Carburetor problem?

[304cj77]

hey guys, so lately the jeep is firing nicely and starts right up. it also idles fine, but when i got to put it in gear and hit the gas it takes alot to get it moving, almost as if the fuel delivery isn't good. but i've checked all the fuel lines, the fuel filter and it's getting to the carb fine... what's the next thing to check? i was leaning toward it being a bad carb seeing as its so old and has only been rebuilt once.... any suggestions help. thanks!

 

[priceg]

Before you go off the deep end, rent a fuel pressure gauge to determine which direction to go.

 

[Abrokjp]

Wow OP. Read my mind. Same exact problem started in my 5 today. It is the AMC 258 i6 / 4.2l w/MC 2100. I was getting ready to post and ask how hard the rebuild was on a scale of 1-10. Mine is actually running fine when you put your foot in it, but if you are just maintaining speed, the Jeep feels almost as if it is being driven w/ the brakes on. Any help for us?

Thanks,
Matt

 

[Old Dog]

hey guys, so lately the jeep is firing nicely and starts right up. it also idles fine, but when i got to put it in gear and hit the gas it takes alot to get it moving, almost as if the fuel delivery isn't good.

Wow OP. Read my mind. Same exact problem started in my 5 today. Mine is actually running fine when you put your foot in it, but if you are just maintaining speed, the Jeep feels almost as if it is being driven w/ the brakes on. Any help for us?
Thanks,
Matt

Neither one of you say if you have problems with it missing, coughing, ect. Do you meen it just feels underpowered?
Did the jeeps run fine in the past and just start doing this?
Do either one of you know what gears you have?
Welcome to the site, I see you are both new here.

 

[Abrokjp]

Thanks Old Dog. Yeah new to here, and not a great diagnostic mechanic either. Definate loss of power, until I put it on the floor. Really bad taking off. Highway speed is not as bad, but definately there. I did drive in a really bad storm yesterday, I usually try not to drive it in the rain. Not for preservation, simply due to leaks. I am wondering if maybe the cap has a crack I can't see and there is moisture there now. Possibility? Or not?

Thanks,
Matt


Oh yeah, 3.54 (almost positive) and this morning is when it started.

 

[Old Dog]

Thanks Old Dog. Yeah new to here, and not a great diagnostic mechanic either. Definate loss of power, until I put it on the floor. Really bad taking off. Highway speed is not as bad, but definately there. I did drive in a really bad storm yesterday, I usually try not to drive it in the rain. Not for preservation, simply due to leaks. I am wondering if maybe the cap has a crack I can't see and there is moisture there now. Possibility? Or not?

Thanks,
Matt


Oh yeah, 3.54 (almost positive) and this morning is when it started.

If this just started after driving in the rain, try taking the dist.cap off and spray it with wd40. to get rid of any moisture in it.

 

[304cj77]

mine's been running fine in the past, couple months ago i replaced the distrubor and distributor drive gear, fuel lines and all. had it checked at shop and all was good. drove it for about a month then this started to happen. it doesn't die, but the idle gets really low and when driving it coughs and loses power and seems as if its not getting fuel, however it gets a good spray of fuel in the carb...

 

[priceg]

Sounds like the bowl vent valve might be stuck closed. If not a low booster signal will cause the lean pop and loss of power. I would also make sure the distributor vacuum is connected to a good source. It can not be a ported source on the carb. All of this is based on having proper fuel pressure and volume.

 

[304cj77]

it's not stuck closed/open. if i remove the airfilter ontop i can see it open and close. all vac lines are connected. i just can't decide what to do. not a misfire, its timed properly. i'm at wits end...

 

[Abrokjp]

I may have solved mine (for now). Replaced the fuel filter = no change. Replaced the fuel pump = back to normal. I went ahead and bought a rebuild kit for my 2100, figured it couldn't hurt.

Thanks for your help,
Matt

 

[gumbycj5]

i had the same problems as well, it runs fine once it gets up to speed, but taking off its a little sluggish. i have all new plugs, wires, rebuilt carb, electric fuel pump, i removed all of my emissions stuff ( anti backfire device) and all those goodies to eliminate the vacuum leak and backfiring. so now all thats hooked up is the egr valve, and the distributor. it has tons of power once i get on it.. think i should just get rid of my carb? its the motorcraft 2100. maybe thinking of going to a 4BBL edelbrock.

 

[AzOsc80]

Hey guys, anyone want to help me out, check out my thread on my carb problems... thanks...azosc80