MK 3.5 1.1 HCS coolant temp question - Ford Fiesta Mk1 / Mk2 / Mk3 Forum - (1976-1995) -

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MK 3.5 1.1 HCS coolant temp question

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#1 takee



  • Members
  • 163 posts
  • Vehicle Driven:ST200
  • Location:Hungary

Posted 19 May 2012 - 06:51 PM

Hi there everyone,

I thought You might be able to help.

Situation is my Fiesta consumes more than she should. It is a 1.1 litre HCS with cataltyc converter and lambda sensor, a CFi one. It consumes 7 litre (33 MPG) in mixed conditions, and 7.89 litre (29.81 MPG) in the city. Never less, never more.

The water temp gauge never goes up than 50-60 degrees in Celsius, which means the upper side of the white section (cold sign). I've tested the thermostat, it was in full working order, opened at 85 Celsius. Then I replaced it with a brand new one, just to be sure. Heating is ok, burns like hell.

The operation of the water temp gauge did not changed at all, consumption remained high. Fan never switches on, no matter how warm the outside temp is, in case of traffic jam, it remains silent. Been tested, works fine.

The other thing to know: if car stands in neutral and the engine is idling everything is fine. If I push the throttle all the way down suddenly, it hesitates and chokes. It does the same thing at cold engine in case of full throttle acceleration (ia.: overtake).

My guess is that one of the temp sensors is faulty and gives a "cold engine" sign to the ECU, which enriches the fuel mixture. That causes choke and high consumption. Am I right?

If so, which one goes to the ECU? The big, or the little one?

As far as I know, the big one (at the top of the thermostat housing) regulates the cooling fan, and the little the temp gauge. Does the bigger one goes to the ECU first, then to the fan? Or the little one goes directly to the ECU, and after to the gauge? Which one should be replaced?

V6 Ghia converted to ST200

Sunroof installed in OEM quality. There is no such thing as impossible...

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