Idle issue, resolved? *not like the others*

thedanned · 11-14-2009, 01:55 PM

Hi all, relative newbie to this site though I have been lurking/reading for a while. I, like many others it seems, have a surging idle problem when warm and brakes applied.

About the truck and problem:

1989 4Runner 3vz manual

Cold idle is about 1800, warm idle is about 1100

Throttle stop and dashpot are not touching the throttle bracket (was this way when I got it)

Idle screw all the way in to slow (like this when I got it)

Cannot find a single vacuum leak, my coolant level is ok and timing is set at 10* BTDC. All vacuum solenoids are functioning properly and at the correct time. My coolant passage through the TB is ok as well.

This all had me stumped because I had spent so much time reading other peoples posts on this problem and had tried EVERYTHING other people have tried. So I then notice that my throttle 'sticks' shut after it has been sitting for a couple hours. So I try it by hand. Sure enough, the throttle butterfly is sticking in the bore. I pull the TB off and when closed (completely, throttle stop screw is not touching remember) there is a 16th of an inch gap between the left and right sides of the butterfly, almost like the butterfly is egg shaped. I can see light between the two. It seems like I have found my culprit: I cannot restrict the air enough to get my idle down to where it should be.

My question is : has anybody else taken their throttle body off and looked at the bore? Has anybody noticed a gap? Or am I reading into this too much looking for boogymen?

I cant begin to imagine what series of events led up to the throttle stop, dashpot and idle screws being adjusted to their respective extremes. Should I adjust the throttle stop screw back to factory specs (with feeler gauges and such) and go from there or should I go to You Pull It and find another TB?

This ad is not displayed to registered members.
Register your free account today and become a member on Yotatech!

DJ99 · 11-14-2009, 03:15 PM

Funny that you should mention this. A while back, when I was trying to nail down my mileage issues, I checked out, and actually replaced the TPS. When I checked it out, the throttle body bracket (?) was not actually contacting the stop. It was at least 1/8" out. This is on a VERY low mileage '93 3vze, like 46K. I ended up resetting the stop to contact the bracket when replacing the TPS, which was probably not the issue. Bottom line is: This probably is not your issue. As long as the butterfly closes, the stop is not your problem. OTOH, mine DID NOT have a 1/16" gap on the sides. That ain't right, AFAIK.

Targetnut · 11-14-2009, 03:58 PM

Yes, set everything to factory specs and see if that helps.

If the idle is still to high it could be because the auxillary air valve, (which may be part of the throttle on that model) is not closing all the way.

Jeremy11 · 11-14-2009, 04:14 PM

I also have a similar problem..
When cold my engine is idle about 1300
Once it warms up its good at 800. BUT when im driving for a while and i apply
the brakes sometimes my truck will turn off completely.
Inorder for my truck not to shut off I havee to put it into Neutral and it will
idle at about 800 where its supposed to be.
I have a 1990 4Runner 3.0 V6. I dont know where to go from this.
Any help is appreciated.

PS: When slowing down the truck drops down to about 500 and drops and rises from there. Then soon dies..

limon32 · 11-15-2009, 12:17 PM

I don't have any real good suggestions for you, but a couple thoughts:

My throttle boday butterfly, and ALL others I have ever seen, seal off the throttle body completely when closed. Yours seems supect to me. I would expect your throttle body thinks there is a HUGE vaccum leak with what you have described. Particularly the idle air valve is essentially useless if the butterfly doensn't close completely.

My butterly was sticking after sitting for as little as ten minutes. I took it off and sprayed it down with a whole can of cleaner. Get the aerosal type and do this, it can only help, even if it doesn't solve your problem. There are 4 vaccum passages in there that you can spray out. All three of the smaller ones on mine had chunks of carbon fly out when I did this. Once I put it back together, my initial problem was not solved but the truck idles better and has better throttle response.

(FYI - my issue was a bad EGR modulator and I think my cold idle injector isn't working).

Teuf · 11-15-2009, 12:57 PM

Open valve up and sww if there is gunk/buildup there, mine used to stick something awful . good luck

thedanned · 11-15-2009, 09:44 PM

Thank you all for the replies.

DJ99 and Targetnut, I went ahead and set everything back to factory specs as per the FSM and went ahead and pulled the battery cable to reset the ECU. I dont know if this computer is smart enough to have learned values or not, but I did it anyway. With the dashpot and throttle stop set the TPS reads within specs. The truck seems to run better overall and the throttle is not sticking anymore but the idle issue is still there.

