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Hope y'all can help out a newbie! Rewbuilt the carb in my 79 longbed 4 months ago. Runs great except it lopes at idle when cold. After about 5 or 10 minutes, it idles like new! I was wondering if it's somehow related to the choke or if I'm barking up the wrong tree. Thanks everyone!

My 80 4x4 does the same exact thing, but then internals of my engine is far from stock
the man who may have the answer to your problem is member "800xl" i consider him The "Luv encyclopedia"

The innards and gizards of my 1.8 are bone stock with a newly rebuilt Hitachi carb. I've been told it's a vacuum problem but wouldn't that affect the idle all the time?

Have you the stock breather, exhaust heat shield and the metal corrugated hose that connects the two. Right after a cold start, the vacuum operated valve in the end of the gooseneck on the breather should close allowing warm air from there to the carb when the engine is still cold.

THIS guy knows his stuff on this subject.i've read too many of his posts, so listen to him "Holy Luv"

i agree with lil blue 800xl is the man to talk too but it couold be timing?

Nevermind...

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I'll check the air breather valve at work tomorrow. We already checked the timing so I doubt that's it, but I haven't looked to see if the valve in the breather is even there! Thanks guys!

I've had two of those vacuum flapper valve deals on the air cleaner (right over the exhaust manifold) go bad on me come to think of it. They leak vac, and depending on how things are screwed up, it could only be doing it when cold.

My first thought is something choke related. It could be just out of adjustment, or the vacuum diaphram that pulls the choke open could be leaking/not working right. On a 79 carb you would have just one, little flying saucer shaped deal that sits just above where the throttle cable is bolted on. Pull the hose on it, push in the shaft with a finger (or something that fits in there) then put your finger over the vac port and release the shaft. It should hold itself in until you let your finger off the port. I've had two carbs where the arm from these gizmos to the choke linkage came loose at one end or the other too, so check for that. An older carb will actually have two of these deals that work similarly. They pull the choke open a bit once the motor starts, but before the electric choke opens it up completely. If they are working correctly, you should see the choke open and close some as you rev the motor.

You could get a feel for how choke related this is by just opening it by hand while the motor is cold and loping along. If just moving the choke butterflies gets it to smooth out, then it needs some adjustment. I'd also look some at the fast idle cam. If it isn't working right, the motor will idle slow until it warms up, which could be the source of your lope.

There are a lot of things on or around that carb that are tied to the choke or to temp. The air cleaner has temp controlled vac stuff, same with the EGR. You could narrow those down by just unhooking the hoses for them and plugging the ports. Between that stuff and the intricate choke mechanism, there are a lot of things that can go wrong.

Thanks, 800xl! I'll check those things tomorrow after church and let y'all know the results. It's great to talk with folks who understand why I drive a LUV!

I need to get my LUV running again first! It died as I was about to leave for work. He's getting spark but no fuel. I suspect a fuel pump. Can I just get a universal pump to put in place of the stock pump? How much fuel pressure is it supposed to have? Any help would be deeply appreciated!!

Yes....the universal electric fuel pump thats available in most parts houses is sufficient for your luv

I couldn't find much on PSI of the stock pump in the shop manual. From what I've seen in my own experience it should be somewhere around 5-7PSI. Too much pressure would be much more of a problem if you disconnect and plug off the return line though. So long as the excess pressure has a way to get back into the tank I'd think a little too much wouldn't be enough to blow past the needle valve in the carb. Just make sure its a pump designed for a carb and not fuel injection and you should be fine. (a lot of FI pumps run in the 30-50 PSI range, we're talking popping fuel lines off with one of them)

A Holley red pump would be a great upgrade and would supply more than enough for even a built up LUV motor. If you are looking for a duplicate stock replacement pump, JC Whitney carries one of the same exact design as the stock luv pump. They also have the internal filter available as a seperate part, just FYI.

Before you toss money into a pump though, make sure its not just an electrical problem. The two relays under that mystery cover on the passenger side inner fender are part of the control system for the pump. The pump should only run with the key turned to start, or the motor running. If you think its completely dead it may just be an electrical problem that will keep your new one from running as well. It has been my experience that stock pumps slowly stop pumping fuel, but don't tend to die outright.

Oh yeah, CHECK YOUR FUSES! I always overlook the simple answer myself. There is a fuse that runs the pump, make sure its good.

Im sorry to hear that your luv quit on you. I know how it is to be without your luv mine has not been running for four months now but hopefully I will have it back on the road tommorrow. I just have the finishing touchs left. But to the subject at hand I would change the idle i know that this seems like a easy solution and it seems to simple but it doesnt hurt to try.

All the fuses check out good! Can I just unplug the relay and jump the contacts to test the pump? If that's the case, the pump is no good! I looked at a wiring diagram off this site and jumped those two plugs and it still won't run! Seems like a bad pump to me, but I may be missing something. Any suggestions?

You could try this if you are still in doubt on the fuel pump:
Find the "hot" wire on your fuel pump, run a wire from there straight to the + side of your battery and see then see if pump works.

there is a plug that comes off of the Battery that will keep fuel from getting pumped also. It is square and has 2 wires on one side and one on the other and you can take them apart like a butt connector. just trying to help......

Thanks guys! I'll check those things out in the morning!

Found the culprit!!! Bad relay! Bypassed it and got the pump running. Getting gas out of the pump and going into the float bowl. But the dang thing still won't start! I don't get it! Good spark, getting gas to the carb now but not into the intake. I just rebuilt this carb less than 500 miles ago! What could be going on? Thanks for all your help everybody! My truck is close to being a good reliable daily driver but I've got to get little quirks like this out of him still!!

Also, should the pump be making a clicking noise when it started running after I bypassed the relay and how long should it run with the key on but not cranking the engine? Is it supposed to run constantly as long as the key is on? I'd appreciate some more direction from the experts on these trucks!