Engine Problem

Hi Juan,

I am afraid that there is no simple basic test for the ECU.

Hi Gentlemen,

I wish you all the Best in the New Year.
Finally my problem was solved by changing the ECU.
Now the engine is running very smoothly.

I have some questions:
First one is about the engine revolution (rpm) during cold start.
1-What should be the upper limit for rpm during cold start i.e 1500-1800, etc.
Second one is about restarting the engine.
2- When the engine reaches 80 deg. Celsius If I turn off the engine the engine would not restart. However If I rev up the engine before turning of the ignition. It would restart easily. When the engine is cold restarting is not a problem. Please advise If you have encountered such a problem. What could be the remedy for this problem?
Third one is about technical specs:
3- I have a V8 engine 3,5 L. M116.982 model yer 1972. The automatic transmission is a three speed one. 722.002.W3A.040.
Is it possible to get the data/graphs regarding the tacho reading at certain rpm. i.e. first gear 2000 rpm 40 km , third gear 3000 rpm 105 km, etc.

Hi Juan,
my Best Wishes for the New Year, too.

Congratulations the engine runs...

Concerning your questions:

The idle-speed in warming-up is no limited or regulated electronically. The speed is given by the amount of air flowing through the auxiliary air-valve. Have a look: jetronic.org/en/d-jetronic/aav
Maybe the valve opens a bit too much... it is not user-adjustable <maybe Volker could do it> and it is quite expensive.

Regarding your warm-start-problems try the folloiwing: Push the gas pedal two times down all the way with 'ignition on' before starting. This gives an extra amount of fuel.

Your question '3' and all other problems about the technical data and repairing the W116 will be answered in Volker's second forum (with a section for the W116), ask your questions there: sternzeit-107.de/en/forum/w116-forum

Regards
Norbert

Hi Juan,

also best wishes for 2018 to you.

Engine revs on cold engine should be aroung 1000 rpm with 700-750 at warm engine. As Norbert correctly states this is done by Auxiliary air valve.
Warm start problems are normally due to steam bubbles in fuel line or leaking injectors. Check how quickly fuel pressure drops after switching off ignition and whether you have leaking injectors.

Technical data for your W116 is best asked in my 2nd forum for MB 107 and 116.

Hi Juan,

I am considering to fly to Istanbul for s ahort trip during this month If u want me to bring any parts for testing, I can do so.

Hi Volker,

It would be a pleasure to meet you in person.
Please let me know when you plan to arrive.
I will be absent between Jan. 8-12 for business.
At least I could ask you to check my old ECU.

Best Regards
Juan

Sorry Juan,

I cannot (YET ?) detect a mistuned ot broken ECU by resting my hands on it.

I could only bring components for you to swap and test if that helps. I remember that I once recorded the 450 ECU wire drawing during another vacation in Istanbul. 2 weeks of vacations while my wife was shopping but testing it requires a test stand that is too large to carry.

I plan to fly 2nd half of January. I wonder whether I will still recognize the city, it is a 3 years that I have not been there now.