M10 auto carb issue automatic advice also converting to manual

[Topher123]

Recently bought a chromie m10 auto. The car one minute runs ok the next stalls or starts running rough then leave it 15 minutes and it fine again. My two questions are is a manual conversion simple enough with the correct gearbox and are the diff ratios way different between auto and manual on this set up? And also I want to sort out the running issue first .... thought about a weber conversion but they all say for manuals only? What will I require for them to work on a auto set up?

[30316]

For Weber conversion you will have to consider the kick down cable connection to the carb. There used to be conversion kit for the existing kick down cable to the auto box. Try any Weber agent to check if it is still available.

[martauto]

I have a weber on my 316 auto and the kick down works fine but it came to me like this.
If you have the original Pierburg carb then it needs to go as they are shit !!!
Try a weber first then see if you still want to convert over to manual.

Mart.

[Topher123]

Cool thankyou so has your weber got the kick down cable all connected the same as the old pierburg rubbish? Or has it been adapted in some way?

[30316]

Cool thankyou so has your weber got the kick down cable all connected the same as the old pierburg rubbish? Or has it been adapted in some way?

Pierberg is not rubbish as you say if it works properly as intended. Having lived with it for almost 37 years, it’s gone wrong 3 times over the years. When it went wrong the first time BMW replaced it as it was still under warranty. Second time when it went wrong after several years BMW replaced the rubber gasket under the carb as it had become porous. Last time it went wrong BMW couldn’t fix it and for the next couple of years I gradually started by getting hold of a spare Pierberg but it had the same running issues.

Finally I started replacing small bits within the carb but none of the external electrical items. It’s a complicated beast which nobody really understands it. Don’t forget the carb has its own ecu! After a while something that I did seem to cure or the ecu got reset and it’s been fine for at least 15 years. When it goes cantankerous it’s not easy to drive especially with an auto. With Weber you have manual choke and economy gauge stops working.

[martauto]

Cool thankyou so has your weber got the kick down cable all connected the same as the old pierburg rubbish? Or has it been adapted in some way?

Sorry I cant tell you as I dont know how it was in the first place.

Mart.

[Speedtouch]

Sounds like the OP's problem may well be heat-related, if it runs OK for a minute, shuts off, then re-starts 15 minutes later.

Perhaps the heat causes expansion of a gasket to create an air leak, or similar; perhaps try spraying WD40 around the inlet manifold gaskets with the engine running and look for bubbles.

[30316]

There won’t be bubbles as the air is sucked into the manifold.