Hooked an oscilloscope up to an AAZ pump

[regcheeseman]

 

am so confused. First pic is an IDI pump and second pic is a TDI pump. AAZs are not TDIs. What am I missing?

The ability to read?

Obviously it's a TDI pump but it's the same solenoid. At least it looks the same

Called a crankshaft sensor by the sellers but impulse sender by VW

I can't check that number but the names make no sense at all. I assumed it was advance related as that is what I was told on here, but it seems like there may have been some confusion on that post as well.

[Mark(The Miser)UK]

am so confused. First pic is an IDI pump and second pic is a TDI pump. AAZs are not TDIs. What am I missing?

The ability to read? Well we had Sherlock Holmes, who have you got? Bay Watch...

Obviously it's a TDI pump but it's the same solenoid. At least it looks the same

Called a crankshaft sensor by the sellers but impulse sender by VW

I can't check that number but the names make no sense at all. I assumed it was advance related as that is what I was told on here, but it seems like there may have been some confusion on that post as well.

That link does go to a parts site with a ghostly image. The 1990's were the start of the rot of unneccessary add-ons.
Pull the part off and dump it, then carry on with your  own developments

[silentdub]

My friend offered me his AAZ that he is selling, I declined but asked if I could hook it up to my scope.

First up I checked the injection sensor - which is a simple NO pressure switch fed with 5v, I knew what I would see here and it was purely to test my scope which has sat on the shelf for 12 months filling with grinder dust and paint mist

Now onto the main item I wanted to test - the advance jobby whatsit in the base of the pump - Unfortunately the results were inconclusive, there was a very small signal present at idle but there was no change in magnitude or frequency with any increase in revs.

Either his is faulty or it does nothing at normal operating temps

Anyone shed any light?

DAMN! I haven't used a scope since college!

[regcheeseman]

DAMN! I haven't used a scope since college!

I 'borrowed' mine from college 

Pull the part off and dump it, then carry on with your  own developments

That's what I've always done n the past but now with engine monitoring on my latest build with a few spare outputs there is no reason to not utilise it to my advantage if possible

[regcheeseman]

Whilst the pump was off and stripped last night I took some pictures so people might know what I'm on about however looking at it

Here is the normal UK AAZ pump - sensor is on the bottom of the pump (white thing under the pump head)


Here is a better view of the device on the bottom of the pump and the castings that for a gallery between the high and low pressure sides of the advance shuttle valve

- I'd say that the solenoid valve retards not advances. It is in essence a solenoid valve that sits in a gallery that delivers pressurised diesel to the retard side of the advance shuttle valve. All that it can seemingly do is bleed pressure away form the advance side of the shuttle and direct it to the other side.

[Mark(The Miser)UK]

Whilst the pump was off and stripped last night I took some pictures so people might know what I'm on about however looking at it

Here is the normal UK AAZ pump - sensor is on the bottom of the pump (white thing under the pump head)


Here is a better view of the device on the bottom of the pump and the castings that for a gallery between the high and low pressure sides of the advance shuttle valve

- I'd say that the solenoid valve retards not advances. It is in essence a solenoid valve that sits in a gallery that delivers pressurised diesel to the retard side of the advance shuttle valve. All that it can seemingly do is bleed pressure away form the advance side of the shuttle and direct it to the other side.

Where did I put my other post on the topic? Yep so it's like the LDA which is actually a fuel limiter, it restricts timing advance. What's the benefit of that? Surely emissions would increase with retardation wouldn't it?

[danster]

I am in the UK so Euroland to those across the pond.
I had an AAZ with all the electronic bits on the pump. Mine still had a real LDA with diaphragm and the flat boost pin, which I swapped out for a proper tapered one.
We also got AAZs that did not have these electrical connections and EGR. Not sure if they are linked?

I just ran mine with the solenoid disconnected. If I energised the solenoid the engine got quieter like it was retarding the injection timing.
I wondered if it was possibly some king of temperature controlled device to limit fuel and stop possibility of cracking heads between the valves when driven hard from cold.

[vanbcguy]

Most likely for NOx control.  Advance = NOx production big time.  Small increases in ignition advance (autoignition for us!) can have exponential changes on NOx levels.

If performance and mileage is your goal, you want the pump to provide all the advance it can.  Same goes for boost - a lot of the AAZ engined cars have boost reduction measures

[R.O.R-2.0]

I am in the UK so Euroland to those across the pond.
I had an AAZ with all the electronic bits on the pump. Mine still had a real LDA with diaphragm and the flat boost pin, which I swapped out for a proper tapered one.
We also got AAZs that did not have these electrical connections and EGR. Not sure if they are linked?

I just ran mine with the solenoid disconnected. If I energised the solenoid the engine got quieter like it was retarding the injection timing.
I wondered if it was possibly some king of temperature controlled device to limit fuel and stop possibility of cracking heads between the valves when driven hard from cold.

no, its not to keep the heads from cracking..

VW idi heads all crack between the valves.. its just like death, and paying taxes, its just part of life 

the device is there to limit NOx emission levels, and keep the tree huggers happy..