'86 CJ7 Shaking after ignition is turned off

A tap with a 2x4 is a good "diagnostic", but don't get in the habit of using
it as a cure-all. One of my vehicles, a Chevy, has hammer marks all over
the starter housing from a previous owner. The actual problem turned out to
be a dead battery. ;^)

Earle

"Mike Romain" > wrote in message
...
> Just so you know, the float needles stick all the time with today's
> 'fuel'. A tap with a piece of 2x4 or a rubber mallet can fix them
> sometimes, but you also can just pull the needle and seat out from the
> front of the carb and clean the needle's 3 wings and the slide area. I
> need to do mine once a year usually.
>
> A carb kit comes with a new needle and seat and the kit costs about
> $25.00 and is easy to put in....
>
> The after running can be caused by too high an idle or more likely
> carbon buildup. There are comments earlier in the thread about the
> carbon and how to get rid of it.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Jay wrote:
> >
> > I just bought this Jeep a few weeks ago and it was running just fine.
> > About a week after I got it, I realized it needed a new carb as the
> > float was stuck in the current one. I replaced the carb with a rebuilt
> > one and it was running just fine again. Now, maybe two weeks later,
> > all of a sudden when I turn the ignition off when I get home, the
> > engine shuts off then maybe a fraction of a second later it starts
> > shaking like it wants to start up again (sort of like bucking?). I
> > have noticed the shaking is directly related to the amount of time I
> > have been driving for. If I run out for a few minutes, it might not
> > shake at all when I turn it off. But if I go for a half hour long
> > drive, when I go to turn it off, the engine starts shaking. Any ideas
> > what could be going on? Any help at all would be greatly appreciated!
> > I have a 1986 CJ7 73K, 5 speed manual with an inline 6. Thanks, Jason



*** Posted via a free Usenet account from http://www.teranews.com ***

When you are at the store and the sucker is puking gas all over the
exhaust, the 2x4 tap is a handy thing to know anyway.... Carbs are
soft, a steel hammer would hurt them unless you use a block of wood as a
buffer.

Mike

Earle Horton wrote:
>
> A tap with a 2x4 is a good "diagnostic", but don't get in the habit of using
> it as a cure-all. One of my vehicles, a Chevy, has hammer marks all over
> the starter housing from a previous owner. The actual problem turned out to
> be a dead battery. ;^)
>
> Earle
>
> "Mike Romain" > wrote in message
> ...
> > Just so you know, the float needles stick all the time with today's
> > 'fuel'. A tap with a piece of 2x4 or a rubber mallet can fix them
> > sometimes, but you also can just pull the needle and seat out from the
> > front of the carb and clean the needle's 3 wings and the slide area. I
> > need to do mine once a year usually.
> >
> > A carb kit comes with a new needle and seat and the kit costs about
> > $25.00 and is easy to put in....
> >
> > The after running can be caused by too high an idle or more likely
> > carbon buildup. There are comments earlier in the thread about the
> > carbon and how to get rid of it.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> > Canadian Off Road Trips Photos: Non members can still view!
> > Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> > (More Off Road album links at bottom of the view page)
> >
> > Jay wrote:
> > >
> > > I just bought this Jeep a few weeks ago and it was running just fine.
> > > About a week after I got it, I realized it needed a new carb as the
> > > float was stuck in the current one. I replaced the carb with a rebuilt
> > > one and it was running just fine again. Now, maybe two weeks later,
> > > all of a sudden when I turn the ignition off when I get home, the
> > > engine shuts off then maybe a fraction of a second later it starts
> > > shaking like it wants to start up again (sort of like bucking?). I
> > > have noticed the shaking is directly related to the amount of time I
> > > have been driving for. If I run out for a few minutes, it might not
> > > shake at all when I turn it off. But if I go for a half hour long
> > > drive, when I go to turn it off, the engine starts shaking. Any ideas
> > > what could be going on? Any help at all would be greatly appreciated!
> > > I have a 1986 CJ7 73K, 5 speed manual with an inline 6. Thanks, Jason
>
> *** Posted via a free Usenet account from http://www.teranews.com ***

Mike, I've never understood why some always recommend ATF which costs
money over water which does not cost money. Water works just fine, I
know of no benefit whatsoever to using ATF over water.

