Topic: need advice! air pushing out of rear valve vent, not in. pvc open

[jmczzz]

  the air is puffing out not in from the rear valve cover pipe to the air cleaner. I checked the front vent pvc and hose it has vacuum and is not stopped up. I pulled the plug wires one at a time and each cylinder seems to be firing. What else should I check or do next.  Oh yeah I re routed the dist vac line to a branch from a bigger vacuum port now the miss seems to be gone but the idle is 3k and will only go lower if the linkage is pushed closed manually. new carb, new return spring, at wits end... need advice

[jmczzz]

I should have pointed out the carb and rerouting vac comments were follow up from a previous thread.

[sharpxmen]

the air is puffing out not in from the rear valve cover pipe to the air cleaner. I checked the front vent pvc and hose it has vacuum and is not stopped up. I pulled the plug wires one at a time and each cylinder seems to be firing. What else should I check or do next.  Oh yeah I re routed the dist vac line to a branch from a bigger vacuum port now the miss seems to be gone but the idle is 3k and will only go lower if the linkage is pushed closed manually. new carb, new return spring, at wits end... need advice

so i guess you were missing the return spring (or was busted) and you found the vac port for the distributor  - that's for the follow up on the previous thread. Ok, for idle at 3k and if you push the butterfly back by hand goes down as i understand - disconnect the accelerator cable and open the throttle by hand: is it still stay at 3k or it goes down nicely - if it goes down to idle rpm then your cable or pedal is the problem.

how much air comes out? can you inflate the tires or is just a breeze - if the later you should be fine, if it's a lot i'd say take the compression on all cylinders and report back - that's what i'm going to do tomorrow as i took out my intake and exhaust to remove a broken stud and i found quite a bit of oil in the  filter pipe - i hope for the best but i might have a piston ring set in the near future.

EDIT: i think i understand a bit better what you meant - check the port on the intake in which the front breather hose goes to (the one you mentioned is not plugged) - also, is the air coming out off the rear one when you have the engine at 3k or with the throttle fully closed?

[jmczzz]

I'll check on the air strength and at what rpm this morning. When I got the jeep it had a 1bbl rochester rigged up to run but the air cleaner was to high and the hold down had busted the yoke straddling the carb top from the hood slamming down on it, (hood had a big rusty dimple) plus the thing took a lot of battery charger and gas poured in carb to start. I bought a rebuilt stock carb but the throttle started sticking wide open when I would try to get it up a hill by flooring the gas. I replaced the regular spring and put an extra one on a different spot. I believed the kick down from the 3 seed auto was part of the problem so I cleaned and lubed that. this worked for a while and I drove it back and forth to work some (15 miles 1 way). However, low power over half throttle and she would just barley creep up the steep hills and the throttle would stick if put all the way down. This happened several times and my having to cut the key off to get it stopped so I could get under the hood and pull the throttle linkage back closed caused enough backfiring that the cat converter blew which i replaced with a flex pipe (The Arkansas Ozark Mountain area has no inspection) then the muffler blew wide open. the missing problem started after I changed dist cap, rotor and plug wires trying to improve its power. The vacuum lines were missing, so I have been learning as I go (and buying books) trying to put them back. getting the dist vac line rerouted to a stronger vac connection in the TB seems to have stop the miss and cutting out above half throttle. But now the idle won't come down by its self. Maybe all that backfiring bent the throttle butterfly shaft. I am gonna pull the carb and see what it looks like this morning. meanwhile I am losing faith in my ability to fix it. thanks for the help...

[jmczzz]

Forgot to mention that I have disconnected the gas pedal linkage and kick down linkage and that did not help the sticking throttle. I've backed off all the idle screws so no contact. I can push the throttle link and it will idle down but then it creeps back up. pulling the carb (again) this am to see what the shaft looks like... will post later. thanks...

[sharpxmen]

if it sticks without the cables attached i'd say take it out and see if it still sticks with the card out of the vehicle - if it does take it back to the store where you bought it and ask them to give you another one. If it doesn't then it could be that the area where the carb is bolted onto the intake is not flat or you have something (like the gasket) that bends the throttle body and makes it stick (this is quite unlikely but check it anyway) - i'd say take the carb back and get a replacement. oh, backfiring won't bend the butterfly (it's in the exhaust) and even if you get flames in the intake thru the carb i still don't think would bend it.

[jmczzz]

took th carb off and checked closing it seems to close all the way sitting on the bench. When I put it own initially i had included a gasket under the manifold spacer/insulator, and a gasket on top. then the carb. So thinking maybe you were right about the gasket I did not put the top one back on when I reinstalled the carb. No help still sticks open at 3k. I put new springs on the throttle return and the trans kick down. no help. extra spring on throttle , no help. I did clean out the pvc port and that seemed to help the air puffing out of the rear vent. I put it all back together and parked it in the shed. I really don't know what to do next. could it be the MCU or the fuel/air mixture 
solenoid? I'm  stumped

[sharpxmen]

for the throttle - check if it catches in the insulator, and definitely have 2 gaskets in.  if that's not it, the only thing i can think of is that somehow when you torque it down it gets bent or there is something getting in the way (screw, nut, gasket, hose) - also take a flashlight and look down with the butterfly open and see if the intake and the spacer is centered with the carb.

for the puffing on the pcv valve - take a compression test (i just did that) - one of my cylinders is lower so i guess that's why i get some blow-by, make sure both of those fittings (the ones that go on the intake) are really clean and free of any obstructions, i would take them out and clean them really well, when you have the throttle closed you should see air going into the breather in the rear of the engine and not the other way around. A compression test will confirm if it's a bad cylinder or not.

[jmczzz]

I'll put the top gasket back on. I've checked and double checked I can't see any thing obstructing the throttle or linkage. I think I'll go back to the vacuum lines as they were before. it would run ok up to 1/2 open throttle then stall and miss. If I get it back to that point then wouldn't that indicate the vacuum line hook up is the problem? Or am I way off base thinking with my head in a vacuum?

[sharpxmen]

i would solve the throttle sticking problem first - is really unsafe driving it like that. You could just for a test remove the vacuum advance line and see how it drives but check the advance with a strobe light first so make sure your distributor runs fine and the initial advance is set properly. I'm not familiar with that model but you might want to ask someone who's got the same year Jeep to take a pic of the vacuum lines and carb/intake - that would be the safest (or check one of the haynes manuals and see if they have the vac lines layout but i found that the Jeep one in my case covers a lot of years and there are quite a few things missing.

[jmczzz]

Thats what I'm trying to do. but I am stumped. any ideas?

[sharpxmen]

maybe someone here has an FSM for your year of manufacturing - that would probably the best. Can anyone can help this fellow jeeper?