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        General >> Problems >> Poor performance when cold
        
(Message started by: pallieter1942 on May 14^th, 2004, 8:29pm)

Title: Poor performance when cold
Post by pallieter1942 on May 14^th, 2004, 8:29pm

I own a scorpio 2 l EFI 16V from 1996.essence
when cold everything goes extremely bad: irregular idling suddenlly up and down between 500 and 2000 revs.
The car drives but is not able to go over 50km/hr (about 40 miles)
after at least 10km (7 miles) suddenly everything is normal and the car easely goes to 140 km/hr.
when hot it starts very good and everything is ok.
next day morning: the same misery.
any suggestions?
i already have renewed the sender valve of the temperature.
i suspect the exhaust recycling valve , but how to test it?
i am very gratefull for your help
best regards
Pallieter1942
Belgium

Title: Re: Poor performance when cold
Post by TonyS on May 15^th, 2004, 10:41am

When cold the engine is running 'open' loop using only intake air volume to determine fueling, switching to closed loop once the HO2 sensors have warmed up to operating temperature.

The limited top speed, and unstable engine control, implies the management computer knows it has a sensor fault so is working the limited operating strategy (LOS). Getting the car scanned for trouble codes would be the quickest way of finding the fault.

Otherwise ignore the EGR as this would not cause the problem (you say the car is fine once in closed loop) but focus on the sensors relating to air mass, air temperature, engine temperature and throttle position.

The wild idle would imply erratic signals so wiring loom should also be checked.

Title: Re: Poor performance when cold
Post by sterio on May 16^th, 2004, 8:33pm

I have the same problem.
where is the sender valve of the temperature located?
I whant to change that and see if it helps.
Where is the sensor for throttle possition?

Thanks
Dave