the clips have bust you could do worse than do what most people do and replace them with the jubilee type used in the M5.
https://www.turnermotorsport.com/p-6540 ... -bmw-part/

samZ4M · Post by **samZ4M** » Wed Jun 13, 2018 11:23 pm

I have tomorrow off, so I will see what BMW have in stock, it's only a mile from home! If not, I'll maybe get some jubilee clips to be safe. Probably cheaper than getting the tool to do up the BMW clips anyway!

You were right with the TPS. It's also the cheapest part, £80, vs the £130 for each intake/exhaust sensor. I'm going to take the spare one I purchased with me. May sound silly, as I've replaced it, but I have it, may as well!

ph001 · Post by **ph001** » Thu Jun 14, 2018 9:36 am

Might be a little premature as I'm guessing you haven't actually tried it yet with the new TPS, but fingers crossed. You can get away with stainless jubilees on the throttle bodies but you have to be EXTREMELY careful where the worm gear bit of the jubilees sit in relation to the throttle actuator bar, otherwise they can clash at full throttle opening.

samZ4M · Post by **samZ4M** » Thu Jun 14, 2018 10:33 am

I did run it for a few mins, but the clips were loosely doneup. I’ve just purchased some better pliers, so will do them up proper and go for a spin!

samZ4M · Post by **samZ4M** » Thu Jun 14, 2018 4:31 pm

Jebus, those clips are mental hard. Should have purchased the proper tool. I found some long nose flat pliers, worked well, but it's so tight you can't really hold the clip in place. Then there are the screws they keep getting caught on. With some patience I was able to do all 6, I had to keep walking away due to frustration!

Anyway, an hours blast and I can confirm the problem is fixed. Lower TPS (under air inlet) seemed to be the problem. Not sure if it's a placebo, but it seems to pull better.

Thanks for all the help and advice.

Yorkie Z · Post by **Yorkie Z** » Thu Jun 14, 2018 5:33 pm

Glad you got it sorted

ph001 · Post by **ph001** » Thu Jun 14, 2018 5:47 pm

samZ4M wrote: ↑Thu Jun 14, 2018 4:31 pm Jebus, those clips are mental hard. Should have purchased the proper tool. I found some long nose flat pliers, worked well, but it's so tight you can't really hold the clip in place. Then there are the screws they keep getting caught on. With some patience I was able to do all 6, I had to keep walking away due to frustration!

...

great fun aren't they! Think of it as character building. I devised a tool from some £3.99 crimp pliers by grinding the ends back (shown in green) to leave a sharp 'pincer' at the end. This worked OK, certainly a lot less swearing then using long nose pliers....

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Awesome that you got to the bottom of it a few hours before setting off to Le Mans though. Good work.

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