machine gun back firing - no power
07-09-2006, 12:55 PM
#21
Guest
Posts: n/a
Re: machine gun back firing - no power
I would suggest that you purchase a bottle of STP gas treatment and put it
in your tank before the next fill up. You may have picked up some water in
your gas. I have had this happen several times. And after 1 bottle, things
smoothed out.
david 91yj 05 sport.
"Rusted" <no@email.com> wrote in message
news:vV0rg.44275$Sl6.33109@fe75.usenetserver.com.. .
> Close, but not yet. I took off the distributor cap to see a ball bearing
> on top of the distributor. The top of the cap had come uncrimped and the
> parts had fallen out. New cap and rotor later and I have much more
> power, but I still get the machine gun effect at 2000 RPM.
>
> I have not cleaned the coil yet, but will do that the next time I get a
> minute. Other ideas??? Being a natural pessimist I am thinking that I
> need to remove the valve cover and check that the bolts that hold down the
> rocker arms have not worked loose.
>
> Side note. When I ask for rotor they always ask if it is a manual or
> auto. There are different part numbers. The rotor for the auto is about
> 1/8" shorter than the rotor for the manual for some reason. I think that
> the short rotors you speak of are probably the parts guy grabbing the
> wrong one.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44ABECB3.C34888EE@sympatico.ca...
>> Bad distributor cap? There are a bunch of bad caps and rotor sets out
>> there. The rotors are too short so they work for a short time, then arc
>> out all over the place.
>>
>> Oil drip onto the coil power connection or loose almost broken wire
>> there?
>>
>> 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)
>>
>> Rusted wrote:
>>>
>>> Over the past 7-10 days I have been loosing power with my '83 258 engine
>>> to
>>> the point where it is difficult to drive and keep running. It feels
>>> like I
>>> am pulling a trailer, and I am getting rapid machine gun style
>>> backfiring
>>> through the muffler when I get around 2000 RPM. It has 215,000 miles
>>> so it
>>> is a little tired anyways. It felt like the timing had slipped, like
>>> possibly the timing chain had slipped, but when I use a timing light the
>>> mark is still in the ballpark of where it should be, so I don't believe
>>> that
>>> is the case. I re-adjusted the timing using only a vacuum gauge to get
>>> the
>>> max vacuum and it now idols better, but I still get the machine gun type
>>> back firing when I get over 2000 RPM.
>>>
>>> A few months ago I replaced the valve cover from a plastic cover to an
>>> aluminum cover to stop the constant oil leak I was having. In the
>>> process I
>>> swapped the valve bridges with the non-bolt style bridge since they were
>>> not
>>> needed any longer. When did replace those I torqued them down, and used
>>> the
>>> original nuts.
>>>
>>> The vacuum advance is still moving properly and has been well cleaned.
>>>
>>> Any ideas what is going on? My first idea of timing seems to be more
>>> or
>>> less ruled out. I am now leaning towards one of the rocker bolts has
>>> come
>>> loose. Any other ideas of what to look for or check?
>>>
>>> 83 CJ-7
>>>
>>> 258 I-6 engine
>>>
>>> MC2100 carb
>>>
>>> stock and original distrubutor
>
>
>
in your tank before the next fill up. You may have picked up some water in
your gas. I have had this happen several times. And after 1 bottle, things
smoothed out.
david 91yj 05 sport.
"Rusted" <no@email.com> wrote in message
news:vV0rg.44275$Sl6.33109@fe75.usenetserver.com.. .
> Close, but not yet. I took off the distributor cap to see a ball bearing
> on top of the distributor. The top of the cap had come uncrimped and the
> parts had fallen out. New cap and rotor later and I have much more
> power, but I still get the machine gun effect at 2000 RPM.
>
> I have not cleaned the coil yet, but will do that the next time I get a
> minute. Other ideas??? Being a natural pessimist I am thinking that I
> need to remove the valve cover and check that the bolts that hold down the
> rocker arms have not worked loose.
