ChefYota4x4

iTrader: (5)

Hey Thook,

Yeah, when I pull the FPR Vacuum line from the VSV, the idle goes up, due to added vacuum, yes, I getcha. I'm going to check again, but I believe I pulled the line from the FPR as well, leaving it on the VSV, which rose the idle due to added vacuum. When plugging it back on the FPR, the idle drops dramatically. I think the reason why I did this, Thook, is to see if; When I pull the vacuum line off the FPR, and it rose in idle, I could then plug the vacuum hose while off the FPR and see if the idle changed as well, .....I'll have to re-check due to life/work/vehicle info overload, but I don't remember the idle dropping when I plug the line that is pulled from the FPR and still connected to the VSV. That seems strange to me, Thook. The only thing I could think of(I'll have to read through the VSV section again and see if the VSV can do this, but...) is, IF the filter end of the VSV is supposed to pull vacuum when the line itself is plugged.

I actually did a video of this, a few pages back. In said video, I was initially confused about which hose to disconnect, but I figured it out and checked what I believe Flecker or yourself or SOMEONE was telling me to check. I will repost it, asap.

I'm going to mind-melt for a while and then come back at it later, lol.

Thanks Thook,

Mark

ChefYota4x4

iTrader: (5)

I will just remove the idle air screw and see if it is all gooky in there and then replace the grommet/o-ring. However; I think the noise and so on is due to the screw having to be so far out under certain conditions. Ahhhhhh, lol. I believe I have some thread-tape, ...I'll try to find some. I think I'll pull it, anyhow, just to see what condition it's in under there.

I was just thinking that, since the idle doesn't seem to drop when the line is pulled from the FPR and then plugged, ....I could just unplug the inlet-hose on the other side of the VSV, plug it, then plug the FPR back into the Plenum, directly. I'm just really curious why, when pulling that line off the FPR, then plugging said line, ....the idle doesn't drop. I think that's the only way to FULLY verify that the FPR is doing it's job, AND, that I'm not, also, losing vacuum through the filter of the VSV.

What I did notice, Thook, is that, ...With the vacuum still on the VSV but unplugged from the FPR, ......even under load, around 2500 RPM, the VSV line was still pulling vacuum equally as hard on my finger.(I'd have to hook a gauge to it to be sure how much, lol). I thought it(VSV) was supposed to stop pulling vacuum as the throttle was opened, no?

ChefYota4x4

iTrader: (5)

Oops, forgot to mention, .........

I'm not using my A/C, as it's empty and apparently has a leak. However, when I DID try to test the switch with the button on the dash, it did alternate in idle when depressing the button. Not drastically, but more importantly, there was a change as you could feel the load on the motor with it depressed.

thook

A vacuum is created in a space when there is less air in the space than when outside the space. When there is less air inside the space, there is less air pressure. The air pressure outside is greater than inside, so a vacuum is created. Open the space slightly, air will be sucked in because of the difference in pressure. Nature abhors a vacuum...the vacuum must be filled once there is an opening to do so. Once the vacuum begins to fill, the pressure differential begins to equalize and less vacuum is occurring. Eventually, if the inside space were to fill completely or equivalent to the outside space, there will be no vacuum.

In a motor, when there is less air coming into the motor (intake) than what is leaving (exhaust), a vacuum is created. Introduce more air.....whether through throttle opening or an opening/leak in a vacuum line, there will be less vacuum created. More air is entering to fill the vacuum. A complete vacuum loss occurs when the volume of air leaving is entirely greater than the volume entering. The motor will not run or combust when there is no vacuum. It won't draw in air.

The manifold is the source of vacuum....period.(Well, really it's the drawing and expulsion of air from the cylinders through the valves, but for the vacuum operated components, it's the manifold they connect to) Disconnect a part from the manifold at any location (or create a leak between it and the manifold) and you lose vacuum to the part because you've disconnected from the source of vacuum. As well, were the opening in the manifold to remain, there is less vacuum present in the engine and, consequently, the manifold. Air is entering and filling the space. So, components relying a certain strength of vacuum or lack of it can suffer in performance. Like combustion or power steering or braking or the regulator, etc.

The VSV does not create or add vacuum. It's creates a loss of vacuum pull from the manifold by opening to cause the regulator to shut under necessary conditions.

Fuel is delivered from the tank (pump and fuel delivery lines), through the rail to the injectors, and circulates back to the tank via return line. The regulator is placed midstream of this route with the return line being on the end of it.

Vacuum from the manifold opens the regulator. It pulls on the spring loaded diaphragm allowing more fuel to enter the rails and creating less restriction.This creates a reduction of fuel pressure in the rail. The restriction of fuel flowing through the rails to the return line to the tank is what creates pressure. The opening and closing of the regulator is what regulates the fuel pressure because of this restriction (opening) or non-restriction (closing).

