Inconsistent TS performance

[Mr Bit]

Hi guys,

There has been one annoying thing about my TS since I bought it. The car seems to have a real Jekyl/Hyde character to it.

Some days the car feels like the quickest car on the road (slight exaggeration!)and others it feels like the slowest.

For example, I can drive my car to the shops and the engine will run well. The accelerator is crisp and responsive, it has good pull from 3000 RPM up and will rev cleanly to redline.
I'll get back into my car, start her up and straight away I can tell something is not right. The engine sounds flat and the car is generally unresponsive and revs harshly and struggles to reach redline.

On only 3 occasions in 9 months (I remember all 3 very well!), the car has had blistering power, surprising even myself. Its frustrating knowing what the car is capable of, yet I rarely get to experience it.

This is most annoying, as I'm sure most of you will understand.

My other Alfa's were like this too, but not to the same extent.

When the car runs bad, fuel consumption seems to suffer. Whens its running well, it seems to improve.

With all the yummy gadgets the TS engine has, I believe some aspect of it is not functioning correctly.

Perhaps it could be one of the following-
Timing/spark/fuel delivery/o2 sensor/vvt???

My mechanic says he has checked everything and cant find any issues.
Fuel pumps and regulator were reaplaced new not long ago.

Any idea's?

Cheers,

Mr Bit

[BigSwede]

Check:
-Plugs
-Fuel filter
-Pre-pump in the tank, is it running?
-Distributor caps and rotors (both)
-Ignition cables
-Coils and ignition modules (check for bad connection)
-VVT, not sure about this but from memory the VVT is supposed to rotate the cam if you feed 12v over it at idle
-Does the catalyst rattle if you shake it?

What kind of oil do you have in your engine? When was it serviced last?
Maybe try that cleaner stuff you pour in the gasoline.

Lift the car up on stands and check the fuel line for sharp bends or pinching. Also, did you change the gearbox mounts recently? Very easy to get your fuel hose trapped between the gearbox support beam and body.

[max_75]

I have this kind of "feel" on my TS before when my alternator is out. I think is becoz my alternator out, the battery can't supply enough power to the VVT.

[turbolarespider]

While you are at it, see if you can get a digital volt meter on the O2 sensor. It might be driving your computer to run lean...

But it sounds like there is some experience running the VVT...

Eric

[Mr Bit]

Thanks for the replies.

I am satisfied that my mechanic has inspected all the things mentioned.

Something happened tonight. When I started the car up I heard a slight rattling/raspy noise coming from down near the manifold/exhaust section as if my exhaust had a leak somewhere.

After about 5 mins of driving the rattle became a full blown roar. It sounds as if there is no exhaust from the manifold back!

The engine itself seemed to run OK and all vital signs are OK.

Perhaps the cat has self destructed?

Could a blown cat be the cause of my problems?

I forgot to mention. It is getting dark here at the moment, but from what I could see, the exhaust seems to be in one piece with no visible holes etc....

[turbolarespider]

Mr Bit
No doubt you will re-install the catalyst, yes? But before you do, use a straight pipe to diagnose what caused the failue. If, indeed, you find that the catalyst is burnt up, and a ball of solid ceramic, there was a significant problem with the engine. Catalysts will NOT do this on their own.

Once you solve the problem, then re-install...

Eric

[BigSwede]

Check to see if the system has split between the primaries and downpipes. Happened to me a couple of times...