I am going to install Vems on Renault 4cyl, 16v engine.
Most of them have 60-2 primary trigger pattern.
- VR, HALL is very common.
- measure for each sensor: if you find 2 pins that measure same resistance in both directions (typically between 300..1400 Ohm), that is VR sensor. Otherwise HALL.
Collect some info (specific engine code, year, ...)
Engine is F4R730, Clio RS 172, year 2000. Specification is:
- primary trigger - VR 230 ohm resistance, 60-2 trigger pattern
- map sensor - Vdo 20-100kpa, 520-4780mV
- camshaft phase shifter - on-off type, 7.5 Ohms
- injectors - marelli, hiZ, 14.5 Ohms
- Iat sensor - ntc, 1500 Ohm at 25C
- Clt sensor - ntc, 2200 Ohm at 25C
- engine is standard, only decat, compression ratio 11:1, max power at 6250 rpm
V3.8b (oid11249 v3/11837) has arrived in late November. Ordered from www.vems.hu. Nice communication, very fast shipping...
I already have some experience with engine management systems, but this is my first vems. No doubt i will need help and support. I started with studying vems tune options. After that i downloaded V3.8 board schematics and other available documentation. It took some time, so board assembleing started on 1st December 2015.
As recommended I will organize this page thematically.
1. BOARD ASSEMBLY
I have some doubts about flyback, sck pullup on V3.8b board and main supply.
Flyback
Can you help me and define which solution is applied when V3.8b is purchased as preassembled with 30V flyback?
I have found two solutions. I am not sure which is right.
1. Only 1K5E30V diode from flyback pad to ec36/pin23.
2. 1K5E30V diode + capacitor (light red one wima mks 4 4.7 uF 100 - 10% which comes with recue kit, probably noise filter but i am not sure) between flyback pad and ground
http://www.vems.hu/wiki/index.php?page=MembersPage%2FCsotiF%2FGenboardassembly
That is correct:
Is ground reinforcement essential or optional?
Optional. v3.8 has 54um
About sck pullup on isp header. Is it optional or essential on V3.8b board? It didnt came soldiered on board.
SCK has no effect if the v3 starts up (always on powerup) and communicates. Without SCK pullup (and 47uF or bigger electrolyte capacitor on 5V) it might happen that (say) once in 20 startups it goes into "ISP" mode (not normal running).
Can you check the bottom of the ISP pinheader ? On v3.8b the diagonal resistor not needed, 4k7 near the pinheader. Try to measure with a 100k pulldown resistor applied temporarily to SCK, SCK voltage should be >4V.
Is main supply on V3.8b preasembled? Diode and ptc fuse were soldered od board. It seems nothing else is needed.
Should be preassembled, yes.
OK. Thanks.
Transient suppressor 1k5 / 18V
Between GND and EC36/pin23: it is NOT BY399 but a transient supressor
- protection: it has no effect if the EC36/pin23 "flyback" is connected properly to the injector common+ (+12V).
- However, should the flyback return wire be forgotten (or accidentally disconnected - eg if connected to the wrong side of the fuse and fuse breaks), this might save the FETs (preventing more than 18V + 31V on the FET drains) and other components of the mainboard (FETdriver, processor)
2. WIRING
Engine bay is too hazardous-very hot and possible leaks from cooling system, moisture... Ventilation bay is populated with battery, air filter, ventilation fan and lots of moisture. The most convenient place i found is under the front passenger seat. But wires will be 3 meters long in one direction!!! Will this be a problem-voltage drop, noise...?
Should be good under the front passenger seat.
- 3m should not be a problem (if the rules are followed, and shielded cable is used for triggers, shield connected only at the ECU end).
I managed to place ecu closer, so wires are about 2 meters long.
3. TRIGGER SETTINGS
Engine F4R is not yet ready. I have one F7P assembled in another car and would like to try v3.8 on this. It has RENIX 44-2-2 trigger and distributor.
Q Is this trigger pattern supported in vemstune and what are the settings?
A This pattern is supported, more details on: VehicleFitment/Renault
Q Finally I put all parts together. F4R engine is assembled. V3.8 is alive, but I have problems with VR trigger. At first there was bad signal, with default arrangement (R30 27k). Lots of missing tooths, when cranking. Then i removed R30 and put 47k in series on vr input line. Now signal is perfect when cranking, but when rpms goes above 250 (engine tryes to fire) there are trigger errors, and engine wont start. When rpm falls bellow 220 signal is clear again. Wiring loom is done with shielded cable, grounded at ecu side, grounds done according to manual. VR sensor resistance is 230 ohm.