Car wouldnt start........what say the Brotherhood?

[Z51JEFF]

I stopped by my brothers house earlier today,got ready to leave and the car wouldnt start.Batteries maybe 6 months old,Alt is charging,turn key and the Security light goes out but no start.Im thinking either clutch safety switch or the starter gettin funny.I jumped it with a battery charger and it starts right up.Drove the car home,put it in the garage and the car starts right up.I drove the car for a few miles yesterday but other than a short drive every other week dont really drive it that much.Why would the car start with a jump from the battery charger?If the starter is acting up would the extra juice from the jump jolt the starter to work?I thought the VATS might be acting up but from what Ive read if the Security light goes out when the key is turned to start the Security light will go out.Id like to think this was a freak occurrence but would like to find out whats goin on here.What say the Brotherhood?

[mike100]

not LT5 specific, but sometimes a boost in battery voltage will get a sticky solenoid to close with a little more authority.

You should load test that battery next time it doesn't start. A fully charged battery that has sat for a few days should still read 12.6v. If that battery is around 4 years of age, you might replace it for gp, even if it turns out the starter has problems.

[cvette98pacecar]

I stopped by my brothers house earlier today,got ready to leave and the car wouldnt start.Batteries maybe 6 months old,Alt is charging,turn key and the Security light goes out but no start.Im thinking either clutch safety switch or the starter gettin funny.I jumped it with a battery charger and it starts right up.Drove the car home,put it in the garage and the car starts right up.I drove the car for a few miles yesterday but other than a short drive every other week dont really drive it that much.Why would the car start with a jump from the battery charger?If the starter is acting up would the extra juice from the jump jolt the starter to work?I thought the VATS might be acting up but from what Ive read if the Security light goes out when the key is turned to start the Security light will go out.Id like to think this was a freak occurrence but would like to find out whats goin on here.What say the Brotherhood?

It is the VAT key. I had the same problem with a 92 ZR1 that I owned before. I'll Bet that you took the key out of the ignition while you connected the battery charger. Have a new key cut or buy the VAT bypass.

[Z51JEFF]

It is the VAT key. I had the same problem with a 92 ZR1 that I owned before. I'll Bet that you took the key out of the ignition while you connected the battery charger. Have a new key cut or buy the VAT bypass.

I may have takin the key out of the ignition with the charger connected,I know I was wiping the $hit outa that pellet.Ive got an extra set of keys and one extra key I have cut right after getting the car.

[Kevin]

my advice is to always bypass the clutch switch. costs $0.15 and then if that doesn't work you can move onto other stuff

[GOLDCYLON]

I stopped by my brothers house earlier today,got ready to leave and the car wouldnt start.Batteries maybe 6 months old,Alt is charging,turn key and the Security light goes out but no start.Im thinking either clutch safety switch or the starter gettin funny.I jumped it with a battery charger and it starts right up.Drove the car home,put it in the garage and the car starts right up.I drove the car for a few miles yesterday but other than a short drive every other week dont really drive it that much.Why would the car start with a jump from the battery charger?If the starter is acting up would the extra juice from the jump jolt the starter to work?I thought the VATS might be acting up but from what Ive read if the Security light goes out when the key is turned to start the Security light will go out.Id like to think this was a freak occurrence but would like to find out whats goin on here.What say the Brotherhood?

Jeff have you bypassed the clutch switch yet? GC

[Z51JEFF]

Jeff have you bypassed the clutch switch yet? GC

I havent done this yet,would like to put a bypass switch in line without cutting anything.I can get some OEM plugs and put something together.How common is the clutch switch being a problem?Cars got 17,000 miles but sometimes mileage doesn't matter when it comes to failures.

[tccrab]

I havent done this yet,would like to put a bypass switch in line without cutting anything.I can get some OEM plugs and put something together.How common is the clutch switch being a problem?Cars got 17,000 miles but sometimes mileage doesn't matter when it comes to failures.

Jeff:

The DNS (Dreaded No Start) can come for many different reasons.
Clutch safety switch is a common failure and easily bypassed.
Corroded battery terminals are another biggie.
Could be a funky starter too, especially if the engine has ever been wet at any time in its' life.
I don't recommend hacking your wiring harness and installing my patented DNS Cure just yet.
Rule out the obvious, less invasive remedies first.
Don't think it's a VATS issue, sounds like everything is working as it should.
The following is the VATS sequence on startup:
When the system is operating in normal mode, the VATS decoder reads the correct resistance during cranking. The module grounds the Start Enable Relay coil. When the start enable relay contacts close, voltage is allowed to the "S" terminal of the starter. The VATS module also sends an enable signal to the ECM. This signal allows the ECM to operate the fuel injectors during cranking. The SECURITY light will also illuminate for approximately five seconds, then turn off and remain off. If an incorrect or no key resistance is read by the VATS decoder module, the module will shut down the start enable and ECM signal outputs for 4 minutes. The SECURITY light will flash during the cranking attempt, and will remain on during the 4-minute duration. Even if the correct resistance is read within that 4 minute duration, the VATS module will not operate the relay or signal the ECM..An error code.53 will also be set if the proper signal is not being received on CKT 229 by the ECM when the ignition is turned ON.
If an incorrect resistance is detected by the VATS module after the engine is running, the VATS module will allow the vehicle to be restarted, even with an existing failure. The SECURITY lamp will remain on to warn the driver that a VATS system fault is present. However, this also means that the car can be started w/o a correct key resistance, and is therefore vulnerable to theft. An error code.53 will also be set by the ECM in this mode.

