Need Help! 83 jeep CJ7 has no top end power

[Ed Bister]

I just has the carb rebuilt and it still has no top end power. I messed with the timing and it seemed to help alittle but the engin idles great and when the secondarys open i get no power just a loud throaty sound from the weber carb but no acceleration past half throtle. new cap rotor and plug even. like i said it idles great and leaves the driveway great but as soon as you step on it there is no power. Could it be a problem with the distributor or igntion? I didn't see any points just a pick up under the rotor. I checked the vacume advance and it seems to advance when vacume picks up just fine but still there is no power after half throtle. I cant even really get it up over 45 MPH.

Any and all help would be great!

Thanks!:awesomework:

 

[Fordzuki]

Those sound like pretty typical symptoms of a jeep. :redneck:

Fuel filter? and are you running mechanical or electric pump?

 

[TreeClimber]

Driveability issues need more info than you are giving.

Year, motor, trans, axle & tire size, etc.....

You could have anything from a clogged catalytic convertor, to a jumped timing chain, to oversized carb in relation to the fuel pump, to a clogged vent on the fuel tank. Too many ideas, not enough facts.

 

[zukkev]

Is fuel even dumping into the secondary when opened???

 

[Ed Bister]

Those sound like pretty typical symptoms of a jeep. :redneck:

Fuel filter? and are you running mechanical or electric pump?

Fuel filter is tomorrow and its a mechanical pump farly new too I think.

I think it's in the ignition/distributor maybe coil or the little capasitor on the side of the coil.

I really dont know whats wrong with it.

I was hoping someone has had this problem before:booo:

 

[zukkev]

Better yet, what was the reason that led you to believe the carb needed overhauled to begin with....???

 

[TreeClimber]

Fuel filter is tomorrow and its a mechanical pump farly new too I think.

I think it's in the ignition/distributor maybe coil or the little capasitor on the side of the coil.

I really dont know whats wrong with it.

I was hoping someone has had this problem before:booo:

Diagnosing the problem will require more info. Re-read the last few posts and type the Paul Harvey version

 

[Ed Bister]

Driveability issues need more info than you are giving.

Year, motor, trans, axle & tire size, etc.....

You could have anything from a clogged catalytic convertor, to a jumped timing chain, to oversized carb in relation to the fuel pump, to a clogged vent on the fuel tank. Too many ideas, not enough facts.

its a 1983 CJ7 renagade stock 4.2l 258ci 5speed weber carb (just got back from the carb shop $200) also de emissioned

This thing used to run great and all of a sudden one day it started not having any power when you put your foot in it. a tune up helped alittle but was told buy the owner that the shop that did the tune up said that he needed carb work. I found a bad power valve and had the whole carb redone but it still has no power when you put your foot to the floor. my toyota with a 22re ang 36 swampers woulde smoke this thing. Are they just a gutless motor?

one question.......whats the other line that runs to the filter? I think it runs to the tank but like a vacume line of some sort. it comes up under the master cylinder and up the engin under the intake manifold.

:beer:

Ps. sorry about my spelling my daughter is banging on the key board making this very hard to type....LOL

 

[Ed Bister]

Better yet, what was the reason that led you to believe the carb needed overhauled to begin with....???

I didn't see anything coming out the secondarys and took it apart found a bad power valve. It's quite loud when I go to full throtle VERY throaty.......... but no go.

 

[zukkev]

its a 1983 CJ7 renagade stock 4.2l 258ci 5speed weber carb (just got back from the carb shop $200) also de emissioned

This thing used to run great and all of a sudden one day it started not having any power when you put your foot in it. a tune up helped alittle but was told buy the owner that the shop that did the tune up that he needed carb work. I found a bad power valve and had the whole carb redone but it still has no power when you put your foot to the floor. my toyota with a 22re ang 36 swampers woulde smoke this thing. are they just a gutless motor?

one question.......what the other line that runs to the filter? I think it runs to the tank but like a vacume line of some sort. it comes up under the master cylinder and up the engin under the intake manifold.

:beer:

The other line off the filter is Jeep's version of the fuel return line IIRC...

 

[zukkev]

I didn't see anything coming out the secondarys and took it apart found a bad power valve. It's quite loud when I go to full throtle VERY throaty.......... but no go.

Have you tested fuel psi/volume at the carb? Have you put a timing light on it and set the timing properly?

