Are these symbols for a Check Valve?

[Output Shaft]

Try installing one of these on the vac hose between the EGR modulator and the EGR valve.
A Toyota VTV should be oriented so the flow is restricted when applying vacuum to the EGR... delaying the activation of the EGR. I think the colored end should be facing the EGR valve if I recall.

 

[Slow Left]

Try installing one of these on the vac hose between the EGR modulator and the EGR valve.
A Toyota VTV should be oriented so the flow is restricted when applying vacuum to the EGR... delaying the activation of the EGR. I think the colored end should be facing the EGR valve if I recall.

Hey, that's an excellent idea, OS! I think I might have a used one laying around...and since there's not a restrictor in sight...on this eve of the eve of Xmas Eve night (see how I worked that so it would still rhyme?...TIME REFERENCE NOTE: UTC-5:00 Dec. 22, 2014)

 

[Slow Left]

From page 3-13 on in the EGR section of the 1981 2F Emissions Control FSM

I think the restrictor on Port P of the EGR Vac Modulator comes into play when the BVSV is OPEN, the throttle valve is positioned above the Advancer Port and is just passing or has just passed the EGR port...this is where the pressure underneath the EGR Vac modulator is regulating the opening/closing of the EGR Valve...after 1,500 rpms and once the butterfly on the throttle valve has completely passed the EGR port, the EGR Valve is supposed to remain open regardless of the pressure acting on the EGR Vac Modulator from below.

I'm thinking that the EGR Vac Modulator needs the restrictor at port P in order to reduce the amount of 'dancing around' it does when it is being regulated by the pressure underneath or switching to that condition...just a thought....

 

[Slow Left]

this is what I have been wanting to say...do the VSVs test as good? could the egr vsv be opening inappropriately?/ stuck open; not closing all the way??? I ask cause you have replaced the other major components there...

Try installing one of these on the vac hose between the EGR modulator and the EGR valve.
A Toyota VTV should be oriented so the flow is restricted when applying vacuum to the EGR... delaying the activation of the EGR. I think the colored end should be facing the EGR valve if I recall.

Early assessment......
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.....
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I think we got it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Reinstalled the carb, fired it up, tuned it up and plugged the hose at the Air Cleaner that runs on the Choke Opener circuit, and put a Blue/Black used VTV before Port P at the EGR Modulator...

That CO hose at the Air Cleaner had some serious vac on it...that was a big ol' internal vac leak on the carb...

HALLELUJAH...now THAT'S how I remember a 60 should run...DANG SON!!

I'LL BET I COULD EVEN GIVE LAMBCRUSHER A RUN FOR HIS MONEY...IN HIS SUPPED UP MONSTER!

@LAMBCRUSHER @Output Shaft Thanks for sticking it out and fighting the fight with me, guys!

I won't know for sure until I give is some more good runs, but this is a nice, big step in the right direction.

Cheers!

 

[LAMBCRUSHER]

good work, flatshoe...awesome bit of tech right there...

 

[Output Shaft]

Who woulda thought that a missing little plastic thingy on the vacuum hose for the CO could be so pesky?
I gotta hand it to you Slow, you figured something out that 99% of the squirming mass of humanity would never figure out. Congratulations!

 

[LAMBCRUSHER]

This should have a link to FAQs. for future reference.

 

[mtnphilosopher]

Waaaaayyyy late to the show, but here is a picture of the orifice restricter in question (that's just not right -- I hereby deem the item in question "3mm vacuum flow modulator" or "3VFM." Sounds FSM-like just enough to confuse):

In my haste, however (and not yet knowing that the 3VFM was indeed a 3VFM), I didn't note an orientation/direction. This seems important, as one side has one large orifice, and the other side two smaller orifi(?) {insert something along the lines of, "that's what she/he said"}.

I'm assuming the direction of vacuum is from the air cleaner side to the choke opener, thus large orifice on air cleaner side, small HOLES on CO side?

And outstanding work -- now I have to track down the other suspect locations (e.g., EGR modulator port P, HAC circuit).

 

[LAMBCRUSHER]

I think two of them are in a tee; that one single is the one by the carb as seen in the foto. if that helps you find the bastards.

