Help required, extra electronic controls on aaz pump

[markb]

Hi guys,

I've done a lot of searching and i have found some info on this, but not enough i'm afraid.

I've just got another car, a mk2 golf (a2 rabbit?) and after enjoying my aaz swap in my caddy (rabbit pickup) i've got myself another aaz engine for this one.

slight problem though. The pump on this aaz is different:

There is no cold start lever, instead it is replaced by an actuator.
The port on the centre of the pump head, usually used for setting advance is replaced with a sensor.
There is a small electronic device (switch, sensor, not sure) on the back of the pump right at the bottom.
There is a plastic box on the back of the box with a 3 pin connector on it.

Can anyone explain the function of the box and the extra device at the bottom of the pump?

Does anyone know how i need to connect this all up to get it working?

I read in some other posts i found that it may be electronic control of advance, or maybe an immobiliser unit...

I can get some pictures of the pump tomorrow if it will help, in the meantime, here are some of the posts i found which seem to relate to this type of pump:

http://www.vwdiesel.net/phpBB/viewtopic.php?t=17866&highlight=solenoid

http://www.vwdiesel.net/phpBB/viewtopic.php?t=9273&highlight=electronic+advance

http://www.vwdiesel.net/phpBB/viewtopic.php?t=11253&highlight=solenoid

I am comfortable with electronics, so if i need to make some kind of control unit or provide signals i can work with that, but i need to know what they do/what inputs they are expecting.

Thanks in advance for the help guys!
Mark.

Oh, also, if anyone in the suffolk/cambridgeshire/norfolk area in UK is breaking a 3 door mk2, I am in desperate need of a drivers side body seal.

[Baxter]

It's a '96 on Golf engine?

It semi automatic electronic control-ish.
There is the glow control unit that also sort out pump advance.
the sensor in the pump head is a peizo electric sensor, similar to a needle lift sensor.
the valve on the bottom of the pump varies the pressure available at the advance piston.
Controller also relies on a VSS.
When people bring them to me I just leave everything disconnected and tell them to go and find me a proper pump with none of that electronic stuff on it, it's not that I'm scared of wires but for them the cost of me making it all work electronically is far outweighed by just buying a true mechanical pump and just bolting that on.

As far as I know there are at least 4 types of pump fitted to the AAZ.

There are 2 different normal fully mechanical pumps.
1 ECO type pump that looks like it has a LDA, but doesn't (flat top)
and the one you have.
Getting the right AAZ pump can be a bit of a mare as some of my customers have found out to their horror!
It maybe easier to rape the cam plate from the pump you do have and fit it to a 1.6 pump.
As far as I know the 1.6Td and the 1.9TD have different cam plates, the AAZ has dual stage injection so the cam plate is ground to suit that.

[markb]

Thanks for the reply!

So to confirm, in my mind what is going on...

The black box in the middle of the pic, where the fuel cut-off solenoid usually sits is the control unit that sorts out advance and the sensor below that in the middle of the pump head is the "needle lift sensor". You can also see the actuator that actually controls the advance(i assume) poking out behind the control unit:


In the following pic the bit just below the pump head is the valve that varies the advance piston pressure, correct?


So, a few more questions, if I may...

Firstly, does anyone have access to schematics so i can see where the inputs to the control unit and bits go to/come from.

The advance actuator only has a single wire to it, I'm assuming in the original application 12 volts is fed to this at some time, but does anyone know when? is it 12volts to help with cold start or does it activate above/below a certain engine revs?

Originally, where is the "needle lift sensor" and the valve on the bottom wired?

See, im a bit confused as the control unit only has two wires on it, so is there an extra control module in the car?

I know i'm not making this very clear, but hopefully with a bit more help i can understand the system a bit better!

Cheers,
Mark.

[Baxter]

Okay.
The thing in the black box is the immobiliser, a sharp chisel sorts that out and once you have cleared the debris away you will find a normal ELAB (Cut off solenoid) beneath it.
As far as I know the timing solenoid is run by duty cycle, it is turned on an of really quickly to modulate pressure allowed past the valve, to vary pump timing, thats the wires at the bottom of the pump.
And, as i said earlier the two wires coming out the pump head are in effect the needle lift sensor.
There is a small ECU for this car, as far as I know it's built into the Glow control unit but open for correction on that one.
The car would have had a chipped transponder type key and tyroidal coil type immobiliser, I don't think that they were built into the dash at that age, just simply a small box accessed once the instrument panel was removed, but again I'm a bit rusty on these details because it's been nearly 10 years since i have done anything like that!

[markb]

You're a legend baxter, cheers!

so as i see it,

PWM on the solenoid below the pump head, can build that no worries, any idea of % values vs RPM?

break immobiliser open and power cut-off solenoid as usual

Link actuator in between pump and engine to glow-lug relay?

How does that sound? Any comments?

Mark.

[Vincent Waldon]

Hi Mark... as per my IM, here's a thread we had a little while ago on the injection start sensor, just for further thought:

http://www.vwdiesel.net/phpBB/viewtopic.php?t=15974