HEI erratic spark - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 9 (permalink) Old Sep 17th, 02, 01:22 PM Thread Starter
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Join Date: Jul 2001
Location: CO, USA
Posts: 38
Hi, I'm having problems with my 67 camaro. I just pulled it out of the garage after replacing the springs and painting the floorboard. I decided I needed to check the timing on it but when I hooked my new dial back timing light to it, the light flashed erraticlly. For example, it would flash steady for a few seconds (maybe 10) and then miss a beat or two. I hooked my old light up and it did almost the same thing.

The things have done to try to fix this are:
-test the power wire to the distributer
-test the module (autozone tester)
-test the coil (multimeter)
-test all the plug wires (multimeter)
-replace the pickup coil (tested it with a multi meter but it looked a little sketchy)
-replace the cap and rotor

I hooked the dial back light up to my 96 chevy pickup to see if the light was good and it worked fine
Any Ideas?

The only thing I have come up with is to hook up the alligator clips for the timing light to the battery on my 96 and the inductive pickup to the 67 to see if maybe the motor is firing but the light is having problems pulling power from the battery in the camaro. Would it hurt anything to have the power for the light coming from another car?

The camaro has a 350, TH400 auto, HEI, Edelbrock 600 cfm electric choke carb, dual plane intake. This is all I know about the motor. The previous owner said work had been done to the heads but didn't have specifics. Also I think the cam is bigger than stock b/c I am having a very hard time getting it to idle well (before I had problems with the HEI)

Any suggestions would be appreciated as I have run out of ideas. If any more info is needed please don't hesitate to ask.

Edit: I did a search and came up with alot of info but nothing that I haven't already tried although I am still sorting through the posts.


[This message has been edited by ratchet (edited 09-17-2002).]
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post #2 of 9 (permalink) Old Sep 17th, 02, 01:41 PM
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Location: Houston, Texas
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Have you tried it on another plug wire on the Camaro?

Could just be a bad #1 plug wire.

Don~ ZZ430DropTop
70 RS
67 RS/SS Convertible, 70 RS
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post #3 of 9 (permalink) Old Sep 17th, 02, 01:48 PM
Join Date: Jan 2002
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Hei needs A full 12 volts,if the engine
harness wire is original,then its a resister
wire and you will have to change it,no big
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post #4 of 9 (permalink) Old Sep 17th, 02, 03:35 PM Thread Starter
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ZZ430- I did try the timing light on all the wires some were fine and some were erratic. I also tested all the wires with a mulitmeter and they were all within the range specified in my Chiltons manual. Also the wires are only about four months old with almost no driving time on them because the car was down for the spring swap. In fact every part in the distributor is only about four months old with the exception of the pickup coil which I just changed.

X66-I ran a new wire from the fuse box for the power wire to the HEI. Also I tested it at the distributor and it has 12v.

Thanks for the replies. Any other ideas?

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post #5 of 9 (permalink) Old Sep 17th, 02, 06:00 PM
David Pozzi
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Location: Central California, USA
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I had that happen this year, turned out it was a bad plug wire.
There was arcing at the distributor cap from plug terminal to somewhere.
New wired cured it.

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67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer
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post #6 of 9 (permalink) Old Sep 18th, 02, 03:52 AM
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I ohmed all my wires and they still behaved the way you described. I replaced them with a solid core set problem gone. I think that when you test stranded core wires you really need to wiggle them around quite a bit to see if they go open. Good luck

67 prostreet BB Camaro
80 z28 Camaro 355ci
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post #7 of 9 (permalink) Old Sep 18th, 02, 08:07 AM Thread Starter
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I can only work on the car on the weekends so this weekend I will try replacing my plug wires and will report the results. Hopefully it will fix the problem.

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post #8 of 9 (permalink) Old Sep 26th, 02, 03:10 AM Thread Starter
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When I got home this weekend I picked up a set of spark plug wires. Before I put them I checked the timing light again, this time with the power coming from my 96 and the inductive pickup on the 67. The light flashed fine. Then I moved the power clamps to the 67. The light still flashed fine. I don't know what the problem was but it seems to have fixed itself. Hopefully it won't come back.

Thank you for taking the time to offer suggestions.

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post #9 of 9 (permalink) Old Sep 26th, 02, 04:25 PM
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Matt Jones
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It will come back.

1969 Base Camaro
Vortec 355, Perf. RPM, Demon Carb., TH-400
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