Anyone know what the proper ecu part number is for a 1975 1. I am thinking Air Flow Sensor but the resistance was within spec. One thing that bugs me about this old fi though is it doesn't have the limp home abilities that carbs do. I don't think it is a short as it only occurs at idle and not at speed on rough roads. I have been chasing this surging rich idle problem on my 75 1. Modeling the injector as a simple inductor, however, will be sufficient to describe the basic behavior.
I think its an emmission issue given the timing. After the pulses stop, C901 slowly discharges over about 2 to 3 seconds, and the acceleration enrichment effect goes away. Under cold engine conditions, this results in a very lean mixture, lean enough to prevent the engine from running. I am left with the Air Flow Sensor, wiring harness and ecu as the last questionable parts theoretically. F , at a simulated 2500 rpm and 10 in. According to Bosch, circuits on the daughter board are specific for each engine application. Hg, the manifold pressures levels map as follows: 0 in.
Basically this means that is the correct 914 1. I am in the process of building a compatibility table that can help identify combinations that will work or that may help performance modifications. We have just seen how this happens with the airflow meter signal in the creation of the basic pulse and the others have a similar effect during the multiplier stage. There is a single output for the injectors, resulting in all injectors firing simultaneously. Someone could have switched it out. When the board is used in different cars, it may have different hybrid modules and may be 'loaded' very differently. The flapper box works good but has lag.
This node is the equivalent of measuring the voltage waveform at the injector. While I have taken readings on my car at idle, they don't apply to stock motors because I have an aftermarket cam apparently , and my mixture is richer due to the low idle manifold vacuum due to this cam. Thus I cannot determine the engine number to ascertain the ecu that is required for my car? I am thinking Air Flow Sensor but the resistance was within spec. I am left with the Air Flow Sensor, wiring harness and ecu as the last questionable parts theoretically. I've duplicated the characteristics that Randy took for three operating conditions: at operating temperature ~100 C , cold start 20 C , and cold-cold start -10 C.
F engine temp or less value of this input would be 8. Note that since D-Jetronic is a grouped injection system, a paired set of injectors experience all of the events described above simultaneously. The operation of the circuit is controlled by T451, which is operated in the linear region. Just because something is in print doesn't mean it is necessarily accurate! That looks like a replacement parts label. You might be better of having a custom house make you a range of sizes.
James The fuel pressure checks out,no vacum leaks, etc. I haven't gotten very far in the book yet! The other thing that really bugs me is that the engine runs perfectly above idle cruising at 80 down 280 is a dream it just purrs…. The output of the Wfm's are buffered by T107 emitter-follower. This is the same as the 944 and 944 turbos. These early Motronic systems integrated the spark timing element with then-existing fuel injection technology. The other thing that really bugs me is that the engine runs perfectly above idle cruising at 80 down 280 is a dream it just purrs….
Pin 50 via main relay 22. A: It would be difficult. More patient men will disagree. I have been chasing this surging rich idle problem on my 75 1. Regards, James It's been my experience that you either tune for idle or you tune for driveability. Early 75 cars had 74 L-Jet systems on it.
Scholl paper is essentially identical in shape and nature to both Randy's and my graphs above: The text associated with this graph states that this is the characteristic diagram of the fuel requirement for one cylinder of a six-cylinder engine, measured on an engine test stand. When the engine is cold, it starts right up and once warm idles almost perfectly. I also verified that this cut-off behavior was independent of engine load and speed. This is governed by R345. It is just 20+ years of working on them. Not just and evening project but those who have done it are happy. The longer pulse enriches the mixture as long as the Start signal is present.