Weak spark
Thread Starter
Race Director
Joined: Oct 2000
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From: Enter Post Count Here
Weak spark
Just got my roomates Chevelle back together, and she refuses to start. We changed the intake manifold, and c*rburetor.
We're getting fuel, air, and spark, but the spark is very weak, like we're just getting 12V without the coil excitement.
The distributor is HEI type, and the coil is a long cylinderical tube(I don't know what this is called), all wires are connected as they were when we took it apart. What could be the problem?
Thanks.
We're getting fuel, air, and spark, but the spark is very weak, like we're just getting 12V without the coil excitement.
The distributor is HEI type, and the coil is a long cylinderical tube(I don't know what this is called), all wires are connected as they were when we took it apart. What could be the problem?
Thanks.
Melting Slicks
Joined: Aug 2000
Posts: 2,310
Likes: 1
Re: Weak spark (NoWorries)
Was it running before the manifold & carb change? Did it have the same coil? What kind of ignition is that? The stock dist has the HEI coil on top of the cap.
Have you checked the timing?
If you didn't get the distributor back in the right spot, your timing could be off.
I would think that or you missed or misplaced a wire first, then I'd check the possibility that the rotor or coil is bad.
Have you checked the timing?
If you didn't get the distributor back in the right spot, your timing could be off.
I would think that or you missed or misplaced a wire first, then I'd check the possibility that the rotor or coil is bad.
Thread Starter
Race Director
Joined: Oct 2000
Posts: 16,477
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From: Enter Post Count Here
Re: Weak spark (jerryp58)
Jerry,
Yes, it was running prior to removing the manifold. We never disconnected the coil or distributor, there was enough enough spare wire to set it safely out of the way.
I need to correct myself, the coil is seperate from the distributor cap, it is off to the side. It is not a points style distributor, my roomate told me it was HEI, but upon inspection, it is just not points. I'm not entirely certain on the different classes of distributor. It is still vacuum advance.
The coil is a "Transistor" type, according to the guy that put the motor in(we called him), and was brand new with the motor(5,000 miles).
The grounds are good, as we traced them, and power is making it to the coil, because it is coming through the wires, we're just missing the voltage multiplication.
My roomate just purchased a new Accel high output coil, we are going to install it tonight. Besides being more aesthetically pleasing, it also has a lot more volts. Hopefully this will fix it.
Thanks for the reply.
Yes, it was running prior to removing the manifold. We never disconnected the coil or distributor, there was enough enough spare wire to set it safely out of the way.
I need to correct myself, the coil is seperate from the distributor cap, it is off to the side. It is not a points style distributor, my roomate told me it was HEI, but upon inspection, it is just not points. I'm not entirely certain on the different classes of distributor. It is still vacuum advance.
The coil is a "Transistor" type, according to the guy that put the motor in(we called him), and was brand new with the motor(5,000 miles).
The grounds are good, as we traced them, and power is making it to the coil, because it is coming through the wires, we're just missing the voltage multiplication.
My roomate just purchased a new Accel high output coil, we are going to install it tonight. Besides being more aesthetically pleasing, it also has a lot more volts. Hopefully this will fix it.
Thanks for the reply.
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: Weak spark (NoWorries)
If you are getting spark then the ignition module and pickup are working fine. A coil can get weak with age and use. Also, make sure the connections on the coil are good, and test the voltage at the coil itself especially while cranking. there should be a resistor bypass wire running from the starter solenoid to the coil which provides full battery power while cranking. If that isn't there then you may be getting a weak spark due to loose connections on the resistor, or a weak coil.
