Re: A2_16v V1 #3185

[LIQUISOLE]

RE:  KE-Jetronic Fuel Injection Device

If anyone one wants to get sophisticated, maybe this will help.  Or.....you 
could get ~$45 (Summit Racing) MSD rpm acitivated switch and use realy to 
switch in a resistor.  If some one on the list is going to construct, I'd 
appreciate a parts list with a vendor (mouser, parts express, etc).  Better 
yet, I'd buy two parts kits (or completed devices) at reasonable markup.

HTH,

Brian D.

Title: 16v Fuel Enrichment Device

16v Fuel Enrichment Device INTRODUCTION This is a fuel enrichment device designed to work with 16-valve Volkswagen engines using the CIS-E (Bosch KE-Jetronic) fuel system, for example, the Scirocco 16V. I've heard of using a similar device on 8-valve engines which use the CIS-E system, but I don't have one to test, so yer on your own. This device will NOT work with standard CIS (non -E) systems, Digifant systems, or Motronic systems. If you don't know which system your engine uses, stop reading now, because you probably aren't qualified to be mucking with your engine management system. ACKNOWLEDGEMENTS Thanks to the following for their assistance on this project: Chris Ng, who sent me plans for his enrichment device, which I based mine on. Here are his original plans Craig Castle, who also sent me plans for a similar device. Here are his original plans European Car, who published a good article on the Techtonics Fuel Enrichment module in the November 1997 issue. HOW IT WORKS The CIS-E system monitors combustion stoichiometry, intake air rate, engine temperature, and several other factors to determine what fuel:air ratio to run the engine at. It controls the fuel:air ratio with a differential pressure regulator on the fuel line. The more current supplied to the DPR, the higher fuel pressure that is supplied to the fuel injection system. It has been observed that the fuel:air ratio in the 16V engine using the CIS-E system is too lean at high RPMs. In order to correct this situation, earlier fuel enrichment systems used a relay to add resistance to the engine temperature sensor when the engine is running at full throttle. This fools the CIS-E control system into thinking the engine is in a cold operating situation, and increases the fuel flow. The problem with this type of enrichment device is that it increases fuel flow at all RPMs. The engine does not need enrichment at low RPMs, in fact it makes the mixture too rich, causing hesitation. One solution to this is to add a manual switch to engage the system only as desired. I decided to improve on this design by adding adjustable RPM sensing ability. This is done by using a National Semiconductors LM2907-8 frequency to voltage converter. This is a versatile chip which is commonly used in digital dwell meters, tachometers, capacitance measurement devices, and ABS systems. I also made the boost level adjustable. I could have used a rotary variable resistor for this, but I wanted an accurate and precise method to select a specific resistance value. I did this by creating a resistor network connected to a DIP switch. By varying the settings on the DIP switch, I can select a specific resistance. Using a 4-position DIP switch gives me 16 choices. I chose a 6-position dip switch to allow some room to expand if necessary. Adding each additional resistor doubles the number of choices available. CIRCUIT DIAGRAM This circuit was drawn using Xcircuit 2.0 for Linux. It saves the drawing directly to a high-resolution postscript file. If you have the ability to view .ps files, I reccomend that get the original postscript file, it's a lot higher resolution than the above .jpg file. COMPONENT LISTING I have provided Tech America stock numbers. They have really cheap shipping if you are just buying components, around $3 Component Value Comments Tech America Stock # Price Var. Resistor 0-100 K adjusts RPM setpoint 900-4745 2.55 R1 120 K +/- 5% Sets max. RPM 900-0429 .09 R2 10 K +/- 1% Sets reference for voltage comparator 900-0560, 2 REQD .14x2 R3 20 K +/- 5% Filters