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1980 Pickup Carb Needs Replacing


The Dude Ranch

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Hello, this is my first post. I have a 1980 Datsun Pickup. Started running rough. seem to be the carb.

I cannot find any identity marks on the carb. Looked at some on ebay. found one that looks 90% the same. some of the tiny hose fittings are not present. I read on here a lot of folks use webber. but i noticed that carb has no tiny hose hook ups. can I just cease using them? or most of them. Im in seattle so no emisions test to pass. I just want to get a new carb.

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Get a Weber 32/36 and you'll be very happy. Every vacuum line coming off the manifold can be capped, all of the EGR emissions stuff can be capped. Make sure you leave the hose going to your brake booster valve, and then run the only vacuum port on the Weber to the vacuum advance on the distributor. So literally remove every vacuum line, but do them one at a time and cap them as you go so you don't end up with a vacuum leak. There's 3 hard lines run along the front of the motor, one of them will go to the vacuum advance already. Leave that one connected and trace it to the other end over by the carb so you can use a short piece of vacuum line rather than a long piece that just lays in from of your valve cover.

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"Started running rough, seems to be the carb" From this can I assume it was running ok? If so then this is something that happened to it recently so the carb won't be worn out or at fault. You might have water in the gas, fuel filter dirty or clogged, dirt in the jet, choke stuck on because the relay quit or alternator is failing to charge properly. Even more likely it's ignition related... dirty plugs, worn out wire/cap or rotor... Could be the valve lash or the ignition timing......  these are things that need to be checked and eliminated as replacing the carb with a $300 weber won't cure it. 

 

You can clean yours for free, almost. Rebuilds kits are 1/10 a weber. Usually the old Hitachi is dirty and adjustments are off. No you can't run without the vacuum advance connected. It's not an emissions thing it just gives better mileage and part throttle acceleration. All webers have a vacuum advance port.

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Speakn of carbs.. Im still workin on some other stuff right now so yeah future planning kinna thinkn right now.. but i have been thinkn of replacing or rebuilding mine andl reducing some of the emmissions crap they threw on it... To be honest im probably gonna eventually replace it then use the old one as a base to learn more and to tinker with. Plastic on the choke arm lever is so old and brittle so i figure ill end up with even more non servicable problems from it later anyway... Plus carb tech has improved a good bit since 84.. And all those extra hoses were thrown on to comply with emmissions .. Not to make the truck run smoother...

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With that said though... Im also aware that a ton of issues that seem carb related can be other things... And its important to fix what needs to be fixed as well.. Slappin a new part on any issue misdiagnosed can lead to some serious headache... (From the repetative pounding of said forhead on the hood while yelling idiot) (only thinkn a what ive wanted to do when ive seen others not acess a situation machanicly before diving in nose first.. The water is shallow) but yeah... Anyone able to tell me of any changes they did to the moter itself as well during the emmissions "improvements" they did in the year of 84

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Actually not much has been done to carbs since '84 as everything went to EFI. Usually a good disassembly and cleaning will do wonders. During assembly several settings can be checked and adjusted, such as the float drop, fast idle setting and choke un-loader.

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Oh.. And in parrallel with what mike said... Yes please fix what needs it first... For all we know this carb may make the truck feel great... Masking the feel of the real problem that needs to be fixed...like that shot of morfine they give you to keep you goin...before you get to the hospital... Itll keep goin but for how long... ... You still need to fix the origional issue.

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Oh nice... Now it shows me your response... Big question bout carbs.. When u open it up is there anything to be aware of?mo meaning.. Will any of the springs pop out of alignment once its opened or are these locked in with a nut/bolt/cap of some sort. ... If you have any references (service manual type) you could piont me towards id really appreciate it... .. Well anyway gonna get back to work... Hopefully once this waterpump is on i can figure more out thinkn somea my sensors are fried now... But not sure which yet.. Ill post about it soon..

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Hello. Thank you for all the info and advice. I ended up getting a Hitachi replacement clone. Identical to the original. Cept it only hase two tiny hose hook ups at the base.  I havent had a chance to take pics of the new one yet. Can i load a pic of the original? Or can someone tell me which hoses must be still hooked up. I do not know what certain things are called, other than carb, battery, easy stuff. I guess i will try and clean the old one too. The story is that the truck would run good. Then suddenly run rough. Then good again. This last time, it never snapped out of it. Stayed running bad. I check spark. Spark good. Checked fuel pump. Pumps good. So I assumed it was the carb. It is very dirty.

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Fuel connection is pretty obvious.

 

The two small hoses on the valve cover side... the front one is for the vacuum advance on the distributor but probably goes to a thermal vacuum valve first that only allows it to pass when engine is warmed up. The rear oneis for the EGR and again goes through the TVV first.

 

There is a large thumb sized hose from the valve cover to the air filter.

 

Electrically, the Red wire goes to the idle cut solenoid and the Blue one to the choke heater.

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Hello. The area where the tiny hose hookups, the steel tubes, is at the base of the carb, on the passenger side. aiming at the wheel well sorta. one bends up a little and the other sticks straight out. They match the old ones in placement. I did take photos of my carb before removing it, and any hoses. but when off they sorta all tangeled up. I just wanted to make sure i had them on right.

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The '80 720 had an L series engine so yours was replaced with a Z22, or you have an '81-'82 truck. Check the door tag for the build date. Anything after June '80 is an '81 model year... good to know if you are ordering parts.

 

Without that 3rd fitting you won't be running EGR... not the end of the world unless you have to pass emissions.

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Hello, and thank you for the help. So do I have the hoses connected right? In the picture. And the other tiny hoses I just cap off? Also the blue and red wires on the new carb. I assume they are for the electronic choke. On the truck the wires are both blue, cept one has a white stripe in the middle. Which should the red wire connect to? I dont want to fry anything.

Oh and I forgot to say that the guy on ebay sells carbs for lots of makes and models, he is in the usa and shipping is free. The carb I bought was $95 bucks. I also in the past 2 months ordered a new right front fender $60. And a new front Valence $25. Both free shipping! Crazy huh. I can provide their ebay id if anyone is interested.

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Blue is for choke. Has power when engine running.

 

Red is for the idle cut solenoid. Should have power when ignition is on.

 

Bottom front hose is vacuum advance to distributor. This is the most important of all the hoses. Looks ok but follow it yourself... should go to distributor.

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I wonder what you get for $95 and free delivery.  A dealer replacement carb for an '82 Z22 is about $900. Vastly easier and cheaper to clean and rebuild or get a new direct replacement Weber for $300. Comes with everything includes the gaskets and adapter, air filter even.

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