2LT-II cold weather RPM is low

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Jan 28, 2021
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Hungary
Hi everybody! Now there are more then 6000km in my reconditioned 2LT-II engine. Everything is fine, no oil leak anymore. However one thing frustrates me. The weather is more and more cold nowadays here in Hungary (-3C in the mornings). The engine starts smooth without any problem, however the RPM is the same as with warm engine (~750). Is it so normal? I’m afraid, that the cold starting system doesn’t work on the fuel pump. What should I look for? Have you got maybe any ideas?
 
Do you have a manual throttle knob? If so, just use that to turn the idle rpm up a bit until the engine warms up. I had a Hilux with a 3L engine and it started perfectly at -11ºC and idled smoothly at around 600 rpm until it warmed up.
 
Do you have a manual throttle knob? If so, just use that to turn the idle rpm up a bit until the engine warms up. I had a Hilux with a 3L engine and it started perfectly at -11ºC and idled smoothly at around 600 rpm until it warmed up.
Yes, I’ve got the manual knob, but I’m wondering why the idle RPM doesn’t rise automatically until the engine gets warm… :oops:
 
Yes, I’ve got the manual knob, but I’m wondering why the idle RPM doesn’t rise automatically until the engine gets warm… :oops:

That is a mechanical injection engine. I think all they have for cold weather is the ACSD? I believe it just advances timing until it warms up? Honestly, if it's starting fine, I don't think I'd worry too much about it....
 
That is a mechanical injection engine. I think all they have for cold weather is the ACSD? I believe it just advances timing until it warms up? Honestly, if it's starting fine, I don't think I'd worry too much about it....
I found this:

The ACSD uses the contractive and expansive properties of thermo wax and the tension of a spring to automatically advance the injection timing in response to the coolant temperature, causing the engine to idle-up (fast idle). This improves the startability at low temperatures and the stability of idling.

Operation

(1) Cold engine
The thermo wax contracts and pulls the plunger. Lever A rotates clockwise by the spring tension. This causes lever B to push the adjusting lever toward the idle-up position, resulting in a faster idle speed. At the same time, the roller ring is rotated, advancing the injection timing.
(2) Warm engine
As the coolant temperature rises, the thermo wax gradually expands to push the plunger out. Lever A causes the plunger to rotate counter-clockwise, gradually decreasing the advance angle of the injection timing and lowering the idle speed. When the coolant temperature reaches about 5C (12F), both injection timing and idle speed return to normal.

Verdict: my pump doesn't function properly... :confused: Question is, how to fix this issue?
 
Coming from a cold climate here, I wouldn’t worry about it. As long as it runs smooth and at a reasonable rpm at startup, it will be fine. Most people seem to delete their ACSD anyway, it can fail due to age and can send metal shavings through the injection pump causing catastrophic failure.

My brother deleted the ACSD on his HDJ81 and there was no noticeable difference in cold starts; it has always idled low when cold (around 500rpm). He started it unassisted last winter at -28°C.
 
Coming from a cold climate here, I wouldn’t worry about it. As long as it runs smooth and at a reasonable rpm at startup, it will be fine. Most people seem to delete their ACSD anyway, it can fail due to age and can send metal shavings through the injection pump causing catastrophic failure.

My brother deleted the ACSD on his HDJ81 and there was no noticeable difference in cold starts; it has always idled low when cold (around 500rpm). He started it unassisted last winter at -28°C.
I understand you. As I see, I've got 2 options. Better to ask: have I got 2 options?

1. Repair the ACSD system. (Is it possible? Is something broken in the part - 227905B010 - because of malfunction?)

2. Delete the ACSD system. (What is the way to do so?)
 
Two diesels without ACSD and also have a fleet of 79's at work.
They all idle lower when cold.
Glow, start, allow some time, then adjust the idle manually via the knob. Ideally bring rpm to 1000.
That's just the way it is.
 
Yes, I’ve got the manual knob, but I’m wondering why the idle RPM doesn’t rise automatically until the engine gets warm
Cold fuel is harder to burn. The engine sends about 3/4 of the fuel through the pump back to the fuel tank. Each time it goes through it gets a little warmer. Some engines come with a fuel warmer next to the fuel filter. You can add one if you want.

This type wraps around the filter

 
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