Partner poor performance

I was called out to a Peugeot Partner 1.4 petrol (M59) suffering from poor performance. It had a general lack of power and flat response to acceleration.

There were no DTC’s recorded, so I went straight to engine live data. This showed me a slightly high manifold pressure. Due to the manifold pressure and the response from the wide open throttle test I made, I suspected the valve timing. This engine does not have a camshaft sensor, as it uses integrated phase detection to determine cylinder reference,  so I couldn’t just do a cam and crank synchronisation check.

This is a pretty simple engine to check valve timing mechanically, but it was even easier to check it with the Pico WPS500. (refer waveform).

cylinderpressurebad
Cylinder pressure with incorrect valve timing

This was enough for me to make the diagnosis of valve timing. As with so many of my cases, I was unable to get back to the car after the repair. But a new cambelt was fitted and the old one had just stretched and jumped 4 teeth.

I did manage to get a known good cylinder pressure waveform  from another car with the same engine, as shown below.

cylinderpressuregood
Cylinder pressure with correct valve timing