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Unread 03-04-2014, 10:21 AM   #1
skylerm727
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jeep wants to die when the gas pedal is pushed down

I own a 1982 jeep jamboree with a 1978 amc 360 i just bought it and have been trying to get it to run to perfection it has sat awhile and has been started maybe once every other month for aboit a half hour anyways it wouldnt start when i bought it so i replaced the fuel pump and it took a bit of elbow grease but she finally fired up...the only problem is when you press the gas down as if you was going to shift it dies but it wont die if you slowly press the gas down or even if you press the pedal down fast but only half way...anyways ive cleaned the holley carb and am awaiting a rebuild kit for the carb via the mail. I just want to know what i should be looking at and believe me if i had any idea i wouldnt be asking questions in other words im not so savvy when it comes to engines but i know enough to get by any help would be awesome thanks

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Unread 03-04-2014, 09:03 PM   #2
sig0jeep
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Just a thought, maybe its over carbureted? I know my 304 is with a 600 cfm Edlebrock. Just an idea though. I'm still learning about carburetors.
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Unread 03-04-2014, 09:29 PM   #3
jp360cj
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Timing, Timing advance, carburetor, choke, and power valve are all possibilities. If it starts and otherwise runs ok, then the timing is probably ok, just need to verify that the vacuum advance is working. Check the choke to make sure its set properly and opening fully. A new power valve should come in the carb rebuild kit, so the kit should take care of that problem as well as any other vacuum leaks in the carb. Make sure to follow directions on setting the choke and PV linkage, as well as for tuning the carb.
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77 CJ-7- AMC 360, Edelbrock cam, MC2100, Fenderwells, CJ T18/D20, Chevy D44/EB 9" rear, Trutrac f/r, 4.11, SOA, 1.25 lift shackles, 35x12.50 BFG KM2s, Shackle Reversal
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Unread 03-05-2014, 04:43 AM   #4
skylerm727
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Quote:
Originally Posted by sig0jeep View Post
Just a thought, maybe its over carbureted? I know my 304 is with a 600 cfm Edlebrock. Just an idea though. I'm still learning about carburetors.
Now when you say over carbureted do you mean my carburetor is too powerful or it might be lifted too high because i have a spacer under it about an inch or thicker i am learning as well and im curious as to what the spacer even does?
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Unread 03-05-2014, 04:49 AM   #5
jeepdaddy2000
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Which carb?
Sounds like a short shot in the accelerator pump or problem with the secondaries(4bbl).
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Unread 03-05-2014, 04:54 AM   #6
skylerm727
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Quote:
Originally Posted by jp360cj View Post
Timing, Timing advance, carburetor, choke, and power valve are all possibilities. If it starts and otherwise runs ok, then the timing is probably ok, just need to verify that the vacuum advance is working. Check the choke to make sure its set properly and opening fully. A new power valve should come in the carb rebuild kit, so the kit should take care of that problem as well as any other vacuum leaks in the carb. Make sure to follow directions on setting the choke and PV linkage, as well as for tuning the carb.
Thank you for laying it out its making it easier to diagnose. However i cant help but think that i might need more help when it comes to tuning the carb. If you have any advice on that or any advice in general i would love to hear it lol ...also yes it starts and runs ok it took a bit after changing the fuel pump and messing with an old fuel line and lots of carb cleaner but it finally started enough to get it to my place but anyways she purrs and its a beautiful sound untill you press the gas down fully
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Unread 03-05-2014, 06:08 AM   #7
skylerm727
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Originally Posted by jeepdaddy2000 View Post
Which carb?
Sounds like a short shot in the accelerator pump or problem with the secondaries(4bbl).
Its. 4 barrel holley carburetor List-1850-2 3503 for anyone that wants to know in other words i believe that means its a holley 850
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Unread 03-05-2014, 06:15 AM   #8
skylerm727
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So im going to take a shot in the dark an say its something to do with the carburetor based on what you all are telling me... well i have a kit on the way so i guess ill go from there and as far as tuning it ill probably have to take it to a mechanic because i am completely blind when it comes to those sorts of things.
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Unread 03-05-2014, 06:35 PM   #9
jeepdaddy2000
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An 1850-2 is a 600CFM vacuum secondary 4BBL.
With the engine off, look down the primaries and open the throttle all the way. You should get two streams of fuel squirting down the throats. If you don't, you have an accelerator pump problem.