Do you know of some benefit that ATF provides over water when used for
this purpose?

Mike Romain wrote:
> No you need a steady slow stream of 'water' to shock the carbon off.
>
> I have had excellent results using a pint of ATF instead of water to do
> this. The ATF makes a massive cloud of smoke though. I have heard from
> enough people about the water instead that I will use that next time and
> see how it goes.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Steve Foley wrote:
>
>>Would a spray-bottle work better than pouring it in? I have one I use to
>>check for bad plug wires. Mist under the hood at night and look for the
>>light-show.
>>
>>"Jerry Bransford" > wrote in message
>>news:juwdg.1012$sP1.459@fed1read07...
>>
>>
>>>The cure, if this is the problem and it sounds like it is, is to get rid
>>>of the carbon build-up. The easiest way to do this is to slowly (!!)
>>>feed 12-16 ounces of plain water into the air intake as the engine is
>>>running, keeping the RPMs up slightly. NO, this will NOT cause
>>>hydrolock providing you feed the water in slowly and in a controlled
>>>manner over a minute to two minutes. Just slowly trickle it and
>>>maintain control over the water so you don't dump it in too quickly by
>>>accident.

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

No. I learned it from mechanics that used ATF as a part of a major tune
up for city driven vehicles to get rid of 'run on' or dieseling. I know
it works perfect because I use it before doing any head work and some of
the chunks of loose carbon left if it isn't driven before head removal
are quite big.

I think it might be for the visual effects? The tell the customer that
they are decarboning their engine and then they see the vehicle out in
the side parking lot making this amazing cloud of smoke.....????

Or maybe they see the cloud of smoke and ask, then get it done for
theirs???

No real idea Jerry.

I will use water before the next head gasket job I help with and see. I
know a water leak into a cylinder sure cleans up the spark plug....

Mike

Jerry Bransford wrote:
>
> Mike, I've never understood why some always recommend ATF which costs
> money over water which does not cost money. Water works just fine, I
> know of no benefit whatsoever to using ATF over water.
>
> Do you know of some benefit that ATF provides over water when used for
> this purpose?
>
> Mike Romain wrote:
> > No you need a steady slow stream of 'water' to shock the carbon off.
> >
> > I have had excellent results using a pint of ATF instead of water to do
> > this. The ATF makes a massive cloud of smoke though. I have heard from
> > enough people about the water instead that I will use that next time and
> > see how it goes.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> > Canadian Off Road Trips Photos: Non members can still view!
> > Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> > (More Off Road album links at bottom of the view page)
> >
> > Steve Foley wrote:
> >
> >>Would a spray-bottle work better than pouring it in? I have one I use to
> >>check for bad plug wires. Mist under the hood at night and look for the
> >>light-show.
> >>
> >>"Jerry Bransford" > wrote in message
> >>news:juwdg.1012$sP1.459@fed1read07...
> >>
> >>
> >>>The cure, if this is the problem and it sounds like it is, is to get rid
> >>>of the carbon build-up. The easiest way to do this is to slowly (!!)
> >>>feed 12-16 ounces of plain water into the air intake as the engine is
> >>>running, keeping the RPMs up slightly. NO, this will NOT cause
> >>>hydrolock providing you feed the water in slowly and in a controlled
> >>>manner over a minute to two minutes. Just slowly trickle it and
> >>>maintain control over the water so you don't dump it in too quickly by
> >>>accident.
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

Hmm, if there is blow-by, and every internal combustion engine has some blow
by, ATF isn't so bad for the oil in the crankcase as water. You can get
around this problem by taking the vehicle for a good long ride to heat up
the crankcase contents, or just change the oil, after the treatment. And
see my previous post regarding mosquitoes. ;^)

