I have a 97 1.6 petrol Renault Scenic with a peculiar engine problem.

It has run for 107k trouble free miles until recently when it has
developed a fault 20 mins after started.  When cold, it starts and runs
fine, and then rather suddenly (no massive jolt or anything) it runs
very rough, loses power, and is incapable of keeping an idling speed
high enough to prevent it stalling.  Once the fault has happened the
car has to go completely cold again before it will start again.

Plugs were replaced less than 10k miles ago.  Air filter is clean, and
we replaced the fuel filter thinking that might be the problem.  It
didn't fix it.

I have a partner who is very capable of repairing my car once the fault
is diagnosed.

Does anyone have any suggestions as to what might be causing the
problem?

If not, then I guess I will just have to take it to a garage :-(

"marzipan"  wrote in message
news:1122335338.956362.72920@z14g2000cwz.googlegroups.com...

> I have a 97 1.6 petrol Renault Scenic with a peculiar engine problem.
>
> It has run for 107k trouble free miles until recently when it has
> developed a fault 20 mins after started.  When cold, it starts and runs
> fine, and then rather suddenly (no massive jolt or anything) it runs
> very rough, loses power, and is incapable of keeping an idling speed
> high enough to prevent it stalling.  Once the fault has happened the
> car has to go completely cold again before it will start again.
>
> Plugs were replaced less than 10k miles ago.  Air filter is clean, and
> we replaced the fuel filter thinking that might be the problem.  It
> didn't fix it.
>
> I have a partner who is very capable of repairing my car once the fault
> is diagnosed.
>
> Does anyone have any suggestions as to what might be causing the
> problem?
>
> If not, then I guess I will just have to take it to a garage :-(
>


Renaults of this age often have failed coolant temp sensors which will give
you repeatable symptoms exactly like this. If you hook up a DVM to the CTS
and monitor it as the engine warms up from cold you'll probably see the
smooth transition suddenly jump to a wildly different reading.

FYI- 20 deg C - ~4v, 100 deg C - ~0.7v.

Main cause is lack of regular coolant changes- which corrodes the end of the
sensor which then fills with water.

Tim..

The message 
from "marzipan"  contains these words:


> Once the fault has happened the
> car has to go completely cold again before it will start again.


If it was any other time of year I'd suggest checking the hot air
trunking from the exhaust shield to the air filter is still there, but I
can't believe it's icing up in this weather.

-- 
Skipweasel.
Ivor Cutler - "Never knowingly understood."

"Guy King"  wrote in message 
news:313030303432373942E5F56470@zetnet.co.uk...

> The message 
> from "marzipan"  contains these words:
>
>> Once the fault has happened the
>> car has to go completely cold again before it will start again.
>


Ive just had this problem with my scenic, turned out that one of the spark 
plugs had somehow got damp and was rusty. How or why that caused the fault 
is beyond me but the garage had it in all day, finally took out the spark 
plugs which they had replaced only two months prior and noticed one was 
rusty where the porcelain meets the metal.
Might be worth a look at that.
Can anyone help with my rear washer problem now in another thread?
Pete

Thanks to all for your suggestions, we will look into those, especially
the spark plug issue.

Re the failed temp sensor suggestion, we were wondering about that.
The engine is extremely hot, yet the temp guage shows normal, and the
fan doesn't appear to kick in.

Certainly gives us a few more places to look
Marzipan