ok... it took way too long to get the new vacuum advance..but i got
it...then i decided it would be a great idea to round off the head of
the bolts holing the old advance down...not such a great idea...2hrs
later i'm able to get those out but anyways... i install a new vacuum
advance/distributor cap/rotor button...reset the timing...and the
backfire is still there..a friend has told me it might be the Catalytic
Converter...is this a possibility?? if not any other ideas??


Mike Romain wrote:
> Ouch.... That engine's timing is also controlled by a computer....
>
> Do you still have the emissions computer running things?
>
> But anyway, the timing is also vacuum and mechanically controlled. That
> line is the vacuum advance. You should be able to take the line off the
> carb and suck on it and it should hold vacuum.
>
> Inside the distributor is a base plate that needs to be lubricated. The
> oil pad for it is under the rotor. You pull the rotor off and oil the
> center of the shaft with 10W30 oil, then work the plate.
>
> You should be able to grab the rotor and turn it. It should be heavily
> spring loaded and spring back into place fast when you let go.
>
> If you suck on that vacuum line when the distributor cap is open, you
> also should see the base plate move or at least you should be able to
> move the vacuum advance linkage with your fingers.
>
> Check that stuff out and get back to us. There are more things to
> 'play' with, but the 'basics' need to work first.
>
> 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)
>
> Danny wrote:
> >
> > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > pretty well restoring it from its previous condition of scarecrow in a
> > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > fuel filter/ air filter... but i have a continuous muffled backfire...
> > however when adjusting the timing while trying to fix this i noticed
> > that it goes away when i block the green tube that goes from the carb
> > to the vassum control(i think...its on the side of the distributor)
> > anyways when i block that the backfire stops...when i unblock it the
> > backfire starts again... if anyone has any suggestion please let me
> > know... Thanks....
> >
> > ~Dan

 

ok... it took way too long to get the new vacuum advance..but i got
it...then i decided it would be a great idea to round off the head of
the bolts holing the old advance down...not such a great idea...2hrs
later i'm able to get those out but anyways... i install a new vacuum
advance/distributor cap/rotor button...reset the timing...and the
backfire is still there..a friend has told me it might be the Catalytic
Converter...is this a possibility?? if not any other ideas??


Mike Romain wrote:
> Ouch.... That engine's timing is also controlled by a computer....
>
> Do you still have the emissions computer running things?
>
> But anyway, the timing is also vacuum and mechanically controlled. That
> line is the vacuum advance. You should be able to take the line off the
> carb and suck on it and it should hold vacuum.
>
> Inside the distributor is a base plate that needs to be lubricated. The
> oil pad for it is under the rotor. You pull the rotor off and oil the
> center of the shaft with 10W30 oil, then work the plate.
>
> You should be able to grab the rotor and turn it. It should be heavily
> spring loaded and spring back into place fast when you let go.
>
> If you suck on that vacuum line when the distributor cap is open, you
> also should see the base plate move or at least you should be able to
> move the vacuum advance linkage with your fingers.
>
> Check that stuff out and get back to us. There are more things to
> 'play' with, but the 'basics' need to work first.
>
> 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)
>
> Danny wrote:
> >
> > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > pretty well restoring it from its previous condition of scarecrow in a
> > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > fuel filter/ air filter... but i have a continuous muffled backfire...
> > however when adjusting the timing while trying to fix this i noticed
> > that it goes away when i block the green tube that goes from the carb
> > to the vassum control(i think...its on the side of the distributor)
> > anyways when i block that the backfire stops...when i unblock it the
> > backfire starts again... if anyone has any suggestion please let me
> > know... Thanks....
> >
> > ~Dan

 

ok... it took way too long to get the new vacuum advance..but i got
it...then i decided it would be a great idea to round off the head of
the bolts holing the old advance down...not such a great idea...2hrs
later i'm able to get those out but anyways... i install a new vacuum
advance/distributor cap/rotor button...reset the timing...and the
backfire is still there..a friend has told me it might be the Catalytic
Converter...is this a possibility?? if not any other ideas??


