L-series VSV problem and a mystery vacuum valve? (1 Viewer)

[advlars]

Hey guys. Working on my 5lt franken-engine. Trying to trouble shoot and put back together my vacuum system. Old engine had no EGR system and the new engine had it all deleted. It would help a bunch if I could ID all the parts and know for sure what the truck wants/needs in terms of vacuum.

First off, I have a valve that I cant seem to ID. Ive googled and searched toyodiy etc. Closest thing I could find was "valve sub-assy, high altitude compensator" off a russian website with no pictures. I dont have HAC but it connects to my boost comp. Best I can figure out by taking it apart is it lets a little bit of air bleed into the vacuum line and regulates how much vacuum the pump has? Can anyone confirm or deny? And tell me how to test that its functioning?





Secondly, I have 2 vsv's on the vehicle. One (attached to the mystery valve) turns on and off when the accessory switch is on. Presumably this just lets the system de-pressurize when you turn the key off? The other (closer to the vacuum pump) I cant seem to make turn on at all. Which prevents any vacuum from getting to the boost compensator For now Im just bypassing the vsv's.

 

[GTSSportCoupe]

Personally I think I'd just scrap all the VSV/HAC stuff and run a boost line from the intake manifold direct to the boost compensator. Now that you've gone turbo I don't think there is a need for the old HAC stuff? Maybe I'm just over simplifying it though.

 

[advlars]

At the moment I just have a boost line straight from the manifold to the top of the boost compensator as youve described.

What im trying to figure out is the vacuum side of the boost comp system (below the diaphram). I ran a vacuum line straight from the vac-pump to the boost comp for testing but probably dont want to leave it like that long term?
The vsv's and mystery valve were in place for the 2lt, im just trying to figure out how to adapt them correctly to the 5lt. Id like to eliminate whatever is not necessary and make sure the necessary bits are functioning correctly.

Lars

 

[advlars]

Does the vacuum line to the boost comp need some sort of regulation? i.e. can the vacuum pump produce too much vacuum for the injetion pump?

 

[CycloSteve]

There is a similar one on the 1HD-FT. I ran mine without and it was really sooty at altitude. Reconnected into the system, and now working on re-tuning the IP.

1HD-FT /1HD-T pump

Full vacuum comes from the vacuum pump to the diaphragm (30+ inches), and the diaphragm reduces it to around 10 inches. This then feeds to a nipple below the boost compensator, helping to pull it down and enrichen when below 4000'. When above that, there is no assistance in the boost compensator, thus less fuel and potential for soot. The pin-spring is heavier than with injection pumps which do not have the BACS.

If you plan on taking it to altitude/spending time above 4000', then you may want to keep this part of the equation.

 

[advlars]

Great info @CycloSteve! Thanks for that. Do you have any info on testing the function of these? And can you confirm for sure whether the center pin is the injector pump side or the vacuum pump side?

 

[CycloSteve]

On the 80 the center pin is the vacuum feed from the pump, and should be the same. I tested by taking it to 7200' and checked to see if any vacuum made it through, which it did not. I could not find any FSM test procedures, nor replacement parts as of yet.

 

[advlars]

hmmm... ok. cool. feed from the VACUUM pump you mean? i.e. not from the injector pump? mind if I ask what the part number is on yours? Might be worth swapping mine just if I cant find a way to trouble shoot it. Mine was pretty dirty and reeked of diesel...