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.

Hi Antonio,
you asked for the throttle valve.

Yes, it must be totally closed.
The screw of the valve is just 'turned by' to prevent the flap from working into the housing.
But you must readjust the throttle valve switch after that.

Maybe someone turned the throttle valve screw before, and you adjusted the switch to this new, false position.

Regards
Norbert

- I can't localize the screw for adjusting the idle speed in your photos. Maybe Volker can help - he owns the Bosch manual for BMW, too.

Hi,

the idle screw is located on the foot of throttle below throttle switch. I have attached a picture of it. Normally you find this in Bosch's wortkshop manual . Unfortunately it does currently (?) not exist in English for your car, only in German. They also describe there how to adjust throttle flap so that if closes fully. But normally that stopper is sealed and no one touches it. Only idle-run screw is changed to adjust idle-run to 850 - 1000/min.

Only when you fully close idle-run screw and engine speed is still at 1200/in, follow my instructions above to verify other sources of excess air.


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Hi Antonio,

when you tell your story of 5 MAP sensors to have one running, this sounds familiar. Type 2 MAP sensors with full-load diaphragm normally fail over time with a torn diaphragm. I had recently bought one on eBay to have an additional reference and of course it was leaking. Seller was not even willing to give a discount (I was willing to repair myself), so I returned it. Hearing that Bosch charges something like 400 to 599€ for repair, he believed it was very valuable.

There are other gossips that one should use the cheaper 0 280 100 111 instead. But that is a type 3 sensor form MB 280 engine and it will of course not fit.

My proposal for an easy test: Draw vacuum and see how quickly it will fall. If it leaks, it is broken. If it keeps vacuum and screws or rivets are still okay (sealed), then it will be okay in 95% of cases.

Wow! Never saw that screw marked with red arrow!!! Neither the "thing" marked as "3"!

I'm running to my garage to check it out!
With expectancy...

Well,

screw 3 is the most important! That's where you adjust fel pressure to 2,0 Bar. 1 and 2 are the ones to loosen and turn throttle switch.

Antonio,

maybe it would be best to contact Bosch Automative Tradition and ask for the English version of the BMW workshop manual D-Jetronic. And if not available, maybe you can find someone to translate it from German. It a very valuable manual to have.

It's there!!! Completelly on a blind angle!!!

Congratulations, Volker!
You did the job again...

Regards
Norbert

Well, thanks for the flowers Norbert ,

at first I assumed a more complicated issue and assumed that Antonio knows where his idle-run screw is located. Good feeling to heve helped to sort it out.

My regards to Portugal. One of the interesting countries I have never vieited. It even was on my wife's list for summer holiday. Currently France and Italy are her favorites.

Fantastic! It did it!
I could even stall the engine with it!! Great!

Now it's adjusted to 900rpm and 6 clicks from the left top on the ECU.

Hi Antonio,

if you mean to adjust idle-run CO by these 6 clicks: Use an exhaust CO tester to adjust or go to a workshop that has such a device and adjust to 1,0 to 2,0%, I would adjust to 2,0%. Counting clicks is not really exact. But before you do it, read my chapter on Maintenance and tuning . There you will find how to adjust fuel pressure, throttle switch and how to grease trigger contacts. Then idle-run CO should be the last job to do. Of course a proper ignition adjusting is the very first thing to do.

Hi, one more addition: Found a 'Owners Manual' at
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,
including the following instruction:


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The manual contains some more information, just as adjusting ignition, valve clearance, brakes, bulbs ... maybe useful,

Regards
Norbert

Lol... You must all be thinking that I'm a completelly begginer on this matters...

After already disassembled and restored my Bmw 2002 engine, 3 weeks before going to the Bavaria Tour 2006, running 5000km with a newly refurbished engine without any problem, and after restoring my E30 M3 motorsport engine by myself also, I feel ashamed...

I was mentally stucked on the throtle lever limiter... Like on a caburator... See photo