low idle when lights are on...

[pmanson]

In the last couple of weeks the car has been suffering from a low idle which then recovers quickly to a rock steady 850rpm.

Just did a test when we pulled onto the drive:

• Lights on/heater on/radio on + a quick rev = revs drop to around 250rpm before recovering

• Lights on/heater off/radio off + a quick rev = revs drop to around 400rpm then recover

• All off + a quick rev = rock steady 850rpm.

It also hesitated yesterday when I was driving along and flashed someone when at low revs.

Where should I start looking for an issue?

Planning on changes plugs and oil fairly soon but this seems to be an electrical issue...

[offroading.net]

tired battery, tired alternator, sticky ICV

[pmanson]

offroading.net said:

tired battery, tired alternator, sticky ICV

i'm planning on checking all those at the weekend - cheers!

[pmanson]

Afternoon All,

I had a busy weekend working on the car and completed the following tasks:

Saturday
1. Oil and filter change
2. Cleaned out throttle body
3. Cleaned up the contacts on the battery
4. Change spark plugs

Result: Idle @ 1250-1500rpm

Plugs were black and sooty

Sunday
1. Replace lambada sensor (the old one was white)
2. Set base idle
3. Sprayed carb cleaner in the ICV

Result idle at 850-900rpm

Then i went for a drive, dropped the clutch and the revs stuck at 1250-1500rpm again. Carried on driving, dropped the clutch and the revs dropped to 1250-1500rpm before falling back to 850-900rpm.

I'm thinking that I need to give the ICV a really good clean out. The car is running smoothly, has a lot more power and feels much more responsive.

Cheers,
Phill

[hcanning]

pmanson said:

In the last couple of weeks the car has been suffering from a low idle which then recovers quickly to a rock steady 850rpm.

Just did a test when we pulled onto the drive:

• Lights on/heater on/radio on + a quick rev = revs drop to around 250rpm before recovering

• Lights on/heater off/radio off + a quick rev = revs drop to around 400rpm then recover

• All off + a quick rev = rock steady 850rpm.

It also hesitated yesterday when I was driving along and flashed someone when at low revs.

Where should I start looking for an issue?

Planning on changes plugs and oil fairly soon but this seems to be an electrical issue...

I had this same issue recently. Resetting the base idle (putting the ECU into diag mode and turning the idle control screw) fixed it

[pmanson]

hcanning said:

pmanson said:

In the last couple of weeks the car has been suffering from a low idle which then recovers quickly to a rock steady 850rpm.

Just did a test when we pulled onto the drive:

• Lights on/heater on/radio on + a quick rev = revs drop to around 250rpm before recovering

• Lights on/heater off/radio off + a quick rev = revs drop to around 400rpm then recover

• All off + a quick rev = rock steady 850rpm.

It also hesitated yesterday when I was driving along and flashed someone when at low revs.

Where should I start looking for an issue?

Planning on changes plugs and oil fairly soon but this seems to be an electrical issue...

I had this same issue recently. Resetting the base idle (putting the ECU into diag mode and turning the idle control screw) fixed it

Yep tried that (and it worked for a short time) but something is getting stuck - I think there is a wax float somewhere in the ICV that needs a good clean...

Will give it another go tonight.

[anonymous-user]

I set the timing on mine and it was then idling at about 1500rpm. Next morning it had returned to idling at 800 and has been like that since, although occasionally it will stick at about 1200rpm for a few seconds or until I blip the throttle.

Can you let us know how you get on cleaning the ICV and how you do it - I thought I'd cleaned mine out properly but perhaps not.

Edited by anonymous-user on Monday 10th November 16:00

[franv8]

Watch out for the accelerator cable. Mine was ever so slightly too taut, so a quick adjustment sorted it out (slight slackness at idle).

[pmanson]

franv8 said:

Watch out for the accelerator cable. Mine was ever so slightly too taut, so a quick adjustment sorted it out (slight slackness at idle).

ours feels almost too slack.

Amy picked me up from the station tonight and it was idling at 800rpm without any problems...

[pmanson]

JimSuperSix said:

I set the timing on mine and it was then idling at about 1500rpm. Next morning it had returned to idling at 800 and has been like that since, although occasionally it will stick at about 1200rpm for a few seconds or until I blip the throttle.

Can you let us know how you get on cleaning the ICV and how you do it - I thought I'd cleaned mine out properly but perhaps not.

Edited by JimSuperSix on Monday 10th November 16:00

Try following this guide - http://www.miata.net/garage/isc.html