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Hi, I have an e21 323i and I have swapped the rotor arm for a rotor arm that doesn't have a rev limiter in it, however there is no difference it still only revs upto about 5000 rpm and still makes the noise like the rev limiter is kicking in. Is there anything else I need to do or need to check?

Thanks

Sounds like you have the wrong type in, there are ignition systems with 1K ohms internal resistors and 5K systems and they have different rotor arms. If you have the wrong type installed it overruns at around 5500 rpm to my experience but that may vary a bit depending on what combo you have (5K system with 1K rotor or 1K system with 5K rotor).

So what do I need to do how do I find out which rotor I need, I have fitted the red coloured one

They're all orange-red colored haha, well at least the OEM delivered Bosch and Beru-Bremi examples. Check the part nos on the two you have, they're likely to be pretty similar even though you have them with rev limits varying from approx 6200-6600 rpm. I'm not sure if the rotors have an internal resistance themselves.

But I've fitted the one without a rev limiter. Will it say the resistance on them?

Which system do u think I need?

Or is it cuz of the warm up regulater does that not allow the vehicle to rev up to it's max when the engine is cold?

Warm up regulator has nothing to do with it.

For others as well, we exchanged some PM's and a Bosch rotor arm is in the car. These models are available:

Distributor rotor
01.78 - 08.80 - GB793 - 1 234 332 196 - 5 KOhm system - 6600 rpm rev limit (now fitted)
09.80 - 08.82 - GB919 - 1 234 332 313 - 1 KOhm system - 6600 rpm rev limit

Based on the build of your car (1979) the one you currently have should be in the car, unless the engine or ignition was swapped at some point. You can check for the part no of your ignition distributor to get an idea:
01.78 - 08.80 - 1 234 332 313
09.80 - 09.81 - 0 237 302 024
10.81 - 08.82 - 0 237 302 032

Yh thanks I will check and get the correct resistance rotor arm for my car . Thanks

Yes the one I need is a 5k ohm rotor, which other vehicle has the 5k ohm rotor which will fit in the e21 323i

We already established that based on build date of the car, and that is also the one you have in the car right now. But did you check if the matching ignition distributor is fitted? See above for part nos. If a complete different engine or a different ignition was built in you may have the wrong one still.

Well the rev limit less rotor that I fitted does has not made any difference and it is 1k ohms, so I definetly need a 5k ohm rotor

It looks like they don't do any 5k ohm rotors anymore, had a look almost everywhere can't find any

That would be weird. However, apparently this doesn't solve your issue which puzzles me, what else could be causing this? Think I'd start swapping ignition parts starting with the control module, coil and pulse sender.

It's weird some times it's redlined but when the engine is hot it will redline without a shadow of a doubt, I think the problem is on the fuel side I'm going to rebuild the fuel distributor and fit a new fuel pump and pressure chamber