input from coil 900-0410 .09 R4 10 K +/- 5% Drops voltage of input from coil 900-0403 .09 R5 1.0 K +/- 1% Sets enrichment value 900-0535 .14 R6 2.0 K +/- 1% Sets enrichment value 900-0542 .14 R7 4.3 K +/- 1% Sets enrichment value 900-0550 .14 R8 8.2 K +/- 1% Sets enrichment value 900-0557 .14 R9 470 +/- 1% Sets enrichment value 900-0527 .14 R10 510 +/- 5% Drops voltage for LED indicators 900-0372, 2 REQD .09x2 C1 22000 pF +/- 10% Timing Capacitor 900-2234 .19 C2 15 uF +/- 20% Controls ripple in output voltage 900-1668 .09 C3 33000 pF +/- 10% Filters input from coil 900-2235 .22 D1 1N4001 Prevents reverse current flow though LED indicators 900-2869 .07 D2 5mm red LED Indicate status of device 900-6097, 2 REQD .20x2 F-V converter LM2907N-8 RPM switch 900-6851 2.75 Relay SPDT Turns enrichment on 900-2388 1.74 DIP Switch 6-posn. Sets enrichment value 900-5876 1.29 Case 1.12" x 2.5" x 3.5" 910-1105 3.49 PCB 2.79" x 1.81" 910-3809 .99 Cable 7 conductors, 5 ft 910-1628, 5 FT. .21x5 Screws #6 x 1/4" lg. Need 4, Get from HW store. cheap... TOTAL: 16.25 CONSTRUCTION NOTES A few construction tips... Make sure your solder joints are clean and bright. If they look "frosty", you probably moved the component when it was still cooling, do it over. On setting the variable resistor: The 0-100k potentiometer lets you set the RPM switch point between 5700 RPM and 3100 RPM. You can set it precisely by using the following formula: R=(15/(RPM*.000000022)). R refers to the total resistance, so it included the potentiometer value and the 120K resistor R1. Use a digital multimeter to measure this resistance. Be sure to disconnect the capacitor C2 first to get an accurate reading. I wrote a computer program in MATLAB to calculate all the possible settings on the DIP switch. The reccomended value for the resistance is 1100 ohms. Here is a chart of the possible resistance values. If you want the source for my MATLAB program, grab it here. In this chart, a 0 means the DIP switch in that position is off and a 1 means that it is on. R1, 1000 R2, 2000 R3, 4300 R4,8200 TOTAL 0 0 0 0 N/A 1 1 1 1 1009 1 1 1 0 1047 1 1 0 1 1087 1 1 0 0 1137 1 0 1 1 1208 1 0 1 0 1281 1 0 0 1 1361 1 0 0 0 1470 0 1 1 1 1640 0 1 1 0 1835 0 1 0 1 2078 0 1 0 0 2470 0 0 1 1 3291 0 0 1 0 4770 0 0 0 1 8670 INSTALLATION Mount the device somewhere convenient in the engine compartment. I used double-sided tape to mount it under the plastic splash guard next to the ECU. Connect the terminal labeled "+12v" to any 12v source that is switched with the ignition. Connect the terminal labeled ground to any convienient ground. Note the second ground connection in the top left corner of the circuit diagram. Connect the terminal labeled "To Ign. Coil" to the negative terminal of the ignition coil. Connect the terminal labeled "To Fullthrottle Switch" to the purple wire leading from the full throttle switch on top of the throttle body. Locate the wires leading to the temperature sensor. It is on the driver's side of the engine, mounted into the cylinder head behind the cold start valve and below the thermo time switch. It is the one on the bottom. There should be 2 wires leading from it, one brown with a blue trace and one blue with a white trace. (Thx to thesciro...@juno.com for this info) Clip the blue wire with the white stripe. Splice the end that leads to the temp sensor to the lead labled "To Coolant Temp Sensor". Splice the end that leads to the ECU to the lead labled "To ECU". You're done! TESTING AND OPERATION Turn the ignition switch on. Press the fulltrottle switch. The LED labled "Full Trottle" should light up. Start the engine and have a helper slowly add throttle and monitor the tachometer. As you pass the RPM setpoint, the LED labled RPM good should light up. The recomended enrichment value is 1100 ohms. I'd love it if someone had a chance to test different values on a dynamometer. The European Car article didn't see a power improvement untill after 5000 RPM, so I'd set the RPM setpoint to 4500 RPM or so. Well, that's about it. Have fun. Dan