Recently got an 84 4runner carbed..

it sat for 8 years maybe started up every couple of months..

So I replaced the usuals..
plugs, wires, cap, rotor, changed the oil, filter, fuel filter, ran seafoam in the tank and poured it down the carb, and used lots of carb cleaner to clean things up get some of the gunk off.

the BVSV broke so I routed the vacumn tubes to each other, my understanding i that when the coolant warms up enough it opens the valve, letting the EGR work.

So the problem I'm having is..

At warm up about 15 seconds after start up, it runs great a bit high of an idle but everything feels nice and smooth and clean.

As soon as the engine warms up the idle drops, the car idles like ass.
idle is so low it stalls at times
idle is rough, and normal driving is a bit rough also.

Lots of back firing when I let off the throttle to slow down or shift

the fuel level on the sight glass is right in the middle.\
timging is dead on 5 deg.
deceleration fuel cut switch works
jets seem clean

let me know what you guys think..
thanks in advance

 

Look down in the carb's throat and see if fuel is dripping or shooting down the carb. If it is, then the carb needs to be rebuilt. Sitting for that long makes me suspect the carb ought to gone through anyway. Make sure you replace the jets. This a key factor for fuel econ. and horse power.

also, look for vacuum leaks around the base of the carb and the legion of vac tubes the 84's have. That carb runs poorly when not set up right. When it's dialed in, it's a nice ride. Let us know how it goes.

 

I'll check on the carbs spray.. and i want it to spray correct..

 

actually when at idle you should see very little. If you see fuel dripping down or pouring down, that's a sign the carb needs rebuilt. Frankly, I'd rebuild it anyway after sitting that long.

 

Maybe I'll be able to look at the jets today

I was hoping not to rebuild... I'll have to start looking for another carb to rebuild..

oh and
the truck also backfires alot when off the gas..
and some times diesles..a bit on shut down.

 

incorrect idle speed could cause that, maybe too rich or lean of a mixture? hows your ignition timing?

 

bump up ur idle a bit. my truck holds at 1500 drops to liek 600 then stabilizes at about 850-900 rpm which is where it should be idling. its prob just ur idle and a little tweakin with the air fuel. try turning it out 1/4 at a time just gotta listen to it.

 

I need to check the ignition timing..

and I have the idle turned up pretty much all the way...to keep it running, and it still stall on deccelleration

I thought the air fuel was find a long as its in the middle of the sight glass?

 

The sight glass is to determine fuel in the bowl. The mixture is regulated by a screw (sometimes/most times capped). It really sounds like you have a metering problem; whether caused by a vacuum leak or poor needle and seat in the fuel bowl. It could be bad jets, but I doubt that's all it is. This carb needs to be gone through, if only to eliminate it as a suspect......

They sure run well when they are built right.

 

thanks again for the info I hope to be able to eliminate possible issues one by one...

I sprayed carb cleaner all over the carb while it was running and listened for any changes and nothing...

this was a couple of weeks back..

I hoping to get a used weber carb soon off another board, and i would just wait to toss that on but I need to pass cali smog still..

so my plan is to
check the timing
and see if the spray pattern is good..

 

let us know what you find....

 

What? So you have direct vacuum going to the EGR valve? Either that or you have the vacuum lines reversed and you have direct vacuum going to the EGR once the motor is warmed up. This would cause the truck to run crappy as it is warming up......like the problem you're having now.

Disconnect and plug the vacuum line to the EGR valve and see if it runs decent. I think you got the vacuum lines from the BVSV to the EGR mixed up or routed incorrectly.

 

The BVSV opens up when then coolant gets warm enough and allows the vacumn to flow through. So I jut bypassed the BVSV, so it would be like the coolant was warm enough.

The problem I'm having is at idle not after warm up.. not during.

 

got a few minutes to mess with it..

Timing is dead on 5 deg

When I pull the throttle the gas is spraying well even saw the gas come out of the accell tube. So the jet looks good..


I checked the vacuum switch for the decelerationfuel cut..and its working..


I was going to play with the mixture screw but I mangled the cap a bit and have not been able to get it off...

I updated the first post to make it easier to get the whole picture of whats going on

 

well, I guess I'm schtumped. I would prolly have to be there poking and prodding to figure it out.....

maybe take some pics of your set-up withand without aircleaner. I wish I could look down the throat and see what's going on in there...

 

too bad you live soo far away..

 

6 hrs from Phoenix to SD right?

 

something like that.. you coming through?

 

Sounds like you may be getting too much fuel? Or you have leaky carburetor gaskets? I would rebuild the carb for sure. A kit is probably only 25 bucks at any parts place. Then I'd check all of the vacuum lines. Are the spark plugs wet, or fouled? Does it smoke when its running bad?

 

Coming through in December on the big Fuster family vacation. If you still have the problem I'd like to fiddle with it.