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#1 |
Registered User
Join Date: Apr 2008
Location: Washington, DC
Posts: 22
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Not Firing on all 8 cylinders
Took the truck out (1970 C-10, 350 crate motor, Accel electronic ignition) out to my motorcycle shop this morning - felt fine.
On the way home it felt strange, like it was struggling somewhat. Got it home, messed around with cleaning the carb (Edelbrock 650) and still not working right - heard a tick-ticking sound but not like valve tick (though it could be). Then I felt the exhaust, the passenger side exhaust was warm, the driver's side exhaust was noticeably cool. Very cool. So clearly I am not firing on all cylinders on that bank (at least that's what I'm assuming). I pulled the plugs, none were gunked up (and they're new - about 3000 miles on them). The plug wires were checked and rechecked (even shocked the piss out of myself with one of them). However that doesn't mean there isn't a break in the wire. So I am on the hook tomorrow to get some new plug wires (needed it anyway as the ones in there are way too long). However I am looking for suggestions as to what else it could be. I'm hoping the new wires fix it, but would like some other things to have ready to check if it doesn't. The exhaust are straight pipes to exhaust manifolds and no crossover so I know that the cool pipe is running straight from the driver's side cylinders. The electronic ignition is sparking (it runs, but there is a chug-chug at the cool exhaust pipe, almost like an old steam train). Thanks guys. Mike |
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#2 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: Not Firing on all 8 cylinders
i'd take out one plug at a time ground it to the exhaust turn the motor over and see if its sparking//at the same time checking overall condition of the plug as well as checking for the proper gap
__________________
71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#3 |
Eat My Rust
Join Date: Jan 2007
Location: Cypress, Texas
Posts: 3,362
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Re: Not Firing on all 8 cylinders
When my carb was junked up, and ran stupid rich, it would chug and barely run at low speed (basically missfiring at idle real bad) and was running so rich that 3 cylinders were noticeably cooler than the other 5 (based on touching the header tubes). Could be something out of tune on the carb.
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#4 |
Too many toys,not enough money
Join Date: May 2008
Location: Bozeman,MT
Posts: 237
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Re: Not Firing on all 8 cylinders
I'd take one of those lazer temp guns and shoot each of your header tubes, or manifold ( a little less acurate on a manifold ), about 1" from the head, that would tell you which cyl. is acting up. Also check your cap on the dist., look at the contacts and see if any are corroded, cracked, bent, etc. Also, Plugs can be bad and not look it. Thats probably where I would start.
Also check your idle mixture screw ports, in the primarys of your carb, if you screw them in too hard they will break the aluminum and cause a very rich condition, and a truck that runs like crap! Last edited by MT71c-10; 03-08-2009 at 07:13 PM. |
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#5 |
Registered User
Join Date: Feb 2009
Location: ANTIOCH CALIFORNIA
Posts: 61
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Re: Not Firing on all 8 cylinders
moisture is a problem with edelbrock carbs,the jets are in the bottom of the bowl and if one drop of water "very common with todays fuel-its how they change octane ratings"gets in the bowl it goes right to the jet and fuel cannot pass.but it sound like you have a distributor problem.check your rotor and cap carefuly.and ignition advance springs and weights flying apart under cap may be problem if using cheap aftermarket HEI.debri gets stuck on pickup and so on..if all is ok try unbolting carb and turning upside down in a pan to see how much water you have collected.good luck
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#6 |
Registered User
Join Date: Feb 2009
Location: ANTIOCH CALIFORNIA
Posts: 61
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Re: Not Firing on all 8 cylinders
any high reving lately??? could be valve spring,rocker stud or arm??check compression
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#7 |
Registered User
Join Date: Apr 2008
Location: Washington, DC
Posts: 22
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Re: Not Firing on all 8 cylinders
I did notice that it seemed there was water in the exhaust on the side in question, and it hasn't rained here nor have I washed the truck (though it did snow a **** ton last week).
