I've read dozens of threads about the no starting issue. My 1978 l82 with 4 speed. Intermittently I turn the key, a meter shows a draw but starter does not work. No clicks, nothing. I have checked and cleaned all the connections including both ends of the ground wires. Guy who rebuilds starters told me to get a voltage reading at the S terminal. I hooked up a wire and routed it to the top of engine compartment so I could do this more easily when it happens. Well, why not run two wires and install a remote start switch? This worked well and allowed me to be lazy about fixing it. When the key wont start it the remote switch does. Now it happens almost all the time. I checked the voltage at the remote switch and only have 8 volts. So help me think this through. The low voltage is a problem in the wiring from the ignition switch to the starter. Most likely a tired fusible link? Do fusible links get tired and move some power but not all?

I won't be able to look at it for a few days so hoping someone can let me know I am on a possible right track or should look elsewhere.

 

Load test on battery shows?

 

Sounds like rod actuating ign switch is out of adjustment. Or clutch switch. If remote sw works all the time, it is the trigger circuit, not the power circuit.

 

Voltage at the 1 year old battery, engine off, is 12.6 volts. Using the hot wire on my remote start switch I also have 12.6 volts. So I don't think this is a lack of power problem. Agree?

there is a really on the firewall in front of the passenger area. I have 12.6 volts on the large red wire which is in continuity with the alternator and pretty sure coming off the starter power connection. There is a plug just to the right of the wiper motor. There is a red wire on one side connecting to a purple wire on the other side. I have 12.6 volts on the red side. Am I right that this purple wire goes to the start switch, then through the clutch switch(which is jumped out by po)?

The remote switch bypasses all the wiring, switches relays etc which is what leads me to think it is an electrical fault somewhere between power going to the start switch then to the solenoid. But I'm not that good with electric to be sure I know what I'm talking about.

a while back I had the start switch out. It was actually very clean. As I recall, the rod from the key switch was intact and moving the mechanism the way it should. But you raise a good point and I will try to look at it again. Remember quite well to much fun it is to look at It!

am I making sense with this?

thanks again for the help.

JIM

 

I second the vote for the clutch safety switch. Use a piece of wire with alligator clips and temporarily bypass the switch. Good luck, you have to be a contortionist to see the switch under the dash.

 

A p.o. had already jumped out the clutch safety switch as well as removed the cable and related parts for the reverse lockout. But I guess the jumper could be corroded so I will check that out.

 

You are correct , the yellow from the ignition switch changes to purple at the safety swtich. This has been jumped. The PO jumped mine and connected the yellow to the purple thus bypassing the switch. On the firewall behind the dist cap is a connection, unplug it because you want to test voltage on the purple wire coming from the ignition . Have someone turn the key to start when this happens again and measure the voltage coming into the connector. If none then you can at least determine it is from that point back under the dash. Hopefully just the bypass he did is intermittent. Mine was the purple wire at the bypass to that connector that broke somewhere. Replaced the wire and been fine ever since.

 

Thanks BK this helps me a lot. The clutch switch is jumped out and the jumper connections are clean and test good for continuity. I made 4 jumper wires so that I can now put a test probe on each wire on the plug just right of the distributor without cutting the insulation. The black wire test good for continuity to ground. Engine off ignition off I have 12.63 volts on the red and red/white wires feeding power to the ignition switch. Testing when the starter won't turn. The purple wire on one side of the plug connects to what looks like an orange wire on the other side which I believe is connected to the S terminal on the starter solenoid. This wire is sending power to the solenoid to engage. If I disconnect these 2 wires and turn the key I have 12.6 volts at the purple wire. When I complete the circuit, purple and orange, the voltage drops to 9.6 volts. Not enough to engage the solenoid.

so, what I think this is telling me is the circuit is good past the ignition and clutch switches but something is causing a voltage drop when the rest of the circuit is complete.

am I on the right track thinking it could be a weak wire or a week fusible link?

The tech at the starter rebuilds tells me if I don't have full or almost full voltage at the solenoid then it is something before the solenoid, not the solenoid.

I hope you guys can followmy feeble attempt at being an electrician and help me out some more.

thanks all.

 

How about running a temporary wire from the key switch connector to the starter to ensure that you don’t have a problem with the harness.

 

Because you have 12.6vdc at the 4 wire connector purple wire behind distributor (that is labeled C403) your fusible link "A" is good.
Fusible Link "A" feeds both BAT2 & BAT3 of the ignition switch and a portion of the fuse panel.
The purple wire "S" terminal wire should be purple in and out of C403.
This connector is prone to overheating. Both fusible links "A" & "B" pass through connector C403.
Connector C403 also has a RED wire feeding common side of the high speed blower fan relay if A/C is equipped.
So inspect that 4 wire connector and terminals for any corrosion or defects.