Mike Romain wrote:
> Ouch.... That engine's timing is also controlled by a computer....
>
> Do you still have the emissions computer running things?
>
> But anyway, the timing is also vacuum and mechanically controlled. That
> line is the vacuum advance. You should be able to take the line off the
> carb and suck on it and it should hold vacuum.
>
> Inside the distributor is a base plate that needs to be lubricated. The
> oil pad for it is under the rotor. You pull the rotor off and oil the
> center of the shaft with 10W30 oil, then work the plate.
>
> You should be able to grab the rotor and turn it. It should be heavily
> spring loaded and spring back into place fast when you let go.
>
> If you suck on that vacuum line when the distributor cap is open, you
> also should see the base plate move or at least you should be able to
> move the vacuum advance linkage with your fingers.
>
> Check that stuff out and get back to us. There are more things to
> 'play' with, but the 'basics' need to work first.
>
> 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)
>
> Danny wrote:
> >
> > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > pretty well restoring it from its previous condition of scarecrow in a
> > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > fuel filter/ air filter... but i have a continuous muffled backfire...
> > however when adjusting the timing while trying to fix this i noticed
> > that it goes away when i block the green tube that goes from the carb
> > to the vassum control(i think...its on the side of the distributor)
> > anyways when i block that the backfire stops...when i unblock it the
> > backfire starts again... if anyone has any suggestion please let me
> > know... Thanks....
> >
> > ~Dan

 

Did you make sure the mechanical advance was working by manually
twisting the rotor to make sure it twists smooth with a strong spring
load back? This is a different animal than the vacuum advance.

Do you have the computer still running the timing? If so did you set it
by the emissions label directions?

You should be able to get an idea of the cat's condition using a vacuum
gauge I think. We are lucky here in Canada, CJ's didn't come with cats
up here.

I also think an air leak into the exhaust can cause backfire. Is the
manifold nice and tight? Might be worth putting a wrench on it to see.

Mike

Danny wrote:
>
> ok... it took way too long to get the new vacuum advance..but i got
> it...then i decided it would be a great idea to round off the head of
> the bolts holing the old advance down...not such a great idea...2hrs
> later i'm able to get those out but anyways... i install a new vacuum
> advance/distributor cap/rotor button...reset the timing...and the
> backfire is still there..a friend has told me it might be the Catalytic
> Converter...is this a possibility?? if not any other ideas??
>
> Mike Romain wrote:
> > Ouch.... That engine's timing is also controlled by a computer....
> >
> > Do you still have the emissions computer running things?
> >
> > But anyway, the timing is also vacuum and mechanically controlled. That
> > line is the vacuum advance. You should be able to take the line off the
> > carb and suck on it and it should hold vacuum.
> >
> > Inside the distributor is a base plate that needs to be lubricated. The
> > oil pad for it is under the rotor. You pull the rotor off and oil the
> > center of the shaft with 10W30 oil, then work the plate.
> >
> > You should be able to grab the rotor and turn it. It should be heavily
> > spring loaded and spring back into place fast when you let go.
> >
> > If you suck on that vacuum line when the distributor cap is open, you
> > also should see the base plate move or at least you should be able to
> > move the vacuum advance linkage with your fingers.
> >
> > Check that stuff out and get back to us. There are more things to
> > 'play' with, but the 'basics' need to work first.
> >
> > 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)
> >
> > Danny wrote:
> > >
> > > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > > pretty well restoring it from its previous condition of scarecrow in a
> > > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > > fuel filter/ air filter... but i have a continuous muffled backfire...
> > > however when adjusting the timing while trying to fix this i noticed
> > > that it goes away when i block the green tube that goes from the carb
> > > to the vassum control(i think...its on the side of the distributor)
> > > anyways when i block that the backfire stops...when i unblock it the
> > > backfire starts again... if anyone has any suggestion please let me
> > > know... Thanks....
> > >
> > > ~Dan

 

Did you make sure the mechanical advance was working by manually
twisting the rotor to make sure it twists smooth with a strong spring
load back? This is a different animal than the vacuum advance.

Do you have the computer still running the timing? If so did you set it
by the emissions label directions?

You should be able to get an idea of the cat's condition using a vacuum
gauge I think. We are lucky here in Canada, CJ's didn't come with cats
up here.

I also think an air leak into the exhaust can cause backfire. Is the
manifold nice and tight? Might be worth putting a wrench on it to see.

