What should 1.8 16v idle speed be?

[Guest]

Thanks to the forum I've got a nice checklist of things to prod for correcting idle speed that I haven't looked at already (earthing, CTS, MAP etc.).

My (failed) MOT emmisions test results sheet says idle speed should be within:

Natural Idle
min 675
max 825

Does that range seem low? My car is idling faster now than it was so I'll try to bring it down.

Any one have a reference value for what idle speed should be?

 

[Guest]

I would say that seems low yes, as a rough guide i would say a good idle should be between 1.1k - 1.3k COLD or 850 - 950 WARM.

 

[Guest]

i think its about 800 when warm mate

 

[Guest]

Yeh mines 1100 when cold and 900 when warm

 

[Guest]

I'm pretty sure its 850 -/+ 50rpm

 

[Guest]

Thanks for all the replies. I did argue with the tester that the max was too low but he said all he does is put it on a computer not set the values himself.

I used to get around 1100 cold and 900 RPM warm too and I thought that was fine.

I got 1050 on test day (but it was -5°C when I dropped my car off). It passed fast idle test on the second run but the "natural idle" test bailed because RPM wouldn't drop low enough.

If I have to get ~800RPM then tbh it's probably going to be temporary bodge of duct tape over the ISCV hose with a hole poked in it. Which is stupid of me...

edit:

VOSA says: "Idle speed is probably something to do with the engine." Uh huh thanks, I'll bear that in mind.

A Renault dealer tech says: "Idle speed varies according to conditions but usually 800 - 900 RPM."

 

[Guest]

A car can fail on idle speed?! News to me!

 

[Guest]

1300 cold idle and 900 warm idle on both mine there or there abouts, never gets as low as 800

 

[Guest]

Thanks again for all the replies - helps to know what I should be shooting for!

Checked everything. Ended up replacing the small hose to the MAP (inlet manifold side), cleaned the ISCV and put a 18mm mini filter on it (I'd only recently cleaned the ISCV but it looked pretty dirty again.

Mine could probably do with a catch tank on the breather hose, imo. That's on a Hillpower foam filter blue fibreglass thing the car came with... thinking about scuttle induction but not convinced it isn't going to suck in water (been there, thrown conrods, pretty keen on never doing it again).

Warm idle now steady at about 900 RPM on the tacho. Last time it was on Clip the tacho was reading +100 RPM so retest here we come!

 

[Guest]

950 i think is the Renault stated idle figure

 

[Guest]

scuttle induction wont suck water mate, loads of us have run it for ages in all weathers, no issues

kiz even ran a filter inside wheel arch with no splash guard, soaked half the time it was, no issues

 

[Guest]

Thanks for the help. MOT retest finally passed!

(Let's skip over the part where I took it for a full MOT at another place, passed the emissions test but failed on other pedantic things...)

Looks like they manually specified the idle speed settings for the retest. "Natural" idle speed read at 960RPM and passed.

Both emissions tests forms from different testers said 'Clio range' but the first stated engine size 1800CC (675 - 825RPM) and the second said correctly 1764CC (800 - 1000RPM).

So if anyone has a problem with idle speed come MOT time - check they're using the correct engine size and idle speed range.

After all that I can de-cat it!

 

[Guest]

lol, at least it got sorted in the end!