Espace Engine rough runing

[Elmo the Espace]

Hi all at the Matra Forum
This is my first post so any help will be great.
My 1994 Espace 2.0 i 8v, starts ok idle is fine but around 2 to 3,000 revs when cold jerks on acceloration apart from that it runs perfectly when hot.
I have replaced the spark plugs,lambda sensor, cam belt and coolent temp sensor.
checked vacum hoses, resistance of the air intake sensor and idle control valve.
Is there any thing i am missing.
Chris

[Anders Dinsen]

Hi Chris - welcome to the forum!

There's no obvious thing you have missed, but I think you should check the fuel pressure.

You say that it works fine when hot... does the pattern change at a certain engine temperature or after a certain amount of running time?

- Anders
(I used to have an Espace with that engine, but I've never experienced this particular problem.)

[Elmo the Espace]

Hi Anders.
Tank you for the reply.
The fault occurs soon after starting the engine when cold then lasts until about the temp sender gets past 1/4 hot on the gauge.
This fault only happens from cold.
If i leave the engine 1 hour then do the same journey there is no problem.
I have also found that the enging hesitates slightly when revved both hot and cold.
Luckily when i checked the pipes to the charcol canister i found my near side gearbox mount has broken the drivers side is ok and  friend has a spare gearbox with the brackets attacthed.
Hope this helps
Chris

[Elmo the Espace]

Hi
I have sorted the problem, it was the air flow temp sender.
It read true at at idle but must of been reading wrong when flow increased and gave the ecu a incorrect value.

[Anders Dinsen]

Hi
I have sorted the problem, it was the air flow temp sender.
It read true at at idle but must of been reading wrong when flow increased and gave the ecu a incorrect value.

That's very good to hear

The temperature sensor is not dependent on the flow, except when the temperature changes rapidly as it can when you enter or exit a parking building, so I think it has run overly rich or lean at all rpm. Except idle, where the oxygen sensor is used to ensure that the mixture is exactly on the spot, even if sensors give slightly incorrect signals.

Thanks for sharing your solution, I'm sure it will be useful to others

- Anders