>
> Side note. When I ask for rotor they always ask if it is a manual or
> auto. There are different part numbers. The rotor for the auto is about
> 1/8" shorter than the rotor for the manual for some reason. I think that
> the short rotors you speak of are probably the parts guy grabbing the
> wrong one.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44ABECB3.C34888EE@sympatico.ca...
>> Bad distributor cap? There are a bunch of bad caps and rotor sets out
>> there. The rotors are too short so they work for a short time, then arc
>> out all over the place.
>>
>> Oil drip onto the coil power connection or loose almost broken wire
>> there?
>>
>> 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)
>>
>> Rusted wrote:
>>>
>>> Over the past 7-10 days I have been loosing power with my '83 258 engine
>>> to
>>> the point where it is difficult to drive and keep running. It feels
>>> like I
>>> am pulling a trailer, and I am getting rapid machine gun style
>>> backfiring
>>> through the muffler when I get around 2000 RPM. It has 215,000 miles
>>> so it
>>> is a little tired anyways. It felt like the timing had slipped, like
>>> possibly the timing chain had slipped, but when I use a timing light the
>>> mark is still in the ballpark of where it should be, so I don't believe
>>> that
>>> is the case. I re-adjusted the timing using only a vacuum gauge to get
>>> the
>>> max vacuum and it now idols better, but I still get the machine gun type
>>> back firing when I get over 2000 RPM.
>>>
>>> A few months ago I replaced the valve cover from a plastic cover to an
>>> aluminum cover to stop the constant oil leak I was having. In the
>>> process I
>>> swapped the valve bridges with the non-bolt style bridge since they were
>>> not
>>> needed any longer. When did replace those I torqued them down, and used
>>> the
>>> original nuts.
>>>
>>> The vacuum advance is still moving properly and has been well cleaned.
>>>
>>> Any ideas what is going on? My first idea of timing seems to be more
>>> or
>>> less ruled out. I am now leaning towards one of the rocker bolts has
>>> come
>>> loose. Any other ideas of what to look for or check?
>>>
>>> 83 CJ-7
>>>
>>> 258 I-6 engine
>>>
>>> MC2100 carb
>>>
>>> stock and original distrubutor
>
>
>
07-09-2006, 12:55 PM
#22
Guest
Posts: n/a
Re: machine gun back firing - no power
I would suggest that you purchase a bottle of STP gas treatment and put it
in your tank before the next fill up. You may have picked up some water in
your gas. I have had this happen several times. And after 1 bottle, things
smoothed out.
david 91yj 05 sport.
"Rusted" <no@email.com> wrote in message
news:vV0rg.44275$Sl6.33109@fe75.usenetserver.com.. .
> Close, but not yet. I took off the distributor cap to see a ball bearing
> on top of the distributor. The top of the cap had come uncrimped and the
> parts had fallen out. New cap and rotor later and I have much more
> power, but I still get the machine gun effect at 2000 RPM.
>
> I have not cleaned the coil yet, but will do that the next time I get a
> minute. Other ideas??? Being a natural pessimist I am thinking that I
> need to remove the valve cover and check that the bolts that hold down the
> rocker arms have not worked loose.
>
> Side note. When I ask for rotor they always ask if it is a manual or
> auto. There are different part numbers. The rotor for the auto is about
> 1/8" shorter than the rotor for the manual for some reason. I think that
> the short rotors you speak of are probably the parts guy grabbing the
> wrong one.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44ABECB3.C34888EE@sympatico.ca...
>> Bad distributor cap? There are a bunch of bad caps and rotor sets out
>> there. The rotors are too short so they work for a short time, then arc
>> out all over the place.
>>
>> Oil drip onto the coil power connection or loose almost broken wire
>> there?
>>
>> 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)
>>
>> Rusted wrote:
>>>
>>> Over the past 7-10 days I have been loosing power with my '83 258 engine
>>> to
>>> the point where it is difficult to drive and keep running. It feels
>>> like I
>>> am pulling a trailer, and I am getting rapid machine gun style
>>> backfiring
>>> through the muffler when I get around 2000 RPM. It has 215,000 miles
>>> so it
>>> is a little tired anyways. It felt like the timing had slipped, like
>>> possibly the timing chain had slipped, but when I use a timing light the
>>> mark is still in the ballpark of where it should be, so I don't believe
>>> that
>>> is the case. I re-adjusted the timing using only a vacuum gauge to get
>>> the
>>> max vacuum and it now idols better, but I still get the machine gun type
>>> back firing when I get over 2000 RPM.
