I have a 87 yj 4.2 , that i swapped out the carb. ( rebuilt from Autozone )the idle problem that they are known for is why.
trouble is the vacuum lines have been hacked by previous owners .
related parts are missing or disconnected.I have tried to connect them by using the Haynes manual but it won't run correctly ,black smoke,hard to start,won't idle ect.
the jeep did run, just bad idle before I started.Can any one tell me the routing of just the bear minimum to get it to run ?? Ihave read about the Nutter bypass and plan on doing it.
The vacuum advance,PCV,and the brake booster I know are needed but not sure on how to go about it .also the vac.disconnect front axle is now manual.
any help would be great.Thanks in advance.
Before you go to far, black smoke is totally seperate from vac issues. If you have vac probs, or clogged idle tubes it'll run rough, not product black smoke.
So on the vac/nutter part. First, cheapest thing is to go to AZ, buy about 20 ft of vac line(s) replace every one of them. Get an assortment of "t"s and m-m couplers also. As these tubes age they crack along the sides, and have small leaks. Individually not too bad, but collectively they add up. Replace them all.
If you want to go with the nutter bypass, (I did) it is pretty easy. All your left with is vac advance to the distributer/axle disconnect, brake booster and the cross flow stuff for the PVC. Definately makes it much easier to tune, more torque and better idle. However you will not pass emissions and possibly not inspection if you have that in your state.
First, cheapest thing is to go to AZ, buy about 20 ft of vac line(s) replace every one of them. Get an assortment of "t"s and m-m couplers also. As these tubes age they crack along the sides, and have small leaks. Individually not too bad, but collectively they add up. Replace them all.
Good advice and you might want to go one step further and zip tie every one of the suckers in place.
Knowledge is what we get from reading the directions.
Experience is what we receive from not reading the directions.
Oil fouled plugs would account for the black smoke. This is prolly caused by blowby, a common occurance in our motors unfortunately. After you replace the plugs, you might wast to look at a heavier oil or a "stop smoke" addative like engine restore. It seals up the tiny scratches in the cylinder walls and slows down the blowby.
There are a lot of opinions on additives, so do a little reseach before you dump something into your motor which may make the symptoms go away, but make the overall problem worse. I have a similar prob with my 4.2 (185K) and run Engine Restore in it about once every six months. It helps in mine, but has the opposite effect in my buddies rig, so do your homework.
If you get hung up on the vac line replacement and have a few lost or not sure where they go, do a search, there are 3-4 good diagrams which show where everything is supposed to go.
Well found our problem ( yj is my 17 yr olds son's )
The plugs not oil fouled but soot and gas. It was the choke sticking closed
causing it to smoke. (it did not smoke be for carb change out).
Allso completed the nutter bypass it runs GREAT! smooth idle & pulls harder
than ever before.
thanks again for feed back