TomC
'Crabs

[Kevin]

I havent done this yet,would like to put a bypass switch in line without cutting anything.I can get some OEM plugs and put something together.How common is the clutch switch being a problem?Cars got 17,000 miles but sometimes mileage doesn't matter when it comes to failures.

Pull drivers side hush panel. Find Purple wire that goes to clutch 
switch. Look at switch and note the color of wire coming back 
up.(Yellow??) Will be able to jumper them right there. I used a 3 in 
wire with terminals on the end and unplugged the wires going to switch 
and plugged in the jumper wire. Use a 12 ga wire at least as it does 
carry a heavy current load which is why the switch fails, it gets hot 
and the resistance across the points stops current flow.

unless someone is really really digging into your car no one will ever see it

[GOLDCYLON]

Pull drivers side hush panel. Find Purple wire that goes to clutch 
switch. Look at switch and note the color of wire coming back 
up.(Yellow??) Will be able to jumper them right there. I used a 3 in 
wire with terminals on the end and unplugged the wires going to switch 
and plugged in the jumper wire. Use a 12 ga wire at least as it does 
carry a heavy current load which is why the switch fails, it gets hot 
and the resistance across the points stops current flow.

unless someone is really really digging into your car no one will ever see it


What Kevin said 100%

The previous owner of my car did this after being stuck 3 times. It has never been a problem since

[Kevin]

What Kevin said 100%

The previous owner of my car did this after being stuck 3 times. It has never been a problem since

mine stranded me 3 times before i said screw it and did the bypass never happened since.

[Z51JEFF]

Has anybody replaced the switch and had no more problems?As a last resort Ill bypass the switch but like the safety feature,but hate the idea of being stranded.Anybody got the part number for a new switch?Is replacing this as much of a pain as replacing the brake switch?Once I get the hush panel off Ill replace the switch but will put a bypass in line thats easy to get to.

[Z51JEFF]

Done some digging.Ive got part# 25529680,AC Delco part# D852A.Does that sound about right?

[Kevin]

Has anybody replaced the switch and had no more problems?As a last resort Ill bypass the switch but like the safety feature,but hate the idea of being stranded.Anybody got the part number for a new switch?Is replacing this as much of a pain as replacing the brake switch?Once I get the hush panel off Ill replace the switch but will put a bypass in line thats easy to get to.
it's been years since i've done mine but it can't be that hard if I did it. I remember moving the dirvers seat all the way back and laying on my back in the footwell and tracing wires back to where the switch is and just running the wires into it and being done.

[Z51JEFF]

it's been years since i've done mine but it can't be that hard if I did it. I remember moving the dirvers seat all the way back and laying on my back in the footwell and tracing wires back to where the switch is and just running the wires into it and being done.

Ive had the CDM controller for the stereo out for repair so anything else in this car is a walk in the park,just not easy.Im not finding the switch.The part is NLA but somebody's got it.

[Z51JEFF]

Thanks for all the tips guys.Im going to stop by a Corvette wrecking yard tomorrow and get a few plugs and make a bypass pigtail to plug into the wiring harness to bypass the switch if I cant find a new switch.Once again the Brotherhood is on the ball.Thanks again!

[Paul Workman]

Has anybody replaced the switch and had no more problems?As a last resort Ill bypass the switch but like the safety feature,but hate the idea of being stranded.Anybody got the part number for a new switch?Is replacing this as much of a pain as replacing the brake switch?Once I get the hush panel off Ill replace the switch but will put a bypass in line thats easy to get to.

Well, if you want the clutch engaged safety feature, you can install a heavy duty relay above the battery and simply use the clutch switch to energize the relay. Or, I suppose you could use a big ol' moss-fet transistor in place of the relay and never have to worry about relay contacts (in place of the clutch switch) going bad.

Dynomite has in his help section a tab with the scematic I drew up for the relay modification. Using a relay that plugs into a socket will allow you to replace the relay if ever it too should ever need replacing.

PM me if you need more info.

P.

[Z51JEFF]

Well, if you want the clutch engaged safety feature, you can install a heavy duty relay above the battery and simply use the clutch switch to energize the relay. Or, I suppose you could use a big ol' moss-fet transistor in place of the relay and never have to worry about relay contacts (in place of the clutch switch) going bad.

Dynomite has in his help section a tab with the scematic I drew up for the relay modification. Using a relay that plugs into a socket will allow you to replace the relay if ever it too should ever need replacing.

PM me if you need more info.

P.

Paul,if I had the switch I wouldnt need my car looking like the Back To The Future Delorean......................couldnt resist,that was funny.Ive got a line on a new part and several used parts.Ill bypass before I put a used part in the car but would like to have the plug and about 3 inches of wire.Thanks for the tip Paul,very much appreciated.Anybody got a dead switch?

[Paul Workman]

Paul,if I had the switch I wouldnt need my car looking like the Back To The Future Delorean......................couldnt resist,that was funny.Ive got a line on a new part and several used parts.Ill bypass before I put a used part in the car but would like to have the plug and about 3 inches of wire.Thanks for the tip Paul,very much appreciated.Anybody got a dead switch?

Ah! You think I jest, eh? Au contraire! This has been installed in at least two Zs to date.

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/Starterrelaymodification.jpg

Personally, if I were opposed to bypassing the clutch switch, I would consider using a solid state "gate" device. No sparking means no erosion of the contacts to the eventual malfunction....Just a thought.

In any case, one of the guys that installed just such a relay placed it in the space just above the battery and under the ECM. Works great, according to him.

Like you, I think I like the clutch interlock switch...at least for now.

P.