Idle Speed for 1989 Mazda Familia Interplay 1500CC Page 1 out of 2

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It is 16 Valve DOHC, I am running 98 octane in it and it warm idles at 1500RPM. How do I set the idles speed or what should the idle speed be.
Should I even run 98,
Suggestions accepted

Driver-nomannz123, Mar 24, 2012, 12:12 am

91 octane is the minimum and absolutely fine to run.
Warm idle speed should be around 850-900rpm.
Cold idle in a manual is around 1250rpm, auto is around 1750rpm.

Driver-jasongroves, Mar 24, 2012, 12:22 am

Here's a picture of the location of the idle adjustment screw:

To be honest though, the idle screw doesn't generally move around on its on, so I would be looking for other reasons as to why it is idling so high.
A faulty temp switch/sender is a possible cause off the top of my head, as if the switch is telling the carby that the engine isnt up to running temp, then the carb will assume that the engine is always cold.making it fast idle (essentially auto-choke).
Another possibility is a faulty thermostat.if its jammed open, the operating temp will stay low.
What does the temp gauge read once the engine has been warmed up!

Driver-jasongroves, Mar 24, 2012, 12:28 am

On a plus note.generally a very sturdy and reliable engine with plenty of parts and support available (including from Ford).
What is the condition of the coolant!

Driver-jasongroves, Mar 24, 2012, 12:30 am

One last question.:)
Whats the service history like!

Driver-jasongroves, Mar 24, 2012, 12:33 am

Hi Jason, it appears to run on the cold side of the temp gauge, not quite to half way where one would expect it to be. Say between midway cold and the halfway mark.
Coolant is straight waterand I will be flushing itout and refilling it with coolant with Antifreeze etc.
Will check the temp sender and the thermostat in the morning.
Other than that the cam belt and water pump were changed 10,000 Km ago and wonder whether it is timed properly. Will look at the first 2 options first.
Just bought it today

Driver-nomannz123, Mar 24, 2012, 12:40 am

Yeah temp sender and thermostat are dead easy to check.
Good on you for doing it yourself:)
Proper coolant/anti-freeze has different cooling properties to straight water, so that's a damned good start.
Timing is a possibility.could be a tooth out, but I would expect more severe symptoms (rough running for one).
I do have the info for timing etc etc if you need anything.

Driver-jasongroves, Mar 24, 2012, 12:46 am

Service History is OK, cambelt done , water pump all done.
Suspect the coolant and the Temp sender and or thermostat.

Driver-nomannz123, Mar 24, 2012, 12:46 am

Actually.strange that belt and w/pump were changed and no one bothered to use proper coolant!

Driver-jasongroves, Mar 24, 2012, 12:47 am

Tridon thermostat part # TT240-192

Driver-jasongroves, Mar 24, 2012, 12:53 am

Does not run rough, smooth acceleration and very good pickup with speed.
The lady that sold it to me said a few minutes ago thatthat she bust a hose and her brother put a new one on and filled it with straight water.
Yes timing would be handy.
You are a great help.

Driver-nomannz123, Mar 24, 2012, 12:57 am

Just as an after thought, check the metal heater hose under the exhaust manifold for corrosion. Just a precaution really, as have seen them rust through before when proper coolant hasn't been used. Unlikely though.
Will see what info I have, as I just realised that the cold idle info I gave you was for a B6 (1600) engine:)

Driver-jasongroves, Mar 24, 2012, 1:01 am

Driver-jasongroves, Mar 24, 2012, 1:05 am

Hi Jason, if you can give the B5 idle speeds or are they the same

Driver-nomannz123, Mar 24, 2012, 1:22 am

Idle speeds are within 50rpm of each other.

Driver-jasongroves, Mar 24, 2012, 1:47 am

Actually, idle speeds are given in link @ post #13

Driver-jasongroves, Mar 24, 2012, 1:49 am

98 is total overkill for that engine. Run 95.

Driver-taim3, Mar 24, 2012, 11:22 am

I had the 93 model of this with the 1500DOHC engine. It too would idle quite high when cold, but at normal idle would be between 600-750rpm. Also should you be running on such a high octane! I ran mine on 91, no trouble!

Driver-family007, Mar 24, 2012, 1:23 pm

I run ahigher octane in mine every now an then to give the engine a clean out, mine idles at 500 to 600 when warm. temp always just sits under the wavy bar.runs on 91 can pink thou when we get crap low octane fuels- generally december , jan. feb. Oil leaks outa the distributor . Have blown frost plugs in the past. comfortable speed it likes for crusing is 120Km unfortuntlay.

Driver-gabbysnana, Mar 24, 2012, 7:43 pm

You have to short the diagnostic box before moving the idle screw.

Driver-karstuff, Mar 24, 2012, 8:09 pm

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