Technical Cinq high idling

[RYX]

I've recently bought a 1995 Sporting and it's idling around 1400 when cold and 1200 when warm.
I've scoured these forums and have assumed it's a lose vacuum pipe or similar.
The only 2 I can see are under the airbox housing the filter. A short pipe goes to the back of the engine, a longer one goes to the right (MAF??). I've also tried swapping them over but it's the same.
Is there anything else I can look for or what should I be replacing?
Thanks for the help guys

 

[arc]

Hi, welcome the forum.

If you take the airbox off, you will see there are a couple of pipes that go into the back of the throttle body. I think there are 2 or 3 vacuum lines there, i forget now.
The tube that goes off to the right does indeed go to the MAP sensor. It's not unknown for this pipe to split. Try disconnecting it, and see if that has any effect on the idle. See if it revs higher, or maintains what its doing at the moment.

 

[RYX]

Thank you for the welcome and also quick response

I started it from cold and left it for a few minutes.
There are 2 thin pipes coming from a small pink thing inside the air box. I removed the one going to the MAP sensor (leaving the airbox in place) and it made no difference.

I'm assuming the "throttle body" is the bit that looks like a carb? My pipes appear to go to the airbox and not the throttle body or am i missing something?

Anything else to try or do I need to replace something?

Thanks again.

 

[arc]

when you removed the one going to MAP sensor, i would expect the engine revs to rise. Completly remove this pipe (both ends) and inspect it for damage. The fact that removing it made no difference to the revs suggests to me it has a hole in it somewhere!

 

[RYX]

Definitely no holes, I've throughly inspected it.

I also removed it from the MAP sensor again with the engine running and put my finger on the end. The pipe stayed stuck to my finger with a very gentle vacuum pressure.
Still no change in engine revs during all of this though.

 

[arc]

ok, hmm

have you checked all the other vacuum pipes, are they all ok? How tight are the bolts that hold the throttle body in place - it def sounds like a vacuum leak somewhere.

 

[RYX]

From what I can tell there are 3 vacuum pipes in total. One small one to the MAP sensor, another small one to the rear of the throttle body and the larger oil breather which splits in 2 (one to the air box and the other to the rear of the throttle body next to the smaller one).

Both small ones seem fine. The oil breather was quite gunked up which I've cleaned out and it can now breathe freely.

It still idles at around 1200

 

[chris4500uk]

have you tried resetting the ecu?

leave the battery off for about 30 min

 

[RYX]

It has a battery isolation terminal and has been disconnected for a few days so I guess it's been re-set.

 

[Asteris]

Mayby your revs are right and the needle is relocated by 300 revs. Mine when it had an air leak was idling at 1500 cold/900 warm.

Are you sure that the previous owner wasn't messing with the dials and relocated the needle's position? Ask another cento to idle right next to you and check the revs by the sound of the two.

 

[chris4500uk]

sure the thottle cable is adjusted correctly? not pulling the thottle open a bit?

 

[mase]

sure the thottle cable is adjusted correctly? not pulling the thottle open a bit?

wats the easiest way to adjust the throttle cable?

 

[Puntodan]

did you get any further on this one as mine is now having similar problems! It idles at around 1700 - 2000rpm on cold and then drops to about 1100 - 1200rpm warm and sometimes bang on 1000.

Dan

 

[HP]

Vacuum pipes on the wrong connections will do it.

 

[chris4500uk]

wats the easiest way to adjust the throttle cable?

2 nuts that hold the whole cable on, just slacken both of these then move towards the back of the car to slacken cable, then retighten.

Might not be that whats causing it tho, but its worth a try for the sake of 10 min, oh also it helps if you remove the breather pipe and airbox but thats optional !