High revs in idle...

me_irl

Marked the thread as "electrical"... but of course it might be something else!

Make/Model: 00 Nissan Almera

Symptoms:
I noticed over the last while that the engine would be in a higher rev (higher pitch) when starting, idle/neutral.

I tested it the other day by starting up, and just turning on my full beams which caused the engine to pitch up... Same thing happened when I repeated this a few times.

So, paranoia aside, should I get this checked out?

Car99

me_irl wrote: »

Marked the thread as "electrical"... but of course it might be something else!

Make/Model: 00 Nissan Almera

Symptoms:
I noticed over the last while that the engine would be in a higher rev (higher pitch) when starting, idle/neutral.

I tested it the other day by starting up, and just turning on my full beams which caused the engine to pitch up... Same thing happened when I repeated this a few times.

So, paranoia aside, should I get this checked out?

How high are the revs ? Does the car have a rev counter?
It is normal for revs to increase slightly if you turn on a high electrical load.

me_irl

Car99 wrote: »

How high are the revs ? Does the car have a rev counter?
It is normal for revs to increase slightly if you turn on a high electrical load.

Cheers for the quick reply.

It's not a substantial spike.

Just something I noticed and was hoping it was something simple (for me!) to fix.

I'm alright with computers, cars and people not so much :pac:

cletus

Try cleaning the iscv, maf and throttle body.

If you are cleaning the maf, use electrical contact cleaner, don't use carb cleaner etc. Also don't actually touch it with your fingers or anything, just spray it and let it dry

biko

Does revs go down after 2 mins?
Has car been harder starting lately?

John T Carroll

Check for cracked hoses as air leakage will always cause higher idling once the ECU has closed the throttle plate to its minimum of ~ 3 Deg., it also then retards the ignition timing but if the air leakage is excessive then it cant reduce the RPM any further. Every car I have ever checked once its fully warmed up will idle at the lower end of the scale, in other words if the idling range is say 750 to 850 RPM then it will idle at 750 RPM once heated up. There are lots of other things as well which have been mentioned here but on a 16 year old car perished hoses are a good place to start. The coolant temperature sensor is another item that can be checked

irish bloke

John T Carroll wrote: »

Check for cracked hoses as air leakage will always cause higher idling once the ECU has closed the throttle plate to its minimum of ~ 3 Deg., it also then retards the ignition timing but if the air leakage is excessive then it cant reduce the RPM any further. Every car I have ever checked once its fully warmed up will idle at the lower end of the scale, in other words if the idling range is say 750 to 850 RPM then it will idle at 750 RPM once heated up. There are lots of other things as well which have been mentioned here but on a 16 year old car perished hoses are a good place to start. The coolant temperature sensor is another item that can be checked

Good advice but I think the OP would be better served answering the queries from posts 2 & 5 before he goes down the mechanical route.

It could actually be quite normal what the car is doing..

vrusinov

With the recent cold(er) weather it's not surprising - revs would be high (up to 1500 rpm or so) until engine heats up. Adding electrical load during that would put more strain on generator, making it harder for engine to rev.

PS: I remember starting my Lada at -20 C. It would rev to 1500 for good 10-15 minutes until engine finally heats up.

Hal1

Well it's not as cold of late and coolant prevents freezing, so it shouldn't take an unusual long time to reach normal temp, I never wait for mine to idle and get to temp anyway. I would be looking at vacuum hoses as said above and the maf sensor.

vrusinov

Well, it's a question of how long does it last. In Ireland it should never take more than 2-3 minutes for engine to heat up and revs to drop.