78 Camaro. Won't crank. Out of ideas. Please help.

Discussion in 'Camaro Questions' started by WallyHawk, Jul 31, 2021.

  1. WallyHawk

    WallyHawk New Member

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    Hey all. Been reading a ton but first time posting. I know this issue has been brought up and I've read all those posts, still at a loss. Hopefully I'm doing this right.

    I have a new to me 1978 Camaro z28. The engine is from a 69 z28. 355, long flow heads, flowmaster exhaust, upgraded cam, auto th400 transmission, upgraded carb. All of this was done before I owned the car. I had a local garage that restores classics give it a thorough inspection before buying it.

    I've had the car about 3 weeks. I drove the car about 400 miles since buying it, loving every second. The only issue I had so far is the cable from the shifter to the transmission fell off cause the clip was missing. Easy fix thanks to info on this forum.

    Wednesday I took the car out after work. Drove around for about an hour. Mix of backroads and a bit of highway. Not driving super hard, never went over 75. Made 3 stops in that hour where the car was off for 5-15 minutes. Started right up everytime, no problems. Drove home, parked in the garage everything normal. Rained all the next day so the car didn't move.

    Two days after the last drive I went to change the section of wire with the tach filter on it. The filer in it was a mess and the wire didn't have a current through it when tested. My tach was the only gauge not working. After what I thought was an easy swap I went to start the car and NOTHING. No crank at all. Power still works on accessory. Lights, signals, radio, etc. Volts testing normal and when I try to start the car the volts don't really dip at all, lights stay on same as they were.

    Could the new filter have fried something? I ordered it from Ecklers Automotive which seems to be very legit. I even tried putting the old crappy one back on just to see if that was the issue, but nothing.

    I checked the metal part that rotates on the steering column to see if that was the issue, nothing. I took the shifter apart to make sure it was actually in park. That checked out. I checked the lever in the engine bay that tells the car what gear its in and if its safe to start. I don't have the rod that goes through because of the headers but I didn't even know it existed until I read about it researching this issue. That checked out as well.

    Battery tested fine. Tried jumping anyway, no change. power from battery to starter tested fine. I took the starter off, cleaned the contacts even though they didn't show any real signs of corrosion or excessive rust. Hooked the starter back up, nothing. I took the gauge cluster out, all connections still solid, all grounds still in place. I checked the semi-round switch (blanking on the name) that's at the base of the steering column and all those connections were firm, no corrosion.

    The only thing I can think is that the wire from the starter into the car is no good but I'm not sure what to do with that. I thought I traced it through the firewall. The wire I was tracing was thick and orange. From what I'm reading the one that powers the ignition is purple? I bought a new inline fuse from advance auto parts but didn't cut up the wire since I wasn't positive I had the right one given the color difference.

    Is there anything else I should be checking before having it towed and paying a garage for a fishing expedition?
     
  2. berg2695

    berg2695 Veteran Member

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    Neutral start switch? Maybe try wiggling the shifter around while trying to crank it.
     
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    If you have power everywhere else… it’s probably the starter trigger wire at the solenoid.
    Purple wire, I believe.

    The tach signal wire won’t keep it from cranking.

    Check for power at the purple wire when the key is turned to “start”.
     
