2jz engine coolant temperature multiplier?

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jerry
Posts: 4
Joined: Mon Jul 05, 2010 4:11 pm

2jz engine coolant temperature multiplier?

Post by jerry »

Hello to all :)
I have some problem with cold start when external temperature is low (say about 0 C degree).
Engine always misfire - do not run on all cylinders.
Usually it ending with remove flooded sparkplugs and warming it on fire.
When it start.
When weather is not cold (say above +10 C degree when coldstart is normal)
I suspecting that maybe engine coolant temperature multiplier is not properly set for cold weather?

It looks as:

C degree/value

-30 = 2.0061
-20 = 2.0061
-10 = 1.97583
0 = 1.94531
10 = 1.91504
20 = 1.875
30 = 1.7478
40 = 1.62085
50 = 1.49341
60 = 1.37769

Not sure for 2jz gte vvti that multiplier sould be as high? :idea:
Injectors are 731cc petrol only, relative fuel pressure is 3 Bar all the time.

Thanks for advice
best wishes
Jerry
stevieturbo
Posts: 1354
Joined: Sun Dec 07, 2008 2:04 pm

Re: 2jz engine coolant temperature multiplier?

Post by stevieturbo »

Is the engine correctly in 720sync when started ?

What are AFR's when started and warming up ?

Datalog it and adjust from there

And a 37% increase in fueling at 60degC, seems absolutely massive.
jerry
Posts: 4
Joined: Mon Jul 05, 2010 4:11 pm

Re: 2jz engine coolant temperature multiplier?

Post by jerry »

Hello Stevie
Thank you for reply :)
Yes it is in 720 sync.
I thinking about second issue I have: valve steam oil leacking.
I have that problem, so sometimes car at start give white/blue smoke. Only at start first second and only sometimes.
Perhaps that problem become bigger when cold weather and too much fuel and some oil on spark cause that problems?

I think it is not injectors/coils problem because this year I change stock injectors and coils for 731 cc new bosch injectors and GTR35 coils and problem still exist as on stock items on cold weather.

Not sure but first any advice how that Engine Coolant Temperature Multipier should looks for 2jz?
now it is:
Image
stevieturbo
Posts: 1354
Joined: Sun Dec 07, 2008 2:04 pm

Re: 2jz engine coolant temperature multiplier?

Post by stevieturbo »

It is whatever it needs to be. That's up to the tuner to decide what the engine wants to start and run with sensible AFR's so that the engine is happy.

There is no one size fits all.
herrylauu
Posts: 1
Joined: Mon Apr 24, 2023 4:41 am

Re: 2jz engine coolant temperature multiplier?

Post by herrylauu »

The coolant temperature multiplier is used by the ECU to adjust the fuel injection and ignition timing based on the engine's operating temperature. As the engine warms up, its performance characteristics change, and the air-fuel ratio and ignition timing need to be adjusted for optimal efficiency and power.
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rcaliole
Posts: 4
Joined: Mon Nov 06, 2023 4:48 am

Re: 2jz engine coolant temperature multiplier?

Post by rcaliole »

Professionals recommend keeping your engine at a temperature between 195 and 220 degrees. In a perfect world, the needle on your gauge would sit dead center.
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