Idle problem and FSM question? (1 Viewer)

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Couple of questions for folks. Hopefully somebody can help.

My truck (1986 FJ60) all of a sudden won't idle. It was running fine, then I drove it about 50 miles and stopped for groceries (going camping). When I started up again, it wouldn't idle or if it does idle its VERY rough. Off idle it runs good and pulls strong, although sometimes a small amount of surging/hesitation.

I've checked the float level, fusible link, and vacuum modulator. Also replaced the air cleaner, put some Seafoam through the gas tank, and sprayed down the carb with cleaner. No dice.

I found a broken wire on the idle solenoid, fixed that and verified the solenoid clicks, but it made no difference. Also, if I unplug the fixed idle solenoid, there's no change in behavior - it still dies.

Then I found the VTV valve connected to the carb was plugged, so I replaced that. No difference. If I take out the VTV and plug the lines I can get the truck to idle OK around 1,000 RPM but there's a slight misfire coming from the exhaust. That doesn't mean anything to me, but maybe it's a clue for one of you guys.

I know there are numerous posts about rough idle and hesitation. I've read them all and they're helpful, but none are the same problem that I'm dealing with.

Any and all ideas about what might be causing this would be SUPER helpful. Anyone?

I just bought a vacuum gauge and some hose, and am starting to go through the emissions manual. One thing that I don't understand is in the upper right corner of the diagram below(circled in red). What and where are those connections? I don't see anything that looks like that under the hood.

Thanks in advance for the advice and help!

borick-albums-misc-picture16386-what-where-thing-upper-right.jpg
 
what you have circled are the vacuum connections on the side of the carb towards the valve cover
 
what you have circled are the vacuum connections on the side of the carb towards the valve cover

Yes. The perspective is if you were standing on the right (passenger side) of the engin bay, looking over and behind the valve cover at the lower right side of the carb. The four vacuum tubes connect to four pipes associated with the vacuum piping manifold.
carb vacuum tubes.jpg
 
Ahhhh. Sounds like they're a little hidden with the big huge intake thingy in place, and I need to take it off to see. I'll do that this eve.

Thanks chesshircat and 2mbb. Much appreciated!

From a quick look through the manual, looks like several of the vacuum lines connected in the 1-12 array (right side of diagram) are miss-routed. Probably the lame dude at the dealership who took my $150 so I could get an emissions exception - he said he'd changed some of them. I'll go through it all this eve and see what happens.

Any other ideas or advice?
 
dont limit spraying carb cleaner to just the carb, spray it anywhere ther could be a vac leak....which is a lot of places. spray it at the manifold/head gasket, and where the brake booster/ac idle up stem comes out of the intake, and on the other side where the three prong vac adapter screws in on the other side of the intake manifold

have you checked your spark plugs, wires, dizzy cap and rotor? PCV valve?

Any difference with the engine hot or cold?

also, just because the ICS clicks does not mean it is functioning properly, there is a vac switch (you can see it in the lower right of the pic 2mbb posted, has a line pointing too it) associated with the system, you should check that too. The procedure should be covered in the emissions manual.

hth

swamp60
 
It is likely the idle solenoid above, although that usually will not idle at all - usually a hard stall.

Another possibility is dirt in the idle jet. I have pulled the two main bolts and sprayed cleaner into the mains and pulled the idle solenoid and sprayed there. Both can be done with the carb in situ. - Dan
 
here is another set of schematics that might help with the vacuum routing. You need to take your time and carefully go through and check and double check that it's corrected properly. If you hoses are in anyway brittle, you should consider changing them out. Use either toyota or get 3mm ID silicone from an autoparts store or someplace like mcmaster carr.
 

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Riddle me this, Batman

Swamp - thanks much for the advice and hints on where to spray the cleaner. I'll take that on tomorrow. PCV valve is fine, dizzy cap and rotor are very slightly burned so will replace those ASAP. Need to check plugs and wires still.

