Set the plugs at .034 because the Ford Ranger label said .032-.036 for my 4 cyl, 2.0 engine.

It runs rough and I don't know whether I should reset them at .032 or .036 or some other gap size. Any suggestions, please.

I'm afraid to call the "Zone" or "Advanced Auto" because they'll probably tell me something else but they may be right.

Thanks.

Carl

 

Well I called Auto zone and they said .034 gap and Advance Discount Auto said .034 also.

Poured some STP Fuel cleaner into the tank. Hope that helps.

But should I go towards .032 or .036 on the gap size?

 

NO, don't bother. They'll still work good even after they've eroded well beyond spec. I've heard guys tell me that they pulled their plugs to gap 'em and they were ridiculously out but they would have never known by how the engine ran. The fuel cleaner may help if its a fuel quality problem, but I'm afraid it might be more. Try cleaning your MAF, pull any codes in the computer, change fuel filter if due, change PCV valve if its due, etc. Let us know with updates.

Fred

 

Thanks for your suggestions, Fred. 83s did not have MAF or computer to pull codes.

Installed new PCV valve, rotor, distributor cap, ignition wire set, ignition coil and of course the plugs.

My fuel filter is new but I coul;d replace that again too. They don't cost that much.

When I rev the enigine up it runs pretty smooth but as soon as it gets into the lower
rpms, it runs rough. And then stalls out.

One thing I do remember. With then old PCV there were 2 small tubes that ran to it but the LARGE hose was not connected. When I installed the new one, I made sure the LARGE hose WAS connected. Do you think it might run better if I disconnect it from the LARGE hose?

The LARGE hose is connected to the part with the rattle in it.

This is a single barrel carb. Should I adjust the air/fuel mixture screw? I don't know much about adjusting that but I wouldn't want to screw it up more.

 

OOps, forgot it was that old. Classic for sure. Easy fuel system. Love 'em. Single barrel carbs rule, easy rebuild and reliable as heck.

The air fuel screw adjusts the mixture only for idle speed and just beyond. It has negligible effect at higher throttle openings as that is guaged by the main jets with their tappered needles. You should adjust this to maximize idle performance by hooking a tach to your distributor and adjusting the screw at idle till you hit max rpm(don't touch the throttle at all during this), then richen the mixture by abou 1/4 turn( you won't see idle increase when you do this, if it decreases AT ALL, you've richened too far). Clockwise to lean, counterclockwise to richen. Then adjust idle speed screw till you at spec.

Did you rebuild the carburator lately? They do like being rebuilt from time to time. Not necessary but you get to know it better. Your float in the fuel bowl may be set too high or the fuel needle valve that the float assembly controls may be leaking, causing the fuel level to be too high in the bowl, making the mix rich. Does your exhaust smell rich at idle or is there black soot in your tailpipe?

Leave the big hose connected to the PCV valve. The small one too. The hose I beleive goes to the throttle boddy portion of the carburator and takes vaccum from the underside of the buttlerfly. Disconnecting is a vaccum leak to the engine.

If your unsuccessfull with adjusting the idle mix, then rebuild the carb. A new needle valve is included in the kit, but buy a new float if it's sold seperately. Be patient and as accurate as possible with the float adustment.

Good luck

Fred

 

Many thanks for your suggestions, Fred.

The carb is only about 1 year old. I think that the rebild would be the very last thing I'd try.

The exhaust is not sooty or black so I'm kind glad about that. Not too rich.

Many years ago I took a car to a tuneup shop and they put a small sensing tube intp
the carb and then I think they adjusted the carb air/fuel for optimum. Sure wish I could do that.

And I don't own a tach so I'll have to see how much they are.

Question: I haven't had the timing belt (chain?) changed in a long time. Do you think that the problem could be a sloppy chain overdue for replacement?

Many thanks for your details on how to adjust the carb; much appreciated.

Carl

 

Fred,

When I have the hood up and am leaning into the engine fron the left side (driver side), there are 2 screws on the carb.

The 1 towards the radiator (front) adjusts the idle speed. Correct? and the 1 toward the firewall (rear ward) restates on a a cam that sets the chke for cold, warm and hot engine start(?).

Is that FRONT screw the one I adjust after I hook up a tach?

Carl

 

Wow. Specifically, never done that year. But, the idle speed screw simply works on a cam connected directly to the butterfly(throttle). Back then, the idle speed was controlled directly by adjusting how much the throttle itself was open. In later years, this was replaced by an IAC valve(idle air control) valve. The throttle remained completely closed while the IAC which is easily controlled by the computer, metered the correct ammount of air into the intake. The computer balancing out the injected fuel with the IAC air to control idle. The idle mixture screw just sticks out from the throttle body. It does not control a cam. It simply controls the ammount of fuel delivered for the ammount of air allowed through the butterfly. The choke cam is easily identified by the fact that it's stepped. As the choke mechanism warms and opens, it rotates the cam to reduce the idle. It ususally does this in a couple of steps. ie, from 1500 to 1200 to 1000 to 750. The linkage is bent to achieve the timing for the steps and the screw associated with the cam controls the revs on that step. The final step limited of course by the main idle speed screw. Yours might not have one and simply uses the final step as the base idle speed adjustment.

Again, the mixture screw will be all by itself and probably have a spring around it to keep the threads loaded to keep it from backing out from vibrations.

Keep me up on what you find

Fred

 

Thanks for your suggestions, Fred.

Just came home form the Advance Discount. Had to get some GOJO to look civilized again. While there I remebered that some where I read that the gas tanks on some vehicles required pressurized gas caps. The one on my truck is ancient and the black cap on top has bee missing for a long time. Installed the new one and made sure it "clicked" closed.

It seems to make a difference but whether it does or not or if its needed or not, at least I've got the right gas cap now. One more item eliminated in my pursuit of a smoother runnin' engine.

 

Newer vehicles rely on tight gas caps to keep the whole system balanced. It's all part of environmental EVAP system. It's designed to eliminate fuel evaporating into the environment like the old systems did. I dont beleive that the fuel tank is pressurized. I beleive its a slight vaccum, and any evaporated fuel gets trapped in a carbon filled canister while the engine is off. This is why its unwise to overfill the gas tank. Liquid fuel can flow into this canister and cause a rich start up problem. That old truck of yours has an EVAP cannister, but I don't think the system relies that much on a sealed gas cap, but it may. But it's a good idea to keep it tight to keep out moisture and not smell gas around the truck when she sits on a hot day.

There are vaccum lines running from the carb to the evap cannister that you might check to see if they're old and cracked/leaking. Good maintenance plan to measure the size and length of all the vaccum hoses and replace them. It's cheap and you might catch the culprit while your at it. The EGR valve is also a usual suspect. If it's leaking at the pintel, it'll affect your manifold vaccum and screw with your idle quality. A lot of people just eliminate it to solve the problem, but that' s illegal. I beleive they're cheap enough and if the engines that old, it's a normal replacement item, so don't feel put out if you replace it and it doesn't help. It meters exhaust gas so it will eventually go and cause problems.

Good luck

Fred