The Quest for more power

[Rzeppa]

Jeff, it looks like your 60 carb is a little different than my '77 FJ40 carb:

On my carb, the choke breaker diaphragm also controls the fast idle screw, or throttle positioner. This doesn't seem to be the case with yours.

By the way, this is different than a throttle positioning sensor. It's not detecting throttle position in any way, but it's rather holding the throttle plates open at certain times.

I don't think the choke breaker "controls" the fast idle screw. The fast idle screw controls the throttle position when the choke is pulled out manually by the vehicle operator. The choke breaker just opens the butterfly a little so the engine can get enough air to run.

And of course I know what a TP sensor does on a FI system LOL! I spent plenty of time with that on my daughter's 1985 4runner!

I had just thought maybe I was overlooking some subsystem or other as I tried to determine why my 60 sometimes stalls when you disengage the clutch. The conditions that my issue occurs is with the engine at normal operating temperature and the choke fully open, thus the choke breaker has no effect.

 

[subzali]

My system doesn't work properly because my VSV is toast for some reason, but it looks to me like my CB/TP diaphragm operates like this:
-at idle there is vacuum acting on the diaphragm, so it pulls the lever for the CB, as you say keeping just a little bit of air running through the carb as soon as the engine starts pulling vacuum. It also pulls the fast idle screw up and away from the throttle linkage so the fast idle is not in effect unless the choke is pulled.

-at high speed (activated by the VSV), there is no vacuum pulling on the diaphragm, allowing the fast idle screw to contact the throttle linkage when the throttle is at rest. During deceleration, the throttle plate would normally be closed. According to my Emissions FSM, this causes an overly rich mixture. But because the fast idle screw is allowed to rest on the throttle linkage at high speeds (because no vacuum is acting on the diaphragm), it keeps the throttle plates open just a tad to even out the A/F ratio.

Again, I have not been able to verify these results yet because my VSV is toast, but it's what the FSM says, and when I manually apply vacuum to the diaphragm I can recreate the action.

I figured you knew what a TP sensor did, but your earlier post made it sound like you were chasing after something that wasn't there, and I wanted to clarify my meaning.

 

[subzali]

Wow, lots of questions Brian! First let me catch up with some more photos and then I'll try to address your questions as best as I have been able to find out.

First, these pictures show my old bracket, as removed, and Dean's new bracket installed. My old bracket has a clip that holds the speedo cable, Dean's doesn't, so I might still repair my old bracket and re-install it. I think this is because in some years (like '76) the speedo cable doesn't go straight to the t-case; it first goes to a secondary speedo that controls things like the EGR maintenance warning light.

Wow, so this thread has taken a huge tangent since page 3. Getting back to the matter at hand, AHorseThief helped me the hole back up in my bracket (that's why I was in my grunge clothes at the meeting Wed. night). Now I just have to figure out how the big the hole is supposed to be and where exactly it's supposed to be located, and drill a new one. I already have new grommets to put on, then I can hook it back up and have the little hook for my speedo cable back again as well! One little step at a time!

 

[wesintl]

I just have to figure out how the big the hole is supposed to be and where exactly it's supposed to be located,

 

[kurtnkegger]

Matt, if you would like to reference my bracket for drilling your new hole, I would be glad to let you measure mine...If you aren't in a hurry, I could do a pencil rub on the bracket, and you could get the right orientation from that...

 

[subzali]

Thanks Kurt, but I have the one from Dean that I have installed and am using at the moment that I can measure

 

[subzali]

An interesting update from driving around this morning:
-I drove over to RMC, going up Quebec, across on Belleview, then up Federal, and back. I was testing to see if the secondary would open, so when I was accelerating I was taking the engine up to 3500 rpm or so on each shift, and flooring it the whole time during accelerations. A few times I stopped and checked the paper clip I had on the actuating rod, and it wasn't moving

So I had an idea: On the way home I got on I-25 at Belleview and took it down to Arapahoe, flooring it and revving the engine to about 3500 rpm, even taking it up to that rpm in 4th gear (about 80 mph)

When I got home (a few turns off of I-25 off Arapahoe), I checked the paperclip again. It had moved!

So, moral of the story is that I guess the secondary doesn't kick in (on a vacuum-actuated version), until you have a sustained load at high rpm. There must be a time-delay factor there, like an orifice or something built into the system.

Anyway, when the paperclip did move, it moved about 1/2 inch down the shaft: see the before and after pictures:
Before:

After:

 

[L43dean]

quest and associated paper clip

Is it possible that the clip is on snug enough to act like a restricter?

 

[subzali]

No, I checked my theory about the orifices just now, and sure enough according to the diagram in the FSM they are there. So the carb has to see sustained high velocity airflow through the venturis before it will open the secondary up. It won't just open because you mashed the pedal to the floor.

 

[subzali]

Any thoughts?

 

[DanS]

Any thoughts?

WHAT??!?!?! I can't hear you right now, I'm going real fast!

 

[subzali]

That's part of it

I guess my question is this:
According to my calculator and others such as this one: http://www.grimmjeeper.com/gears.html

A stock FJ40 (29" tires) should be turning 4000 rpm at 85 mph. But according to my tach/speedo combination 4000 rpm is only 75 mph. My actual road speed with 31" tires at 4000 rpm should be 90 mph, but if my tach and speedo are reading accurately my actual road speed is probably closer to 80 mph. What gives?

I guess I need to get a GPS...

 

[kurtnkegger]

I guess I need to get a GPS...

There's the answer Matt!! Stop all the math madness!!

 

[rover67]

That's part of it

I guess my question is this:
According to my calculator and others such as this one: http://www.grimmjeeper.com/gears.html

A stock FJ40 (29" tires) should be turning 4000 rpm at 85 mph. But according to my tach/speedo combination 4000 rpm is only 75 mph. My actual road speed with 31" tires at 4000 rpm should be 90 mph, but if my tach and speedo are reading accurately my actual road speed is probably closer to 80 mph. What gives?

I guess I need to get a GPS...

4k sounds like a lot for the 2F.

 

[Hulk]

4k sounds like a lot for the 2F.

90 mph sounds like a lot for an FJ40.

 

[subzali]

FJ60 redline is at 4k right? And Wes did 80 in his '64. And Toyota advertised the FJ40 to be able to cruise at 85 mph all day with 7 grown men inside

Not saying I make a regular occurrence of this kind of driving, but just want to be sure that it's possible.

 

[60wag]

Any thoughts?

That dash rug has to go.



My '82 2F sounded like it was going to come apart at 3200 rpm.
My rebuilt '84 2F was relatively quiet and quite smooth up to 4200 rpm.

I think your speedometer is misreading at that speed.

 

[DaveInDenver]

I guess I need to get a GPS...

Come now soon-to-be PE, 60MPH is how many miles per minute? Bueller, Bueller?

Mile markers, a flat section of highway, a steady foot and the second hand on your watch. Assuming you wind your watch (and let's be honest, who doesn't, right?), you don't even need power or satellites. That is the true Cruiser speedo checking method.

 

[farnhamstj]

 

[subzali]

That dash rug has to go.

Yes. I inherited that from the PO and haven't been able to justify replacing it considering everything else the 40 really needs...