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autotech2612

Idle Quality - Low To High When During Cold Temperatures

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^^^ Likely due to the compression needed to properly seal a composite intake on the 9th gen vs the aluminum plate on the 8th gen. intake manifold.

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Update:

 

Screeching and whistling noise is still gone.

 

Idle quality has improved and so has the temperature gauge in these colder temperatures Michigan has returned to.

 

No idle hunting

 

Still, sometimes it will idle up to 1800 for a few seconds upon start-up. Is this normal? It does go down eventually to 1400 until fully-warmed.

 

Also, how many miles do you typically drive in temperatures 30 or less before the gauge is up to the mid-point?

 

So, how does a bad intake manifold gasket affect both the idle quality AND temperature gauge operation?

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Yes, those rpm's are good and normal for initial startup and subsequent warmup in cold enough ambient temps... How long depends on initial engine temperature, if a block heater is used or not, ambient temperature, driving speed, heater blower speed, etc. It'll warm up better with front grille covered in sub-freezing temps.

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I could've mentioned to torque manifold bolts from center to outside in a cross pattern and in gradual steps up to specified torque... You could check them again after gasket is seated over a couple heat cycles.

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But what about the gasket having an affect on both the temperature gauge and the idle.

 

To really see if this is solved, I am going to install the genuine Toyota ECT sensor tonight and will update on that.

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Update: I removed the SMP/Intermotor aftermarket ECT sensor and re-installed the Toyota/Denso sensor. Gauge seemed a little slower to move, but it did get to the half-way point this time and it stayed there while in a drive-thru restaurant. Before I replaced the intake manifold gasket, the gauge would never get to the half-way point. And it was idle hunting severely.

 

27 degrees.

Edited by autotech2612

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Right on. Only 7 pages to get to this point... :blink: Have you covered your front grille or part of the radiator for the cold season?

Edited by dom

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Not yet, I have the cardboard ready to do it like last winter.

 

I did gradually torque starting from center as you stated above. I use my fingers on the socket until snug, then very gradually start torquing.

 

My question again: How does a bad gasket affect the temperature gauge's behavior?

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It doesn't... No relation whatsoever between a vacuum leak at intake manifold and coolant temperature sensor.

Edited by dom

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Apparently I spoke too soon about the temp. gauge.

 

Temp is 22 degrees.

 

Engine completely cold

 

Started up, idle is normal for this outside temperature.

 

Drove for about eight minutes city driving speeds 35 in fifth gear. Also did some coasting.

 

Got to destination one: idling at 1100. Temperature gauge is moved only up by about half an inch.

 

Idled for two minutes, then back on the road, and needle dropped a little. Apparently two minutes of idling causes the coolant temperature to drop?

 

Drove 5-6 minutes, coasting at times, in fifth gear at 35. Needle moved up a little, so now it has roughly moved up to one inch, but still well below the half-way point.

 

Enter the highway on-ramp and get up to 55. Now, the needle is starting to move. After three minutes on the highway, it's at the half-way point.

 

Arrived at next destination. Pull into parking lot Idling at 800 and needle is at half-way point.

 

Turn it off. Re-start in about ten minutes. Now an Equal mix of highway and city driving for the next ten minutes. No issues. I pull into my garage and the needle is still at the half-way point and it is idling at 800.

 

 

This reminds me a lot of the 98 Geo Metro I had that also had a clogged heater core like this car. The needle barely moved when cold in low-speed driving, but when it got on the highway, needle moved quickly.

 

Idle issues are resolved.

 

Please note, I did replace the thermostat last winter with a genuine Toyota part.

Edited by autotech2612

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Having the blower motor at higher than low speed cools down the engine while idling in cold enough ambient air. It'll be better with the radiator partly covered.

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Dom, the blower motor was never on. Off the factory line, radiators aren't covered with cardboard for winter months, and 22 degrees is hardly cold. Last winter -- in temps of -7 at times without windchill -- I did not experience this problem. With a non-Toyota sensor, the gauge moves faster again.

 

So, are we back to an electrical issue?

Edited by autotech2612

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There's an issue? You didn't have the same ECT sensor last winter... Just cover your grille or something. It's cold enough for it.

Edited by dom

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Dom, I had the same ECT sensor until it got cold in November.

 

A gauge moving that slowly is not normal. I stated above the temperatures last winter, and for part of it, the radiator was not covered.

 

Today after a highway drive, when idling, needle fell again. That's not an issue to you?

 

Covering my grille "or something" does not solve the actual problem.

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