Earle

"Jerry Bransford" > wrote in message
news:rgEdg.1020$sP1.945@fed1read07...
> Mike, I've never understood why some always recommend ATF which costs
> money over water which does not cost money. Water works just fine, I
> know of no benefit whatsoever to using ATF over water.
>
> Do you know of some benefit that ATF provides over water when used for
> this purpose?
>
> Mike Romain wrote:
> > No you need a steady slow stream of 'water' to shock the carbon off.
> >
> > I have had excellent results using a pint of ATF instead of water to do
> > this. The ATF makes a massive cloud of smoke though. I have heard from
> > enough people about the water instead that I will use that next time and
> > see how it goes.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> > Canadian Off Road Trips Photos: Non members can still view!
> > Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> > (More Off Road album links at bottom of the view page)
> >
> > Steve Foley wrote:
> >
> >>Would a spray-bottle work better than pouring it in? I have one I use to
> >>check for bad plug wires. Mist under the hood at night and look for the
> >>light-show.
> >>
> >>"Jerry Bransford" > wrote in message
> >>news:juwdg.1012$sP1.459@fed1read07...
> >>
> >>
> >>>The cure, if this is the problem and it sounds like it is, is to get
rid
> >>>of the carbon build-up. The easiest way to do this is to slowly (!!)
> >>>feed 12-16 ounces of plain water into the air intake as the engine is
> >>>running, keeping the RPMs up slightly. NO, this will NOT cause
> >>>hydrolock providing you feed the water in slowly and in a controlled
> >>>manner over a minute to two minutes. Just slowly trickle it and
> >>>maintain control over the water so you don't dump it in too quickly by
> >>>accident.
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/



*** Posted via a free Usenet account from http://www.teranews.com ***

Normally this is caused by your throttle being open excessively at idle.
This can be caused by several things, but the most common a

1. Improper idle speed (too high)
2. Improper ignition timing or idle mixture adjustment, which causes the
need for excessive throttle opening at idle to compensate for poor engine
tune.
3. A disconnected or misadjusted idle solenoid.
4. Excessive carbon buildup in combustion chambers which can cause "hot
spots" which will continue to ignite the fuel even with the key off.

If you don't have a solenoid, you can probably add one. They are quite
common on automatic trans equipped vehicles. The purpose of the solenoid is
to provide the correct idle speed when the engine is running, but when the
key is turned off, the solenoid deactivates and lets the throttle close
almost completely. All you need to install the solenoid is the bracket that
attached the solenoid to the carb, and a 12 volt source which is only
charged when the key is in the run position. If you install the solenoid,
just set the idle speed screw on the carb so that the throttle plates are
just barely open, and then set the idle speed with the adjustment on the
solenoid.

Chris

"Jay" > wrote in message
oups.com...
>I just bought this Jeep a few weeks ago and it was running just fine.
> About a week after I got it, I realized it needed a new carb as the
> float was stuck in the current one. I replaced the carb with a rebuilt
> one and it was running just fine again. Now, maybe two weeks later,
> all of a sudden when I turn the ignition off when I get home, the
> engine shuts off then maybe a fraction of a second later it starts
> shaking like it wants to start up again (sort of like bucking?). I
> have noticed the shaking is directly related to the amount of time I
> have been driving for. If I run out for a few minutes, it might not
> shake at all when I turn it off. But if I go for a half hour long
> drive, when I go to turn it off, the engine starts shaking. Any ideas
> what could be going on? Any help at all would be greatly appreciated!
> I have a 1986 CJ7 73K, 5 speed manual with an inline 6. Thanks, Jason
>

The solenoids used on CJ engines were just for upping the rpm when you
put an auto in drive or if you have AC, when the AC comes on.

Properly tuned, the engine will not run on.

Adding a solenoid to fix symptoms can lead to a dead engine from carbon
pinging and/or really bad gas mileage or performance or holes in the
pistons because the carb is way off.

