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Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 20362
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Peugeot boxer 1999 petrol 2 litre , running very ( hc level

Customer Question

Peugeot boxer 1999 petrol 2 litre , running very rich ( hc level is 600 plus cuts out on deaccarcelerailing )
Submitted: 4 months ago.
Category: UK Car
Expert:  Matt replied 4 months ago.


This could be incorrect fuelling due to a faulty water temp sensor. If this is the problem then the ECU will be leaving the car constantly ' on choke' and not reducing the fuelling as the engine warms - so unplug the sensor and clean the contacts on both sides with some switch / electrical cleaner (not WD40) and inspect the wiring for any signs of damage to the insulation especially where it runs over other components and through the bulkhead- if this doesn't help consider replacing the sensor as they're not expensive

Also check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

Expert:  Matt replied 4 months ago.


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