Which Control Unit?

Hello,

I'm having the following problem: I have a Seat Toledo TD, manufactured in 1995, with a 1.9-liter engine and 75 horsepower, and it has air conditioning. Five weeks ago, the engine seized (a piston seized). After consulting with a specialist workshop (a Seat dealership), I purchased a VW Golf III engine (engine code 1Z, mine was AAZ), manufactured in December 1994, with a 1.9-liter engine and 90 horsepower. The engine was installed, and it's running great, but the fuel pump from my old engine (mechanically controlled) was used because the fuel pump that came with the new engine is electronically controlled.

"Since the car wasn't going faster than 155 km/h, I took it back to the workshop. Now, the workshop would like to install the original fuel pump, but we're missing the control unit. So, my question is: Can anyone tell me which control unit I need (the exact model number), and where I might be able to get it?"

I would be very grateful for a quick response.

Best regards,

Hi,

You probably mean the diesel fuel injection pump? Maybe your diesel really doesn't go any faster than 155 km/h .
Control unit: Be patient when searching at auction houses, otherwise, search Google for "used parts" and call various salvage yards.

Normally, any VAG dealer can find the necessary VAG part number for the engine control unit in their spare parts catalog; they just need to look it up for a Golf 3.
The wiring harness leading to the control unit could be problematic.

Best regards, Rainer.

Hi Rainer,

First of all, thank you for the super-fast response. Of course, I mean the diesel injection pump. Thank you for the correction.

I checked eBay and also all the local junkyards and car recyclers.
Checking the VAG part number with a VAG dealer is a great idea.
I will do it tomorrow morning. Thank you.


Best regards,

stalker

What exactly was taken over from the 1Z engine? Just the block? The cylinder head?

Hi Wolfi,

Cylinder head, diesel injection pump, turbocharger.


Best regards,

stalker

Hmmm, I don't quite understand that...
So, a 1Z engine block with a turbocharger from a 1Z engine and an injection pump (ESP) from an AAZ engine was installed? What exactly is this Frankenstein-like creation?
The control unit is responsible not only for the ESP (Electronic Stability Program) but also for the turbocharger. Currently, the turbocharger is not operating correctly and, as far as I know, is only reaching 0.6 bar of pressure.
"To make this a true 1Z conversion, you need all the sensors (boost pressure, MAF sensor, intake air temperature, etc.) because without them, the engine control unit won't function properly."

"Wolfi, you misunderstood. My AAZ engine is broken. That's why I bought a "complete" 1Z engine from eBay without any auxiliary components, as it's called."
However, those models included turbochargers and ESP.

Best regards,

stalker

And then you installed the ESP system from the AAZ engine into the 1Z engine? Does that even work?

Or should I just run the 1Z pump without the control unit? Nah, that's probably not going to work.


*I'm a bit confused.*

No, not "you" (plural). I don't know anything about the Seat workshop. Yes, the workshop installed the mechanical pump from an AAZ engine, and the engine is running, but it's not producing the expected performance. At full throttle, it only reaches the mentioned 155 km/h, and then it's done.
Therefore, I now believe that the Seat workshop doesn't understand its craft, and I'm considering consulting a lawyer.


Best regards,

stalker

Oh yeah, I've now found the exact part number for the used engine control unit.

Part number: 028 906 021FB, New price: €903.00.

Hello,

Either you don't really know what they did there, or the workshop is very bold.
Did they simply install an AAZ pump onto a 1Z engine block?
How do they guarantee that the injection quantity is correct and that the injection timing is correct, and that you won't burn out the pistons? The AAZ pump has a 9mm distributor piston, while the 1Z has a 10mm one.
What about the turbocharger? The 1Z turbocharger is controlled by a solenoid valve from the engine control unit (ECU). The AAZ has a wastegate without any control.
Is there a hose connected to the LDA (Low-Pressure Distribution System) at the pump? The workshop must have somehow tapped into it.
Where exactly do you plan to connect the engine control unit (ECU)? It seems you don't have the wiring harness.
I highly doubt that a Seat workshop can make a profit by carrying out a conversion to 1Z.
Very strange and not very believable .
Of course, you don't have an operating license either. You can probably rig something like that up yourself, but a workshop shouldn't sell such nonsense to a customer.

Regards,

Maciek.

Maciek wrote:

... What about the turbocharger? The 1Z turbocharger is controlled by a solenoid valve from the engine control unit (ECU). The AAZ has a wastegate without any control. ...

The turbochargers are the same for both engines (wastegate turbochargers with a boost pressure of 0.6 bar).
Only in the 1Z engine is the wastegate controlled by the engine control unit (ECU) via a pneumatic auxiliary circuit in the boost pressure regulation system. This increases the boost pressure to 0.9 bar.

I'd be more concerned about the fact that a fuel injection pump (from the AAZ engine) is being used on a direct injection engine (1Z). There's a difference of several hundred bar in pressure. How can such a setup even function properly? The fact that the vehicle can even reach 150 km/h is a miracle.

If you know what you're doing, it's definitely possible to build a mechanical TDI engine. The higher injection pressures don't come from the electronics, but from the steeper pumping element and the thicker piston.
I would find the internal pressure and injection start control to be more challenging.
Regardless, a workshop shouldn't be selling something like that.

Regards,

Maciek.

Hello.

A Seat specialist workshop is installing an engine that you purchased on eBay!!!