Classic no start “relay fix” – what does it do?

[ghlkal]

Thanks everyone

Originally Posted by Dynomite

No.....never stuck

Does starter solenoid click when you turn key?
Does battery voltage drop when solenoid clicks?
Are your battery hot wire and ground clean and tight?
The issue could be internal to the starter electric motor but I have found that the Solenoid points were the most often issue.

When "no start" happens, there's no solenoid click. I turn the key and nothing. When it does happen, I usually haven't been able to measure voltage. The last time it happened was at home, I got my meter and was ready to measure, but when I turned the key, it started up.


Connections are clean and tight.

[lfalzarano]

It will always push start if you can get one.


Sent from my iPhone using ZR-1 Net Registry

[tccrab]

Be forewarned, push starting a ZR1 by yourself can be unhealthy.
One of our former members got his leg caught in the back wheel when trying to hop back into the car.
I'll have to go digging for the posting, it was quite graphic.


'Crabs

[Paul Workman]

Originally Posted by lfalzarano

It will always push start if you can get one.


Sent from my iPhone using ZR-1 Net Registry

There IS another start relay that has not been discussed yet.

In the 90-92 schematic there is a START RELAY which is commanded by the CCM. That relay sends power to the clutch safety switch (which you say is bypassed).

That being the case, you'd like to know if the purple wire leading to the starter solenoid was reading ~ 12 volts when you turn the switch. IF NOT, then start tracing the circuit and find out where you are loosing voltage when the ignition switch is turned to START.

The schematic says it all. And, Marc has listed the normal voltages at the various locations along circuit.

Get some test leads w/ alligator clips on each end soze you can connect your VOM and place it were you can see it when you turn the START switch. (NOTE: If the START switch were not working, THAT TOO would cause the problem.

My point is, the solution requires that the circuit be tested along the path until voltage with the start switch ON dissappears. Then find out WHY before changing anything. (RULE OF THUMB: A device isn't bad until it has "gozeinto but no gozeouta" )

Have no fear. this little ditty can be found. It is a bit unusual - not the usual culprit in the dreaded NO START ISSUE. But, NO POWER problems are usually pretty straight forward.

Start with measuring voltage on the purple wire leading to the solenoid. With the ignition switch in the START position, do you have ~12 volts. If not, then divide the circuit in half and test again.

(NOTE: With the clutch switch bypassed, there is only the START RELAY, (assuming connections are not corroded: but, you checked that, right? RIGHT??) The relay (black-yellow wire) is connected to the CCM and when the IGN switch is in START, the voltage at that wire should go to zero, or very close to it [indicating the CCM has grounded the START RELAY coil as it should when starting the car]. And, as always, CONNECTIONS, CONNECTIONS, CONNECTIONS....!!)

[ghlkal]

Originally Posted by Paul Workman

There IS another start relay that has not been discussed yet.

In the 90-92 schematic there is a START RELAY which is commanded by the CCM. That relay sends power to the clutch safety switch (which you say is bypassed).

You're right Paul.



Bypassing the Start Relay has the added benefit of disabling the VATS system also.


Every time I tried to "catch" the no-start issue, the engine decided to start so I couldn't get readings when it didn't start.


I bypassed the Start Relay and so far I haven't experienced a no-start condition.


Gary

[Paul Workman]

Originally Posted by ghlkal

You're right Paul.



Bypassing the Start Relay has the added benefit of disabling the VATS system also.


Every time I tried to "catch" the no-start issue, the engine decided to start so I couldn't get readings when it didn't start.


I bypassed the Start Relay and so far I haven't experienced a no-start condition.


Gary

Yup, VATS relay. FINGERS CROSSED!

[Z51JEFF]

It was recently brought to my attention I may have gottin the wiring wrong on my installation so that might need to be verified before anybody does this modification yet I have had not a single -no start- issue in the 4 years since I did it.

[Paul Workman]

Originally Posted by Z51JEFF

It was recently brought to my attention I may have gottin the wiring wrong on my installation so that might need to be verified before anybody does this modification yet I have had not a single -no start- issue in the 4 years since I did it.

Are we 'talking' about the auxiliary (90-92) relay inserted in the starter solenoid (purple) wire, or the VATS relay?

.

[WVZR-1]

Originally Posted by Z51JEFF

It was recently brought to my attention I may have gottin the wiring wrong on my installation so that might need to be verified before anybody does this modification yet I have had not a single -no start- issue in the 4 years since I did it.

Have you actually confirmed that yours is wired as you mentioned and it's NOT just typo in your thread?

[WVZR-1]

Originally Posted by Paul Workman

Are we 'talking' about the auxiliary (90-92) relay inserted in the starter solenoid (purple) wire, or the VATS relay?

.

This thread is Jeff's concern!!

https://www.corvetteforum.com/forums...made-easy.html