really weird stuff with buddies inline 6

[mike4089]

my buddies inline 6 which is a rebuilt motor runs really great except for right now...he had to turn the idle all the way up to get it to idle and when giving it a little throttle it will rev up and slow down over and over...if you hammer or the gas it accelerates fine...just part throttle cruising or at a stand still it revs up and down considerably....we checked all the vacume lines wire connections and are at a complete stand still....any ideas on what it could be would be great...

[jeepsr4ever]

Sounds like it has a leak somewhere

[mike4089]

thats what we thought but we cant find anything....and it just stated happening while driving down the road

[Goose]

Get a can of wd-40 or carb cleaner and spray all the intake gaskets, and under the carb gasket.. Sounds to me like the intake manifold bolts may have backed out. it really sounds like a vacuum leak,

[ironman_gq]

check to make sure that a vacuum line didnt split. If it has a break booster make sure that isnt leaking. I definately would be suspecting a vacuum leak.

[striker]

so I was just reading thourgh some of the post last night and came across this one.... Annnd while driving back to my house tonight suddenly it stops idleing. :(: let me ask a dumb question. what should i look for the carb cleaner/wd-40 to do has I look for leaks. oh and does me being able to hold me hand over the carb and restrict air flow to make it sound and run correctly (after the engine is warm, and choke is wide open) still coinside with the same problem?? it makes sense to me.thanks

[73hornut]

Fuel filter?

[ironman_gq]

sounds like you have a clogged carb. you probably have a piece of dirt in your idle circuit. I would clean your carb completely dissasemble it and blow out every circuit with carb cleaner or brake kleen and change the fuel filter.

[jfair72]

Thats my jeep mike post about.I will start at the carb and check for dirt and then run down all the lines. Thanks for the help on this. Last night I started it and drove about 8miles and it did great. I shut it off started it about 5minutes later and it ran terrible doing the same rev up and down think ignition module would be a problem? Oh yeh I will check the intake real good to.

[76-cj7]

My buddy have a 4.2 doing the same...run great one minture then the next nothing.......ran great with choke halfway shut......tried 2 diff carbs and then came to the conclusion the fuel pump was bad when i had him crank it with the gas line to the carb off and it barely squirted any gas.......18 bucks and some odd change later we were back to 4-wheelin!

[Goose]

Well the carb cleaner or wd/40 will temporarily seal a vacum leak and you will hear the engine change rpm as it is sucked into the leak.. and it is a lot easier to spray something around suspected gaskets as a quick check..

But If you can put your hand over the carb and it suddenly runs better.. I would put money on a vacum leak.. see when you get a leak the engine is getting unmetered air (not measured by the carb so the mixture is wrong and the rpm is high cause its getting air from somewhere else. If you rev it up and the rpms come down slowly, that indicates a leak.. if you accelerate and its boggy and runs out of gas that is fuel supply.