I highly recommend the Haynes CJ manual. It is spot on for things like
carb tuning and wiring issues.

The 'most' common cause for carb issues and carbs needing to be adjusted
wrong I have run across is trouble with the PCV or Charcoal canister
(gas tank and float bowl vents) circuit.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

c wrote:
>
> Normally this is caused by your throttle being open excessively at idle.
> This can be caused by several things, but the most common a
>
> 1. Improper idle speed (too high)
> 2. Improper ignition timing or idle mixture adjustment, which causes the
> need for excessive throttle opening at idle to compensate for poor engine
> tune.
> 3. A disconnected or misadjusted idle solenoid.
> 4. Excessive carbon buildup in combustion chambers which can cause "hot
> spots" which will continue to ignite the fuel even with the key off.
>
> If you don't have a solenoid, you can probably add one. They are quite
> common on automatic trans equipped vehicles. The purpose of the solenoid is
> to provide the correct idle speed when the engine is running, but when the
> key is turned off, the solenoid deactivates and lets the throttle close
> almost completely. All you need to install the solenoid is the bracket that
> attached the solenoid to the carb, and a 12 volt source which is only
> charged when the key is in the run position. If you install the solenoid,
> just set the idle speed screw on the carb so that the throttle plates are
> just barely open, and then set the idle speed with the adjustment on the
> solenoid.
>
> Chris
>
> "Jay" > wrote in message
> oups.com...
> >I just bought this Jeep a few weeks ago and it was running just fine.
> > About a week after I got it, I realized it needed a new carb as the
> > float was stuck in the current one. I replaced the carb with a rebuilt
> > one and it was running just fine again. Now, maybe two weeks later,
> > all of a sudden when I turn the ignition off when I get home, the
> > engine shuts off then maybe a fraction of a second later it starts
> > shaking like it wants to start up again (sort of like bucking?). I
> > have noticed the shaking is directly related to the amount of time I
> > have been driving for. If I run out for a few minutes, it might not
> > shake at all when I turn it off. But if I go for a half hour long
> > drive, when I go to turn it off, the engine starts shaking. Any ideas
> > what could be going on? Any help at all would be greatly appreciated!
> > I have a 1986 CJ7 73K, 5 speed manual with an inline 6. Thanks, Jason
> >

You're right Mike, I didn't read the end of his post where he said he had
the manual trans. It is always best to correct the problem rather than use a
band-aid.

Chris

"Mike Romain" > wrote in message
...
> The solenoids used on CJ engines were just for upping the rpm when you
> put an auto in drive or if you have AC, when the AC comes on.
>
> Properly tuned, the engine will not run on.
>
> Adding a solenoid to fix symptoms can lead to a dead engine from carbon
> pinging and/or really bad gas mileage or performance or holes in the
> pistons because the carb is way off.
>
> I highly recommend the Haynes CJ manual. It is spot on for things like
> carb tuning and wiring issues.
>
> The 'most' common cause for carb issues and carbs needing to be adjusted
> wrong I have run across is trouble with the PCV or Charcoal canister
> (gas tank and float bowl vents) circuit.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> c wrote:
>>
>> Normally this is caused by your throttle being open excessively at idle.
>> This can be caused by several things, but the most common a
>>
>> 1. Improper idle speed (too high)
>> 2. Improper ignition timing or idle mixture adjustment, which causes the
>> need for excessive throttle opening at idle to compensate for poor engine
>> tune.
>> 3. A disconnected or misadjusted idle solenoid.
>> 4. Excessive carbon buildup in combustion chambers which can cause "hot
>> spots" which will continue to ignite the fuel even with the key off.
>>
>> If you don't have a solenoid, you can probably add one. They are quite
>> common on automatic trans equipped vehicles. The purpose of the solenoid
>> is
>> to provide the correct idle speed when the engine is running, but when
>> the
>> key is turned off, the solenoid deactivates and lets the throttle close
>> almost completely. All you need to install the solenoid is the bracket
>> that
>> attached the solenoid to the carb, and a 12 volt source which is only
>> charged when the key is in the run position. If you install the solenoid,
>> just set the idle speed screw on the carb so that the throttle plates are
>> just barely open, and then set the idle speed with the adjustment on the
>> solenoid.
>>
>> Chris
>>
>> "Jay" > wrote in message
>> oups.com...
>> >I just bought this Jeep a few weeks ago and it was running just fine.
>> > About a week after I got it, I realized it needed a new carb as the
>> > float was stuck in the current one. I replaced the carb with a rebuilt
>> > one and it was running just fine again. Now, maybe two weeks later,
>> > all of a sudden when I turn the ignition off when I get home, the
>> > engine shuts off then maybe a fraction of a second later it starts
>> > shaking like it wants to start up again (sort of like bucking?). I
>> > have noticed the shaking is directly related to the amount of time I
>> > have been driving for. If I run out for a few minutes, it might not
>> > shake at all when I turn it off. But if I go for a half hour long
>> > drive, when I go to turn it off, the engine starts shaking. Any ideas
>> > what could be going on? Any help at all would be greatly appreciated!
>> > I have a 1986 CJ7 73K, 5 speed manual with an inline 6. Thanks, Jason
>> >

