can any re link that pluggy thing DIY that does away w/ our rpm's hanging up?

[jrkoupe]

I recall pics/diy were posted here....but now they are gone due to photo bucket crap.

I have a 99 28 coupe........

and I recall reading by unplugging this dew hickey our revs will no longer "hang up" between shifts....

[328 Power 04]

Curious, I haven't ever heard of that. I wonder what.


But I do know some tricks in the tune that will cause some very nice engine rpm drop.

[deni2s]

Second post here:
http://www.romraider.com/forum/viewt...p?f=42&t=11393

[328 Power 04]

Second post here:
http://www.romraider.com/forum/viewt...p?f=42&t=11393

His 2.8 is MS42. Even though the info is correct on RomRaider, there's a few maps that make it even easier.

[rf900rkw]

OP is talking about one of the clutch switch/sensors, I don't remember which. You'll have to go back about five years in forum dredging. As I recall, the side effects made this mod less useful.

[rf900rkw]

https://www.bimmerforums.com/forum/s...elay-on-M52TUs


You'll have to ask photobucket for the details.

[328 Power 04]

So there's a connection from the clutch switch to the MS42? Hmm, obviously that's how it does the cruise control control.

There has to be a method to do this with more finesse... to the MS42 tune!

[Muzz258]

I have solved the rev hang between gear shift problem on a M52TUB25 engine by cleaning the idle control valve. It didn't make a sound with the ignition on 2 (should be able to hear it vibrating) and it didn't rattle when it was shaken when out of the car. Brake cleaner sorted it out and some CRC 5.56 was sprayed though it before reassembly.

[jrkoupe]

OP is talking about one of the clutch switch/sensors, I don't remember which. You'll have to go back about five years in forum dredging. As I recall, the side effects made this mod less useful.

Randy..

what did u mean here?

"As I recall, the side effects made this mod less useful"


were there negative side effects?

- - - Updated - - -

https://www.bimmerforums.com/forum/s...elay-on-M52TUs


You'll have to ask photobucket for the details.

that was the thread yes!......but I need pics.......drat

[rf900rkw]

To me bypassing the switch is not a fix; it's merely a kluge to hide the symptoms of the real problem (whatever it is). You end up disabling the clutch safety interlock for the cruise control and the starter. The later will not pass safety inspection in some states.

But I don't own a M52TU manual, so I have no way of doing long term testing.

[jrkoupe]

To me bypassing the switch is not a fix; it's merely a kluge to hide the symptoms of the real problem (whatever it is). You end up disabling the clutch safety interlock for the cruise control and the starter. The later will not pass safety inspection in some states.

But I don't own a M52TU manual, so I have no way of doing long term testing.

understood...


all non issues to me.........I never use cruise......and always depress clutch upon start up

thnx

[Zoupe6]

I did this mod to my clutch switch a few years ago, but can't remember the exact details, unfortunately. It was just a matter of jumping a wire to another pin on the connector. However, my cruise control works fine but I do have to be sure and engage the clutch before starting if in gear.

[deni2s]

all non issues to me.........I never use cruise......and always depress clutch upon start up

Make sure your ignition has some TouchID or FaceID, in case someone else finds himself in your car... You know, sometimes strange things happen to us/our cars/others...

[328 Power 04]

Lol. Having a manual transmission car in the USA is one of the best theft deterrents, or joy rides.

[Mr Bingley]

I agree that it's not reasonable to disable the clutch safety switch--it is begging for someone to get hurt. There was a question posed in that thread in post #23 as follows:

came across this post after someone on the e36 forum was searching for a solution to this problem. I have a question or 2.
From what I gather, the 3 wires here are as follows. Ground, clutch interlock signal for starting, and clutch depressed signal which is causing the problem of hanging rpm's.
Seems to me that you have removed the switch from the circuit and shorted the clutch interlock circuit so that the ECU will allow the car to start. The problem I see here is that the car can now start when it's in gear with the clutch out.

