[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]
MAT, I have taken the EFI apart so many times and studied every peice that I can probably troubleshoot your problem by e-mail or drive an hour to you house in San Juan Capistrano. You say that the brand spankin new pressure sensor seems not to perform as well ? Rough idle, less power lost that umph! I had that happen before. I have taken these apart into little peices and put them back together again and still worked unless I found something broken inside. I have a box of peices of these. I have mixed and matched my parts from old units and Bret rebuilds. I had one old one from Bret instruments that worked, an old adjustable that worked, a new one from Bosch, and some old ones (broken). When you get a new one grom Bosch, these units are riveted together and the cover on top of the adjustment is epoxyed in. I have removed the rivets an replaced them with screws and nuts for some guys Porsch, his unit was full of oil. I remove the epoxy after removing the back case and hardware that has the epoxy with a blow torch, heats melts it (epoxy) and a screwdriver turns the screw for cleaning., remember remove the parts inside the rear case. Why I am telling you this? I had your problem, even the right pressure sensor was unsatisfactory. Just imagine that the manufacturer sell you a carburator with no mixture adjustment and that the factory adjustment was set too lean for you but good for the smog laws. I had this problem with carburators on my stock gigantic detroit monsters ( 8 liters) arg!, arg! arg! . Well since these were from the smog control 70's and 80's the carburator mixture screw had a plastic cap to prevent the user from adjusting the mixture wich was set factory lean to pass the smog test. If this cap was missing the smog test station would fail the smog test until you either got a new carb or a new seal cap (unbroken). My engines suffered from heating, knocking, low power and nice round holes in my pistons when I towed something. So I had to cheat and that corrected the problem and prevented damage and some real smog due to poor performance. Every time I drove in different countries (Mexico) I had to change my mixture to compensate the different fuel formulations or else nice black smoke and/or poor performance would be experienced. When our own oil companies changed formulation I had to compensate or my truck would knock and have poor performance. The formulation changes such as oxigenation would change performance from great to sucking on engines with long intake runners (dodge slant six) because of it's less evaporative properties among others. Modern EFI compensates this problem by using its undependable oxigen sensors to adjust for poor burn (too rich or lean) Going back to our sensor In germany where Bosh company was born and lives, everything is adjusted by part number since their first design in germany, with german gas and in the old days when engines used the real gas . Even if the specs were upgraded (i doubt it), to todays crappy gas, the spec could not be made for every country unless you had a differnt part number every time gas changed every few years at all the countries that used this fuel injection. It would not be practical so a comprimize at a center/ midpoint may be used. Since I do not think the fixed adjustment spec has changed since the part number came out (last time 1972 is used) I think we have those carburator vs smog rule (mixture seal ) situations going. I f you get the really old pressure sensors form the junkyard (i have one regurdless of brand of car (volvo, porsch, jaguar ,mercedes) the pressure sensor is adjustable until 1975 when laws got tough (mercedes you can see it) the adjustment was sealed to prevent good performance and to make it lean with all of the bad stuff that goes with it. So when I got my Bret instrument one (adjusted and sealed to german spec and sealed) my engine ran not too smooth but drivable (I thought that's how these engines felt since this was my first aircooled a year ago, Detroit monster guy) so I thought our engines were like 80 pound weaklings that gave good gas mileage and was cheap and easy to work on ,(Detroit monster = $400 month gasoline bill plus hundres to put in every few months when abused , Crank now broken in 3 places, saving money for crank ) Later no longer satified with my purposely manufactuered weak belief (after reading) all of your guys e-mails I decided to replace my bought used Bret unit with a new Bosch unit it ran better and I thought I was happy until I went up a steep long grad to the latest rage aircooled warehouse in Alpine CA. I decided to experiment, so with my junk box (sensors) I decided to mix and match parts until I got one good sensor that was adjustable (Mercedes , Volvo and VW sensor parts) I did not want to break my good ones: OLd but not so good ajustable one ( smaller than the others , no disc diaphram), the used Bret one and the new Bosch one. I made one good one and performed the surgery described. Installed it : no start , adjusted , no start , adjusted , bad start, adjusted, missing, adjusted more ,. missing with black smoke, now the tuning began, lets see if I remember now: I turned clockwise until missing, smell of gas, black smoke and almost turning off , turned counterclockwise and experienced missing, low power and almost turning off. Does this sound familiar to you carburator knowledgeable guys ? Two and a half turn from "midpoint" in any direction caused missing. So I adjusted just slightly more on the richer side of midpoint and the results were glass smooth idle and much better acceleration, reguardless how my engine performed in the past i always pushed my car to 75 to 90 on the freeway. These experimental and final adjustments I performed when driving on a dirt road to check performance. Accelation and power was great now in comparison. Now i found the high speed , high rpm hesitation during downshift when attempting to zoom even more. This problem I corrected read my last essay on my distributor fix a couple of days ago on the list. I now have that porsche feeling under the gas pedal on a stock displacement engine, quite fast for me now. ZOOOOOM!!!!!!!!!! Rice burner door blower. HEE! HEE! HEE! Any questions, Want me to drive over ther one of these days or you want to do it yourself? LEON MARTINEZ martinezl@ftscpac.navy.mil 1969 SQUAREBACK EFI/AUTO SAN DIEGO AND TIJUANA 7 So you see all after marke ------------------------------------------------------------------- Unsubscribe? mailto:type3-request@vwtype3.org, Subject: unsubscribe