How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask stone314 Your Own Question
stone314, degree
Category: Toyota
Satisfied Customers: 70
Experience:  Automotive Degree
Type Your Toyota Question Here...
stone314 is online now
A new question is answered every 9 seconds

1986 toyota pickup: trying to get running for awhile now..carbs

Customer Question

I have a 1986 toyota pickup I have been trying to get running for awhile now. The problem that I am having is, I have tryed about four rebult carbs. that work at first then from four days to as long as three weeks it does not want to work anymore. Right now it idles good but if you accelerate it will die. I have looked for vaccum leaks, it is getting gas, already changed the fuel filters. I am confused with it works then it wont. Any help or ideas would be appriciated.
Submitted: 6 years ago.
Category: Toyota
Expert:  stone314 replied 6 years ago.
Chat Conversation Started
stone314 :

Thank you for choosing Just are you getting enough fuel?


yes the fuel glass shows plenty of fuel, I did have a problem with that earlier but I put a new fuel pump on already

stone314 :

I have you checked the filter again since you changed it last?


on the sight glass the fuel is just above the half mark and stays there as I try to throttle up the carb.


Is there anything electrical on the carb that could cause this problem? or is the connector just for the choke?


I have turned the truck off and looked to see if there was a good stream of fuel as I turned the throttle and it looks like there is.


This last carb. I have is a Vapex from O'Reilly, all of the carbs. are from this place.

stone314 :

So it starts and stalls?

stone314 :

Try this may help

stone314 :


<!-- var HIGHNONE = ''; var LOWNONE = ''; // -->

<!-- var CAPTION62574868 = &#34;&#34;; // -->


<!-- var HIGHNONE = ''; var CAPTION62574868 = &#34;&#34;; // -->

<!-- var HIGHNONE = ''; var LOWNONE = ''; // -->


Expert:  stone314 replied 6 years ago.
Chat Conversation Ended

If you are still working with your Expert on this question, you can post additional replies and receive additional information on this page.  If you received a satisfactory answer in Chat, you can accept the chat conversation above.
Expert:  stone314 replied 6 years ago.

Customer: replied 6 years ago.
No, It starts good, idles good, but as I throttle up it will start to die, if I let off the gas it will go back to idling good again, but if I continue giving it gas it will die.
Expert:  stone314 replied 6 years ago.
Check your egr valve
Customer: replied 6 years ago.
Ok I will check that and get back with you, I think I replaced that it already but not positive. Thanks
Customer: replied 6 years ago.
Ok I did what the books says, to disconnect the hose that comes out of the EGR valve, then disconnect the hose that comes out of the exhaust manifold and hook the hose from the exhaust to the other side of the valve and the car should stall. It does not stall unless I give it gas like it has been doing. Does that mean I need a new valve and should the truck work if I plug the hose coming from the exhaust manifold and give it gas or should it still stall?
Customer: replied 6 years ago.
I made a mistake, I did not check the EGR valve I removed and checked the EACV. I have found the EGR valve now but am not sure how to check it, the book says to disconnect the vac hose leading from the valve, then disconnect the hose coming from the intake manifold and connect it to the empty pipe on the valve, but I only have one hose to the valve, in the book I do see other years have two hoses.
Expert:  stone314 replied 6 years ago.
Testing and Inspection
  1. Disconnect and plug vacuum hose to EGR valve, start engine and observe engine idle. If engine runs rough or stalls, check for improperly seated EGR valve.
  2. Apply manifold vacuum directly to EGR valve with engine running at idle.
  3. If engine does not run rough or stall, EGR valve is defective.


Customer: replied 6 years ago.
I dont have a manifold vacuum hose only one hose that come from a tube that looks like it comes from the BVSV, this tube also hooks up to either the choke opener or choke breaker on the carb and some other hoses that go to the carb. Sorry for being so difficult but I am looking at the book also and wanted to try that but could only find the one hose, I looked at buying a new one and notice the other port for the hose but mine does not have that.
Customer: replied 6 years ago.
I was able to create a vacuum on the EGR valve and the truck did stall. If I put my hand over the carb., not completely but about half and give it gas it seems to accelerate pretty good, does that help any. It acts like it is not getting enough gas, but like I said before I watch the glass on the carb and the gas stays alittle above the half mark. I have been working on trying to get this truck to work correctly for about 6 months now. Everytime I put a new carb. on like said it works for awhile then it acts up like this again.
Expert:  stone314 replied 6 years ago.
Is there good clean fuel in the tank?

Customer: replied 6 years ago.
I am pretty sure the gas is good, The last time I put gas in it was about three weeks ago the truck was running good, then started acting up, I put it away for about a week replaced the carb. with a rebuilt one again, it started right up ran great, drove it that day, let it sit for about two days, after about two days I went to drive it again, it started good, idled good but trying to accelerate it would die.
Expert:  stone314 replied 6 years ago.
I am leaning towards the egr valve

Customer: replied 6 years ago.
I did the vacuum test but the car did not stall or die, do you still think it could be that, is there another test I might be able to try. It make sense but I dont want to spent $160.00 and that not be it.
Expert:  stone314 replied 6 years ago.
Ofcourse I understand
Expert:  stone314 replied 6 years ago.

Some 1985 carbureted, federal emissions specification trucks may exhibit a slight hesitation when accelerating from a stop, or during light throttle acceleration at low speeds.


This condition may be caused by:

(1)Lean air fuel mixture.
(2)EGR influence on lean mixture.



(1)Operating temperature of the EGR valve BVSV has been changed from 40~C to



(2)Diameter of the slow jet has increased from 0.50mm to 0.52mm.


(3)Diameter of the main jet has increased from 1.14mm to 1.17mm (ATM) or 1.16mm (MTM).


(4)On high altitude specification vehicles, the carburetor air horn has also been changed to allow installation of the new jets.


PRODUCTION EFFECTIVE: From Engine Number Production Date


22R-1590303 September, 1985PART NUMBER INFORMATION:


The following part numbers have changed in production as of September 1985.

Previous Part Number New Part Number Part Name


21100-35290 21100-35291 Carburetor Assy (MTM) 21100-35301 21100-35302 Carburetor Assy (ATM) 25820-13010 25820-13020 Valve Assy Bimetal



To correct a hesitation condition on vehicles produced prior to September 1985 the following parts must be replaced as a set.

Part Number Part Name


21205-35210 Jet, sub assy, slow (ATM & MTM) 90999-41116 Jet, first main (MTM) 90999-41117 Jet, first main (ATM) 25820-13020 Valve assy bimetal, (ATM & MTM)


On high altitude specification vehicles the air horn must also be replaced.

Part Number Part Name


21112-35291 Horn, air (MTM, high altitude) 21112-35300 Horn, air (ATM, high altitude)



Related Toyota Questions