 

[Ed Bister]

The other line off the filter is Jeep's version of the fuel return line IIRC...

hmmmmmm well i will check the filter tomorrow...........he tolde me he ran outta gas a couple times so maybe its pluged.......knowing my luck it wont be that easy.

thanks for trying to help Kevin!:beer:

 

[TreeClimber]

its a 1983 CJ7 renagade stock 4.2l 258ci 5speed weber carb (just got back from the carb shop $200) also de emissioned

This thing used to run great and all of a sudden one day it started not having any power when you put your foot in it. a tune up helped alittle but was told buy the owner that the shop that did the tune up that he needed carb work. I found a bad power valve and had the whole carb redone but it still has no power when you put your foot to the floor. my toyota with a 22re ang 36 swampers woulde smoke this thing. are they just a gutless motor?

one question.......what the other line that runs to the filter? I think it runs to the tank but like a vacume line of some sort. it comes up under the master cylinder and up the engin under the intake manifold.

:beer:

CJs have a fuel return line from the fuel filter.
Put it in low range without locking the hubs and drive it. See if it clears up or not.
You could have a clogged catalytic convertor. Loosen the exhaust at one of the flanges between the motor and the cat, to allow excess pressure to escape. Yeah, it'll be noisy, but re-drive it, and see if the problems gone.
You could have a bad fuel filter, not allowing enough fuel to flow into the car, starving it.
You could have a bad fuel line, that's collapsing, and starving the motor,
You could have a bad fuel cap, which is not venting properly, thus creating a vacuum in the tank, preventing fuel from pumping properly
You could have a weak fuel pump.
You could have too much tire for the motor to turn.
You could have jumped timing, and the camshaft and crankshaft are no longer in sinc. You can verify by bringing the crank to TDC, and looking at the timing marks of the distributor.
I'll think of more could haves....
t

 

[zukkev]

CJs have a fuel return line from the fuel filter.
Put it in low range without locking the hubs and drive it. See if it clears up or not.
You could have a clogged catalytic convertor. Loosen the exhaust at one of the flanges between the motor and the cat, to allow excess pressure to escape. Yeah, it'll be noisy, but re-drive it, and see if the problems gone.
You could have a bad fuel filter, not allowing enough fuel to flow into the car, starving it.
You could have a bad fuel line, that's collapsing, and starving the motor,
You could have a bad fuel cap, which is not venting properly, thus creating a vacuum in the tank, preventing fuel from pumping properly
You could have a weak fuel pump.
You could have too much tire for the motor to turn.
You could have jumped timing, and the camshaft and crankshaft are no longer in sinc. You can verify by bringing the crank to TDC, and looking at the timing marks of the distributor.
I'll think of more could haves....
t

Just a small list, eh???!!! And yes, there are more 'You could have' 's, such as the carb still not working properly...And no prob, Good luck with the fix Ed!!! :awesomework:

 

[Ed Bister]

You could have a clogged catalytic convertor. Loosen the exhaust at one of the flanges between the motor and the cat, to allow excess pressure to escape. Yeah, it'll be noisy, but re-drive it, and see if the problems gone.
You could have a bad fuel filter, not allowing enough fuel to flow into the car, starving it.
You could have a bad fuel line, that's collapsing, and starving the motor,
You could have a bad fuel cap, which is not venting properly, thus creating a vacuum in the tank, preventing fuel from pumping properly
You could have a weak fuel pump.
You could have too much tire for the motor to turn.
You could have jumped timing, and the camshaft and crankshaft are no longer in sinc. You can verify by bringing the crank to TDC, and looking at the timing marks of the distributor.
I'll think of more could haves....
t

OK this is Great stuff!

I will do the exsaust trick tomorrow along with a fuel filter. should I blow air throught the lines and try running it with out the gas cap and see if that helps? Will it mess anything to blow air back through the lines?

Also check timing marks. how does checking the Distributor help i thought you would need to check cam to crank timing. Ok i think i know the answer the dist is turned from the cam.......... but like I said it does run great till you put your foot into it. So I doubt that it is that as i have never herd a backfire or even a fart come from this motor.

This a stock rig with stock tires so it should be able to go over 45mph. I'm not a huge jeep guy but I have done a few head gasket jobs on the fuel injected 4.0 and they had a ton of power, but this carb motor is giving me hell.

Thanks so much for helping me out!

Do you know John aka avetone from auburn car repair? he is a PNWJEEP guy and lives right around the corner from me and i'm good buddys with Horus.

 

[boardbysled]

Those sound like pretty typical symptoms of a jeep. :redneck:

That was my first thought:haha::flipoff:

 

[Jeepasaurusrex]

I could never get my 258 to run correctly when setting the timing with a light. I always kept a 1/2" wrench with me and would turn the dizzy a lil, drive it, turn some more until I got it to run right. :redneck:

 

[Damnyankee]

it ran fine one day and not the next..
Idles fine and put your foot into it nothing.

I'd start with a vaccum guage on the intake manifold personnaly

 

[white-rhyno]

Do you have any idea what your total advance timing is? Initial dosent mean **** unless the mechanical advance is working. Id check that. Check with your vacuum advance disconnected.

 

[Ed Bister]

IT WAS THE DAM CAT!

Thanks to everyone that offerd adviced!:beer: