I've got an '86 K5 Blazer. it has a 305 w/ a 4 bl. carberator. Running rough and a mechanic told me that I had Carb. problems and that it was not worth me paying him to work on it if I was wanting to sell for $1,000 or less.\

I am looking for a skematic/diagram showing all the vacuum lines, there are quite a few and I have many disconnected and dry-roted/broken.

Several years ago I was out of state and had to have the carb. rebuilt (major mistake)...the guy lost parts I think. Anyway, after switching out 8 remanuf. carb. It worked ok (not great).

I am looking to reup with a new remanuf. carb. but I would like to know that I can get the vacuum lines right.

ANYBODY KNOW IF CAN I CONVERT TO A FUEL INJECTION SYSTEM? WITH/WOUT COMPUTER

 

Full size 305. Carb stock on that Year? Do you need to pass inspections? Is this a vacuum and/or electronic carb, run by computer?


I'd bet the vacuum lines is the reason the car doesnt run right. lets see, one to brake booster, one to distributor. Oh well, all I need, I'm done. Just kidding. Is this a four or three speed auto? One off manifold to th350 if need be. One valve cover to air cleaner and one to carb/base of carb from pvc valve in valve cover. Right size lines needed here.

How many others do you have?


Let me know. If no serious pollution inspections are needed its much easier to make the 86 run like a 68? Not only that, in actual reality its really running cleaner. Totall trash dumped into mother nature is actually less but the way they are measuerd is not in totall trash, get it? They never check the junkyards for all those canisters and cats that sit out there and rot and send it back to mother nature in some other way, do they????? Got news for the pollution control experts, what goes in has to come out. it all stays on mother earth. The rest is BS.

Had a 1970 town and country wagon with four barrel and single point that passed pollution control standards in the early 80' as it was; stock. The factory polution controlled vehicles only one year old could not run cleaner. Actual tests were done by the company I worked for at the time. I dared them to check my old wagon and won the bet.

 

I think you should replace your vacuum lines. I mean, if its broken, might as well fix it. If that doesnt help ya out, you can always convert to a throttle body. Im sure you can do the conversion if you know a bit about engines. If you have replaced your vacuum lines and it still doesnt run right, look into a throttle body. Also dont trust any mechanic. He might just want the rig. Get a second opinion too. if your up to it, you could just swap your engine from a junk yard rebuild. Throw in a 350, with fuel injection and all. They are fun!

 

Fuel injection a heavy investment UNLESS you happen to have a donor truck of some sort that has the exact requirements. A 305 with a throttle body and all the sensors, computor and wiring harness.

If your own was meant to be a carb, then its set up in the computer and wiring harness differently that the throttle bodies later on. I still dont know, havent heard from you. Is this an original carb like many of the camaros built back then or was it once stock with fuel injection. I do not have the book on this truck, but there is a good way to work on this and the factory has a plan. Its not just a matter of checking vacuum lines and replacing them. If you have some serious doubts about how they are run there is an approach that ought to be followed.

The approach is laid out in most manuals and consists of taking EACH SYSTEM and going through it seperately so as to not get overwelmed with the larger picture. Pick out a small piece of the picture and make it 100% correct and then move on to another small part of the bigger picture. The factory decided long ago that these systems should all have seperate names just to make things easier.


The most confusing to me are the Emissions systems. For instance, do you or did you have a thermostatically controlled air cleaner? Simple system that switched the way air was taken into the carb/tbi based on a small thermo sensor located on the air cleaner in many cases that passed vaccum to the right hose to open or close/both a path to the heat stove (flexible metal hose running to manifold) or to the direct air into the air horn. Once warmed to the right temperature the heat stove path should close and the direct air should open.

This system is defunct in many older cars, folks just wont take care of it, but it has a couple of vacuum lines and vacuum CAN LEAK here. A few terms associated with just this ONE system, Thermal vacuum switch, aircleaner vacuum motor, air cleaner temperature sensor. Blah blah.

One more example of a system no one pays any atention to is the Evaporation control system. ECS. A very simple system using vacuum and carbon filter canistor to remove fumes from the tank and supply the needed ventilation to keep tank pressure proper. Also a system which may in fact cause a badly running engine very easily, though also very seldom.


I guess what I am trying to say is this. There once was an actual diagram right on that car/truck as soon as you opened the hood. But it was also never really complete because all systems are not contained there. The best way is the find this diagram AND a good manual and go step by step through all the individual systems replacing lines and vacuum motors and switches/sensors as you go. You might spend a couple of hundred just to accomplish this, so take your time.

There may well be web sources for these diagrams, have never checked, any others out there?

The carb itself is also a major expense but no new carb can fix things that are wrong elsewhere. As a matter of fact a good carb can get mighty mucked up with a badly running engine under it. Backfiring and such, bad vacuum and so on do not contribute to a good carb staying in good health. Many good carbs are worth way too much to beat to death because the vacuum system is so bad you are losing engine vacuum and causing other problems.

Fix the individual systems and, as a result, the whole, or eliminate the system altogether and properly so that its not interfering with operation of the engine anymore. Remember the whole time that some of these systems are very needed while others may not be. A heat stove while living in florida might only REALLY be needed 2 days a year, see what I mean?