My initial question is, what is the state of your vacuum system? I'm betting it is either mostly ripped out or full of holes and the various functions that it performes are failing, (Not all those functions are for emissions control). I'd also bet that the EGR is not functioning properly. An 83 engine can run just fine without the EGR function BUT the EGR valve must be totally closed and not stuck open by carbon. If you removed the carb, I'd bet you would find the tons of carbon in the EGR spacer plate as well as in the valve. What I'm starting to get at here is that If you want the 83 engine to run nice and smooth with plenty of power in reserve, you have some fun
/ (serious, depending on how you view working on an engine)
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I don't know where you are, but I'm assuming you may have to pass some sort of emissions inspection. Also, I am assuming you want the truck to have reasonable cold start and run characteristics. My response is based on the above assumptions. I don't believe your problems on an old engine are the result of a single cause, but a combination of problems. Don't waste your money buying parts untill you have pretty much determined what parts are not functioning, then go ahead and spend it wisely
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OK first my bronco is a 1983 with a 302 carb. The carb is th original and that is what i am thinking is the problem. But here is what is happening. First of starting my truck and keeping it started is very hard. I have adjusted the idle regulator and it is as far back as it gets but yet it still idles too high in park and not high enought in drive or reverse. I have to literally drive with both feet and keep my foot on the gas and brake at teh same time when i am stopped while it's running. I can't think of anything else it ca be.
By idle regulator are you talking about the fast idle adjustment? If so, that has nothing to do with the the idle when in gear (curb idle), other than it needs to be set properlly first. Once
fast idle has been set, then the
curb idle needs to be set, (see procedure on the emission sticker). The problem here is that if the carb is in bad shape and/or you have vacuum leaks, there is no point in wasting your time on either adjustment. Also, an engine with automatic transmission needs to idle faster in neutral than a standard transmission with the clutch depressed. With curb idle set properly, (automatic transmission), the engine idles around 1200 to 1400 RPM when in neutral, (curb idle ending up around 600 to 650 RPM), while a sandard transmission engine is around 550 RPM with the clutch depressed). Those are not hard and fast numbers, just approximates, (some people like to idle a little faster and others a little slower).
The first thing I would do is get a new carb,
not a rebuild kit. Rebuild kits don't address vacuum leaks caused by worn parts. Most likely there are clogged ports and channels in the carb causing the fuel metering to be at best poor.
I also lose rpms and speed going up hills and this is not a little amount of speed either. When i start losing the speed i try to accelerate but it won't i have to floor it just to maintain speed. This happens on the litlest of hills too.
Most likely carb and vacuum problems.
Any suggestions? I think i just need a new carb but if you guys know of any sensors or anything....oh and that idle regulator i told you about. I think i am going to replace that first. I don't know f those are sold by autzone or not. i will check with them. But if you have anything else to add. i won't mind. Thanks in advance
Now, getting back to your vacuum system in general. Every vacuum line has a specific function and not all of them are for controlling exhaust emissions. If you decide to remove some of it, here are some controls I would suggest that you leave because they do actually benefit you and
Do Not mess with your engines ability to produce power.
A sample of my sticker attached, (color enhanced lines), followed by the diagram of what I have connected in my truck. You might note it is a sticker for an 85 Bronco, that is because the engine is from an 85 Bronco and I decided to use the 85 vacuum hookup.
1. Heat control valve function -
Orange lines on your emissions sticker (Cold Start and Run characteristics -Allows the engine to run better when cold, it shuts off automatically when the engine temperature is up to around 125 degrees), ( especially desirable during winter in colder climates as it helps cold fuel vaporize before it is sucked into the combustion chamber). (Another note here: This is what used to be called a heat riser when it was controlled by a bi-metal spring. In a vacuum controlled system, it is called a "heat control valve" and it diverts exhaust gas into the intake manafold. It has two parts one on the exhaust and one on the intake manafold. Often the device on the intake manafold is stuck closed or open by carbon or the flapper is burned off completely and needs replacement, and the one on the exhaust may be burned off as well. That results in it never functioning or it is always feeding some exhaust into the intake manafold. Neihter case is good, the first causes poor cold start and run characteristics and the second causes poor worm/hot run characteristics. I'm saying take them off and check them for physical and functional problems.
2. Evaporative emissions function - Usually
black (benefits you by keeping the gas tank presure even, especially from over pressurizing in the summer from expansion as the sun heats the air up). It also keeps evaporated fuel out of the atmosphere.
Black is sometimes indiscriminately used for other functions as well.
3. The Air cleaner vacuum controls -
Red (main vacuum direct), In the summer it does nothing but just allow fresh cold air in from the front scoop. When it is cold out it mixes in warm air as needed for better cold start and run characteristics based on the components installed in the vacuum line, (improved fuel vaporization when the engine is cold).
4. Ignition Vacuum advance -
Yellow, need I say more
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Other vacuum lines shown on the enhanced color diagram are:
1. The throttle kicker system -
Blue sometimes shown as dashed lines, I use it for adjusting the carb idle speed when the electric fan kicks on and momentarily lugs the engine down, (prevents stalling when setting in traffic at idle). The original use is for the same reason but when the A/C compressor kicks in.
2. Exhaust Gas Recycling -
Green exhaust emissions (In later model Broncos, they use it take advantage of the cooling effect of this function on the combustion chamber gasses to allow the EEC controlled engines to be more agressive with timing, use lower octane fuel, and control knock). Also,
White is mainly used as the EGR vacuum source which is different than main vacuum.
3. Thermactor (air pump) controlls -
Pink, Also, used to controling the amount of oxygen in the exhaust to assist the CAT in burning off undesirable combustion byproducts plus it also controls the point and amount of air injected under different running conditions.
OK, that is my .02 on the subject, hope that helps. Sorry to have bla bla blabed so much but I couldn't help myself :blush: .
Good luck,
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isn't it supposed to NOT rev up? I am confused as to what that wil tell me. Can you expound please. Thanks!
This technique is used to expose vacuum leaks. A vacuum leak will **** in some of it in and cause the engine to speed up. I find that a controlled release of propane using a hose to direct it at specific points makes it easy to locate a vacuum leak. (Move the nozzle along a vacuum line, near vacuum components, around the base and pivot points of the carb, etc. and listen for the engine to increase in speed).
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