# 86 Nissan 720 4X4 low idle, stumbles and stalls



## georgegroeg (Sep 24, 2008)

Hello I recently got my dads 1986 Nissan 720 4X4 running again. It was sitting for 12 years. I changed the spark plugs, the air filter, oil and oil filter. The carb was gummed up a bit. so i used carb cleaners and ran the truck to clean it out. It was running good for a couple months and now its stalling out. I thought it was the fuel pump so i changed the fuel filter and took apart the fuel pump and cleaned it. it seems to be working fine and was working fine when i first got it running because I had tested it then both off the truck and to see if fuel was getting to the engine. I've checked for vaccum leaks in the hoses. they seem to be fine as well. I've turned the idle up so it won't stall all the time and turned it down if its too high. But when i turn it up that causes it to have bad run on when you turn off the truck which is accompanied by a whining noise. I also had a cracked EGR tube which I replaced. If anyone has any idea what could be causing the stumbling idle and then stalling please let me know.

Thanks George.


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## georgegroeg (Sep 24, 2008)

*the truck if anyone wants to see.*

http://photos-d.ak.facebook.com/photos-ak-snc1/v276/150/0/553660715/n553660715_3555523_246.jpg

here is a pic of the truck if anyone would like to see.
Its been raised and has 31 x 10.5 x 15R
The interior has been redone. All black
It has an extra bench seat in the back. 
With a roll bar and soft top.
Carpeted right to the back.
It has a pioneer deck with 12 speakers and 2 12" subs.
Pretty sweet ride when it was running well.
Hopefully it will be fixed soon.


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## dvdswanson (Nov 6, 2005)

did you check the gasket for the carb? what about the IAC?


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## georgegroeg (Sep 24, 2008)

Are you talking about the gasket on the breather that sits on top of the carb? whats the IAC?


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## dvdswanson (Nov 6, 2005)

georgegroeg said:


> Are you talking about the gasket on the breather that sits on top of the carb? whats the IAC?


gasket under the carb, between it and the intake manifold. IAC - idle air control valve.


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## georgegroeg (Sep 24, 2008)

Well the gasket looks fine from what i can see. Is the idle air control valve the metal flap on the passenger side of the top of the carb. if so, it seems to stay open. I don't know if it only closes when the engine heats up or if it should close when you give it gas? It seems tobe staying open when i give it gas too. Sorry i don't know all the names for everything. As I am a do it yourselfer. 

Thanks for your help.
George


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## zanegrey (Dec 5, 2005)

re-route the vacumn to the fuel pressure regulator to a manifold source...


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## georgegroeg (Sep 24, 2008)

Thanks dvdswanson 
It is a vaccum leak under the carb. I'm going to atempt to remove it and make my own gaskets for above and below the mixture heater(i think thats what its called). I was told to replace the mixture heater but i think I'll wait to see what it looks like when i get it all apart. I was also told to get a carb rebuild kit. but that seems like something I'd rather not do myself after looking in the hanes manual.

Well thanks again and wish me luck.
I'll post if this solves the problem.


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