Provided there are no leaks, at idle, vacuum is at it's strongest.The throttle plate is almost entirely closed. (Less air is entering than leaving). The idle bypass screw is the only other source of air entering (other than the AAV when the motor is cold). And, this is how air induction is regulated....by the idle screw and throttle plate setting.

So, at idle with the strongest vacuum, the regulator is open the most, the least amount of fuel pressue necessary/present. Introduce more air through throttle opening and there is less vacuum on the regulator.The regulator begins to close and creates more pressure.

Before start up, the regulator is shut. No vacuum is on it. This means the maximum amount fuel necessary to fire the engine is in the rail. Turn the key, the engine begins cranking and creating vacuum. This pulls the diaphragm in the regulator open just enough to allow flow, but still create enough pressure to start. Were the regulator to not open at all, the motor would probably flood.

However, in the case of hot soak conditions, fuel in the rail can become vaporous or gaseous and less dense.....more of a lean condition and therefore less pressure regardless of the regulator's position/restriction. In this case, there may not be enough pressure to start the vehicle reliably. The engine needs a certain fuel ratio or richness (determined by pressure and fuel volume) to fire properly. This is where the VSV seems to be important. By opening (creating the small vacuum leak/loss) in hot coolant/engine conditions (controlled by ECU according to ECT voltage signal and STA signal relationship), the pressure regulator will remain more shut to raise fuel pressure to maximum amount necessary at the time of hot cranking. During normal cranking conditions (other than hot soak), the regulator would normally open because of the vacuum pull in the manifold. Create the slight loss of vacuum via the VSV, the regulator can't open as much as it normally would, if at all, and therefore the pressure and fuel ratio are back up to maximum. Of course, the fuel from the tank is cooler than what is in the rail. So allow more fuel (that is cooler than the vapor) to be restricted and the vapors condense become more liquid again.


That is how the fuel pressure up system is designed to work.

Given all that I've said here, if a regulator does not respond to vacuum or loss of it, it is bad. Response is noted by a change in the running of the engine when vacuum is applied or removed. No change means the regulator is not responding. Your regulator is responding. The VSV is a different story. If it did not open when voltage is applied, it is bad. Atleast, it will not open under hot cranking conditions where voltage would be supplied by the ECU based on ECT and STA input. However, it is atleast closed in normal cranking, so it is not a problem then.

Like I said, further research on my part is necessary to varify if your/our model vehicles energize the VSV under heavy load. This would be ECU controlled determined by Vs, PIM, and Ne input. Not sure what Vs or PIM is at the moment, but I atleast know Ne means RPM signal from the distributor. Vs may be from the AFM.

Okay....more later. I gotta go.

ChefYota4x4

iTrader: (5)

Wow, ....DANGGG, LOL. That was a VERY informative read, Thook! Thanks.

I think my problem is mainly in explanation, but reading through what 'YOU' said, thereafter the yeller, ....You get what I'm saying.

Ok<> I tried something, today, while out picking up meat, fat and fresh spices to make my famous Sweet & Spicy Italian Sausage.... hehehe, ......

I totally disconnected the VSV, connected the FPR vacuum line to the Throttle Body, blocked off the empty port on the three port filter toward the rear, created by the removal of the vacuum line that feeds the VSV.....and I drove around.

It was WAY more responsive, seemed to "pup-..........pup-pup-pup.....pup-pup" less(it's still there ,just far less 'jerky'), and drove well off the line and through all gears without any bogging or hesitation.(It's still a bit of a puppy up the hills--which I realize might have something to do with 1.) Having 4.10's with 31x10.50's, and 2.) BECAUSE IT'S STILL A LIL 4BANGER SEWING MACHINE! HAHAHAHA .......)

HOWEVER; "DUN-DUN-DUNNNNNNNNNN", HAHAHA, ....When I drive around, fully warm, giving it plenty of throttle and getting through all the gears(you know, basically, 'driving it a few blocks and getting to 4K rpms at times, etc.)...when I stop, it seems to have idled up again to even 950 at times. As usual, when I kill the motor, restarting it again, without touching the throttle.....the Engine Light is gone(when I tap the throttle to 2000 or more, back comes the light). I stopped at a store for about 20 Minutes, walked back out and it starts on the first crank of the starter, LITERALLY, ...and then idled at around 750-800. Again, after driving around a bit, it idled back up to 900 when I'd come to a stop..........