Another thing to check is the secondary linkages. Many a shade tree mechanic has decided to turn his vacuum secondary carb into a mechanical secondary drag demon by inserting a screw or bolt into the linkage, forcing the secondaries open manually. This will create an open accelerator bog the likes of which simply needs to be experienced to appreciated.
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Unread 03-05-2014, 06:54 PM   #10
skylerm727
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Originally Posted by jeepdaddy2000 View Post
An 1850-2 is a 600CFM vacuum secondary 4BBL.
With the engine off, look down the primaries and open the throttle all the way. You should get two streams of fuel squirting down the throats. If you don't, you have an accelerator pump problem.

Another thing to check is the secondary linkages. Many a shade tree mechanic has decided to turn his vacuum secondary carb into a mechanical secondary drag demon by inserting a screw or bolt into the linkage, forcing the secondaries open manually. This will create an open accelerator bog the likes of which simply needs to be experienced to appreciated.
Ok ill try it tomorrow and let yall know the outcome...so just to clarify hit the gas if there are no streams of fuel its the accelerator pump? Which should be okay considering i have the kit to fix that. Also are you suggesting i put a bolt in the secondary or just stating that there might already be one in it? Im not so much a drag demond yet lol at this point im just trying to get the jambo to run properly... also a buddy of mine just told me that basically to tune the carb i just have to screw both bolts in on either side an then twist them out two and a half times for it to be/run "normal" ? Is this true or is it something more complicated?
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Unread 03-06-2014, 05:02 AM   #11
jeepdaddy2000
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Quote:
Originally Posted by skylerm727 View Post
Ok ill try it tomorrow and let yall know the outcome...so just to clarify hit the gas if there are no streams of fuel its the accelerator pump? Which should be okay considering i have the kit to fix that. Also are you suggesting i put a bolt in the secondary or just stating that there might already be one in it? Im not so much a drag demond yet lol at this point im just trying to get the jambo to run properly... also a buddy of mine just told me that basically to tune the carb i just have to screw both bolts in on either side an then twist them out two and a half times for it to be/run "normal" ? Is this true or is it something more complicated?
Correct. short, weak streams or dribbles are unacceptable. When you open the throttle, there is a momentary drop in vacuum. This causes a lean mixture in the intake. The accelerator pump mechanically counters this lean condition by shooting a charge of fuel down into the engine. If the pump fails (very common) or is incorrectly adjusted, it will not work properly and the lean condition will translate into an acceleration stumble. Most times this condition is accompanied by backfiring in the intake due to a lean mixture.

I'm suggesting that some one else has put a screw or bolt into the linkage. The secondaries are designed to open using intake vacuum. Back in the day, high schoolers with no real knowledge used to get the bright idea of "modifying" the carb for better performance. All this did was force the secondaries open too early and allow the engine to fall on it's face. This condition was prevalent under hard acceleration or in the last 1/3 of throttle pedal travel. If this is the area your having issues in, you may also want to take a look at the secondary float and jets. You may have gotten something in there and if a jet is blocked, you will have a lean mix in the upper end of the throttle travel.



Idle mixture adjustment needs to be done with the engine running. 2.5 turns is only the starting point.
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Unread 03-06-2014, 05:14 AM   #12
skylerm727
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Originally Posted by jeepdaddy2000 View Post

Correct. short, weak streams or dribbles are unacceptable. When you open the throttle, there is a momentary drop in vacuum. This causes a lean mixture in the intake. The accelerator pump mechanically counters this lean condition by shooting a charge of fuel down into the engine. If the pump fails (very common) or is incorrectly adjusted, it will not work properly and the lean condition will translate into an acceleration stumble. Most times this condition is accompanied by backfiring in the intake due to a lean mixture.

