N/A 4AGE 16V in AE86 - help needed, trying to "VEMS it"

[GintsK]

Sounds good to go.  Make sure the trigger sensor mount is solid, should not vibrate much if hit with a wrench, nor be able to move/bend with your hand.

So far it's solid.
I had problems with polarity of sensor, i had to exchange the wires. Looks like polarity for Motronic is VEMS is inverted. Maybe someone will have use of this info

If you have VR sensor [probably have, because Hall sensor do not give any signal with mixed wires] then you must set trigger edge to 'rising' and recheck your timing.
Have you self made trigger wheel? It is recommended to leave some material within missing gap if VR sensor used. Most of OE do so. E.g. http://www.msextra.com/doc/ms2extra/Ignition_Pixs/rx8trigger.jpg
It prevents from signal disturb.
VEMS do not like such self-made wheels at high rpms.
My first attempt would be to remove R55 from board (just for VR sensors). it helps in many cases.
Sadly but fact - close to 50% self made triggering solutions fails to work properly

Do not hesitate to use ego correction. It works pretty fast. and it is possible to drive even with hardly off VE table and make usable datalogs for further analysing.

Gints

[uzelac]

I use HAL sensor, taken together with 60+2 wheel from stock Alfa Romeo 164, 3.0 V6 12V engine. It should be possible to make it work 100%.
Falling should be OK for HAL with 60+2. Not sure what mixed wires mean ?

Do you thing filtering can make some difference ?
Mount for sensor is really solid, but i will check it.

[GintsK]

mix wires I meant = 'exchanging wires' from your post.

With Hall things becomes simpler. Falling is OK then.

Regarding filtering. It is very difficult blindly find right solutions for unclear reasons with no oscilloscope. Sound card O-scope is enough.

[uzelac]

I just exchanged wires on VEMS, it's still shielded and nothing soldered on sensor/wires from sensor to ECU.
Will try to find O-scope if trigger logger doesn't help.

[uzelac]

Few advancments in past weeks

I made gap between HAL and wheel smaller, now i don't get errors that often, only from time to time, not sure to what that is related. For 20 minutes everything works great, then i get trigger error.... still searching.
I cleaned injectors one  more time, played with FPR and VE table and car is idling almost great. It's between 1000 and 1050, not perfectly stable but OK.

Only issue i have with idle is when i start it cold, i must throttle it few times for revs to past 1500-2000. After that, most of the time, idle settles at ~1400 rpm which is value i set for cold start.
If i just crank it and it starts, i gets in 600-800 rpm zone, very rough idling and it can't raise revs on it self.
In that situation, if i just touch the throttle, engine shuts down.

Until i figure that out, i would like to  connect RPM signal to tachometer.
Stock rpm tachometer was fired off of the igniter output.

I understand the best solution is to use P259 ch 0 which already has pull up resistor? I just connect that to wire coming from tachometer and  configure tachometer in VT and set divider to 16?

Other option:
I have free wire going from pin6, that would be Inj.G ch 64. Can it be connected to RPM tachometer directly or need to put some pull up ? I see ppl talking about pull up, but I really don't know what that means . Since I'm not really familiar with electronics, so don't know what pull up means, please explain what exactly needs to be connected to what.

Beside, I can use these not used inj. channels for some other stuff. For instance, i would like to have warning light or shift light?
If that's possible, will it work if i just trace wire from ch16 (for example) to the + of small LED or light bulb and configure output as Warning.

Thanks!

[uzelac]

Pull up, anyone?

[jrussell]

Here's more detail if you like: http://en.wikipedia.org/wiki/Pull_up_resistor

But in short, the p259 chip switches the output to ground. When it's not switched to ground (switch is open) what is the voltage level on the wire? You don't know. The pull-up fixes that. When the switch is open, the voltage on the line will be the same as the pull-up source (12v in the case of the p259 on-board pullups). When the chip switches to ground, the line is at 0v since there's no resistor between the wire and gnd when the switch is closed, but there is a resistor between the wire and 12v, so the direct path takes precedence.

To see if there is a pull-up on p259 ch 0 (there should be), just check the voltage on the wire when the engine isn't running. It should be 11-14v.

[uzelac]

Thanks.
Now i understamd what it does, but still don't know how to wire it .
If there is no pull up on channel, where to put resistor?
sorry, i'm real bad with electronics :/

[uzelac]

Think i got it.
Connect wires from Vems output and tacho input and add extra wire on them goes to to resistor (1000 - 10 000 ohm) and ends on +12V.

Can someone confirm this ?
Thanks

[mattias]

Yes, that's how you do it.

Like Jason said, normally one of the P259 outputs already have a pull-up. Channel  0 is on pin 4.

[uzelac]

I don't use standard case and connector, and have pulled some other wire/output already, the one that doesn't have pull up.
So i needed to know how to put it

Thanks all.

[uzelac]

Nope, tacho wont move a bit with or without pull-up resistor.

Searching for a solution, i came up on info that stock tachometer needs much more than 12V.
Found info that it needs 36-40V since it's genuinely run directly from ignitor/dizzy.

So, on my way to make "tacho booster" : http://www.toymods.org.au/forums/tech-conversions/22574-how-tacho-booster.html#post1017046

Hope to make it tomorrow and post results, trackday is on Sunday, really could use working tacho

[mattias]

Use a free IGBT as output, connect one side of the solenoid of a common relay to it and the tacho, the other side of the solenoid to +12V. Done.
You might have to remove the mechanical part of the relay,  or it will make noises..

While it's nice with a tachometer, a shift light is probably as useful for trackdays, depending on the performance of the car it can be pretty difficult to have time to check any gauge at all.

[uzelac]

Unfortunately, i dont have free iGBT, i had one spare but had to use it when i burned one used for coil :/.
What voltage is coming from IGBT?

Lots of newbie questions, sry

[mattias]

The IGBT doesn't create any voltage, the solenoid does as the current is removed and the voltage is in the order of 100s of Volts, which is why you use an IGBT to drive it (it is designed for it) and this voltage is also necessary to trigger the tachometer in your case.