Thanks Miah. Will see what happens when I hit the workshop later.

Blimey! To get to screws in the bottom you'd need to drill up through the floor to get at them, so I hope not!
The cold was to give you the incentive to get the heater sorted and if it had been warm you wouldn't have appreciated the toasty end result :)
Your pic of the evap housing really helps though. Now I can see where it splits I can work from there and the heater won't end up looking like the headlight I removed...

Might well be my problem then Morat!
I'm trying to get the whole thing out, when, as can clearly be seen in your pic, I need to split off the back section. From your close observation of the work, is it just the one screw (centre top on evaporator housing) that holds the two parts together?

There's a screw which you can see by peering down the top vent holes, that holds the front and back halves together, and means you don't need to disturb the air-con gubbins.
Is that all that holds the heater to the evaporator? That could be the secret!

We (ok, Marty but I was watching REALLY hard) took the side vents off too... a bit more space to play with
By side vents Morat, I'm assuming you mean the ducts that are dangling down each side to feed air to rear?
They're not attached- just sitting there, but I see what you mean.

I'm thinking I've missed unclipping the back (aircon) section of the box, then taking out just the front! Never having seen one of these in bits, I assumed that it was taken out in its entirety?

Need a little advice before I break out the crowbar!

Have got this far with removing the heater unit to dismantle and free flaps, swap Distribution motor and put in an Audi matrix, oh and remove front carpet for an intensive clean.
I've removed or dislocated all ducts and hoses, taken out 2 bolts top rear and 2 underneath on floor, but on trying to lift out heater (moving toward rear of car and rotating to clear remainder of dash frame) I get little movement and a metallic graunching noise from the back somewhere, which I'm guessing is the evaporator.
Is there another fixing or two that I've missed or is there a technique, apart from brute force, that I should be using?
Any advice or "how I did it" pictures welcome!

But you might swear at the centre rail that fits in front of the heater box...

Why's that?

I'm thinking I'll go with the audience heater core :)
Now have lots of 22mm hose- bought off the bay, but...
...getting the old pipes out was such a faff I don't want to go through that again!
O rings were solid, rectangular and crusty and would have completely failed soon.
Now to have a hunt for the Nissens part number for the Audi, which I know Marty posted on here somewhere...
Gottit 70230. Should be here Wednesday.
Gives me tomorrow to sort starter motor on blue one, which clicked for the last time when trying to drive back from workshop. Had the deep joy of taking old one off, outside workshop, in the dark. Thread came out with top bolt. Now 2 disabled P38s and a walk home :(

Do-over time! Whilst digging into the centre console/ under dash to remove bodged in wiring and replace gear selector cable, found a telltale drip under the heater matrix O ring.
Bugger- so I did disturb it, despite being hyper careful putting on new hoses.
Oh well, at least I had most of the bits off to get to it anyway..

Like I said in the other place, until you sort out your broken battery connector and have reliable electrics, there's no point in dealing with other issues that are most likely related to that anyway

Cast your mind back to Summer Camp prep Marty. Who was it said...
"... so I can be chauffeur for people with clean arses :)..."
Morat is very particular about his seats. You're lucky not to have had a close examination of your seating area :)

Strange- only took 44.8L and steadfastly refused to take any more. Lot slower to fill than my blue one too.
Yet more little whimsical things to get used to.
Ah well, back to calibration...

Had to abort autocal due to running out of gas!
Just about to have a run up the road to fill up. Autocal will resume after that...

I'm surprised you let Marty lean on your seats without him wearing a clean room oversuit.
You need to get a bit of hose polish on those pipes :)
Must be nice to have some warmth back in the car- good job, well done

Ah well, if the target engine speed issues not just mine I will ignore!
The 2500 limit is self imposed due to the sprag clutch inversion problem. I'm sure the engine would rev to whatever the lifters decided was maximum, if I let it :)
When some idiot transposed the plug leads and the idle was, understandably, a bit unstable, I had to jump for the key as I saw it hit at least 4000 before I managed to kill it.
No sprag clutch inversion disaster then, fortunately

Sloth wrote:

The motronic 'target engine speed' is, so far as I've come to know, normal. I'd ignore it.

Not sure what this 2500rpm stationary limit is? Mine will happily rev all the way to the top in park/neutral. I'd rather not for upsetting the box, but I've accidentally done it once or twice.

Can't see much actual impact damage on water pump or cover. For the impeller blades to be that bent they should have hit something pretty solid.
Good luck with the gasket removal. I remember how much of a pain it was in the workshop in summer daylight. Outside on a winter's night with a lead lamp- I feel for you!

Petrol Lambdas look pretty good to me

Awww g'wan, share the pictures :)

Thanks gentlemen!
As the Target v. Actual rpm in the Motronic is a red herring (although an issue), I'll deal with that separately.
For autocalibration, although the software manual says nothing about it other than follow onscreen prompts, suggestions on how to get around the 2500 rpm static restriction on the P38 with autobox would be welcome.
When doing the run earlier- before gas ran out- I was holding 2500 rpm and when system switched to gas during process, revs started to climb to a point where I had to come off the throttle and thus broke the
Do not try to bring your RPM back to the level it reached when the vehicle was
using PETROL
rule and messing up the calibration, no doubt.

I agree, but it's interesting that, on the blue one, I don't have to top up pressure at all in summer. Haven't had the black one long enough to know.
I don't have a tyre changing rig in my workshop so it'll be my friendly local tyre fitter that does the removal/ refit, but that won't happen until I have the money to get the rims refurbished and powder coated at the same time.
In the meantime I'll just keep topping them up. It's not like I don't have compressed air to hand in the workshop!

It's connected to the tacho output from the ECU- C0636, pin 17

Gilbertd wrote:

Where is the brown wire connected? Is it on one of the coils or on the rpm output from the petrol ECU? You won't do any damage if you change the settings and see what it shows you. By fiddling around you should be able to get it to display the revs correctly.