Haven't checked the vac switch you mention - will do that tomorrow too.

For hot/cold behavior, see below....

Tonight found that in the array of 12 vacuum hoses, only 3 of the twelve were connected right. Idiot dealership mechanic I guess. Or the PO (I bought the truck just this past June). Re-routed all the hoses per the FSM. The problem is not totally fixed but a huge improvement. Truck runs smoother, feels like it has more power, and WILL idle where it wouldn't before.

The riddle is: how the heck was the truck running with all the hoses routed wrong, and what caused it to stop idling so suddenly?

Still problems, though...

Things feel really good after it warms up: truck DOES idle (woo hoo!) around 900-1,000 and idles smooth.

Things are not so good after a warm start, say after stopping, sitting for 10 min, then starting. The idle will be erratic and range between 500 up to 1,500, or maybe 800 up to 1,400. Basically it swings about 700 RPM, back and forth, each swing takes about a second or two. Pulling the choke out doesn't seem to change things too much.

Could something be up with the choke mechanism?

Dan - think the idle solenoid is probably working at this point, but I'm going to test the vac switch anyway. Have any more detail about cleaning the idle jets with the carb on?

Thanks again, guys, for the help. Any other ideas or thoughts?
-Rick
 
if the air conditioner is on and the ac idle up screw is set too high, it causes the kind of cycling you describe. I guess I would confirm the ac is off and that those vacuum hoses are connected properly.

the choke cable opens the throttle plate up to the fast idle stop, and also closes the choke plate. There are a couple of vacuum actuators, choke opener and choke breaker, that open the choke when the engine is hot and/or when the engine starts. I think the fast idle speed is mainly set by the cable, and can only be slowed by pushing the cable in. I don't think the vacuum actuators effect the speed, only the mixture.

There are a couple of BVSV's (temperature vacuum valves) mounted near the thermostat housing. You should try to confirm that those are working proplery per the emissions manual.
 
2mbb - thanks for the diagram. That's not in the FSM, is it? Where's it from?

It seems to show one thing different (or missing) from the FSM: the large tube at the bottom of the HAC valve. The HAC has 4 smaller vacuum hoses at the top. Your diagram shows a larger hose near the bottom, but it's not shown in the FSM anywhere that I can see. My HAC has a place where it looks like that larger hose should connect. Is there really a hose there? If so, what does the other end connect to? (I'm talking about the red hose in the diagram below.)

borick-albums-misc-picture16397-vac-piping.jpg


I will check out the choke opener and choke breather ASAP. They sound like a likely culprit/contributor.

Thanks again! Any more ideas? Let me know.
 
The diagram above is from the parts microfich. If you look closley, most of the lines are identified with a part number followed by L=(number). The part number specifies a fixed length toyota part. The sell vacuum tube in fixed lengths--short, medium and long. The L=(number) is the length in millimeters that the tube is cut to for the correct lenght.

The larger diameter tube at the bottom of the HAC valve does not connect to anything. It is used as an atmoshperic vent. That is the tube you have colored in red above.
 
2mbb - thanks for the info on the tube. I'll stop worrying about it now. :)
 
Update: pulled the air cleaner off and checked the vacuum hoses on the backside of the carb. All were hard as a rock, two were broken, so I replaced them all. Vacuum switch checks out.

Still need to check out the choke breather and choke opener.

Truck runs pretty much the same. The RPM swings seem to be gone, which is an improvement. But on a cold start it won't idle on it's own for about a minute, but after a short warm up it will idle about 1,000 RPM (even with the choke pulled all the way out).

Since it was idling I went and sprayed carb cleaner around the way Swamp60 described. I do get a noticeable RPM increase when spraying around the base of the carb, and around that 3-pronged thingy sticking out of the manifold to the left of the carb (when standing at the drivers fender).

Assume I should replace the carb gasket, or anyone think it might be worse - like something cracked?

Does that little 3-pronged thingy have a gasket? Is there a recommended way to stop a leak in that area?

