Intermittent DNS - ZR-1 Net Registry Forums

ALLTHECAMS · 04-24-2017

So I now have the intermittent DNS (dreaded no start) on my 91 Z. I want to try to bypass the clutch safety switch to see if that helps. Can I just unplug it and jumper across the plug or is there more to it?

Sent from my XT1080 using ZR-1 Net Registry mobile app

-=Jeff=- · 04-24-2017

Is it DNS when hot only? If so.. starter contacts

Sent from my iPhone using ZR-1 Net Registry

QB93Z · 04-24-2017

Verify that both battery terminals are clean and tight. Disconnect any after market systems attached to the battery terminals.

Put the ignition key to ON, Engine not started. Note the battery voltage on the instrument panel. Turn the key to start, while watching the battery voltage meter. If the needle does not deflect, then investigate the starting circuit, ie clutch switch, VATS, TDS.

If the volt meter does deflect, it means that the starter solenoid is energizing but the solenoid contacts are not passing current to the starter motor. Rebuild the starter solenoid or replace the starter.

NOTE, keep this procedure handy because it has to be done when the car won't crank. For an intermittent problem like you stated, you will have to wait until the next failure.

Good luck,

Jim

ALLTHECAMS · 04-24-2017

Quote:

Originally Posted by -=Jeff=-

Is it DNS when hot only? If so.. starter contacts

Sent from my iPhone using ZR-1 Net Registry

Yes so far its only when hot and not every time. Thanks for the advice. Hoping I don't have to pull the plenum again.

Sent from my XT1080 using ZR-1 Net Registry mobile app

RICHARD TILL · 04-25-2017

EXACTLY the same symptoms I had when the starter solenoid contacts were dirty.

ALLTHECAMS · 05-10-2017

OK, so it happened again. I watched the volt meter and the needle didn't move when I turned the key to start. I was able to get a push start. What's the next step?

QB93Z · 05-11-2017

TDS is the theft deterrent system, the resistance chip in the ignition key that is checked to allow the computer to allow the starter circuit to energize.

The next step is to rebuild the starter solenoid or replace the starter.

Jim

ALLTHECAMS · 05-11-2017

Quote:

Originally Posted by QB93Z

TDS is the theft deterrent system, the resistance chip in the ignition key that is checked to allow the computer to allow the starter circuit to energize.

The next step is to rebuild the starter solenoid or replace the starter.

Jim

OK now I'm confused LOL. In your first post you said if the needle did t move it wasn't the starter but to into the clutch safety switch or VATS? Sorry but I'm a dummy when it comes to diagnosing electrical issues.

Sent from my XT1080 using ZR-1 Net Registry mobile app

QB93Z · 05-11-2017

Quote:

Originally Posted by ALLTHECAMS

OK now I'm confused LOL. In your first post you said if the needle did t move it wasn't the starter but to into the clutch safety switch or VATS? Sorry but I'm a dummy when it comes to diagnosing electrical issues.

You are correct. I am on the road in Colorado right now and wasn't following you comments carefully enough. I suggest troubleshooting the starter circuit to identify a switch or wiring that is failing. I don't have any manuals with me so I will leave the explanation to others.

Jim

Z51JEFF · 05-11-2017

Bypassing the switch is easy. Pull the hush panel and look up under the dash and look for the 10 gauge PURPLE WIRE plug,it should be towards left of the steering column. I have a jumper I made,if you were closer I'd loan it to you for some trouble shooting.

04-24-2017	#1
ALLTHECAMS Join Date: Jul 2016 Location: Bloomington, MN Posts: 127	Intermittent DNS So I now have the intermittent DNS (dreaded no start) on my 91 Z. I want to try to bypass the clutch safety switch to see if that helps. Can I just unplug it and jumper across the plug or is there more to it? Sent from my XT1080 using ZR-1 Net Registry mobile app

04-24-2017	#2
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,156	Re: Intermittent DNS Is it DNS when hot only? If so.. starter contacts Sent from my iPhone using ZR-1 Net Registry __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Shelby Series 1 - Wilwood Brakes Custom Interior NCM Lifetime Member #978

04-24-2017	#3
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	Re: Intermittent DNS Verify that both battery terminals are clean and tight. Disconnect any after market systems attached to the battery terminals. Put the ignition key to ON, Engine not started. Note the battery voltage on the instrument panel. Turn the key to start, while watching the battery voltage meter. If the needle does not deflect, then investigate the starting circuit, ie clutch switch, VATS, TDS. If the volt meter does deflect, it means that the starter solenoid is energizing but the solenoid contacts are not passing current to the starter motor. Rebuild the starter solenoid or replace the starter. NOTE, keep this procedure handy because it has to be done when the car won't crank. For an intermittent problem like you stated, you will have to wait until the next failure. Good luck, Jim Last edited by QB93Z; 04-24-2017 at 07:32 PM.

04-25-2017	#5
RICHARD TILL Join Date: Aug 2005 Location: Iuka, Mississippi 38852 Posts: 756	Re: Intermittent DNS EXACTLY the same symptoms I had when the starter solenoid contacts were dirty.

05-10-2017	#6
ALLTHECAMS Join Date: Jul 2016 Location: Bloomington, MN Posts: 127	Re: Intermittent DNS OK, so it happened again. I watched the volt meter and the needle didn't move when I turned the key to start. I was able to get a push start. What's the next step? Last edited by ALLTHECAMS; 05-10-2017 at 11:48 PM.

05-11-2017	#7
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	Re: Intermittent DNS TDS is the theft deterrent system, the resistance chip in the ignition key that is checked to allow the computer to allow the starter circuit to energize. The next step is to rebuild the starter solenoid or replace the starter. Jim

05-11-2017	#10
Z51JEFF Join Date: Dec 2007 Location: Fremont, CA Posts: 3,087	Re: Intermittent DNS Bypassing the switch is easy. Pull the hush panel and look up under the dash and look for the 10 gauge PURPLE WIRE plug,it should be towards left of the steering column. I have a jumper I made,if you were closer I'd loan it to you for some trouble shooting.