Z won't start

[Jetjock]

I went out to my garage to move my 93Z to do some work and the carwon't start. I had this problem before but always able to get the car started. I suspect the clutch safety switch is the culprit. I have the part but was wondering if anyone ever changed one out or did something else.


Thanks for any input.


Roy

[Ccmano]

Define “won’t start”. Turn the key, nothing happens. Or engine turns over but won’t start? If it’s the first, item one to check is the battery. If the resting voltage is anything less than ~12.4 volts the battery is suspect. Have it checked with a proper “load” test. There are many other conclusions you can jump to but more often than not it’s simply the batter or connections.
H
:cheers:

[Jetjock]

Define “won’t start”. Turn the key, nothing happens. Or engine turns over but won’t start? If it’s the first, item one to check is the battery. If the resting voltage is anything less than ~12.4 volts the battery is suspect. Have it checked with a proper “load” test. There are many other conclusions you can jump to but more often than not it’s simply the batter or connections.
H
:cheers:



I wrote a response to defination; however, my computer signed me out before I could post it. Bottomline, the battery is new and is on a battery tender. I had over 12 volts. There was no sound like the starter or the engine trying to turn over. It wasn't the VATS. I had this clutch safety switch go bad on my 92Z and I bypassed it and haven't had a problem with it since. I did the same with the 93Z but it hasn't worked that well. I am exploring other considerations.


Roy

[Ccmano]

Roy,
Please double check your battery for the voltage I noted above before you go any further. Just because the battery is new and on a tender in no guarantee. I’ve seen stranger things. If the battery is good the issue is likely the starter solenoid. The contacts corrode/burn even on low mileage cars. Do a search on starter solenoid and you’ll find volumes. Also, the excellent “Solutions” sticky at the top of this section has a complete run down.
H
:cheers:

[oldpro]

Here is the way to fond out if it is your clutch switch . Push the clutch in and watch the battery gauge on the dash panel if the needle moves when you try to start then it's the starter if it doesn't move its the switch hope this helps

[Jetjock]

Here is the way to fond out if it is your clutch switch . Push the clutch in and watch the battery gauge on the dash panel if the needle moves when you try to start then it's the starter if it doesn't move its the switch hope this helps



I went out to the car as soon as I saw this post. The needle did not move at all until after several attempts, it twitched. The digital readout did not change until after several attempts. It then jumped up in voltage and then back down. Could it be both?


Roy

[oldpro]

Hmm sounds like you have a problem. With the clutch switch like a bad contact causing voltage to behave erractiy : if it were me I would either bypass the switch or put a new switch first if that doesn't work then it pull the plenum and ck the starter out

[Paul Workman]

Some 93-95 specific circuit diagram my shed some light on the issue?

First...the high current (arching) that eventually eroded the contacts of the (90-92 model years) clutch safety switch (that was in series with the starter circuit) was fixed in the 93-95 ZR-1s (see the switch, circled in RED, in the GREEN circuit path).

The current and so too the erosion due to arching is all but eliminated from '93+ ZR-1s. So, if there is intermittent issues with the starter not turning, chances are it is much more likely an issue with erosion of the internal SOLENOID CONTACTS inside the starter solenoid housing (likely) or the START ENABLE RELAY (rarely the likely problem).

First things first: you can eliminate the clutch safety switch as being the issue by temporarily connecting the two ends of the wires leading to/from the clutch safety switch. It is doubtful that on a 93+ ZR-1 that you'd notice much if any change to the problem's characteristics. But, if the starter issue is resolved - never to return - then it was that clutch safety switch perhaps after all that needs to be replaced. HOWEVER, if there's no change to the starter characteristics, leave the clutch safety switch bypass intact for now, and try to next identify which relay(s) may be the problem. Read on...

To eliminate the (very unlikely) STARTER CONTROL RELAY, probe the large purple wire leading to the STARTER SOLENOID and monitor the voltage on a VOM as you turn the ignition switch to START.

If the voltage immediately reads battery voltage OR SLIGHTLY LESS than what the battery reading was when everything (except the under hood lights) are at rest, the problem is @ the starter. Off with the plenum! But, if a NO VOLTAGE reading ensues with the ignition switch in the START position, then either the problem is with the STARTER ENABLE RELAY UNLESS there is an issue @ the CENTRAL CONTROL MODULE where it is not grounding the ENABLE relay for some reason e/g., is the SECURITY light flashing with the door closed??

If you observed the battery voltage on the dashboard as you turn the ignition switch to START, if the voltage dips slightly, the problem may be a defective solenoid coil or other internal starter winding issue (shorted). But, if there is no dip in the dashboard volt meter when you roll the ignition switch to START position, then it is likely the relay contacts in the starter solenoid - good news b/c it is usually around only $10 to replace the contacts.