I'm suggesting that some one else has put a screw or bolt into the linkage. The secondaries are designed to open using intake vacuum. Back in the day, high schoolers with no real knowledge used to get the bright idea of "modifying" the carb for better performance. All this did was force the secondaries open too early and allow the engine to fall on it's face. This condition was prevalent under hard acceleration or in the last 1/3 of throttle pedal travel. If this is the area your having issues in, you may also want to take a look at the secondary float and jets. You may have gotten something in there and if a jet is blocked, you will have a lean mix in the upper end of the throttle travel.

Idle mixture adjustment needs to be done with the engine running. 2.5 turns is only the starting point.
Okay ill keep you posted when I get some daylight thanks for all the knowledge by the way...im sure ill have plenty more questions haha
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Unread 03-06-2014, 02:54 PM   #13
skylerm727
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Quote:
Originally Posted by jeepdaddy2000 View Post

Correct. short, weak streams or dribbles are unacceptable. When you open the throttle, there is a momentary drop in vacuum. This causes a lean mixture in the intake. The accelerator pump mechanically counters this lean condition by shooting a charge of fuel down into the engine. If the pump fails (very common) or is incorrectly adjusted, it will not work properly and the lean condition will translate into an acceleration stumble. Most times this condition is accompanied by backfiring in the intake due to a lean mixture.

I'm suggesting that some one else has put a screw or bolt into the linkage. The secondaries are designed to open using intake vacuum. Back in the day, high schoolers with no real knowledge used to get the bright idea of "modifying" the carb for better performance. All this did was force the secondaries open too early and allow the engine to fall on it's face. This condition was prevalent under hard acceleration or in the last 1/3 of throttle pedal travel. If this is the area your having issues in, you may also want to take a look at the secondary float and jets. You may have gotten something in there and if a jet is blocked, you will have a lean mix in the upper end of the throttle travel.

Idle mixture adjustment needs to be done with the engine running. 2.5 turns is only the starting point.
Okay so i hit the gas with the vehicle off and no gas...i looked into the carb and there is fuel level with the screw holes now ive put gas directly into all the barrels and it dont even sound like it wants to start not a spudder or anything
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Unread 03-06-2014, 03:39 PM   #14
jeepdaddy2000
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Quote:
Okay so i hit the gas with the vehicle off and no gas.
Opening the throttle, you should see this



If not, then this is your issue

This is on the bottom of your front bowl.
Typical linkage




linkage


Dis-assembled


Malfunctions are caused by broken/missing/mal-adjusted linkage
Bad diaphragm (hardened or leaking)
Frozen check ball
Plugged passage/jet


Quote:
now ive put gas directly into all the barrels and it dont even sound like it wants to start not a spudder or anything
Very possible you have flooded the engine.
you may need to crank it for a while or pull the plugs and dry them out.
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Unread 03-06-2014, 05:11 PM   #15
skylerm727
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Quote:
Originally Posted by jeepdaddy2000 View Post

Opening the throttle, you should see this

If not, then this is your issue

This is on the bottom of your front bowl.
Typical linkage

linkage

Dis-assembled

Malfunctions are caused by broken/missing/mal-adjusted linkage
Bad diaphragm (hardened or leaking)
Frozen check ball
Plugged passage/jet

Very possible you have flooded the engine.
you may need to crank it for a while or pull the plugs and dry them out.
I got it to finally crank ...and i got my kit in the mail for the carb rebuild but the accelerator pump plunger gasket lookin thingy dont look like the rite size which is pretty much tellin me i got the wrong kit...and the accelerator pump hardware was pretty much my soal purpose for buying the kit.
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