Limon and Teuf: I went ahead and cleaned the bejeesus out of the TB while I had it off. Made sure there was no blockage or carbon build up anywhere. And I agree with you, that every single throttle bore I have seen seals COMPLETELY when shut.

I think my next step is to go down to U Pull and examine some throttle bodies. I will let everyone know what I find!

thedanned · 11-15-2009, 09:46 PM

Actually, what I should do next is check the adjustment of the Aux Air Valve as Targetnut has suggested. Looks like its time to read the FSM!

limon32 · 11-15-2009, 11:02 PM

I could be wrong but I don't believe the aux. air valve is adjustable, I think it either works or doesn't and if it doesn't you get to replace the throttle body. I could be wrong, can someone confirm this?

abecedarian · 11-15-2009, 11:05 PM

The AAV can be serviced, i.e.: cleaned, but should not be adjusted unless you have the facilities to test and adjust it. On the up side, it can be replaced.

limon32 · 11-17-2009, 07:49 PM

Quote:

Originally Posted by abecedarian

The AAV can be serviced, i.e.: cleaned, but should not be adjusted unless you have the facilities to test and adjust it. On the up side, it can be replaced.

I didn't see a procedure for that in the FSM, did I just miss it?

abecedarian · 11-17-2009, 07:54 PM

Nope, you didn't miss it- service procedures are not there.
Though it can be taken apart, cleaned and reassembled, getting the valve adjusted properly through trial and error would take quite a while. Only recommendation I could give to this would be to count turns on everything your have to unscrew and re-assemble exactly as it came apart.

thedanned · 11-18-2009, 08:30 AM

Quote:

Originally Posted by limon32

I didn't see a procedure for that in the FSM, did I just miss it?

I couldnt find it either. I think I may just clean it, maybe try and adjust it this week. Im waiting for the weekend to run to u pull and look at some other TBs.

DupermanDave · 11-18-2009, 08:57 AM

Is the silicone seal around the VAFM still intact? If you adjust the air/fuel mixture that will also raise the idle. But if this were the case, you'd smell gas fumes as a rich mixture. It's still a place to look. Previous owner might have tinkered with it.

thedanned · 11-18-2009, 09:08 AM

Quote:

Originally Posted by DupermanDave

Is the silicone seal around the VAFM still intact? If you adjust the air/fuel mixture that will also raise the idle. But if this were the case, you'd smell gas fumes as a rich mixture. It's still a place to look. Previous owner might have tinkered with it.

!!!!!!! I am running rich! I can smell my brand new cat working hard! And come to think of it, there is a self tapping screw point (the 'drill' part) sticking out of part of the VAFM, like someone was trying to fill a hole they created. Its not like they drilled a hole in the "airway" of the meter, its somewhere in the outer areas of the body of the meter. Ill look closer when I get home. Is the VAFM something that people tinker with? Ill search around for while. Thanks dude!

DupermanDave · 11-18-2009, 10:30 AM

Quote:

Originally Posted by thedanned

!!!!!!! I am running rich! I can smell my brand new cat working hard! And come to think of it, there is a self tapping screw point (the 'drill' part) sticking out of part of the VAFM, like someone was trying to fill a hole they created. Its not like they drilled a hole in the "airway" of the meter, its somewhere in the outer areas of the body of the meter. Ill look closer when I get home. Is the VAFM something that people tinker with? Ill search around for while. Thanks dude!

It's something people mess with to "mod" the 22re to run a richer mixture to try and get more HP.

There was a post here with pics how to adjust the VAFM. I can't find it now, but I'll keep searching.

-edit-
well here's the post, without pics. http://yotatech.com/f116/adjusting-maf-119680/

Seems the photobucket account went inactive.

thedanned · 11-18-2009, 04:45 PM

So here are a couple pics of my VAFM. Does this look like it has been futzed with? Notice the self tapping screw point sticking out of the round piece. The silicone seal seems to be intact.

abecedarian · 11-18-2009, 06:07 PM

The screw is sticking out of the plug that covers the idle fuel mixture adjustment. Normally, it's plugged with a blank, but it looks like someone drilled it out with the screw then inverted it so it would be plugged but easily removable.
Turning it in should decrease the amount of air that bypasses the vane in the meter, thus enriching the mixture, and turning it out should increase the bypass air thus leaning the mixture.

