Tuning an AAZ - best settings and modifications

[mm289]

Originally posted this over on the 'yard but not much response and as the idea is to create a bit of a "How to" it might be better here anyway!

I re-sealed and rebuilt the pump on Myrtle (1.9 AAZ) and am now playing around with setting it up.

Thought it might be useful to run a thread just on tuning/setting up the AAZ as there are a lot of modifications you can do and there isn't anything in the wiki on it.

So feel free to contribute with your views\experiences, questions etc. and I'll update this first page with useful links as they are added.

So looking at how do you tune an AAZ diesel fuel pump for improved perfomance and running. My understanding is there are 3 basic phases for tuning these units which I think of as "standard", "non-invasive adjustments (Stage 1)" & "modifications(Stage 2)". So assuming the base engine is working fine and all is good you have:

1. Standard:
- ensure cam/valve timing is spot on (cam locking plate dead flat with TDC on no. 1) adjust cam sprocket as necessary.
- check pump is aligned at TDC (marks on pump, mounting plate and pump sprocket align and locking pin will fit through sprocket)
- set pump timing to 0.85mm with dial gauge
Read this http://vincewaldon.com/index.php?option ... &Itemid=28 for a great guide on how to do this.

2. Stage 2:
- advance pump timing upto a maximum of 1.05mm
- increase fuel by adjusting in (clockwise) fuel screw (above cut off solenoid)

3. Stage 3:
- modify governor spring rates to allow extra fuelling as the rev's increase
Read this http://www.vwdiesel.net/forum/index.php?topic=24323.0
- modify/replace boost pin to give more aggressive fuelling when turbo is on boost
- Increase boost from turbo (required to compensate for extra fuelling and to reduce exhaust gas temperature (EGT)
- Fit intercooler to reduce intake air temperatures and help reduce EGT
- Fit boost and EGT gauges to monitor the above!
- Upgrade injectors (larger size/different pop pressure????)
- Other mods????

I'll keep this space for adding stuff later.....so comments and questions can be added below. I'll start the ball rolling in a minute

MM

[mm289]

I'll start the questions off....

Before I rebuilt the pump it was set at 1.00mm of advance and fuel screw was 1/2 turn away from fully wound in.

On refitting I have upped the timing to 1.05 but it feels like it is struggling to get enough fuel. I now have the fuel screw wound nearly fully in and performance is slightly up on what it was originally and I have very little/no smoke.

Just went through the MoT with emmisions (smoke test) of .75 against a limit of 1.5 so very clean.

So I am wondereing what (if any) is the relationship between advance increasing and needing more fuel.

Next step would be to change the bost pin to increase fueling on boost but that needs the boost pressure to be increased (to increase the air flow) otherwise you just make smoke and heat (EGT's).

So, anyone got any good links on altering boost on the turbo - running a K3 at the moment.

Cheers

MM

[sportsterrider]

hello folks.Just found this post and wonder if you can give me a few tips.Just bought a transporter with an aaz 1.9 diesel turbo (with intercooler) in it and it spews black smoke under load and when you rev it..look behind when driving and its probably the reason cars back off a bit .Now how do i get it so the smoke aint as bad.It seems to run ok although its not fast and i dont expect it to be.Dont know a thing about these vans so any help welcome.Thanks

[dekhelia]

You don't have to know anything about these vans specifically, to narrow down the smoking problem: it's more a general diesel engine issue.

Diesels produce smoke of various colours, depending on what's going on with them. Have a look here, for the basic idea:

http://www.uniteddiesel.co.uk/diesel-engine-smoke.php" onclick="window.open(this.href);return false;

Some smoke is normal in a diesel engine, especially under acceleration. Due to the properties of the fuel itself (it doesn't burn very quickly, which is why, as a general rule, diesels don't rev very high compared to petrol engines), some of it will come out unburnt = smoke.

The very first thing you must do it get the crank-cam-injection pump timing spot on. It's pretty easy to do this yourself, if you're the kind of person who likes getting personally involved with sorting things out. Otherwise you will have to find a competent diesel technician.

When you know the timing is right, and if the engine still smokes, you can start to look for other causes. But until this is done, it's pretty pointless.

[sportsterrider]

Thanks for the reply. yeah smoke tells you a lot and we have other diesel cars too but a lot more modern.Anyway i found the fuel screw on the pump and backed it off a little,as the PO had altered it to give him more go but to be honest he just created a smoke screen, and now the black is almost gone and i cant say i have noticed a lack of go due to me altering that .But yep take your point about the timing and i will get all that looked at.Like i say we have only had it a few days and we did a first time run out in today and all seemed ok.Not the fastest of things and the gearchanges were a bit hit and miss on occasion but it felt good at around 60 cruising along and its has a bit more if needed.I do realise looking around this forum that i will soon end up knowing a lot more about both this van and diesels in general which is no bad thing.Thanks..

[keith]

Good to see its working out for you...I think as with most things....when its new its all very complicated...when you know it ..it's easy

[sportsterrider]

ha ha yeah you are so right there..I di think we had bought and old shed when i first saw the smoke..or should i say how much smoke but i will work me way around it all in time.Love the van though.Slow, noisy, and still a bit smoky with a lovely diesel aroma but its a smart old thing and not the same as anything else that flew past us today so thats good

[dekhelia]

As others have said, I'm sure you'll get to know all the ins and outs of the van as issues present themselves.

Your other point about the gearchange: this is a pretty common (age-related) thing. You'll most likely have to source a couple of the parts that are immediately under the floor where the gearstick disappears. There is a cage/ball apparatus under there that wears and makes selecting gears, as you say, a bit of a challenge.

You'll appreciate that there is a hell of a travel from gearstick to gearbox, so when one or two parts get worn the effect is much more magnified than if the distances involved were shorter.

Very easy to sort, too (you'll be pleased to know)!

[ultraviolent]

I ported my Aaz and used a 1y inlet as it had larger and smoother bores, the k14 turbo will also give you a few extra horses, uprating the clutch will also pin the power down.

You'll also need to get those hot gases out, the shorter and fatter the exhaust as possible, you won't need silencer boxes as the turbo will shut it up.

Even things like inline oil coolers will make a difference, a large cooper fuel filter can also have an effect as it won't restrict the fuel,

Remove any egr valves and blank them off.


Your 90bhp engine with pump mods will be hitting somewhere near the 130 bhp mark