Random misfire while cruising - Team Camaro Tech
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post #1 of 15 (permalink) Old Apr 19th, 15, 10:15 PM Thread Starter
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Chaz
 
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Random misfire while cruising

Yesterday I noticed my car bucking/misfiring at highway speed, around 70-75. My tach needle would also jump like crazy. WOT is fine and idle is fine.

So far I'm thinking bad coil, bad wire, or bad plug. Up till now ,it's ran fine! This was also sporadic. It would act up like that then be fine for 20 miles.

I already ordered new wires, a new coil, and some better wire retainers which mount to the valve covers.

I have a Mallory ignition setup, aed 750 carb, roller cam, edelbrock etec 200 heads.

68 Camaro

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post #2 of 15 (permalink) Old Apr 19th, 15, 10:36 PM
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Steps
 
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Re: Random misfire while cruising

Quote:
My tach needle would also jump like crazy.
1st thing that says is the primary ign circuit has a loose connection... ie the ign wires to the coil..
if the tach dosent jump the issue is after or in the coil.. or HT side

Quote:
This was also sporadic. It would act up like that then be fine for 20 miles.
this also indicates loose wire....a plug or coil general is consistent.. or in other words once it has sucked a kumura thats it it doesnt work right...or not at all

My Spelling is not incorrect...it is creative

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post #3 of 15 (permalink) Old Apr 19th, 15, 11:11 PM
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mike
 
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Re: Random misfire while cruising

Check the cap, especially the carbon ball, ask me how I know. lol
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post #4 of 15 (permalink) Old Apr 20th, 15, 10:51 AM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

I will check all these things. The ignition wires to the coil are good and tight... A few months ago i made a homemade tach filter.... don't think it should have too much to do with this but will check all those connections as well.

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post #5 of 15 (permalink) Old Apr 20th, 15, 10:57 AM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

Quote:
Originally Posted by Steptoe View Post
1st thing that says is the primary ign circuit has a loose connection... ie the ign wires to the coil..
if the tach dosent jump the issue is after or in the coil.. or HT side


this also indicates loose wire....a plug or coil general is consistent.. or in other words once it has sucked a kumura thats it it doesnt work right...or not at all
Kumura? I'm confused

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post #6 of 15 (permalink) Old Apr 20th, 15, 11:36 AM
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Re: Random misfire while cruising

Quote:
Originally Posted by 68SSlemans View Post
Kumura? I'm confused
How to Understand a New Zealander:

http://www.lonelyplanet.com/new-zeal...articles/76787

And from another site:

Knackered, Tit's up, Sucked a kumara
3 phrases all rougly meaning that something is not working i.e. a possible real scenario could be "Yeah, the car's knackered, the whole day has gone completely tit's up - man, it sucks a kumara!".

We might say something "has given up the ghost"

Is that about right Steps?
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post #7 of 15 (permalink) Old Apr 20th, 15, 12:07 PM
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George
 
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Re: Random misfire while cruising

...I'm still not sure I understand...


Kiwis....

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post #8 of 15 (permalink) Old Apr 20th, 15, 12:37 PM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

In California would just say it f#%^ed up LOL

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post #9 of 15 (permalink) Old Apr 20th, 15, 01:02 PM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

it almost feels like a lean surge from the carb but why would the tach needle start bouncing everywhere?

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post #10 of 15 (permalink) Old Apr 20th, 15, 01:22 PM
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Re: Random misfire while cruising

Quote:
Originally Posted by 68SSlemans View Post
it almost feels like a lean surge from the carb but why would the tach needle start bouncing everywhere?
Check the rotor and cap...might be corroded or cracked!

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post #11 of 15 (permalink) Old Apr 20th, 15, 01:53 PM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

Yea i'll check the cap and rotor... didn't even check because they're only like a year old. I think it's a coil problem. Sitting at the light the other day the car just shut off. I read on the Mallory site that this is a symptom of a coil headed south.

Thanks for the advice. I'll let everyone know what I find!

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post #12 of 15 (permalink) Old Apr 20th, 15, 08:56 PM
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mike
 
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Re: Random misfire while cruising

Even though the cap is fairly new check it. Sometimes moisture can corrode the carbon ball causing misfires especially while low rpm cruising. This happened to me twice now. I got an ugly brown Accel cap and hope this stops the problem.
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post #13 of 15 (permalink) Old Apr 21st, 15, 09:47 AM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

Quote:
Originally Posted by bigblockragtop View Post
Even though the cap is fairly new check it. Sometimes moisture can corrode the carbon ball causing misfires especially while low rpm cruising. This happened to me twice now. I got an ugly brown Accel cap and hope this stops the problem.
will do. I'll order a cap and rotor kit too. I just found out Mallory was bought out by MSD and will no longer be producing parts

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post #14 of 15 (permalink) Old Apr 21st, 15, 02:17 PM
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Steps
 
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Re: Random misfire while cruising

Quote:
We might say something "has given up the ghost"

Is that about right Steps?
yep its knackered.. stuffed....

We might say something "has given up the ghost"

the tach is the give away.. it runs on the primary circuit.. ie it counts each time the electronic 'points' open and close....so if there is an issue here then the tach will jump around/ momentary die.
If the issue is in the secondary circuits ie cap rotor spark plug HT leads.. the tach will not momentarily die or jump around .....
And as mentioned the primary circuit (which goes from the battery right thru to the coil) was been resently messed with...before that no issues.

My Spelling is not incorrect...it is creative

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post #15 of 15 (permalink) Old Apr 21st, 15, 04:04 PM Thread Starter
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Chaz
 
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Re: Random misfire while cruising

yes no previous issues with this. The car was in the body shop recently getting the driver's side rocker panel redone. I noticed they had to jump the car several times. I read on the mallory site that jumping the car can damage the coil...

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