thedanned · 11-19-2009, 04:32 PM

Ok so I played with the screw (heh) for a little while, seeing what it does. Just as Abe said, in richens the mix and out leans it. When I pulled the plug, it was all the way in ie bottomed out. I then went all the way out, counting turns and seeing what it did to my idle. I am now twelve turns out (it is about a turn and a half from coming out) and it is idling at about 950-1000. So something still cannot be right here.

abecedarian · 11-19-2009, 04:50 PM

I wouldn't suggest you play with that screw unless you have an exhaust gas analyzer on hand to dial in the idle fuel mixture. Off idle, that screw has little effect on the mixture.

thedanned · 11-20-2009, 08:34 AM

Quote:

Originally Posted by abecedarian

I wouldn't suggest you play with that screw unless you have an exhaust gas analyzer on hand to dial in the idle fuel mixture. Off idle, that screw has little effect on the mixture.

But Im not worried about off idle. Maybe Im missing something here.

abecedarian · 11-20-2009, 08:40 AM

Well anyhow.

Did you adjust the throttle stop and dashpot so they contact the throttle cam? (please say you didn't)
Have you checked for the throttle cable itself holding the throttle open, not letting it close all the way?

thedanned · 11-20-2009, 08:53 AM

Quote:

Originally Posted by abecedarian

Well anyhow.

Did you adjust the throttle stop and dashpot so they contact the throttle cam? (please say you didn't)
Have you checked for the throttle cable itself holding the throttle open, not letting it close all the way?

Non sequitur. Read post 7. Why shouldnt I have adjusted the stop and dashpot?

abecedarian · 11-20-2009, 09:01 AM

Well, the dashpot is okay to adjust if it's malfunctioning, but the throttle stop should not be adjusted.

It would seem to me that if the throttle stop has to be adjusted out to get the TPS reading properly, the throttle wasn't closing all the way to begin with and the TPS needed adjusting instead.

thedanned · 11-20-2009, 09:30 AM

The throttle was closing all the way, enough to stick closed. I dont think the throttle stop was adjusted all the way out from the factory. I honestly did not measure the TPS before I adjusted the stop, so I dont know what exactly my starting point was. I assumed it (TPS) was correctly adjusted because it was reading correctly after setting the stop to factory specs. IE my immediate goal wasnt to get the TPS to read correctly, it was to see why the throttle was sticking. So perhaps I need to back the throttle stop all the way out again and read the TPS. But then the throttle blade will be sticking in the bore again.

For the record, on my drive to work today (after backing the idle mix screw out) the idle issue has not subsided and seems to be the same. So I will screw it back to where it was tonight and go from there.

I honestly think that the PO had all these adjusters at their extremes to compensate for something. My theory:

I bought this truck from a hay farmer in southern Colorado. Nice guy, just a little backwards on his repairs. I have been pulling house wiring and wire nuts out of his "mods" sinse I took possession. I found the factory zip tube (flex rubber tube from TB to VAFM) badly cracked and letting in all kinds of unmetered air. He put a K$N cone filter kit on it and I think this is when the zip tube cracked. It was a tight fit and that rubber was brittle. I think he then backed the throttle stop out all the way to try and lower the idle (thats the way it works on carbs, right?!!) only it didnt work. He then found the idle screw and jammed that in all the way, which lowered the idle but he didnt set the throttle stop back. I dont think these throttle blades are meant to sit "flush" or whatever inside the bore, thus the reason for the throttle stop. So a few years of driving like this and the throttle blade wore down enough to get stuck and basically "clearance" itself, hence the gap I described in my first post.

I may be waaaaaayyyyy wrong and reading too far into this, but tomorrow I am going to u pull and I will examine some other TBs. Ill take pics of what I find.

Anyway, I should get back to work...

11-14-2009, 03:15 PM	#2 (permalink)
DJ99 Registered User Join Date: Sep 2008 Location: SW Washington Posts: 68	Funny that you should mention this. A while back, when I was trying to nail down my mileage issues, I checked out, and actually replaced the TPS. When I checked it out, the throttle body bracket (?) was not actually contacting the stop. It was at least 1/8" out. This is on a VERY low mileage '93 3vze, like 46K. I ended up resetting the stop to contact the bracket when replacing the TPS, which was probably not the issue. Bottom line is: This probably is not your issue. As long as the butterfly closes, the stop is not your problem. OTOH, mine DID NOT have a 1/16" gap on the sides. That ain't right, AFAIK. __________________ 1993 T100 3.0L V6 3VZE 4x4 (47K) Last edited by DJ99; 11-14-2009 at 03:18 PM.