Hey guys thanks for all the help! Any chance someone who has the same
carb I do can tell me step by step what to do to adjust the fuel
mixture? I am not very mechanical and really not sure what to do.
Thanks again, Jason

Ouch!

It would sure be worth your while to pick up the Haynes CJ manual. It
is in the twenty dollar range and has excellent steps to fix most CJ
stuff. A carb kit for it also is in the twenty dollar range and has the
setup procedure.

The carb mix screws are supposed to be sealed and are down in the front
of the bottom plate. There are two of them. The computer is supposed
to adjust the mix as the O2 sensor tell it.

Meanwhile it needs a base mix setup.

Is the computer still part of the ignition system on your Jeep? One
sure way to tell is to look at the ignition module wayyyy down under the
washer bottle on the fender. The one plug coming out of it will have a
black, and orange and a purple wire. If the purple wire is connected to
anything, the computer has been disabled and the carb mix directions
will be different.

Figuring the computer is still in there, you need to take off the air
filter and look down inside the carb. At the back center you will see a
pin that moves in and out as the computer adjusts the mix. When the mix
screws are right, the pin edge you can see will be in the middle of it's
travel range as it idles fully warmed up.

I would recommend you warm it up and have a look first. It might not
need to be touched.

I would also recommend you pull the sparkplugs to have a look before
touching the carb. If the carb is rich, the plugs will be black and
sooty.

The mix screws should end up somewhere around 3.5 turns out when this
happens.

You start with the engine off and screw the mix screws all the way in
counting the turns so you can go back there if needed.

You then put the screws at 3.5 turns and start it up. You adjust the
idle to 650-700 rpm, then look down the carb to see where the pin is
sitting. If it is moving back and forth around it's center mark, it is
fine. If it is all the way in, the mix screws are too lean or too far
in. The pins control air and all the way in means no air or the
computer has gone rich. If the pins are all the way out, it is too rich
or the screws are too far out and the computer is letting air in to lean
it.

When adjusting the mix screws, you turn both only 1/4 turn at a time,
then give the gas a shot to rev it up.

If there is no computer, you start at 5 turns out with the pins pushed
all the way in (they don't move by themselves with no computer) and turn
then the 1/4 turn at a time, then rev. You have to adjust the idle as
you go along. When the rpm 'just' starts to stumble, you back the mix
screws back out 1/4 turn and have what's called the best lean idle mix.

I think I got all that right, if not I am sure someone will correct
me.... ;-)

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Jay wrote:
>
> Hey guys thanks for all the help! Any chance someone who has the same
> carb I do can tell me step by step what to do to adjust the fuel
> mixture? I am not very mechanical and really not sure what to do.
> Thanks again, Jason