Help! No spark on an '86 Vette

[larry bud]

As the tree said to the lumberjack, I'm stumped! Been trying to resolve this for 3 weeks...

Car was running beautifully for last 2-3 years, parked it one night, next night, it cranks, but no start.

I replaced the plugs, cap and rotor (it was time anyway), and no go. So I bought a spark plug tester and new ign coil. Still no spark.

I have the service manual and am up to step 5 (pg 6E3-C4-5), but I'm not really understanding the test or what that accomplishes (especially since I already have replaced the coil).

I have 12V at the bat connection. At that point, what would be stopping the coil from firing? Is it possible that the rotor isn't hitting the points in the cap? If so, how would I check that?

BTW, a note about the cap. When I replaced the cap, the bolts for the rotor were loose, and the rotor was flopping around a little bit. I don't know if that matters at this point since the rotor was replaced (and it's firmly attached).

TIA!

 

[tmkassin]

Are you sure the rotor is turning? Could be a broken distributor.

 

[Schrade]

Are you sure the rotor is turning? Could be a broken distributor.

BTP (beat to punch) again...

Only thing I can think of is the drive ain't spinning. Pull the cap, turn the key, and watch the rotor (unless you can already turn it freely).

 

[larry bud]

Yeah, it's spinning.

Can it be the ignition module at this point?

 

[gmjunkie]

If the rotor is rotating and you have B+ at distributer with No Fire

4 things come to mind!!

1.Faulty Ignition Pick Up Trigger coil in Distributer!!
2.Faulty Ignition Module in Distributer!!
3.Sheered Roll Pin in Distributer Gear!!(Weak or No Fire and completely out of time!)
4.Jumped Timing Chain, (But you should still have Fire unless the chain has Completely Snapped and then the Rotor wouldn't be Rotating!)

 

[vigman]

My 88

Chews thru ignition modules every 2 years.. and I cannot figure it out..

When it's hot ( summertime ) and the car sits for a while...

The next time I try to fire.. nuttin...

So every time I got to Pick your part.. I grab 4-5....

The Standard ( brand ) ignition module is 25 bucks or so

Some times it's the actual pick up coil....


Vig~

 

[LLC5]

Try wiggle/pulling on the pick up coil wires inside the distributor to see if they are broken.

 

[larry bud]

Had Autozone check the ignition module and it was fine (the guy tested it about 10 times)...

What else?

 

[LLC5]

Had Autozone check the ignition module and it was fine (the guy tested it about 10 times)...

What else?

Have you checked the pickup coil inside the distributor?


Also, when you replaced the cap and coil did you transfer the ground tab for the coil, and install the button and spring with the insulator washer?

 

[larry bud]

I did transfer the ground tab (came new with the new ignition coil I bought), and installed a new button and spring.

Have not checked the pickup coil... quick google says measure it's resistance, between 800-900 ohms, correct?

 

[LLC5]

I did transfer the ground tab (came new with the new ignition coil I bought), and installed a new button and spring.

Have not checked the pickup coil... quick google says measure it's resistance, between 800-900 ohms, correct?

That ohm reading sounds right, make sure that the wires going into the coil aren't broken, wiggle and pull lightly on them to make sure they are tight in the coil right where they enter it. The vacuum advance moves the wires and they are known to break at the coil where they are attached.

 

[G Winter]

That ohm reading sounds right, make sure that the wires going into the coil aren't broken, wiggle and pull lightly on them to make sure they are tight in the coil right where they enter it. The vacuum advance moves the wires and they are known to break at the coil where they are attached.

You are thinking a little to old for vacuum advance.
But the wires can still break.

Glenn

 

[LLC5]

You are thinking a little to old for vacuum advance.
But the wires can still break.

Glenn

How right you are, I was just reacting and not thinking. I have seen it so many times I just ASSumed, my mistake. BTW, I am pretty old. :L

 

[larry bud]

DING DING DING! We have a winner!

It was the pickup coil. Wire WAS broken. Replace with new coil, fired up like a champ (besides a couple of trouble codes... doh!)