Trying to get my Nissan 200sx to get started with VEMS after it went dead.

Warning: jap coils are mostly low dwell !!! Much chance for danger if you neglect this




Head: 16 valve

Trigger: 24/1 CAS

FW: 1.1.50

Map sensor internal: 400Kpa

Connected with Vems loom v3

Vemstune v0.9.88


The car is now running had to lower the dewll time to 2ms.


Having a problem with the vems solenoid not working it dosent operate. It's configured under alternate boost settings.

I use output EC36 pin 18 (inj 6)

injector output is set to Injector 5 under alternate boost.

The injector output is set to injector 5 = 32.

The solenoid is klicking when changing the output to inverted and reversing to none inverted.

The stepermotor driver isn't installed after the repairation. Dose this controll the solenoid?

2009-12-29Answering my own question

The Steppermotor driver has to be installed to get the boost solenoid to work.


The enginde is now reving through the 0-7500 rpm with a steady rpm signal. The problem is located to poor coil grounding.

Installed a new ground wire to the coils and it works.

Might have a problem with the box dying at higher rpm when driving in street, but i will check this later and try lowering the dwell time from 2,5 to 2.

Update 2009-07-23

I got the box back from repair, all sensors now working.

Having a big problem. When I rev the engine to 3000rpm the box locks up

until the power is switched off and the box restarted.

We've seen this before. The problem was, and in this case also, most certainly misconfigured too high dwell (together high slope in function of MAP). The extreme currents lock up the box. Especially with jap coils, that need even lower dwell. Configure 2-2.5 msec dwell with zero slope..

With poor grounding or flyback this can be a problem at otherwise normal dwell values. But even with good grounding, you will see this at too long dwell. (the mean current is roughly proportional with the second power of dwell, but peaks can be bad anyway). With our coils this lockup happened around 4.5msec dwell, but with jap coils it can much lower, maybe at 3 msec (somewhat depends on wiring).

This is resulting in a floaded engine if I dont switch the power off.

HISTORY(will clean up later)

Update 2009-07-14

What happens to the box if i get 12V supply through EC18 pin 16 and 17. This is what happened.

I missed placed two coil connectors to EC18 nr 16 17 so the box got killed buy this.


. .

The problem:

I'm having trouble geting the sensors to work. I have some kind of earthing problem that im trying to fix.

Grounding problem can be one cause.

(The grounding is throug the vems v3 harness. The ground point is at the chassie frame, the connection surface is clean metall with a M8 bolt securingit to place.

The box is answering ("Hello") when using "Terminal v1.9b".

The main problem now is that my sensor don't give a reading.


CLT= -40

IAT= -40

Map=405Kpa (internal)is it an internal MAP sensor or an external sensor ???

These mean that the microcontroller sees 5V for each. Something in the install is seriously broken. What is the voltage measured on these inputs (with EC36pin26 as base) ?

RPM meter is working.

Ignition is dead.

injectors dead.