SPONSORED LINKS

1990 Toyota Corolla Idling rev

Tiny
JACKOLSON
  • MEMBER
  • 1990 TOYOTA COROLLA
  • 4 CYL
  • FWD
  • MANUAL
  • 80,000 MILES
Hi Guys,

When I start my engine from an overnight parking, the engine will set at 500rpm idling rev. Then after 15 minutes it will rise to 700rpm. Or I have to rev it at a constant 1000rpm for 2 minutes then it will finally settle at 800rpm. I have a 4AFC carb engine.

Is this normal? I know it's because of the car not in it's working temperature yet, but is this okay? If it's not, how can I maintain the idling rev at normal even at start up?

Thanks and more power.
Jack
SPONSORED LINKS
Tuesday, June 30th, 2009 AT 4:04 AM

3 Replies

Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
No it should idle higher when cold, then settle down after a few minutes.

Try a can or two of SeaFoam and see if it helps, if not the carb will have to be cleaned and possibly rebuilt.
Was this
answer
helpful?
Yes
No
Tuesday, June 30th, 2009 AT 8:00 AM
Tiny
JACKOLSON
  • MEMBER
  • 67 POSTS
Wow, this is a shock to me, thanks for this info. I always thought of it the other way around.

What is SeaFoam?

I'll try to clean the Carb first. Would it help if I use Carb cleaner sprays first? But if rebuild is inevitable then I would.

What's the recommended idling rev?

One more thing, when I turn the AC on, the idling rev decreases about 200rpm, when I turn the AC off, the idling rev goes back to 800rpm. Is this okay?

You're a great help, many thanks and more power.
Jack
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
+1
Tuesday, June 30th, 2009 AT 9:51 AM
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Seafoam is a cleaner that you add to gasoline, it will clean varnish in fuel system.

The idle should go up when the AC is commanded, in FI cars the IAC will control this, in carb cars there is a solenoid that will increase idle speed under a load.

Idle speed is around 800 rpm.
Was this
answer
helpful?
Yes
No
+1
Wednesday, July 1st, 2009 AT 6:52 AM

Please login or register to post a reply.

Related Engine Revs Up Content

Idle Air Control Motor Replacement
GUIDE
Idle Air Control Motor Replacement
The idle air control motor or idle speed control motor is designed to adjust the air flow into the intake manifold at engine idle. Engine idle speed is monitored by the PCM...
VIEW MORE

Sponsored links