1HDFT... BACS, ACSD, SICS Systems Explanation?

[Gifu]

First, definitions:
BACS Boost and Altitude Compensation Stopper
ACSD Automatic Cold Start Device
SICS Starting Injection Control System

First... I realize that the 1HDFT can survive without any of these systems... BUT, i often go to the mountains near where I live, and it will be sub-freezing and very high altitude.

so, can anyone explain the SICS system that appears on later model Denso IPs? (starting injection control system).

I have a 1996 1HDFT. From what I can figure out, the SICS is operated by vacuum, via a VSV. I think... that when there is no vacuum, the lever causes increased (or, maybe decreased?) fuel (for starting). When it is given vacuum... it pulls the lever away, so while engine is running the injection is decreased (or increased)? I think. I'm guessing. So, my question... when should the VSV operate? When should the SICS get vacuum

While we are at it... lets talk about the ACSD thermo wax. I do understand how that works, when the wax is cold, it pushed out the lever and brings the idle up. But, it also effects the timing advance, correct? So, would this be nice to have operating as well? Mine seems intermittent... the idle sometimes stays at 1000, sometimes it comes down (30 minutes after starting). I could remove it and put a block off plate there... or i could try to save the thermo-wax thingie. I'm all for neat systems that are automated and such, but i'm also a fan of simplify simplify simplify. I could control the idle speed with a handthrottle, but the timing advance that the ACSD performs might be missed.

Lastly... how the heck does the BACS system work? This appears as a second port on your boost compensator, but it's *below* the boost diaphram. So... i'm not even sure if it gets boost or vacuum.

thanks all. no one has this engine where I live (USA has no diesels from Toyota). It's rare as hens teeth. [/b]

[+dj_hansen+]

First, definitions:
BACS Boost and Altitude Compensation Stopper
ACSD Automatic Cold Start Device
SICS Starting Injection Control System

First... I realize that the 1HDFT can survive without any of these systems... BUT, i often go to the mountains near where I live, and it will be sub-freezing and very high altitude.

so, can anyone explain the SICS system that appears on later model Denso IPs? (starting injection control system).

I have a 1996 1HDFT. From what I can figure out, the SICS is operated by vacuum, via a VSV. I think... that when there is no vacuum, the lever causes increased (or, maybe decreased?) fuel (for starting). When it is given vacuum... it pulls the lever away, so while engine is running the injection is decreased (or increased)? I think. I'm guessing. So, my question... when should the VSV operate? When should the SICS get vacuum

While we are at it... lets talk about the ACSD thermo wax. I do understand how that works, when the wax is cold, it pushed out the lever and brings the idle up. But, it also effects the timing advance, correct? So, would this be nice to have operating as well? Mine seems intermittent... the idle sometimes stays at 1000, sometimes it comes down (30 minutes after starting). I could remove it and put a block off plate there... or i could try to save the thermo-wax thingie. I'm all for neat systems that are automated and such, but i'm also a fan of simplify simplify simplify. I could control the idle speed with a handthrottle, but the timing advance that the ACSD performs might be missed.

Lastly... how the heck does the BACS system work? This appears as a second port on your boost compensator, but it's *below* the boost diaphram. So... i'm not even sure if it gets boost or vacuum.

thanks all. no one has this engine where I live (USA has no diesels from Toyota). It's rare as hens teeth. [/b]

SICS is used for warm starts and reduces the fuel supplied on start up so there is no black cloud, this is controlled by the VSV on the inlet manifold, the boost part of the BACS is used to control fuel delivery at low RPM (and also at different RPM's) to minimise black smoke, the ACSD i havent come accros, but a quick search on the LCOOL forum suggests that it is controlled by a coolant sensor and there should be 2 coolant pipes running to the pump; and there also should be another VSV attatched for the air-con idle up, and if you have an auto model there may be a vsv to reduce throttle input when in 1st gear low range.

Some info here on ACSD: http://www.lcool.org/forum/viewtopic.ph ... light=acsd

[bj on roids]

Lots of high tech questions there, basically the only one I can help you with, is on start up it is increasing the pump to full fuel, then dropping it right back.

[Gifu]

hey guys... thanks for the...uhm... conflicting information. Can we get a tie-breaker on the SICS? Does it decrease fuel during start or increase fuel? since my VSV isn't there...at all... should I:

A) leave it capped
B) connect vacuum to it all the time
C) zip tie the lever forwards or backwards

For the BASC... how does it actually work? sending it vacuum would increase fuel (because it's below the diaphram), sending it boost would decrease fuel. I guess... I'll just not connect it to anything.