Dead G60

[scoffer]

We've got a 91 G60 carrado at work that barely runs, and stalls after a minute or so.
Compression is around 115 psi in each pot, timing belt intact, lots of fuel pressure (65psi) and a good spark.
The thing I cant figure is this, when it's running (if you could call it that) it doesnt change at all when you open the throtlle. I've disconnected ducting at the throttle body to eliminate a blockage in the charger/cooler/filter, and still the engine will not react to the throttle. Not even a little bit.
We've got the proper VW scan tool, and it won't communicate with any of the control modules at all.
Since these great cars are scarce in our neck of the woods, it's got us scratching our heads as to what to check next.

I've also checked all the powers and grounds at the ecu and found nothing amiss there either.

Ideas anyone?
Thanks

[Fourt1thirty]

Compression is 115 and you don't see a problem with this?

[scoffer]

It does seem low, but as each cylinder read the same and it wasn't a wet test I wasn't too worried.
So, what should it be?
As I said, I'm looking for help, so actual info would be great.

[Fourt1thirty]

VW claims the wear limit is 109 but experiance tells me it should be above 130. Most low compression 8vs pump around 145.

Is this 65psi of fuel pressre is in question. Is that with the vacuum hose connected or disconnected? With the hose unhooked you should only see 44psi so you might be having an issue with the regulator. How do the spark plugs look?

Odd that it doesn't find the control module. But who knows... VW was ahead of themselves in '91 as far as diagnostics go.

[scoffer]

The fuel press is with the hose connected and the engine cranking. It doesn't run long enough to take any meaningful measurements.
The thing that is most puzzling is the total lack of response when the throttle is opened.
As I understand it the corrado's digifant system differs from others in that it doesn't use an AFM but rather manifold pressure to control fuel flow. Is that right? If so, know of any tests to confirm the functionality of the MAP sensor?
Thanks

[halfofnothing]

Originally Posted by scoffer

The fuel press is with the hose connected and the engine cranking. It doesn't run long enough to take any meaningful measurements.
The thing that is most puzzling is the total lack of response when the throttle is opened.
As I understand it the corrado's digifant system differs from others in that it doesn't use an AFM but rather manifold pressure to control fuel flow. Is that right? If so, know of any tests to confirm the functionality of the MAP sensor?
Thanks

map sensor is built into the ecu.

[Fourt1thirty]

Fuel pressure should be as above with the engine on or off, either way. Digifant 1 can't change fuel pressure, but it does monitor it to regulate fueling accordingly. Either way... something is wrong with the fuel pressure. To the tune of about 20psi

There is a map line running to the ECU. Make sure it's connected.