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Here is everything you ever wanted to know about the internals of D-Jet. It's for the 914 systems, but I'd be gobsmacked if the Type 3 systems aren't 99% the same, which just a few calibration values differing between them. The MPS does appear to be different for the Type 3 v. the 914, in that the Type 3 MPS has only one coil, where the 914 has two, and integrates the air temp signal, making the MPS a true air-density meter, not just a manifold pressure sensor. http://members.rennlist.com/pbanders/ jamesm --- Russ Wolfe <russw@classicvw.org> wrote: > On Thu, 2005-06-16 at 06:14, Mark Davis wrote: > > So that means it isn't a matter of the cold start alone, but most likely > the > > time the injector is on. Now you guys have done it. Prior to becoming > > disabled I was an Engineering Technician with Electronics and Optics as my > > discipline. This will now bother me until I get a schematic and figure out > > how it works. Anybody know if one is available anywhere? From physically > > looking at the electronics I would say there is probably a differential > > circuit that cuts on/off based on the difference in voltage at some point > in > > the circuit. If the upper extreme is lower than the design calls for the > > transistors used to switch the voltage on/off across the coil in the > > injectors may not be shutting off all the way allowing some small leakage > > current to remain across the coil causing the injectors to remain on longer > > than the spark remains in the chamber. Any other thoughts? > > > > Mark-69 fastback F.I. > > > The D-Jet FI systems is a dwell type system. The variations in > temperature and such change the amount of time that the injector stays > open. IIRC, it is in the range of 25-45ms. > The ECU does not have any built in voltage regulation, and therfore is > effected by fluctuations in system voltage. > I think I saw a functional, hand drawn, schematic of the ECU on one of > the 914 web sites. > I have it here someplace, but I think it on the hard drive of a dead > computer. > Our injectors are not timed exactly with the engine. They are fired in > pairs. One of each pair fires onto an opening intake valve, and the > other of the pair fires onto a closed intake valve. > > -- > Russ Wolfe > '71 FB AT > '66 FB MT > '64 T34 (not running) > '65 T1 (not running) > '05 KIA Sorento SUV > russw@classicvw.org > http://www.classicvw.org > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > __________________________________ Discover Yahoo! Get on-the-go sports scores, stock quotes, news and more. Check it out! http://discover.yahoo.com/mobile.html