I'll replace the wires just because I've been meaning to and also check the carb. It's weird that it just suddenly started. The gas was fairly low, but then I filled up and it's still acting that way. |
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#8 |
Registered User
Join Date: Sep 2001
Location: Hacienda Heights, California USA
Posts: 474
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Re: Not Firing on all 8 cylinders
Sounds like one of your plug wires is arcing. Best time to check, is at night. Just open the hood with the motor running and you can then see the blue arc going towards the metal. I have had several plug wires burn on the stock iron manifolds. It wont take much to cause the problem. Just get some good guides to keep them off the pipes.
Then again, maybe a lifter went bad?
__________________
'72 GMC custom camper 350/350 |
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#9 | |
Too many toys,not enough money
Join Date: May 2008
Location: Bozeman,MT
Posts: 237
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Re: Not Firing on all 8 cylinders
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#10 |
Registered User
Join Date: Apr 2008
Location: Washington, DC
Posts: 22
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Re: Not Firing on all 8 cylinders
Well I cleaned the distributor, removed the carb and cleaned it (as best I could without tearing it apart), and replaced the wires with all new wires.
Still have a chug-chug and some smoke out of the driver's side exhaust. Pulled the valve cover gaskets and they're all moving up and down, however some of the rods are spinning, some arent. Some will spin when it is stopped, some won't. I don't know much about valves (I'm a 2-stroke motorcycle guy) but I would assume that some rods should spin in certain positions, and they shouldn't in others? Also they should all spin at times when running, and there seem to be two cylinders where they don't spin at all at any time. |
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#11 |
Registered User
Join Date: Oct 2006
Location: Dundee, Oregon
Posts: 311
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Re: Not Firing on all 8 cylinders
Are you running a dual plane manifold? I have seen a plugged idle jet kill all of the cylinders on that plane of the manifold. Basically it was running on every other cylinder at idle. Rev it up and get it off the idle circuit and it ran great.
Jason |
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#12 |
Registered User
Join Date: Feb 2009
Location: ANTIOCH CALIFORNIA
Posts: 61
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Re: Not Firing on all 8 cylinders
re-adj. your valves one cylinder at a time,v-c off looking at #1 cyl. rotate eng.while watching valves,the one on the left is exh. so watch the one on the right open completely and starts to close.about half way closed means eng. is on compression stroke and you can now adj.the exh. valve "the one on the left" back off adj. not until pushrod spins freely now slowly tighten until you just take out all the lash.once you reach zero lash turn adj. nut another 1/2 turn in. Exh. valve is now adj.now adj. int.valve by continuing the rotation watching the exh. valve you just adjusted start to open slowly rotate eng untill exh valve gets to about half way open and repeat adj for intake valve-repeat on all cyl's/again-int opens and half closed adj. exh..exh.just starts to open adj. int.after this is done check compression on all cyl's and post results,should be no more than 15 psi variation. let me know what you find and good luck
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#13 |
Registered User
Join Date: Apr 2008
Location: Washington, DC
Posts: 22
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Re: Not Firing on all 8 cylinders
Can I just adjust the valves while it is running by backing off the nut until it clacks, then tightening until it doesn't, then tightening 1/2 to 3/4 turn?
If so, does it matter which valve I start with? Just start at the far left of the cylinder bank and work my way back? |
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#14 |
Registered User
Join Date: Feb 2009
Location: ANTIOCH CALIFORNIA
Posts: 61
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Re: Not Firing on all 8 cylinders
yes and sorry havent checked on ya but no it does'nt matter really where you start,just do it quickly cause of oil splash.hint:cut out an old valve cover to put on durring adjustment,this should keep oil under control. good luck again.
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#15 | |
Registered User
Join Date: Apr 2008
Location: Washington, DC
Posts: 22
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Re: Not Firing on all 8 cylinders
Quote:
My distributor was butt. The inside was rusted, the weights were ovaled out and just swung around freely, etc. I'll keep the thread updated on what works out. |
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