  4. grzewnicki

    grzewnicki Veteran Member Lifetime Gold Member

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    First check the purple wire at starter solenoid is tight and not damaged, tach filter will not cause this problem, since you were working on it when problem occurred seems to point to a problem in the harness around/near where you worked. Purple wire from starter "S" terminal goes straight to firewall connector under power brake booster. 1; I'd unwrap the harness and check the condition of that wire from starter to firewall. Pain in the but to get to firewall connector, you have to drop the drivers side inner fender well (just the rear part, but you still have to take majority of bolts out of it to do that). Hopefully problem is where purple runs horizontally across firewall behind engine, Have someone hold key in crank position and move harness around that may help pin point problem area. It is a pretty heavy wire 12 ga, hardly ever see them get damaged. If you do find a break, I'd cut out bad section, and replace with same gauge wire, using a non insulated butt connector, crimp then solder the new wire in place, slip some shrink tube on wire prior to soldering. 2. If purple wire under hood is good I'd think neutral safety switch. The system wiring is very simple on this circuit, power from "key" when in start position, goes from ign switch through purple wire with white stripe to the neutral safety switch at bottom of column (on top of column near firewall-this switch also works your reverse lights, might want to give them a quick look if they are not on in reverse then the switch or linkage may be out of adjustment). Then power goes through the switch (purple wire lets current flow in park and neutral) then through the firewall connector to starter. Turn key to start, with test light, check at neutral safe sw connector to make sure you have 12 V at both terminals, if you have no power at either, it is not getting power from ign switch, the actual ignition switch is on top of the column, a rod runs from key cylinder to this switch to work it. Since all this wiring is pretty well protected and ign switches hardly go bad this is a long shot. But I believe the ign switch is adjustable, 2 or 3 screws old it to column and it slides a little. 3. If you do have power into neutral safe sw but not out of neutral safety switch then I believe this switch is also slightly adjustable, 2 screws hold it to column and holes are slotted for adjustment. If that doesn't work; could be the back drive linkage from trans needs adjusting, this linkage moves the arm on bottom of column which rotates sleeve on column to actuate neutral safety switch, (rod that goes down from arm on column fits into a barrel with a lock bolt on linkage from trans, loosen bolt in the barrel, that is where the adjustment is made). You can have a friend check for power at the connector while you move rod to get it in right spot). Let us know what you find.

    Wiring diagram, under hood, follow 12 PPL wire from starter to firewall connector, goes in hole #6.
    https://nastyz28.com/camaro/wire/1978-camaro-engine-wiring.html


    Wiring diagram, inside car, ign sw is bottom center, NEU START SW is left side little over 1/2 way up. Fallow Purple/White wire from Neu Start Sw to Ign switch and Purple wire from Neu Start Sw to firewall connector goes in hole #6. You'll see two neu switches, in diagram, one is the clutch pedal switch for manual cars and the other is the column switch for automatics. Don't worry about the manual car one.
    https://nastyz28.com/camaro/wire/1978-camaro-dashcolumn-wiring.html




    Back drive linkage:
    backdrive linkage.jpg
     
    Last edited: Aug 1, 2021
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  5. WallyHawk

    WallyHawk New Member

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    Thanks so much for the awesome responses! I had to go out of town today but tomorrow I'll get back in there and try everything.
     
  6. WallyHawk

    WallyHawk New Member

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    OK tried a ton more stuff. I don't think it's an electrical issue at this point. I opened up the harnesses best I could without hacking. All wires seem fine, all grounds I came across were secure. No breaks or weirdness.

    I got the purple wires off the switch on the bottom of the steering column. Held the tester on and had my wife try to start. Purple wires got full 12v as they should.

    My car does not have the back drive linkage. Headers would be in the way from everything I read. I was hoping this could be the solution since all the electric keeps testing well everywhere I try it.

    I read a lot of people don't have this linkage and it's fine. At least wouldn't stop car from starting. I checked the wire on my transmission as my wife switched gears and it moved as it should. The lever behind what I think is the power steering pump moved up and down a small amount. Maybe 2 inches of play. I tried moving that while my wife held the key in start position and nothing.

    The weird thing with that lever is sometimes I get the full range of play, pushes way down deep toward the road then can come all the way back up. Then it moves outside the 2 inch range I can't remove the key. Hopefully this is narrowing it down.

    Something I hadn't considered before but maybe it's relevant... the idle was always a bit off. It was a bit uneven and the car actually stalled a couple times in creeping traffic. Anytime I was driving it normally if I gave it some gas no issues. Could the carb/idle stop the car from even cranking?

    Thanks again for the help so far.
     
  7. berg2695

    berg2695 Veteran Member

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    Try twisting the shift sleeve behind the steering wheel on the column while trying to start.
     
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  8. tom3

    tom3 Veteran Member

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    If you have power to the purple wire when you turn the key to start, double check that that current is getting to the starter. Have to crawl under there for this. Might be time for a new starter?
     
  9. WallyHawk

    WallyHawk New Member

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    I tested power at starter and got 12, then power to purple wire and got 12. Moved the sleeve all around, tried every direction, tried holding it in different places or putting different pressures, nothing.

    The purple wire tested 12 when my wife turned the key to start the car only. I thought that meant power went through the starter to the purple wire. I also think the ignition would have to be good since the acc power works and all.
     
  10. MChamp

    MChamp Veteran Member

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    If you're not hearing a click at the starter solenoid I too feel it's a neutral switch. Gawd I hate electrical issues, I'd rather be covered in bondo dust. G'luck!
     

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