11-14-2009, 03:58 PM	#3 (permalink)
Targetnut Registered User Join Date: Jul 2005 Location: Manassas, VA Posts: 554	Yes, set everything to factory specs and see if that helps. If the idle is still to high it could be because the auxillary air valve, (which may be part of the throttle on that model) is not closing all the way. __________________ Targetnut don't talk about it, just do it! Precision Import Service '93 2WD 22RE, Ported w/os valves, custom intake manifold, crane cam,Megasquirt, 295cc injctrs, Supra fuel pump, adj fuel pres reg, 70mm throttle, LCE header, V6 Taco cat, 14lb flywheel, Kevlar clutch, W58 and short shifter, 4.10 gears w/Truetrac, drop spindles and blocks, 245/50-16 Yokos on 16x8 wheels, 4WD fenders, bumper, and valence, skinned tailgate

11-14-2009, 04:14 PM	#4 (permalink)
Jeremy11 Registered User Join Date: Sep 2009 Location: Corpus Christi Texas Posts: 32	I also have a similar problem.. When cold my engine is idle about 1300 Once it warms up its good at 800. BUT when im driving for a while and i apply the brakes sometimes my truck will turn off completely. Inorder for my truck not to shut off I havee to put it into Neutral and it will idle at about 800 where its supposed to be. I have a 1990 4Runner 3.0 V6. I dont know where to go from this. Any help is appreciated. PS: When slowing down the truck drops down to about 500 and drops and rises from there. Then soon dies.. __________________ "Stay far from timid, only make moves when your hearts in it, and live the phrase sky's the limit." -- Notorious B.I.G. http://s492.photobucket.com/albums/r...nt=gifs_21.gif

11-15-2009, 12:57 PM	#6 (permalink)
Teuf Registered User Join Date: Apr 2009 Location: Napa, Ca Posts: 468	Open valve up and sww if there is gunk/buildup there, mine used to stick something awful . good luck __________________ !988 Toyota pu 4x, 22re, Downey Header, Borla Exhaust, Performance Cat, Schneider Cam, K&N air, Rancho 3" ifs lift, 3" Downey Springs Rear, Rancho rs9000, SR5 Bucket Seats, Misc doodads here n there. 278k as of 11/09, Lce head installed 5/09, so far so good, Using 10/30 Castrol dino, I am changing over to Valvoline 5/30 Syn blend next oil change / and Toyota filter. FAHRVERGNUGEN

11-18-2009, 08:57 AM	#14 (permalink)
DupermanDave Registered User Join Date: Aug 2008 Location: Northern Colorado :-( Posts: 1,276	Is the silicone seal around the VAFM still intact? If you adjust the air/fuel mixture that will also raise the idle. But if this were the case, you'd smell gas fumes as a rich mixture. It's still a place to look. Previous owner might have tinkered with it. __________________ 1989 Toyota pickup 22re - K&N filter with custom air intake

11-15-2009, 12:17 PM	#5 (permalink)
limon32 Registered User Join Date: Mar 2009 Location: Kenai, AK Posts: 156	I don't have any real good suggestions for you, but a couple thoughts: My throttle boday butterfly, and ALL others I have ever seen, seal off the throttle body completely when closed. Yours seems supect to me. I would expect your throttle body thinks there is a HUGE vaccum leak with what you have described. Particularly the idle air valve is essentially useless if the butterfly doensn't close completely. My butterly was sticking after sitting for as little as ten minutes. I took it off and sprayed it down with a whole can of cleaner. Get the aerosal type and do this, it can only help, even if it doesn't solve your problem. There are 4 vaccum passages in there that you can spray out. All three of the smaller ones on mine had chunks of carbon fly out when I did this. Once I put it back together, my initial problem was not solved but the truck idles better and has better throttle response. (FYI - my issue was a bad EGR modulator and I think my cold idle injector isn't working).