See, when I start it, cold, the idle is much lower(the IACV is working, but only to about 900 and then down to 600 or so when warmed up a bit). So, I have to screw out the idle/air screw in order to get it to idle at around 750-800. I guess, by the time I warm it up, fully, then drive around a bit, whatever is going wrong is causing it to eventually come up in idle and needing of screwing back in of the Air/Fuel screw. (I KNOW, strange! lol).

I'm cooking dinner, so I'll have to come back and add some other side notes that I left in the truck.

Thanks again, Thook, for that great read. I'm learning, .....writing it down on the inner tablet so to speak, .....I'll get it eventually! lol.

Mark

(all in all, it seems to run a bit better with the VSV out of the picture.)

thook

Well, alright. Success! So, I'd suggest keeping the VSV out of the equation until you get a reliable replacement.

Next thing to check is that idle bypass screw. I'm sure you know to mark and then count how many turns the bypass screw will turn inward before you remove it? That way when you reinstall it, you turn it all the way in again, but back it out as many as you counted to the mark you made???? Anyway, try the tape, if you have it on hand. It would be a quick indicator for you. The screw needs to seal or you will get the funky idles. When you're sure of that, then you can move on. One more down, and only a little more to go.

I'm still digesting all I've read on open loop/closed loop, O2, diagnostic codes, etc. Still have more reading, too, to get the complete picture. When I do, I'll do my best to compile and make a post like I did above.

Thanks for compliment, Chef. Took me a couple of hours to collect all my thoughts on the matter based on what I'd read, cognize how it all works, type it out, and then edit so it made sense.

Alan's Classic

I wish I could read something and completely comprehend it. I read this stuff and my mind goes haywire LOL. I'll keep reading and maybe it will click someday. I definately know more now than I did 2 months ago. Y'all rock!! Congrats Chef on the progress!!

ChefYota4x4

iTrader: (5)

Hahaha, you're funny, Alan! I hear ya, btw! This is me after reading so many new things>>>> hahaha. However, what I do, when reading something that is, basically, brand new to me(like taking Calculus for the first time, lol)....I think about what's being said with analogies. For instance, 'A Straw, removing all the air from a Ziploc Bag', etc., etc.

Yeah, Thook, it felt good to finally feel some DECENT, steady, uninhibited 'GO-GO' out of it, you know? I'm still curious, however, if there is a way to VERIFY, once and for all, 'Is this the right ECU?' I know Flecker got it out of an 87, and the guy is VERY knowledgeable, ....so no doubts there. I just wonder if later in 87 then went with some new, higher resistance things, etc., and used the 88 and up ECU. When I say "88 and up ECU", I'm not even sure that exists, lol....However, reading my Haynes, it appears to say "88 and Newer Models" for the type of codes that I'm getting, ...you know, such as, "2 blinks, pause for a split second, then 1 blink", or "4 blinks and then 3"(or whatever it was) for the AFM and so on with the removed TPS, etc.

The one thing I know for sure, ....even when removing nearly everything when tearing down the intake,(TPS, Switches, CTS, etc.), the one we removed NEVER threw a code....so I'm fairly comfortable in saying that it just wasn't working properly for whatever reason(FRIED?) LOL.

ChefYota4x4

iTrader: (5)

EDIT; I removed the Idle Air Screw, Matthew, ...but I didn't mark it. I pulled the screw and the o-ring was in seemingly good shape. However, underneath was TONS OF CARBON.... I cleaned it all out, and the Screw now goes down all the way, but IT'S STILL tight after only a couple turns in. I put a small coating of motor oil on the o-ring, but it's still going in hard(not quite as hard). I don't think with this throttle body(the donor with the new TPS) that the Idle Air screw port was ever cleaned, as TONS of crap came out of there. As I got near the bottom out point, ....it was squeaking a lil bit(the o-ring on the cylinder wall, I would imagine). I wasn't able to start it and check anything, as when I just got it back in I had to run in and pull the Sausage Provencial, with roasted New Potatoes in garlic and fresh italian herbs/Parm. Reggiano, plate the Caesar Salad and serve it up! lol. I just sat down to let you know what I'd done. OOPS on the not marking the screw. However, it seems to be nearly pointless, to some extent, since it's still idling at whatever it wants once warmed up or when cold, lol. (I know, ....it's not pointless...I just mean that I'm a dork and forgot. HOWEVER, I have PRETTY MUCH photographically memorized where that screw was, .....So I'll back it out to where it was, then turn it '? turns' and mark that down,.....ok?

Alan's Classic

I probably missed it somewhere, but have you searched the PN of the ECU on the web to see what info you can pull up? I'm not doubting anybody here just offering the option.