Thanks for the help!
 
If your choke cable pulled out all the way only increase the RPM to 1000, then you may need to adjust the fast idle screw. It is on the backside (firewall side) of the carb. There are two adjustment screws on that side. The one closest to the carb base is the idle speed screw, and the one farther away is the fast idle speed screw. Screwing in (clockwise) the fast idle speed screw should increase idle with choke pulled (assuming your choke cable is connected properly).

You do need to take care of all manifold leaks. First try tightening the nuts that hold the carb onto the intake manifold. If they are already tight, then you should take the carb off and inspect the insulator/gasket. The 3-pronged thingy is a intake manifold vacuum port. I believe it is threaded into the manifold. You should be able to take it out, clean the threads and apply some thread sealant. First check that the vacuum lines are not cracked--it could be that simple.
 
If your choke cable pulled out all the way only increase the RPM to 1000, then you may need to adjust the fast idle screw. It is on the backside (firewall side) of the carb. There are two adjustment screws on that side. The one closest to the carb base is the idle speed screw, and the one farther away is the fast idle speed screw. Screwing in (clockwise) the fast idle speed screw should increase idle with choke pulled (assuming your choke cable is connected properly).

You do need to take care of all manifold leaks. First try tightening the nuts that hold the carb onto the intake manifold. If they are already tight, then you should take the carb off and inspect the insulator/gasket. The 3-pronged thingy is a intake manifold vacuum port. I believe it is threaded into the manifold. You should be able to take it out, clean the threads and apply some thread sealant. First check that the vacuum lines are not cracked--it could be that simple.

X2

One time, a long long time ago...
My 60 would die at stop lights and such or really any time i went to neutral unless i gassed it or pulled out the choke. Basically would not idle unless RPM's were over 1500....

did the carb cleaner thing, reved when i sprayed the base of carb...

Grabbed carb, lifted it up about 1/8 of an inch off the base!! the nuts had backed out...so definatly check the tightness of the nuts, grab your carb and see if you can wiggle it, you should not be able to....

Like 2mbb said above, take care of all the known vac leaks first, then adjust idle screws. if that dont cure it move on to the bigger stuff.

keep us posted.

swamp60
 
This is great imformation guys, thanks for sharing your knowledge. Im going over my engine today and this info is what I needed. Thanks!
 
Well, damn...

Swamp - checked out the carb. Couldn't lift it 1/8" but bolts were only finger tight. Went to tighten them down and the rear drivers-side stud is stripped. I can probably drive it with 3 studs, but that sucks.

Carb is off at this point, and the gasket/insulator has a corner missing so should probably be replaced.

Are there options for re-threading the stud hole while the manifold is still on the vehicle? I've heard of helicoil - would that work? Can I buy a kit or do I have to take it somewhere? Are there other options?

Guys - thanks a lot for the help so far. Really appreciate it.
 
Also - any recommendations for best place to get the gasket? My local dealer says that Toyota doesn't sell them individually. So... Napa? Fel-pro? Other?
 
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I did everything your doing and it turned out to be the idle solenoid, mine also clicked when checked But I replaced it with a toyota part ($198.00) runs great
 
How much of the insulator is missing? is it the same corner as the stripped stud? can you post a pic?

as for the insulator i would replace it, it is $126 new from the dealer. the gaskets are "built in" to the insulator, so i would (and just did) get a new one instead of buying a used one in "good condition" cause you will probably be needing another one soon after and wind up getting a new one in the end IMHO.

As far as the stripped stud, is it the threads for the carb nut that are stripped (nut spinning on stud) or is the stud turning with the nut, or have you extracted the stud from the manifold?...i have never dealt with that situation yet, but i have seen a bunch of threads about it. i'll try to see if i have one book marked, but i bet 2mbb has the info you need, he always seems to have that s*** close at hand....

In the mean time you can work on the three prong vac port...

swamp60
 

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