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I (LEON)was the one that adjusted Mark's pressure sensor. The pressure sensor had a broken seal and was previously adjusted. I have units that I have adjusted myself and what this does is change the length of injection spray time. I have a "virgin" new one that I installed for a little while , while I had new injectors, new pump, 29 lbs fuel pressure, new points, newly refurbished wiring and rebuilt engine with stock 1600 displacement. The engine ran quite lean with the new pressure sensor, it even shook slightly (little perceptable,I listen for perfection). >From the information an old VW dealer mechanic retired in Mexico: I don't beleive that Bosch assumes that gasoline is the same all over the world and every system built will work exactly the same, even with different gas formulations (good and bad) and different engine wear that changes compression and also assumes that no engine will ever be modified in any aspect. The seal was placed not because the Germans felt that perfect preadjustment was acheived but because emission standards in different parts of the world were requiring it, to prevent the backyard mechanic setting it "wrong". The original pressure sensor in 1968 with part number ending in 001 (still available but with epoxy glue on the screw)had no seal because emission standards were not enforced and requirements were very loose. I have one of these original ones. In the 70's this "seal" requirement was enforced and many American cars with carburators had sealed mixture screws with caps that limited adjustment. The computers in our cars had a modefication done on them to have a limited mixture adjustment in order to pass emissions. Other components like the temp sensors and their accompaning metal washers were added with different part numbers in order to adapt the engine to pass emission tuneup requirements. If engine wear took it's toll or different gas was placed in gas tank the engine's fuel requirements would change thus requiring adjustment. On newer carburated car the emissions test often fail on slightly worn engines or engines that are running "perfectly" with it's carburator adjusted by the owner. These cars pass when the technician sets the mixture "correctly" and places the seal back on the mixture screw the engine runs really crappy after that, misses, heats up, loses power etc... Until the owner places the adjustment back to the better working position. Between my brothers and my Dad we have 20 cars and have gone through this many times. My Dodge truck with Carburated engine must have adjustments changed when I go deep into Mexico because the exhaust would have black smoke out of it's pipe. Why do you think our stock carb setups have idle mixture adjustments and a variety of jets to purchase or modify. The newer type of injection system including the continous K-jetronic has oxigen sesor to act as it's "automatic" mixture adjustment when it directly detects fuel inbalances due to wear of compression, load, different gasoline, injector wear or the infamous oxigenated gasoline that made many cars run like crap. When I removed my virgen pressure sensor and placed a "newly devirginized " unit in it's place the engine did run like crap at first but when I adjusted mine (this one had fine adjustment , some seem to have rough adjustment because of the center screw stuck in the outer screw) the engine smoothed out like glass , much better than my sealed unit and accelerated gorgeously, Mark Healey can attest to that, he test drove my car and he even did not zoom it at all and he felt how a stock EFI type 3 should feel. When I first did this a year ago or more with the non virgin one I had 75 pounds of compression on my newly rebuilt engine (after 5000 miles ,too many shims worked very well with an adjustable unit) shortly after I installed the virgin pressure sensor and the engine engine ran weak and like crap so I determined that my engine's compression was too low for the factory adjusted sensor and needed either to be adjusted richer or increasing the compression was warranted. You have seen my past posts on my low compression with good power but this was with my adjustable sensor. The same week I tried my new sealed sensor I increased engine compression (removed thick shims) I now had 100 to 105 pounds of compression (and still have). The new sensor did not perform as I thought it would but it was better, the engine was still not as smooth as glass. So I installed a non vigen unit that I put together (I have several doner units) and after a quick adjustment by ear (Yes some people think it is bad)the engine was as smooth as glass and accelerated beautifully even with a 100 pounds of compression. I was able to vary the adjustment 2 turns one way and 2 turns the other way just like a carburator, it would rough up as soon one went too far either way. Too lean it would knock and loose power, too rich it would smoke black and actually "flood" at stop signs but when adjusted slighty richer than perfectly centered it would run beautiful. Some units cannot adjust this easily because the adjusting screw is stuck inside the larger rough threaded insert that is turning causing impossible adjustments which frustrates the non experimentor. Sealed one needs higher compression or better gas. To use my "vigin" sensor I must either raise my compression or increase my fuel pressure , I do not wish to increse my linear fuel pressure as to compensate for my dynamic pressure sensor. I think increasing fuel pressure works best for bigger engine displacements but I still don't like to increase pump, hose and regulator stress as well as injector winding stress since they were designed for a certain pressure. Increasing my compression for my good sensor adjustment will not be practical so guess what ? I adjust my sensor. Originally these sensors had a completely exposed adjusting screw. The D-Jetronic Porsche and Jaguar experts on the internet explain how to "devirgenize" these sensors. If it is good enough for these cars...... So Mark and other people who have inherited devirginized pressure sensors, do not feel hopeless about this, your worn engines and worn lean injectors need this compensation adjustment just like a carburation adjustment and when your engine and injectors are tip top bone stock working conditionyou can "FActory" set it again with an oxigen sensor you purchase for your dash or go to a emissions shop that can do this easily. I did this once , I had them adjust it just above 14 to 1 ratio, a little richer to get some more perfomance; this setting is always done to rally cars. Mark, if your stuck and need help on your ingition, just e-mail me and I will check it out at your house . The adjustment to your predevirginized pressure sensor was warranted because, boy did your engine shake at first when started, seemed very lean probably caused by dirty or worn original injectors. I was just trying to compensate for a badly running engine. The pressure sensor is my carburator. If we get togther I will check all of your injectors this time to see if they are spraying well, with this malfunctioning you will never get a good tune out of your engine, I went through this before (frustrating!!). LEON MARTINEZ 1969 SQUAREBACK EFI/AUTO SAN DIEGO AND TIJUANA ------------------------------------------------------------------- Too much? Digest! mailto:type3-d-request@vwtype3.org Subj=subscribe