Need help with D jetronic.
 

Hi,
I'm working on a vw type 3 with D jetronic and is the same for some 914.
The issue is that in part throttle the cloud of black smoke is impressive.

Any advice?
Can anyone share with me a copy of the ecu connectors diagram ?

Thanks.

Correct, your system will have the same issues as the 914,have you followed all the repair guides on this system on here and others sites ;).
I remember some of the early T4 stuff shared part numbers mainly the 411 1.7.
Same stuff really but an earlier system production wise,some say this was the first mass produced EFI built.
You don't say how it starts? is the power ok during the over-rich condition (not good),I'am thinking straight off you may have a fuel pressure/regulation problem.
Lots of things to go thru and more info needed,cheers.

Here is the ultimate reference site for these old time FI systems: 914 D-Jetronic Parts and Troubleshooting

Mr PB Anders has all the info you'll ever need and if you decide to go through the troubleshooting steps, do them in order and follow each one and do not go to the next step unless the one you are on is finished okay.

black smoke, so maybe to rich. could be excessive fuel pressure, could be leaking injector, could be head temp sendor is out of wack or its wiring failed, could be cold start injector is leaking or always on. could be pressure sensor is defective. could be bad wires (open or shorts) on any of the sensors. could be worn injector trigger point that bounce and thus give double injection pulses (usually worse as rpm increases)

if black smoke only at part throttle but not at idle nor during acceleration, I would tend to rule out leaking injectors. could be trigger points, examine them if taper is worn off the fiber lifter on the points, then they are worn out, the tips of the lifters should be tapered, not squared off. the head temp sensor failure if it goes rich will make the car very hard if not impossible to start, but they can fail intermittently if the pigtail wire on the sensor breaks, (wiggle the pig tail vigorously when doing an ohm meter test of the temp sendor this will detect intermittent wire damage, the wires often fail right at the sendor near the crimp

ander's website has good info.