 

[Slow Left]

Waaaaayyyy late to the show, but here is a picture of the orifice restricter in question (that's just not right -- I hereby deem the item in question "3mm vacuum flow modulator" or "3VFM." Sounds FSM-like just enough to confuse):

In my haste, however (and not yet knowing that the 3VFM was indeed a 3VFM), I didn't note an orientation/direction. This seems important, as one side has one large orifice, and the other side two smaller orifi(?) {insert something along the lines of, "that's what she/he said"}.

I'm assuming the direction of vacuum is from the air cleaner side to the choke opener, thus large orifice on air cleaner side, small HOLES on CO side?

And outstanding work -- now I have to track down the other suspect locations (e.g., EGR modulator port P, HAC circuit).

Nice! Thanks for posting up that info, mtnphilosopher...

I'm not sure on the correct orientation, either. I have yet to swing by Toyota to see if they are still available. The vac is being generated on the side away from the air filter. Presumably, looking at the circuit above, the '3VFM' allows for a small amount of air to 'leak' into the circuit at the air filter, so that when the choke is turned off the vac doesn't remain pulling on the choke opener indefinitely...at least that is how I interpret it at the moment...

So I'm not sure what affect the orientation of the '3VFM' would have on that process.

On a further note,
@LAMBCRUSHER @Output Shaft , I've been getting 15 mpg (maybe even 16 mpg if I drive 55 mph) after the fix. Once the cold weather breaks for the season, I think I'll try removing that VTV that I installed in front of Port 'P' on the EGR Modulator and see if the performance changes...

 

[Output Shaft]

15 mpg.. whoo hoo! An FJ60 hypermiler

 

[LAMBCRUSHER]

15 is a good number for these monster mills...as long as they do better than my 350 at 10/gallon on premium, I'm happy.

 

[mattressking]

Bringing this one back to life.

Been going through vacuum related things and when I plugged off my EGR, the truck is smooth, the lightest hesitation is gone. However, I went through all other EGR related systems and replaced what failed, checked all vac lines and still a light hesitation occurs (mainly when cold). It is then a very light hesitation when warm, sometimes almost nonexistant.

Vacuum measures at 19inHg but dances around 18/20, it's not solid at 19. I haven't been able to locate any other vacuum leaks so I find this thread and am curious. The 'restrictor orifice' exists on my Choke breaker, but based on the vac diagram...and what was mentioned in this thread, should there be a restrictor on Port P into the EGR modulator?

For those curious, I did find a part number for the restrictor orifice, 90412-05001, however I am not having any luck locating it outside of some Japanese parts diagrams, perhaps it has been superceded, I'm not sure yet (I can't seem to remember the website with complete parts diagrams, if anyone knows it, please let me know!)

 

[Output Shaft]

Yeah, that little plastic choke opener vacuum line restrictor is NLA. Gone.

A slight hesitation on an old EGR valve is par for the course. You could try replacing the modulator.

What's happening is the valve is opening too far. Maybe because old diaphragms become less rigid. At any rate, when you get that hesitation, it's because the EGR valve is leaning out the mixture with dead anoxic air. Most of us try to take it easy on the gas pedal to try to conserve fuel, but driving with a light pussy foot & old EGR valve spells trouble. Just push the pedal down farther & faster to get more fuel & air into the engine. You won't be wasting gas, you'll just be giving the engine the A/F mixture it needs.

 

[mattressking]

Yeah, that little plastic choke opener vacuum line restrictor is NLA. Gone.

A slight hesitation on an old EGR valve is par for the course. You could try replacing the modulator.

What's happening is the valve is opening too far. Maybe because old diaphragms become less rigid. At any rate, when you get that hesitation, it's because the EGR valve is leaning out the mixture with dead anoxic air. Most of us try to take it easy on the gas pedal to try to conserve fuel, but driving with a light pussy foot & old EGR valve spells trouble. Just push the pedal down farther & faster to get more fuel & air into the engine. You won't be wasting gas, you'll just be giving the engine the A/F mixture it needs.

That's how I've been driving the truck, haha. Funny how quick you learn to modulate throttle. EGR Modulator is already replaced... :/