Bmw 3.0Si D-Jet Bj 1974 - fine tunning

Dear members,

This is my first participation here.

I have a Bmw 3.0si bj 1974 with D-Jet.
The Car is running fine, very fast and powerfull, and since I found a good MAP (after 5 used ones) the Car os running smooth also.
The last fine tunning I need is to achieve a normal idle speed. I can't go below the 1200rpm. The tps was cleaned today and ajusted and it sticks on the 1200rpm (not 1900 anymore. The tps was not giving the zero throtle position).

I didn't check the water temp sensor yet.
The air temp sensor is ok.

O have red dot Ecu and blue dot Map. Is this a big problem.
The Car is responding to the ECU mixture adjustment knob.

All the exhaust and intake gaskets were replaced and fuel hoses also.
Auxiliar air valve new and not passing any extra air.

Any ideas?

Regards
António

When Norbert said to disconnect the Map to test, he meant to say to release and close the intake manifold hose to the Map? The Map doen't matter while idling?

Regards and Thanks a lot!
Mota

Photos of original condition before my restoration

It's easy to inspect the air intake valve?
The flap should close completelly?
O could't locate any adjustment extra air screw. I only see the throtle low limit screw as in any carburator.

Hi Antonio,

thanks for opening the D-Jetronic discussion here again. Now when it comes to idle speed: When you close idle speed screw completely and it still runs 1200 rpm, following comes to my mind:

1. Throttle is not fully closed. Check whether throttle linkage is correct and whether it really fully closes (remove air filter to check
2. Check auxiiliary air regulator. Ob BMW there is a filter on one side and an air hose on the other. Try to squeeze hose until it closes. Does that reduce speed. If so, auxiliary air regulator hangs. Common failure.
3. Other false air by leakages on intake manifold, sealings under injectors or hose from intake manifold to MAP sensor. Use brake cleaner to spray and see whether you see an enigine rev change

Too high revolutions always come from too much air for the engine. ECU and MAP sensor only determine fuel being injected. Thus they can only reduce engine speed by wrong fuel mixture. When your engine speed is high, ECU notices that and increases fuel accordingly. You should have 0 280 001 007 ECU and 0 280 100 030 MAP sensor. BMW only has this single combination together with 0 280 150 036 injectors. BTW they are the only ones still available as new. Expensiv, bu tmaybe a good idea to have a stock as long as they are still available.

Hi ANtonio,

and removing the hose from MAP sensor would futher increase false air. It will not help here. Keep MAP sensor as it is and find the excess air that your engine sees.