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Subpage of MembersPage/Skassa

Note that name of this page does not match conventions, should be MembersPage/Skassa/Trigger?

Anyway, keep trigger notes together, don't scatter to MembersPage/Skassa/Questions


Timing from cam is inferior. But why would you remove 2 teeth ?

  • i just didnt know better,and now its to late to put it back on//Skassa
1 missing tooth is better, because with 1 missing tooth on cam you get complete engine sync suitable for COP (without separate 1 pulse camsync signal). I saw another have moved on to a newer firmware at that helped on trigger problems,so maybe i will try this next weekend.


This is a sample pic and not mine!.

I have made the mistake to remove the tooth right before tdc and not 3 tooth before like on the pic,

Can this be of any trouble?

Trigger problem

noise when cranking

Ignition on, rpm shows 0, then crank it, running around 300rpm, with the spikes to 1800rpm, then i stop cranking,but leave the ignition on the rpm will show 100rpm(must times); than the fuelpump stops, rpm reads 0 again

Yep, the tooth after the missing is TDC.
  • exact config ?
That is under config,i only changed the tabels,as part of the mapping

Problem candidates

Grounded the same place 20 cm from the ecu.

results in trigger noise, that is most significant during cranking (and suppressed during normal operation)

The gounding is made something like this:

This is not what you need, please consult MembersPage/PhatBob/UserGuide to read more on the correct grounding method

  • On the 20V I grounded all five grounds on a ring crimp and bolted that to the water blanking plate on the just behind the exhaust manifold. I then connected large grounding wires between a bolt on the alternator and the chassis, and on the front of the engine on the opposite side to the point on the chassis where the battery is grounded. This provides two good ground paths for the starter and alternator. On the 16Vs I used the standard injector grounding point on the inlet manifold, the owner used an aftermarket grounding kit because even though the grounds looked okay, there was an issue where the EGT sensor found a ground path through the EGT chip which obviously killed the chip. //PhatBob
  • I have seen this happen with two 16V AE86s, using a spare FET for the Fuel Pump causes a ground-loop that holds the VEMS and fuel pump on. The problem was solved by using the Fuel Pump relay pin. //PhatBob
Sorry, i dont know what this is,i was explaining that i just unplugs the injectors,so i can continue trying cranking,without the engine starting.
  • It would be an exellent idea //PhatBob

Thanx peter

Iīm using the OE Toyota 24teeth NE(cranksignal) trigger,were i removed 2teeth,to make it a 12-1.

Why we removed 2 teeth 180 degrees apart on the 24 trigger become PhatBob? recommended this set-up.

Next trigger is tooth 6

The trigger and vr is located at the camshaft i.e. distributor driven.

Primary trigger

Edge = Rising

Type= Multitooth

Filtering= Disabled

Advanced Filtering= Disabled

Special N-1= Disabled

Fiat Stilo= Disabled

TDC after the trigger=127.5

Number of teeth on the wheel=11

Trigger tooth=1

Next trigger tooth=6

Crank min. period= 3000

Tooth width=

Angular width of tooth=30

Tooth Relation normal=121

Tooth Relation Missing=181


Angular width of missing tooth=60

Engine phase when to reset=216

This setup is not working very well, with the VEMS,as it cant read the signal proppely,

The signal on a scope, looks fine,but it only makes a wave,at 0.5volt,in megatune that will make the rpm gauge jump around, showing sometimes, 50-400 rpm with spikes to 2000rpm,this will make the car backfire and dump fuel into the cylinder,before it stats,so not working well,

but ones the car starts , it runs without trooble,

i will see if i can get someone to make a amplifier, or something to make the vems able to read the signal,

Otherwise it will probbely be replaced by a better ducumented setup.

This have now been corrected,and is working with no spikeing at all,i will explain it later,as i think this can be done on alot of the ones that have rpm spikes,itīs now rock solid,this is a build in feature of the lm1815 chip,it have been pulled low, with a solder on two pads,just left of the chip(if you hold the plugs towards yourself)there is 3 pads, and there is made a soldereing between the top two,this is done by a friend that looked at the board for 5min,and then said, thatīs it,and it was :D

MembersPage/PhatBob Thats good then, you're now in a position to go to wasted spark and semi-sequential injection. I've been very happy with the Mitsubishi coil pack from the EVO4, its 2.5mS charge time allows the sort of RPM that the 4A-GE likes. Other than that its possible to run the Nissan S15 coil on plugs, these have a very short charge time.


THE CAR STARTED with another Vems ecu,and i found out that the ecu is not working right!

Check [your configuration's pinout in webshop]

Verify p259 outputs (eg with mdh commands) GenBoard/Manual/DigitalOut/Table, if the p259 chip was damaged it needs to be removed or replaced.

Will check more tommorrow!.

make sure to publish your used config in Manmcdmct dump format to make it easy to reprocude (and eliminate any problem with using unsuitable MegaTune for given firmware, or vemsv3.ini error)

Similar engine

Can someone provide a pic, were the 2 teeth ae removed from the 24teeth wheel?,or does it not matter what teeth i remove,as long as its 180degees apart?

why do you want 2 missing teeth? 1 missing tooth, like 24-1 is much better, especially if you want camsync (and COP) later. The only advantage of 2 missing teeth 180 crankdegrees apart is slighlty faster (1/4 crankrot average vs. 1/2 crankrot) sync at cranking, but Mik (MembersPage/MichaelKristensen) hated his 36-2 (180 crankdeg apart) missing tooth so much he patched one of the missing teeth (which was harder than it seemed).

And do i run it VR or Hall?

do you hav HALL or VR sensor ? Measure resistance between sensor leads, each pair of pins, both direction, and document it - so we can tell if it's HALL or VR. Scopeshot of the signal also reviels, of course

And it would be perfect if i could get the wire color of what wires, that is what, on both the TPS(3 wires) and the the OE trigger sensor(4wires)on the toyota blacktop wiring




All the 4age wiring diagrams are here:

Development of the Toyota 4a-ge installation goes on at a pace: The standard Toyota MAP sensor will work fine with VEMS for NA.

The knock frequency for this engine is 7KHz.

I am making plug and play looms for 20V engines so if you email me phatbob at with any wire questions I can look at the loom I will be working on tonight and will be able to help with your queries.

I am banking on the dual-solanoid IAC thing working as the whole IAC thing has caused the first 20v I did to behave very badly at idle.


I have now conntected the OE 24 teeth wheel,but the triggersignal is jumping aound from 25-350rpm,so there is something wrong, can somebody help me?

probably, start with uploading config (Manmcd, mct dump). Don't forget firmware version, just in case.

I run it as VR, and have grinded the tooth,so that next tooth is trigger tdc,and then 180degrees oppesite.

12-1, next trigger tooth 6.

Or is it better just to mount a new triggerwheel on the crank?

I also need some helt on the injector settings,as this is really bad explained, there needs to be some standard settings!!

There are very many examples on MembersPage, consider any working setting as standard setting. Your better explanation is highly welcome, please remember to take a few mins with this after you understand GenBoard/Manual/DigitalOut/Table better. There is a proposal to use the "injgroup" naming during configuration so it's clearly separated from injector outputs (one knows that if he configures injgroup6, injgroup6 must be configured elsewhere regarding what injector output or outputs to contain).