76 Ignition Gremlin!!!

[caribbee]

We are getting ready to start the engine for the first time since the resto but have come up on a problem with the ignition. When we try to start the engine by turning the key the starter makes a fast clicking sound but the engine dosent turn over at all. Now when we take a set of jumper cables and jump the starter (black on any engine bolt an red on both main and purple wire terminals) it turns over no problem. The wiring harness has a good ground inside under the dash, from birdcage to frame and engine to harness but all we get are clicks from the starter. What do you guys think?

 

[Vettehead Mikey]

Sounds like a bad battery, cables or cable connections. Pretty common on cars this old.

 

[Artsvette73]

Do you have the ground cable on the pass. side engine to frame hooked up? It's right by the starter and engine mount.

 

[caribbee]

Dont tinhk so, never took one off. Only ground cables I have connected is the copper braided one on the drivers side coming from the #1 mount to the frame, one from the starter wiring harness to the engine and 2 ground cables by the fuse panel under dash. Checked the ground from engine to battery and frame and all is well. Wierd thing is when I have the battery hooked up to the harness and try to "screwdriver" start it it does the same clikety-click thing but when I take my jumper cables direct from battery and jump the starter it works. I did a voltage measurment and i get 12V to the switch but when I swing the key over to start I only get 8-10 volts coming out of the switch to the purple wire going to the saftey switch then to starter. Was thinkning it was the switch till I tried the screwdriver start mentioned above and still got nothing. Gonna check my main + and - cables connecting to battery and see. In the meantime any thing to add??

 

[Mr. Chuck]

Starter Trouble shooting Ideas

Dont tinhk so, never took one off. Only ground cables I have connected is the copper braided one on the drivers side coming from the #1 mount to the frame, one from the starter wiring harness to the engine and 2 ground cables by the fuse panel under dash. Checked the ground from engine to battery and frame and all is well. Wierd thing is when I have the battery hooked up to the harness and try to "screwdriver" start it it does the same clikety-click thing but when I take my jumper cables direct from battery and jump the starter it works. I did a voltage measurment and i get 12V to the switch but when I swing the key over to start I only get 8-10 volts coming out of the switch to the purple wire going to the saftey switch then to starter. Was thinkning it was the switch till I tried the screwdriver start mentioned above and still got nothing. Gonna check my main + and - cables connecting to battery and see. In the meantime any thing to add??

The following method is a quick and easy way to tell if battery, it's cables and the starter / solenoid are in good working condition and the problem is in the switch and related wiring. Disconnect the small gauge wire from the solenoid "S" terminal, leave all the other cables / wires connected to the starter / solenoid terminals. If you have a starter switch by-pass switch (a push button switch with two wire leads with alligator clips ends) connect one clip lead to the large terminal (battery side) on the solenoid and the other clip lead to the "S" terminal on the solenoid. If the starter and solenoid are good, when you press the push button switch, the starter should run and the engine should turn over. Same method used in the days when the igintion points had to be manually adjusted with feeler gauge.

Trouble shooting tips: Don't assume battery cables and related grounds are good just because they are tight. The real test is a through inspection of all cables and ground points are clean, free from rust and the battery cable terminal ends are not burnt or corroided, or the cables aren't real stiff or the insulation is cracked or split or missing, especially under clamps or near metal frame where they may short out. Corroided cables have higher resistance to current flow and will cause a voltage drop between the battery and starter, greater the voltage drop the less energy to run the starter. These are common problems in older cars that still have the old wiring, especially with the larger gauge cables that carry high currents during starting. If you think a cable is bad have a buddy crank the engine while you measure the voltage drop across the suspect battery cable (connect a volt meter lead on one end of the cable and the other meter lead to the other cable end), if the reading is 1 volt or higher, I would replace the cable. Always use the same gauge or greater, never smaller. The rule is smaller the gauge number larger the wire diameter and more current it will carry.
I hope this helps and doesn't confuse you with all the detail.
Good luck

 

[jdp6000]

Is there a fuelible link on your year? Usually two of them spliced into the wiring about 8 inches from the starter. If one is starting to go it will not allow enough voltage through to power the starter.

Jim

 

[LVMYVT76]

I think you have a bad connection, either corrided battery terms or ground to frame problem. Clean the battery terminals and clean the battery cables where they are bright. Check the battery ground cable at the frame to see that rust or paint is the problem. It sounds like the starter is working OK.