>>>
>>> A few months ago I replaced the valve cover from a plastic cover to an
>>> aluminum cover to stop the constant oil leak I was having. In the
>>> process I
>>> swapped the valve bridges with the non-bolt style bridge since they were
>>> not
>>> needed any longer. When did replace those I torqued them down, and used
>>> the
>>> original nuts.
>>>
>>> The vacuum advance is still moving properly and has been well cleaned.
>>>
>>> Any ideas what is going on? My first idea of timing seems to be more
>>> or
>>> less ruled out. I am now leaning towards one of the rocker bolts has
>>> come
>>> loose. Any other ideas of what to look for or check?
>>>
>>> 83 CJ-7
>>>
>>> 258 I-6 engine
>>>
>>> MC2100 carb
>>>
>>> stock and original distrubutor
>
>
>
in your tank before the next fill up. You may have picked up some water in
your gas. I have had this happen several times. And after 1 bottle, things
smoothed out.
david 91yj 05 sport.
"Rusted" <no@email.com> wrote in message
news:vV0rg.44275$Sl6.33109@fe75.usenetserver.com.. .
> Close, but not yet. I took off the distributor cap to see a ball bearing
> on top of the distributor. The top of the cap had come uncrimped and the
> parts had fallen out. New cap and rotor later and I have much more
> power, but I still get the machine gun effect at 2000 RPM.
>
> I have not cleaned the coil yet, but will do that the next time I get a
> minute. Other ideas??? Being a natural pessimist I am thinking that I
> need to remove the valve cover and check that the bolts that hold down the
> rocker arms have not worked loose.
>
> Side note. When I ask for rotor they always ask if it is a manual or
> auto. There are different part numbers. The rotor for the auto is about
> 1/8" shorter than the rotor for the manual for some reason. I think that
> the short rotors you speak of are probably the parts guy grabbing the
> wrong one.
>
>
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:44ABECB3.C34888EE@sympatico.ca...
>> Bad distributor cap? There are a bunch of bad caps and rotor sets out
>> there. The rotors are too short so they work for a short time, then arc
>> out all over the place.
>>
>> Oil drip onto the coil power connection or loose almost broken wire
>> there?
>>
>> 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)
>>
>> Rusted wrote:
>>>
>>> Over the past 7-10 days I have been loosing power with my '83 258 engine
>>> to
>>> the point where it is difficult to drive and keep running. It feels
>>> like I
>>> am pulling a trailer, and I am getting rapid machine gun style
>>> backfiring
>>> through the muffler when I get around 2000 RPM. It has 215,000 miles
>>> so it
>>> is a little tired anyways. It felt like the timing had slipped, like
>>> possibly the timing chain had slipped, but when I use a timing light the
>>> mark is still in the ballpark of where it should be, so I don't believe
>>> that
>>> is the case. I re-adjusted the timing using only a vacuum gauge to get
>>> the
>>> max vacuum and it now idols better, but I still get the machine gun type
>>> back firing when I get over 2000 RPM.
>>>
>>> A few months ago I replaced the valve cover from a plastic cover to an
>>> aluminum cover to stop the constant oil leak I was having. In the
>>> process I
>>> swapped the valve bridges with the non-bolt style bridge since they were
>>> not
>>> needed any longer. When did replace those I torqued them down, and used
>>> the
>>> original nuts.
>>>
>>> The vacuum advance is still moving properly and has been well cleaned.
>>>
>>> Any ideas what is going on? My first idea of timing seems to be more
>>> or
>>> less ruled out. I am now leaning towards one of the rocker bolts has
>>> come
>>> loose. Any other ideas of what to look for or check?
>>>
>>> 83 CJ-7
>>>
>>> 258 I-6 engine
>>>
>>> MC2100 carb
>>>
>>> stock and original distrubutor
>
>
>
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