4+1 type (c004) trigger setup. (4 primary pulses + 1 sectrig pulse in a 720 crankshaft-degree cylce).
Toyota 4+1 trigger status
Car is running well now but have to crank long time to get cync but itīs ok.
Mode select to 5V on Pre and sec trigger
Mounted a 500 ohm to Sec trigger pull down
Mounted a 1 Kohm to Pre trigger pull down
Log and config will be added later
- [triggerlog without the ignition coil connected]
- Both trigger signals are perfect without spark.
- [triggerlog with ignition coils connected]
- But both triggers are quite noisy when the coil fires.
Out two triggers are located in the distributor so there are plenty of noise from the ignition coil!
- The primary trigger signal is clean, but the second isnt.
- primary trigger VR sensor: 572 ohm
- secondary trigger VR sensor: 280 Ohm
Ideas for hardware mods?
- We tried to insert a 1k ohm resisor across the + and on the sensor but it is still very noisy..
- Can you try a shielded cable (3 or more wires inside + shield outside) for the VR signals ? Remember to connect shield on one end only (preferrably the ECU-end of the cable). The ground wire which is connected on both ends, must be a wire inside the shield
- try to route the shielded cable away (as much as possible) from ignition and injection wires, especially from HV spark wires.
- since this is a low pulsecount trigger (the VR-detection must be able to handle 270 pulses per cycle eg. for audi 135 tooth) you only have 4 pulses => this allows a higher input "filter" capacitor (parallel with the sensor, between VR signal and signal ground): 22nF (22nF*280 Ohm= 6 usec) or even 100nF (100nF*280 Ohm = 28 usec) if necessary.
I got some scope pictures, as you can see the ignition coil is making some noise ( aprox 200mv )
Hello, we are planing to build one of our private cars with VEMS
Our goal is to make a PnP? install.
Q: Our only concern is about the trigger! Our car is driving whit a 4 + 1 trigger system. The 4 triggers comes 10 degress before TDC, and the cam sensor trigger comes in TDC for cylinder one.. Is that posible ?
A: This trigger is easy, but you must use VemsTune to make a triggerlog and check the timing of the primary and secondary trigger pulses. The cam sync must always appear between the same two primary trigger events, if not then you will see "sec trigger late/early" in VemsTune and datalogs. You can try off setting the signal using the trigger edge setting for both or either of the triggers, change from falling/rising to the other will offset the signal by a trigger tooth width. //Mattias
Q: Great. I took the scoope picture here:
The Sec trigger occur at TDC on cyl 1.
The primary trigger occurs at 15 degress before TDC.
Kind Regards Daniel