3.2 has trouble accelerating from idling speed to 2500 rpm, need help diagnosing
 

Hi, I hope someone can help me diagnosing the problem with my Euro specs 3.2 Carrera.

Above 2000 – 2500 rpm the car is running fine, but getting there can be a bit of a problem, it will have some hick-ups, misfires etc. Before 2500 rpm it is impossible to flatten the gas pedal, I need to be very careful with the throttle otherwise it will have hick-ups and misfires, not only one cylinder but on all six. Fore a smooth takeoff I need to be very gentle on the throttle till it is above 2500 rpm after that it will pull strong.

Sometimes the engine is idling smooth and then I don't have the hick-ups at takeoff, but most of the times the engine is idling rough on 600 rpm running on 5 cylinders I guess.

When the engine is on working temperature the problem get worse. I also had a SW chip, but that made the problem worse as well, so it is now running on the stock chip again.

I did replace the air flow sensor and the ignition coil but no result.

Please what could this be?

We seem to be getting a lot of cars with head temp sensor problems lately that have symptoms like this.

head+temp+sensor would be a good search

Thank you Milt, I’ll start my search there.

Thanks,

If you can borrow the ecu box from a friend, replace it with yours and see the result.
My 84 US spec had the same problem as yours.
After replacing many other parts, finally I got a second hand ecu put in.
It works.
Burint

When was the last time the fuel filter was changed?

Hi Burint, I did borrow an ECU box (one with SW chip in it) same story only worse as I guess the SW chip is more sensitive to the troubled fuel system.

Hi Joe, I do not know when the fuel filter was changed for the last time. I guess puting in a new one won't hurt. Thanks.

You mentioned that you replaced the "air flow sensor". ie the whole flapper box unit?
If not, your symptoms could be from a worn track, see here for remedy:

Air Flow Meter (AFM) - from "The 944 Motronic DME" by FR Wilk

Other thoughts are both Motronic sensors as Milt mentions.

My old Audi ur-quattro had a similar problem once but that ended up just getting better...ie it was an audi poltergiest.

"Sometimes the engine is idling smooth and then I don't have the hick-ups at takeoff, but most of the times the engine is idling rough on 600 rpm running on 5 cylinders I guess."

You could have a bad ignition wire ends. Is it worse on humid days vs. dry cool days?