 

Don't agree. LOAD TEST battery to determine status. Make sure your battery is up to snuff as first troubleshooting step.

Mapman

 

I'd like to add something that just might help. On my E77. on the firewall, just to the passenger side of center. the purple starter wire has a plastic one wire connector. A few years ago I started my car and headed off to meet the club. We all assembled and when ready to go my car wouldn't start.
We push started it. I headed straight home. I too checked the clutch switch. Battery connections. all that stuff.
only to find that the plastic connector basically above the right side valve cover had come apart.
Something to look for.

 

Yes you are checking the right circuit. There is a voltage drop in the circuit somewhere. The GM solenoid demands a very "clean" circuit as the stock setup is just barely adequate to actuate the solenoid. Many years ago GM issued a TSB that used a softened return spring in the solenoid to help stop the problem. All starters began using the softer spring after that.

You need to repair the losses in the circuit, try a PMGR starter, OR add a relay to crutch relay.

Some crutch relay options - click here

Crutch - The factory solenoid trigger wire is moved to the new relay signal terminal (2) new 12ga wires need to be fabled up. One wire runs from the relay "high side" to the large starter "+" terminal lug and one wire from the other "high side" of the relay to the small "S" terminal on the starter. This does not modify the harness in any way. Relay needs to be grounded. Painless Wiring sells this kit or you can make it yourself. This relay basicaly takes the place of your manual pushbutton mod.

I also like to use it as an easy way to attach a remote starter button for setting my valve lash, compression test and varous other engine service operations. Ugly? -yes. Functional? - your engine will start.


Not a Corvette but it might help if you can see it.

 

Mapman, by load test do you mean a voltage drop test?

I did a voltage drop test on the main cable from the battery to the starter. I made up a long 16 gauge stranded wire with an alligator clip on each end. I used a send piece of #16 wire connected to the positive battery post. on the end of each wire I have another alligator clip to which I clip to the leads on my meter. Cranked the starter and I show a volt loss of 0.27 volts. Is that acceptable voltage drop? Is my test method with the extra lengths of wire and alligator clips giving me a false reading? This is the first time I ever did a voltage drop test.

Thanks for the advise as always.

Jim

 

Simple answer is No...
The Analyzer I have you can do a in car battery test that includes the charging system...
Take your battery to any major chain auto parts store and they can do a load test for you.
Top left and top right image (Or page 1 and page 2) would be the load test only, bottom left and bottom right (Or page 3 and page 4) would include the charging test if battery was tested in the car.
So what my battery test says is my battery is rated at 650 CCA, when a load is applied my actual measured load test shows 768 CCA at 12.94 vdc.

 

if the battery is good try bypassing the other wires that are going to the starter. Corrosion inside the insulation is hard to see and will reduce the voltage and current and give you these issues. I had a similar issue that was the battery, then another issue that was solved with a new engine harness, yours has just a starter harness that is less expensive
without A/C
https://www.lectriclimited.com/catal...category/1083/
with A/C
https://www.lectriclimited.com/catal...category/1083/

 

Heres the engine harness part if you need it but the other harness will eliminat mots of the issues that would have corrosion, you can see the black plastic connector that was discussed that could be an issue as well
https://www.lectriclimited.com/engine-harness-182716

 

The car has been behaving itself for the last week so I have not been able to do any voltage tests when it is not starting. This afternoon I took the car to Interstate battery and they did a load test for me. I drove about 20 miles and parked in their lot. Spent about 5 minutes at most in the office to arrange the test. When i got in the car to drive it to the service bay it would not start. Used my remote switch. They tested the battery and it tested just fine at 10 Volts under load. Their tech said there is no reason why the battery would be part of the problem. Ready to leave the car started right up!

I talked to the guy who I got the rebuilt starter from five years ago and he offered to check the starter out. Said he can do it in about 15 minutes or so. I will try that. next. and report back.

Other next step is to use the suggestions above and run a new wire. I think I will run it from the jumper on the clutch switch as that is relatively easy to reach and run a # 14 AWG wire to the S terminal on the starter and see what happens.

Back later with hopefully a solution.

 

you can take starters to autozone or Oreillys to have tested as well, but unless it is hot it probably wont fail. Maybe have the rebuilder check the solenoid or just install a new one

 

I installed a new #14 stranded wire from. The yellow terminal on the clutch safety switch to the S terminal. Now all I can do is wait to see if it happens again or if this is the solution. I don't think my issue is with the power supply up the the clutch switch because I have 12.6 volts at the switch. Thanks for all the help so far.