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Just replaced the timing belts, auxiliary belt, and water pump on my 2002 9n. I'd done the belts a few years ago so this was a job I've done before. Forgot a few of the finer details but got in done anyway. Turned the engine over via the crank bolt and all seemed well. Put everything back together and started the engine. Started almost on the first cranking and fired up. After a few mins it started to run irregularly and cut out.

EPC warning light on.

Could not get it to start again despite a lot of cranking. Used a code reader which showed 17961 & 17604.

17961 - Barometric / Manifold Pressure Signals (something about implausible correlation)

Fault Location:
Manifold Absolute Pressure (MAP) Sensor (G71)/Barometric Pressure (BARO) Sensor (F96) - Range/Performance Problem

Possible Cause:
Intake/exhaust leak.
Exhaust Gas Recirculation (EGR) system.
Evaporative Emission (EVAP) Canister Purge Valve (N80).
Throttle control unit.
Wiring.
Manifold Absolute Pressure (MAP) Sensor (G71).
Barometric Pressure (BARO) Sensor (F96).

17604- seems to be oxygen sensor

I then did the following:

Check vacuum pipes - all OK.
Had a look at the plugs (sparking OK), a bit sooty, but dry.
Checked fuses in the fuse panel
Erased the codes

Tried to start the engine again and after a few turns it caught. Gave it some throttle and it revved up quickly and cleanly. When I backed off the throttle the revs dropped quickly and it would not idle. Tried to hold it around 1500rpm on the pedal but revs dropped and it stalled.

A couple of things I noticed/had not noticed before:

Plugs were bone dry despite giving it some throttle while cranking
With the ignition on the throttle butterfly does not open when I press the pedal. There is a mechanical noise - sounds like a motor/vibration.
I removed the throttle body to have a look. Again a bit sooty underside but not over the top. Not sure if my memory is correct but the butterfly seemed to be resisting rotation much more than I could recall from when I took it out a few years ago to decoke/clean. It was a heavy resistance this time and I seem to recall it being lighter before.

It seems a coincidence this problem materialised after doing some work on the car.

Any ideas where the fault might be?

Any ideas or suggestions on this please?

I'm thinking it is throttle body related, adaptation, or something of that nature.

Have you performed a TB adaptation?

alexperkins wrote:Have you performed a TB adaptation?

No I have not. What would I need to do that please ( I can see the actions needed from the forum but what equipment is needed)?

One other point, I forgot to disconnect the battery before starting the work on timing belt, waterpump, etc. What would be the impact of that?

I got hold of someone with VCDS and did a throttle body adaptation.

Whereas the engine previously ran up and did not idle, stalling after 30 secs now it will not fire up at all.

The engine now appears to be overfueling (wet plugs). The plugs (when dried off) are sparking OK.

There are no fault codes or warning lamps.

Any suggestions please?

Incidentally, with the ignition on and the engine not running, when I press the throttle/pedal should the throttle body butterfly move or not? It is not moving at all.

Thanks.