(NOTE: I've said this many times before, but the more expensive solenoid repair kit for the Denso starter usually includes a new solenoid armature. Compare the length of the new armature plunger pin with the OEM part. I have found it may have a shorter plunger pin than the stock solenoid armature has. If so, DO NOT install that part. Instead, brighten up the contact ring with fine sandpaper and reuse the stock solenoid armature. To use the replacement part with a shorter plunge pin will result in only a portion of the contact area between the pinion and the flywheel ring gear. Eventually, this will result in excessive wear at the least. Or worse, it may lead to missing teeth on the ring gear...no bueno

[oldpro]

Great explanation Paul I learned a lot from your post .

[RussMcB]

There is a "purple wire mod" discussed occasionally in ZR1.net. It allows you to make a more direct connection between the battery and starter, bypassing the clutch switch, VATS and ignition switch (sort of). It includes a relay that uses the signal from the ignition switch to send a strong 12v directly from the battery. A search should bring up details. It worked for me in 2015 and has been on my car since with no more no-start issues. Before then I tried the VATS bypass but it didn't help.

[Jetjock]

I've been wrestilng with this problem for a while now. When I got my 92Z, I pulled the starter and replaced it with a new one as well as fuel injectors, plugs, coil packs, etc. When the first time that the car wouldn't start, I had just had the clutch replaced by Jim Van Dorn. When it happened, he told me that it was the clutch safety switch. When I got home, I bypassed the safety switch and have not had another problem since then.


Jump ahead to 2014 and I bought the 93 Ruby Z. Low mileage, fun to drive and then the problems started. Minor issues at first like cruise control not working, stuff like that. Gordon fixed a lot of problems with the car. However, when the car started it's current problem, I did bypass the clutch switch and it seemed to work. However the fix did not take. I have removed the kick panel many times to get it started. However, now I have this issue.


I have another issue to correct while I'm under the steering wheel. I want to get the car ready for NCRS so I will get a new battery for the car and go through the testing. I do have the car manuals and the checklist items to check for what is wrong. However, if I do have to pull the plenum, there might be a problem. I have pulled the plenum on my 92 many times and have had no issues. I tried to pull the plenum on my 93 for an another issue and I had to stop because I ran into many issues with it. It has a lot more connections with it than the 92 did and really surprised me. However, if I have to do it, I'll just have to take my time with it.


Anyway, I'll get to work on this tomorrow and let you know.


Roy

[Jetjock]

Update:


I went through the checklist and checked for any CCM codes. I got one for Code 51 which is the VATS. I have three keys to the car so I checked out each one of them. Two out of three started the engine. The original key, that I got from the previous owner, did not. I don't know if the pellet goes bad after a time or what. The car starting issue has been resolved. Now for the hi/lo beam problem. Thanks for your help.


Roy

[viper107]

the vats ignition switch(key part) also has micro wires running from the switch(keys) through the colum and plugs down by your feet, those wires break at the switch from turning on and off the engine, this can cause a intermit start fault due to the wires breaking current,then not,then again, never saw a key go bad,but im shure somebody has

[viper107]

i have also seen the vats brain go bad once, 99 .9 % i see the vats switch broke wires

[oldpro]

I had a key go bad on my 90'once been using the second key ever since

[Paul Workman]

I had a key go bad on my 90'once been using the second key ever since

My local locksmith and GM dealer both have readers that will tell which pellet you need on your ignition key. With your working key as a blank, the new key can be cut. Then you'll have a fresh key with the right pellet.

OR, you can read the resistance across the pellet and compare it to the (attached) chart and select a blank yourself.

[Starman]

Have been temporarily stranded twice now with no starts with 1991. 1-2 year old battery, kept on a tender. Drove the car several miles on the highway and parked. After about an hour sitting, no starter, no fuel pumps. Cold had 13.9V at battery and 12.4 cranking. Was jumped 2nd time, nothing, then just up and started as getting ready to look for match to burn it down.

Assumed original, 57K mile starter getting heat soaked. Drove car for 45 minutes without shutting off (learning). Parked in garage and let sit an hour, started right up (note - did not lock in garage). Using "new - unused original" key. Hot voltages were lower.

Going to repeat test and lock in garage this weekend. Anyone know the VATS retry window off the top?

[DRM500RUBYZR-1]

About ten minutes.

However, next time observe your security light, before, during and after to confirm or eliminate VATS as the issue.

Vats also sets a DTC in history. check and see what you have stored.

Clean your key and try your other.

Keep us posted.
:cheers:
Marty

[Young1]

Yes to Marty. Clean the key pellets and ignition with contact cleaner. That was the fix for me once for a no start. Took me several days to figure that one out.