1.8 16v f7p rough idle

[car.crash]

My Clio valver has a rough idle and bounces from 1500rpm and drops to a 1000 and nearly stalls then back up to 1500 again. I have changed the idle control valve but this made no differance.

 

[Fastchip]

Make sure your throttle position sensor (red thingie on the side of the T-body) is positioned right.
If it after starting this behavior occurs ( up and down 10 times, then stops) replace your oxygen sensor.

 

[car.crash]

it keeps going up and down constantly.

 

[jamesd1263]

Vacum pipe

 

[Laine_16v]

Id try changing the lambda sensor too

 

[car.crash]

thats a expensive guess, have any of you had this problem first hand?

 

[sophiesdad]

yes , and both the above can give similar symptoms , and are expensive guesses , but they are a good guess.
Going and getting it diagnosed correctly will always be the cheapest , quickest and best option.

 

[bv58bar]

Hi.
Did you find the fault?
My f7p has some crazy symptoms and one is unstable idle.
Thanks.

 

[car.crash]

Not sure if I did mate. i kinda lived with it.

 

[dangerous dave]

Get on the renault 5 gt turbo forum on Facebook, james Sargent on there has a clio turbo lump in his 5 and it's broken 90% of the time.. I can bet my nads that he's had the same problem before.

 

[MicKPM]

Plug it in to diagnostics and... LOL

H02, CTS and potentially a faulty speedo cable could all be the causes. Having access to a good scope and some basic diagnostic skills will help prove any of the above as the issues though.

 

[car.crash]

I threw it in the crusher.

 

[bv58bar]

Unfortunately i don't have diagnostic soket on my loom
At first my engine wouldn't start when hot and when it started it had terrible idle and almost stalled.
But recently the idle problem started to occur even when the engine is cold.
i have changed water sensor, coil, map sensor and checked idle contol valve.
Even played a bit with the tps.
Then i found this in my ecu

 

[MicKPM]

You know these have two coolant temp sensors right? One for the temp gauge and the other to feed the ECU... Are you sure you changed the right one.

Easy way to test would be to unplug them and see how it runs.

 

[bv58bar]

yup, i changed the white one.

 

[bv58bar]

i unplugged them and no change.
i found a crack in the exhaust manifold at piston no 1
i'll be back with feedback after i replace it

 

[ben_blablabla]

I had a similar problem a few years ago, turned out to be a cracked inlet manifold. It was right underneath near one of the bolt holes. Hard to spot on a F7 without taking it off.


Ben.

 

[bv58bar]

i have changed the whole exhaust and lambda.
i pulled out the inlet manifold and checked it for cracks.
Changed the gasket but no change... it runs like this
only when the engine is cold. whet it warms up a bit, it runs fine and idles at 900rpm

 

[rctempire]

Have you changed the MAP sensor and adjusted the throttle body?

Mine blue one does this every now and then, turned out to be the two above.

Edit - spelling

 

[Justin_16vT]

It'll be the coolant temp sensor

 

[Justin_16vT]

@rctempire they don't have a maf sensor. Only map sensor

 

[rctempire]

@rctempire they don't have a maf sensor. Only map sensor

My mistake ment map.

Oh also, checked the ICV unplug it while running see if it changes at all.

 

[bv58bar]

i have changed the map sensor and adjusted and even unplugged the tps.
i actually unplugged air sensor, coolant sensor, tps, lambda, icv and the engine still runs fine then starts to drop rpms until it gives it's self "gas", then starts all over again....

this is how the injectors work
the 5th injector din not work.
after checking him with wires and finding out he actually is good i checked the wiring.
so i have positive but no negative...
after looking on line i have learned that the negative comes from the coolant sensor, witch is brand new....
temp out side was about 12degrees c
Big question: does the cold start injector work until the engine is a bit worm ?

 

[Justin_16vT]

As far as I know the 5th injector doesn't work until it's really cold out side

 

[bv58bar]

Yup, it seams you are right.
And i've checked all the wires in my loom and they all have continuity.
So if the engine behaves the same with all electric components disconnected, except the coil, map and crank shaft sensor, the problem must be with one of these 3.
Since i've changed the coil and spark plugs look ok, there is no problem here.
Map i've changed is sh, so it could be....
Crank shaft sensor i haven't changed but will do tomorrow.
Have i missed anything?

 

[bv58bar]

So i have changed the crank shaft sensor and air temperature sensor, but nothing changed.
So i had a friend loan me his ecu and problem solved...
But.... there is a but.... won't start immediately after being turned off.
it crank's like crazy but won't start
i have to wait half a minute, even if the engine was on just for 2 minutes....
it's driving me crazy!

 

[AhmetZ]

My Clio valver has a rough idle and bounces from 1500rpm and drops to a 1000 and nearly stalls then back up to 1500 again. I have changed the idle control valve but this made no differance.

Throttle potentiometer that measures air mass. if moisture gets in and coats the sensor takes wild readings and fuels erratic.