ChefYota4x4

iTrader: (5)

Yeah, I'll take down the number tomorrow, Alan, and give it to my Buddy at the Toy-Parts Counter to look up, see what he can find.

Even then, SOMETHING is causing it to have that lil 'pup-pup', type of miss, which would definitely be something else. Good idea, Alan.

I'm going to pull the A/C VSV, tomorrow, and see if I don't find something similar to the FPR VSV.....Because, .....well, while it is supposed to be closed during times where the A/C isn't in use, and it appears to be switching on when the A/C is turned on.... if it's not closed FULLY, for some reason, ..maybe it's causing vacuum leaking right through the filter on the end of it or something like that?

Well, I just started it with the screw out 3 turns from total bottom....I should say I tried, lol. It had to be screwed out a couple more, and then, when warming it back up a bit, I got it to stay at around 750rpm. When I drove to the store, sitting there I noticed that it was back up to 900rpm again. It also, earlier today, seemed to be dropping more in idle when turning the wheel at a stop. It wasn't doing that, not really noticeable, before.

I gotta clean up, THANKS, GUYS, ....Y'ALL ARE GOOD PEOPLE! I appreciate the help, immensely!

Mark

thook

Go ahead and block the lines to and from it. Use a BB or something. Checking it won't hurt anything, and it's easy to do.

I've wondered about the ECU a little myself. I even wonder if on that ECU your code 21 isn't equivalent to a code 5 on my year.....'86. If a code 5 comes up on my vehicle, it's means a problem on the O2S circuit. However, it could mean a problem with the circuit, the sensor, OR the sensor is detecting a reach or lean condition. I wonder if your ECU is like that in that it's maybe not newer enough to use a code 25 or 26. You see, I get lost on year differences, but I've said that before.....

This oughtta be interestin'.

ChefYota4x4

iTrader: (5)

Hahaha, it's always interesting with Rojo, my Rig! lol, hahaha.

Yeah, I'll do that with the A/C VSV....., and I'm going to find a once and for all verification method for the booster as well. I had a major Guru checking it out, today, but he really doesn't have time to diagnose it for me.(Not without charging me, hourly). He was impressed with everything I'd done and by the knowledge I've obtained since the last time we'd spoken in February, lol. Nonetheless, he's not going to be able to help me out with a major diagnosis panel without my forfeiting an arm and leg! hahaha.

For now, I must hit the sack before my long day, tomorrow. Talk to you soon, Thook, guys!

PS> I believe I've read that after either 88 or 89, the resistance on quite a few sensors went up/down, and subsequently, that's why the ECU was modified, ....yadda, yadda, yadda! hahaha.

thook

A fellow that goes by sb5walker here at YT (he's also on toyotanation) says the changes weren't made until '89. I believe it was in Alan's (?) thread.....maybe. The injectors require a higher voltage, atleast. Seems most everything was the same, though, requiring only 5volts. I'm lookin' into it ma'self.

I'll be gone all day today. Gotta go pic up critter food about 1 1/2 hrs from home.

Later, skaters........

ChefYota4x4

iTrader: (5)

Oh, ok, ....thanks Thook. Drive safe!

ChefYota4x4

iTrader: (5)

Hey guys,

I took Phil's advice and took a break from the motor(oh yeah, only after BREAKING OFF one of the vacuum inlets on the A/C IDLE UP! Ahhhhhh, lol.

I put in the Zuk's, and DANG IF I'M NOT ALREADY HAPPY! I'll get pics asap, but had to do some work before I go see Predators tonight. Heading out to get pics, now.

THANKS PHIL! lol.

Mark

ChefYota4x4

iTrader: (5)

I will post some before pics, later, but my neighbor showed up, torch in hand and I pulled out my SawZaw, Diablo Blades, he took out his and we did the whole thing in 1 HOUR! Dang straight.....2 GUYS CAN KNOCK THIS OUT IN AN HOUR, 1.5 ,MAX, I PROMISE! lol.

After Pics.........






Yep, with the top off, it went from 10" from top of rim to wheel well to 13", ...and the ride is SO MUCH NICER!

THANKS ZUK!

PS> Yes, SawZaw with 9" Diablo or Torch blades cut through these in 2 MINUTES, each side. Just start from the inside of the bumpstop and work your way out, rocking back and forth with the saw, ...VOILA! BEST 60$ MOD I'VE DONE! I'll get pics of the springs when I have time, tomorrow.

ChefYota4x4

iTrader: (5)

PSS> I think I'm losing a U-Joint....time to get in there and check that out as well. Grrr,lol.

ChefYota4x4

iTrader: (5)

Lil video for now....still have more and I'm going to do a "Zuk Thread"....

92 TOY

niiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii iiice!!!!!!!!!!