 

[caribbee]

Is there a fuelible link on your year? Usually two of them spliced into the wiring about 8 inches from the starter. If one is starting to go it will not allow enough voltage through to power the starter.

Jim

Thanks for the reply but we had to make up our own Starter harness so there is no fuseible link .

 

[caribbee]

I think you have a bad connection, either corrided battery terms or ground to frame problem. Clean the battery terminals and clean the battery cables where they are bright. Check the battery ground cable at the frame to see that rust or paint is the problem. It sounds like the starter is working OK.

I installed a new Battery and I will put a ground from the starter to the frame and see if that works. Will keep you posted . If any one has any other Ideas on what else I can try please let me know.

 

[Mr. Chuck]

81 Starter Circuit

Is there a fuelible link on your year? Usually two of them spliced into the wiring about 8 inches from the starter. If one is starting to go it will not allow enough voltage through to power the starter.

Jim

My 81 starter circuit is complcated by the addition of the "Theft Deterrent" components: namely the Starter Interrupt Relay, plus the "Neutral Safety Switch" (Auto Trans) or "Clutch Start Switch" (Manual Trans) and the "PPL" wire which I think is the same as a fuselink, part of the wiring to the "S" terminal on the solenoid switch. Any of these components can go bad and cause the solenoid contact not to stay closed, i.e. the clicking sound you hear. Attached are the Starter circuit and the trouble shooting pages from my shop manual.
I don't know if the older Vettes had the Theft Deterrent components, but most likely would have a trany switch for safety and the fuse link wire to protect the car wiring from a shorted solenoid coil.
I hope this info helps!!

 

[caribbee]

Got Rid of 76 Ignition Gremlin!!!

Thanks guys for all your help it was very much appreciated we did what you sugested we put a ground cable from the starter to the frame and it took care of the starting problem.

But now we are not getting any spark from the plugs we are thinking it could be the HEI coil or the module that's bad as we checked the timing and it seems ok. Is there any way of trouble shooting the HEI coil please let us know?

THANKS AGAIN FOR ALL YOUR HELP.

 

[bmotojoe]

Any good auto parts store should be able to check both coil and module.
Brian

 

[Mr. Chuck]

HEI Trouble Shooting

Any good auto parts store should be able to check both coil and module.
Brian

My 81 shop manual give trouble shooting method defined on the two attachments included with this reply. Hope they help, assuming your 77 ignition HEI is very similar.
Additional here are some of the problems / fixes I have made to my 81 HEI over the years, that may give some other causes no spark problems.
1. Check the Distributor electrical connectors (my system has three) for missing / broken retention snap clips (part of the connector housing), without the clip the connector may have fallen off or backed off enough to kill the spark output.
2. I made a retaining strap from some stainless steel safety wire, it goes around the back of the connector housing and up and over the HEI coil / distributor cap terminal housing.
3. Check connector loose, or damage contacts, replace anything suspect.
4. Remove distributor cap assembly, mark each spark plug wire for error free re-connection. Then check: the center spring loaded contact end for excessive wear or a weak or broken spring, worn contact seal, check rotor contact finger & contact posts inside the distributor cap (transfers the high voltage from HEI coil to rotor, then to spark plug via the spark plug wire). Check inside of the dist cap components for cracks, contact wear, erroision, deposits, oxidation, etc.
5. Using the two attachments; Check HEI electrical condition, with an ohm meter, perform the resistance checks as defined, to determine if coil is good or bad.
6. If the coil test shows bad, then remove the coil cap assembly and inspect all electrical contacts (hard wired to the coil) are position correctly and are undamaged, verify the coil secondary ground lead is connected correctly and un-damaged (no ground, no voltage output).
If you are up to these trouble shooting steps, then you may not have to go the professional test / repair cycle.
The above condition are more likely if your ignition system is either factory original or to OEM spec and have been in service for years or have been subjected to less that desirable garage conditions. I have even had a case were a mouse eat through several ignition wires and spark plug wires, etc, which caused all kinds of weird ignition malfuntions.
I hope all this detail helps and doesn't cause too much confusion, this is a prime case where it really helps to write down each step and the result of same.

Good Luck!

 

[caribbee]

Thanks I will try the test but in the mean time I ordered a new Modulator and Coil from Summitt because in the Caribbean we dont have any parts dealers who carry Ignition parts . The parts should be in Antigua today .