11-15-2009, 09:44 PM	#7 (permalink)
thedanned Registered User Join Date: Oct 2009 Location: Albuquerque, NM Posts: 23	Thank you all for the replies. DJ99 and Targetnut, I went ahead and set everything back to factory specs as per the FSM and went ahead and pulled the battery cable to reset the ECU. I dont know if this computer is smart enough to have learned values or not, but I did it anyway. With the dashpot and throttle stop set the TPS reads within specs. The truck seems to run better overall and the throttle is not sticking anymore but the idle issue is still there. Limon and Teuf: I went ahead and cleaned the bejeesus out of the TB while I had it off. Made sure there was no blockage or carbon build up anywhere. And I agree with you, that every single throttle bore I have seen seals COMPLETELY when shut. I think my next step is to go down to U Pull and examine some throttle bodies. I will let everyone know what I find!

11-15-2009, 09:46 PM	#8 (permalink)
thedanned Registered User Join Date: Oct 2009 Location: Albuquerque, NM Posts: 23	Actually, what I should do next is check the adjustment of the Aux Air Valve as Targetnut has suggested. Looks like its time to read the FSM!

11-15-2009, 11:02 PM	#9 (permalink)
limon32 Registered User Join Date: Mar 2009 Location: Kenai, AK Posts: 156	I could be wrong but I don't believe the aux. air valve is adjustable, I think it either works or doesn't and if it doesn't you get to replace the throttle body. I could be wrong, can someone confirm this?

11-18-2009, 04:45 PM	#17 (permalink)
thedanned Registered User Join Date: Oct 2009 Location: Albuquerque, NM Posts: 23	So here are a couple pics of my VAFM. Does this look like it has been futzed with? Notice the self tapping screw point sticking out of the round piece. The silicone seal seems to be intact. __________________ 1989 4R 3VZ Manual 32X11.50 BFG AT Saggy Rear My first 4x4 Toyota and I love it!

11-19-2009, 04:32 PM	#19 (permalink)
thedanned Registered User Join Date: Oct 2009 Location: Albuquerque, NM Posts: 23	Ok so I played with the screw (heh) for a little while, seeing what it does. Just as Abe said, in richens the mix and out leans it. When I pulled the plug, it was all the way in ie bottomed out. I then went all the way out, counting turns and seeing what it did to my idle. I am now twelve turns out (it is about a turn and a half from coming out) and it is idling at about 950-1000. So something still cannot be right here. __________________ 1989 4R 3VZ Manual 32X11.50 BFG AT Saggy Rear My first 4x4 Toyota and I love it!

11-20-2009, 09:30 AM	#25 (permalink)
thedanned Registered User Join Date: Oct 2009 Location: Albuquerque, NM Posts: 23	The throttle was closing all the way, enough to stick closed. I dont think the throttle stop was adjusted all the way out from the factory. I honestly did not measure the TPS before I adjusted the stop, so I dont know what exactly my starting point was. I assumed it (TPS) was correctly adjusted because it was reading correctly after setting the stop to factory specs. IE my immediate goal wasnt to get the TPS to read correctly, it was to see why the throttle was sticking. So perhaps I need to back the throttle stop all the way out again and read the TPS. But then the throttle blade will be sticking in the bore again. For the record, on my drive to work today (after backing the idle mix screw out) the idle issue has not subsided and seems to be the same. So I will screw it back to where it was tonight and go from there. I honestly think that the PO had all these adjusters at their extremes to compensate for something. My theory: I bought this truck from a hay farmer in southern Colorado. Nice guy, just a little backwards on his repairs. I have been pulling house wiring and wire nuts out of his "mods" sinse I took possession. I found the factory zip tube (flex rubber tube from TB to VAFM) badly cracked and letting in all kinds of unmetered air. He put a K$N cone filter kit on it and I think this is when the zip tube cracked. It was a tight fit and that rubber was brittle. I think he then backed the throttle stop out all the way to try and lower the idle (thats the way it works on carbs, right?!!) only it didnt work. He then found the idle screw and jammed that in all the way, which lowered the idle but he didnt set the throttle stop back. I dont think these throttle blades are meant to sit "flush" or whatever inside the bore, thus the reason for the throttle stop. So a few years of driving like this and the throttle blade wore down enough to get stuck and basically "clearance" itself, hence the gap I described in my first post. I may be waaaaaayyyyy wrong and reading too far into this, but tomorrow I am going to u pull and I will examine some other TBs. Ill take pics of what I find. Anyway, I should get back to work... __________________ 1989 4R 3VZ Manual 32X11.50 BFG AT Saggy Rear My first 4x4 Toyota and I love it! Last edited by thedanned; 11-20-2009 at 09:31 AM. Reason: clarity

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search