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This was from LEON MARTINEZ - I found this to be very helpful. All the problems I show you happened all at the same time among other serious ones. EFI ::: 1. Serious vibration problems (I had many different types ). Does it vibrate in idle or only upon acceleration or during high speeds ? A. Mine vibrated in low speeds too, in addition to high speeds . In low speeds I found that one of my injectors was not firing and the second one fired sometimes, at times I only had two cylinders firing, all other times I had three cylinders running slow freeway speeds (max 60mph) with much vibration. To find problem I disconnected each injector during idle and found one that did not affect the vibration more (just like pulling dist cap wires) . The one that was not affecting the engine had a break inside the wire connection. The other wire I found by bending the wire until it began to fail badly. To fix these I had to go to the VW dealership with the connection and wires. To separate the wire or spade from the plastic plug, I had to push a needle or pin into the slot in the plug and pull or push the spade out. The dealership sold me two spades with one foot wire attached for a couple a bucks. The plasic connector was about three bucks(bare no wires). I replaced all wires and their connectors to the injectors. The rubber boot is no longer available but it is available through Porsche (914?), Mercedes 1975 (luxery with v8) or 1973 Volvo ( staight six cars or 244 sraight four) all with D-Jetronic. For exact model ask a mechanic that is an expert of each of these, then go to the dealership and order them. West coast metric may have these too. That is it for the injectors wiring. B. Vibration at high speeds , even during just gassing it in neutral (no tranny connection). I found this very annoying but it is the most major problem for all of us with EFI. The problem mostly shows up during highway speeds. I found part of the problem when I pulled each injector and pumped each injector manually. Does your car have the gas pump feature? You can hear clicks when key is on and the engine is on while you manually turn the trottle at the manifold. I got an injector at the opposite cylinder that was "clicking". Two cylinders always inject at the same time these are "1" and "4" at the same time and "2" and "3". Choose the pair that is clicking at that moment. Pull both injector pairs and put both in jars pump the throttle several times to see the injector patterns of both pump faster and faster each time to see if the cut off at higher speeds happens turn the engine a little until the other pair is activated , do the same. Did you see any get less spray ? Did you see any cut off when quickly making pulses? If you do not have the pump feature remove the distributor and turn it back and forth very quickly to see if spray cutoff happen. I found all my injectors cutoff when pumping very fast. I purchased Python rebuilt brand and found that each one flowed differently in a graduated test tube. A couple cut off at higher speeds, I returned them several times and gave up the quality was not good. I never installed them, most peoplle would not test but would install them and would not know that they were bad until they got worse. I bought rebuilt one from Bret instruments and three new ones from Bosch (experimenting) and I found that they flowed a lot and all exactly the same. The flow rate exeeded all injectors I have tried before. I installed them and wow what a difference and it was also smooth. The loss of flow is caused by solids that are not soluble in fuel injector cleaner (micro fine sand, dirt that got through the screen including a chunk of corrosion). The high speed cutoff is caused by the pentle scraping the side of the inside of the injector. The gouged pentle and "tube" create friction during higher speeds and slow down or get stuck completely. This is very common, more than everyone thinks. I understand you have two yellow injectors and two black injectors . As I understand, the black injectors are the original ones that came with the car they are 30 years old. The yellow ones are the ones you buy at the dealer. the tips of the new ones have a plastic cover to help with the spray pattern and protect the tip. I think you may have a problem with old injectors that are either dirty or gouged or both. The injectors if used heavily (lots of driving, I drive 140 miles per day) will last 5 years or 10 years with normal driving until they are rebuilt at BRET INSTRUMENTS or replaced with new ones from BOSCH. C. The other scenario of vibration that started to get noticed little by little during high speeds was caused by the injector points, located in the distributor. The grease in the injector points was 30 years old and was turning into glue. At slow speeds the points turn the injectors on and off at proper times and at high speeds the points start to float open at random times. This causes much vibration at different speeds and sometimes they steady out and then change. This happens at higher speeds and works in city driving. The reason for this is because the grease gets so thick with age that the points (efi points that is) open and close slowly and at higher movement they stay open randomly. To fix this, I removed the points, checked the movement and found that they were not closing crisply. I cleaned them by leaving them in solvent or kerosene. I moved them until I loosened them. Dried them and placed the proper drop of oil on the hinge and also greased the cam rubbing blocks with lithium or cam grease. I reinstalled them and the high speed missing stopped completely. D. Another cause of missing was a randomely faulty pressure sensor. The missing happened even to the point of bogging. This was caused by the original sensor that still held vacume perfectly . I adjusted it for more richness and corrected many missing instances. Though the missing was much less than that vibration I experienced, it was caused by the sensor. As soon as I tried a junkyard unit the car the problem was completely corrected. I purchased a new one and the engine has worked for over a year. E. After placing the engine back in after an egine disaster I did something bad. I did not install my flexplate in my automatic tranny properly and after a few months, my engine seemed to vibrate but it seemed to shake my car. This lasted until I broke my flexplate and replaced it . I put a wrong gland nut in it and broke it again. Finally did it right again. All my vibration problems were either overlapping or at the same time or a little after each fix. This was a nightmare that ended. The fixes should last another 20 years but a carb rebuild on cars are every six months to a year, depending on driving condition. If you have any questions, please ask, I know I have given you a lot and I may have not explained it clearly but I can clearify each item you may ask. All of this and more has happened to me. You must understand that these electrical items are 30+ years old and have to fail. Some carbs this old have been discarded long ago, sometimes. If you cannot correct this try to find someone near by that can help you or do it. If you lived near by I would have swapped out my stuff with your's until we found the bad item or items. IF you spend on a new carb kit, you can put the money into many items in the EFI. If you change the EFI to carbs, I would like to buy the EFI system for another engine I am building in the future. LEON MARTINEZ 1969 SQUAREBACK EFI/AUTO SAN DIEGO AND TIJUANA ------------------------------------------------------------------- Search old messages on the Web! Visit http://www.vwtype3.org/list/