Starting issue

[LGAFF]

Having an issue with my 90

-Car starts fine; then I come out and car does not start, no cranking, dead silence.(I believe the fuel pump energizes).

-There is a voltage drop when I turn the key, but no clicking, nothing happens

-Had the battery checked: no issues 12.6 volats

-Checked the alt: outputting 13.8-14.1 volts; steady output

**If you jump start it, bang....starts right up and will run good for days

**Starter is new

[LGAFF]

Starter interupt relay?

[-=Jeff=-]

VATS?

[Dynomite]

-Car starts fine; then I come out and car does not start, no cranking, dead silence.(I believe the fuel pump energizes).

-There is a voltage drop when I turn the key, but no clicking, nothing happens

-Had the battery checked: no issues 12.6 volats

-Checked the alt: outputting 13.8-14.1 volts; steady output

**If you jump start it, bang....starts right up and will run good for days

**Starter is new

When you jump start (from another car running) you are probably jumping with 13+ volts. I would say your starter solenoid is a bit sticky and does not move with less than 13+ volts. A voltage drop when key is turned but no clicking would suggest current is being applied to Solenoid coil but Solenoid is not moving. Or......you have some poor connections taking voltage (getting warm) reducing the voltage the starter Solenoid sees.

I may be missing this all together but just saying.

[LGAFF]

I am puzzled on this one; I will try driving with the other keys in hand...and also watch for the security light to address vats.

to me it seems the battery is not fully charged but it tests ok, will test in the morning. When I turn the key the volts drop close to the "8"

I replaced the cable to battery bolts today to see if that makes a difference.

Not sure, might swap the relay to make sure, I noticed the relay has the same symptoms as the stuck starter solenoid.

[Tyler Townsley]

This is the classic description of a 90-91 no start condition linked to the clutch switch, Check the problem section for suggested solutions including jumping the switch at the purple wire at the dash. The final fix is to leave it jumped there and deal with the start in gear or replace the switch with one that can handle the amperage.

Tyler

[LGAFF]

Tyler, would there be a volt drop if the clutch switch was not working?

[Tyler Townsley]

Tyler, would there be a volt drop if the clutch switch was not working?

yes dash etc gets energized. the clutch sw gets hot and will stop current flow but sometimes the additional amperage can jump the sw points. thanks to some earlier troubleshooting by scot fabre, I believe, it was determined the sw was way undersized for the current flow. the whole ckt design was changed in 92.

tyler

[Z51JEFF]

I had a no start issue and ran a separate ground from the stater relay.Its hard to say if that fixed the problem,its only happened 3 time in 6 years but 2 of those times were in the last 6 weeks.The separate ground wire fix was from a suggestion someone got from Gordon Killebrew.I was able to eliminate the clutch safety switch before I did the ground mod.

[RICHARD TILL]

from experience i vote starter solenoid.

[LGAFF]

Connected the clutch wires......replaced what I think was the starter relay....did not seem to jive with the diagram, but the wires were yellow/blck and connected to thec clutch switch....so I think I have it right;)

[Z51JEFF]

Connmected the clutch wires......replaced what I think was the starter relay....did not seem to jive with the diagram, but the wires were yellow/blck and connected to thec clutch switch....so I think I have it right;)

The yellow stripped black wire is for the starter relay,thats the ground I believe.

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/DSCN5277.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN5277.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN5278.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN5278.jpg.html)

http://i134.photobucket.com/albums/q115/lgaff/DSCN5280.jpg (http://s134.photobucket.com/user/lgaff/media/DSCN5280.jpg.html)

[LGAFF]

Is this the backside of the Starter relay? one with yellow wires?


http://i134.photobucket.com/albums/q115/lgaff/Corvette-VATSStarterEnableBypass8.jpg (http://s134.photobucket.com/user/lgaff/media/Corvette-VATSStarterEnableBypass8.jpg.html)

[Z51JEFF]

The starter relay is the one closest to the column,I think.I pulled the relay and tried to start the car just to make sure.The yellow stripped black wire should be the relay ground,the 14-16 gage wire with the non factory blue splice connector on it.

[Z51JEFF]

Its hard to make out anything in these pictures but this is the splice I made for the new ground,I ran a 10 gage ground wire from the splice to a stud coming off of the dash support.http://i10.photobucket.com/albums/a136/FLYTYM/DSCN1394_zps0cba7089.jpghttp://i10.photobucket.com/albums/a136/FLYTYM/DSCN1396_zpse778ad28.jpghttp://i10.photobucket.com/albums/a136/FLYTYM/DSCN1397_zpsdde498f6.jpg

[scottfab]

...snip...

-There is a voltage drop when I turn the key, but no clicking, nothing happens

Can you explain "voltage drop"? On the battery? or ???

-Had the battery checked: no issues 12.6 volats

-Checked the alt: outputting 13.8-14.1 volts; steady output

The important number is what the battery measures when the key is turned. If 11.5 - 12.6 then fine.

**If you jump start it, bang....starts right up and will run good for days

**Starter is new

Just by this I'd say battery but more info needed.
Thing about the clutch switch on the early cars is you never want to turn the key before fully depressing the clutch peddle. The contacts can handle the current just fine IF the switch is engaged. Problems happens when the key is turned first and the then the peddle pushed (or at the same time). The switch gets arced in this case. Too many times arcing the switch damages them. I had a problem in 97 but none since then.

[LGAFF]

I almost think its the battery also, it was made 6/2012 and installed this year. They did a load test yesterday and its fine.

We will find out

[LGAFF]

Scott by volatage drop I am referring to the fact that when you turn the key volts drop on the dash

[Tyler Townsley]

Connected the clutch wires......replaced what I think was the starter relay....did not seem to jive with the diagram, but the wires were yellow/blck and connected to thec clutch switch....so I think I have it right;)

90-91s do not have a relay in the ckt which is the problem, usually the clutch switch activates a relay to better handle the current. As I said the clutch switch takes all the current and becomes unstable. If you follow the purple wire you can just jump around the switch where they go down to the switch.

yler

[Toyvet1]

Lee, All the same spring same issue with my79, clutch saftey switch, all the same symtoms. Hot wire the swith and havent had a problem yet.

[XfireZ51]

Lee, All the same spring same issue with my79, clutch saftey switch, all the same symtoms. Hot wire the swith and havent had a problem yet.


I did that when I first got my 92. Intermittent starting. I figured it was the clutch switch because i could pump it a few times and then it would catch. Now I have it shunted with a jumper wire I made.

[scottfab]

Scott by volatage drop I am referring to the fact that when you turn the key volts drop on the dash

On the next "no start"......
Measure it right on the battery both from the frame rail AND the battery neg to pos post as the key is turned to start. If those don't drop bellow 11.5V or so then proceed to look into the clutch switch. (that is if the security light is not flashing).
If necessary bypass the clutch switch temporarily for testing but get it replaced if it's the problem. (safety issue) From there just make sure to fully depress the peddle before turning the ign switch and you'll not see the issue again.
Keep in mind, by far the most common "no start" issue is a tiring battery. Whereas in most cars a "soft" battery is tolerated, not so in the ZR-1.
Good luck. Intermittent issues are by far the worst.