Mike

Danny wrote:
>
> ok... it took way too long to get the new vacuum advance..but i got
> it...then i decided it would be a great idea to round off the head of
> the bolts holing the old advance down...not such a great idea...2hrs
> later i'm able to get those out but anyways... i install a new vacuum
> advance/distributor cap/rotor button...reset the timing...and the
> backfire is still there..a friend has told me it might be the Catalytic
> Converter...is this a possibility?? if not any other ideas??
>
> Mike Romain wrote:
> > Ouch.... That engine's timing is also controlled by a computer....
> >
> > Do you still have the emissions computer running things?
> >
> > But anyway, the timing is also vacuum and mechanically controlled. That
> > line is the vacuum advance. You should be able to take the line off the
> > carb and suck on it and it should hold vacuum.
> >
> > Inside the distributor is a base plate that needs to be lubricated. The
> > oil pad for it is under the rotor. You pull the rotor off and oil the
> > center of the shaft with 10W30 oil, then work the plate.
> >
> > You should be able to grab the rotor and turn it. It should be heavily
> > spring loaded and spring back into place fast when you let go.
> >
> > If you suck on that vacuum line when the distributor cap is open, you
> > also should see the base plate move or at least you should be able to
> > move the vacuum advance linkage with your fingers.
> >
> > Check that stuff out and get back to us. There are more things to
> > 'play' with, but the 'basics' need to work first.
> >
> > 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)
> >
> > Danny wrote:
> > >
> > > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > > pretty well restoring it from its previous condition of scarecrow in a
> > > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > > fuel filter/ air filter... but i have a continuous muffled backfire...
> > > however when adjusting the timing while trying to fix this i noticed
> > > that it goes away when i block the green tube that goes from the carb
> > > to the vassum control(i think...its on the side of the distributor)
> > > anyways when i block that the backfire stops...when i unblock it the
> > > backfire starts again... if anyone has any suggestion please let me
> > > know... Thanks....
> > >
> > > ~Dan

 

Did you make sure the mechanical advance was working by manually
twisting the rotor to make sure it twists smooth with a strong spring
load back? This is a different animal than the vacuum advance.

Do you have the computer still running the timing? If so did you set it
by the emissions label directions?

You should be able to get an idea of the cat's condition using a vacuum
gauge I think. We are lucky here in Canada, CJ's didn't come with cats
up here.

I also think an air leak into the exhaust can cause backfire. Is the
manifold nice and tight? Might be worth putting a wrench on it to see.

Mike

Danny wrote:
>
> ok... it took way too long to get the new vacuum advance..but i got
> it...then i decided it would be a great idea to round off the head of
> the bolts holing the old advance down...not such a great idea...2hrs
> later i'm able to get those out but anyways... i install a new vacuum
> advance/distributor cap/rotor button...reset the timing...and the
> backfire is still there..a friend has told me it might be the Catalytic
> Converter...is this a possibility?? if not any other ideas??
>
> Mike Romain wrote:
> > Ouch.... That engine's timing is also controlled by a computer....
> >
> > Do you still have the emissions computer running things?
> >
> > But anyway, the timing is also vacuum and mechanically controlled. That
> > line is the vacuum advance. You should be able to take the line off the
> > carb and suck on it and it should hold vacuum.
> >
> > Inside the distributor is a base plate that needs to be lubricated. The
> > oil pad for it is under the rotor. You pull the rotor off and oil the
> > center of the shaft with 10W30 oil, then work the plate.
> >
> > You should be able to grab the rotor and turn it. It should be heavily
> > spring loaded and spring back into place fast when you let go.
> >
> > If you suck on that vacuum line when the distributor cap is open, you
> > also should see the base plate move or at least you should be able to
> > move the vacuum advance linkage with your fingers.
> >
> > Check that stuff out and get back to us. There are more things to
> > 'play' with, but the 'basics' need to work first.
> >
> > 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)
> >
> > Danny wrote:
> > >
> > > I have an 84 cj-7 and i dont know a lot about them... but i've done
> > > pretty well restoring it from its previous condition of scarecrow in a
> > > field.. anyways i have replaced the carb/spark plugs/spark plug wires/
> > > fuel filter/ air filter... but i have a continuous muffled backfire...
> > > however when adjusting the timing while trying to fix this i noticed
> > > that it goes away when i block the green tube that goes from the carb
> > > to the vassum control(i think...its on the side of the distributor)
> > > anyways when i block that the backfire stops...when i unblock it the
> > > backfire starts again... if anyone has any suggestion please let me
> > > know... Thanks....
> > >
> > > ~Dan