Would it not have been easier to just cut the wire that provides the ground signal to the ECU for the hanging RPM's and leave the connector plugged in thus not disabling the clutch/start interlock circuit?-J

and another suggestion in post #56:

Here is something you may want to consider doing. I had my seats out to replace the clutch pedel bushings and seat bushings and I took a good look at the switch that needs to have contact made to prevent throttle hang. In my car, there was a fair amount of room between the tab on the clutch pedel and the switch when the clutch pedel was fully released. I installed a self tapping screw and washer into the tab that hits the switch, I made sure that I wasn't pushing the plunger on the switch through the back of the switch causing damage. The screw and washer took out about a quarter of an inch of play at the switch. This relates, I'm guessing here, that the switch is making contact one to two inches before the pedel is at rest or full release.

Since I have done this, I have not had throttle hang one time.

And then there is the last post in that thread, #78, which, I think, clearly points to the problem with the initial idea:

So I have a remote starter / push to start system with a brown wire that needs to be connected to my "clutch pedal wire" rather than my "brake pedal wire" obviously cause it is manual tranny. I need to connect this to which wire? One of the browns or the violet. I do not want too burn anything out. Of course my remote start manual does not tell me which one or what to test for using multi. From this thread I am thinking middle brown but want to get some advice if possible first...

Thanks,

[jrkoupe]

to me.......just me


"I agree that it's not reasonable to disable the clutch safety switch--it is begging for someone to get hurt."

so what is the issue for you?

I couldnt care less about this......Im an ol skool guy....... get hurt?......not me.....and Im the only driver of said vee hickle

- - - Updated - - -

Lol. Having a manual transmission car in the USA is one of the best theft deterrents, or joy rides.

yup

[328 Power 04]

I believe I just discovered the map in the tune that controls the clutch switch rev hang behavior.
No more cutting wires needed.

[Randy Forbes]

I believe I just discovered the map in the tune that controls the clutch switch rev hang behavior.
No more cutting wires needed.

Interestingly enough, in my Autologics, I can enable/disable the "auto-manual" function. This was an accidental discovery, as when going through the car's parameters, it was set to "auto"; well an M Rdstr certainly has a manual xmsn, so I set it to that!

It was at some later date that I discovered that I no longer had to depress the clutch pedal to engage the starter__trust me though, it's a habit to always put the car in neutral, because the Healey I've had for coming right up on forty (<40) years does not have that safety feature.

At the time, I thought maybe it was broke, but then I set my other car's parameter the same way, then it too no longer had to have the clutch in to start. One of those AHA! moments ensued. Once I had figured it out, I switched them both back to "auto" just in case my other half was to ever get caught out.

Of course, that only covers the starter function, but what is this rev hang of which you speak; do the Ms not have this (I haven't driven too many Z3s for any great distance or time)?

[328 Power 04]

Ya, autologic needs to word it better.

BMW worded that coding as "auto/US Clutch switch" and manual (European mode) in the factory coding.

It will not make a difference on either of your M roadsters DMEs and programmed lag though.

[BimmerBreaker]

Wait, so on non-M's there is something making the RPM's hang a bit between shifts? Like a programming-based CDV?

[jrkoupe]

kinda sorta ....yup

[raubritter]

I believe I just discovered the map in the tune that controls the clutch switch rev hang behavior.
No more cutting wires needed.

Any chance for further improvements for your M54 3.0 magic? =)

[328 Power 04]

Any chance for further improvements for your M54 3.0 magic? =)

You of all know that it's exactly what I have been doing for MS43 in the last 3 hours, it has very similar clutch switch behavior... hahahah, expect email.

[ixlr08]

I just installed a copy of the code that Abel has been working on for this. It is still a work in progress, but initial testing shows promise that thru software changes the rpm spike during shift changes on my M54 3.0 can be reduced or eliminated. It makes shifting smoothly much easier, I am very happy with what he has done so far. I can't wait to see what it is like when he sorts it all out.

[jrkoupe]

sounds good......pretty pretty good