intermittent problem - car starter dead, no start

[mlipmd]

Twice now I have gotten stuck with a no start situation. The car has always started instantaneously on turning the key but on 2 occasions after a 15 mile drive and stopping for 15 min., it wouldn't start, wouldn't engage the starter. The battery is good, connections are tight and clean, all lights, radio, AC fan, seats, etc., work, but when you turn the ignition key on, nothing happens, dead, no sound at all. After 20-30 min. it starts like nothing ever happened. I don't know if it's related to the heat under the engine compartment (works when cools off a little?), or to a faulty clutch interlock switch, or to the starter solenoid failing, or to the starter failing. Anyone else ever have this happen or have an idea of cause. It's hard to find the cause when you try it and it works, easier after it fails. Very annoying.

[Andy]

Had the exact same problem on two cars - one a '90, the other a '93. In both cases, it was the solenoid. Since replacement of the starters, I've not been stranded once. I chose to replace rather than rebuild because the cars had 50k-80k miles and their prior maintenance was unknown.

[DRM500RUBYZR-1]

Observe your volt meter when this happens.
If the needle does not move at all then the diagnosis is more detailed.
If the needle deflects when you turn the key from run to start then it is likely your starter, actually the solenoid.
Get it hot, try it, and let us know what you see.
:cheers:
Marty

[tccrab]

An all too common failure in the early ZR1's, easily and permanently fixed.
It's known as the Dreaded No Start.
http://www.zr1.net/forum/showthread.php?t=11727
However, before you decide to perform my mod, you've GOT to rule out all other possibilities.
My mod involves cutting into the wiring harness and bypassing a problem area of the wiring.
Before you do that, do your research.
Rule out everything else before you start cutting wires.
Go to Cliff's Solutions page, start reading.
http://www.zr1.net/forum/showthread.php?t=16778

Then go to Marc Haibec's web site, here's a link:
http://zr1specialist.com/HAT%20Web/articles/diagnosing%20starter%20problems.htm

If and only IF after you've been through it all and it still won't start reliably, then the DNS mod is what you need.

'Crabs

[Matt B]

+1 one Crabs' post. I had the same issue (but only once) and when the car cooled down everything was good. I added the proposed relay recently as a precaution measure. Cutting wires always hurts - a stranded super sports car hurts even more.
Benefit of the relay is that it adds a "diagnostic port" allowing you to measure current, switch state and resistance conveniently at the relay pigtail in case of issues. And you can direct 12V current (or 24V as sometimes suggested as "boost shot" or "wake-up call") easily to the starter just by using a proper bridge lead. I'm not a fan of mods but this one is worth it.

[Paul Workman]

After owning my Z since 2007, I've experienced both of the more common "no start" situations:


The clutch safety switch (primarily on the 90-92 ZR-1s) and
eroded starter solenoid contacts.


The safety switch closes when the clutch pedal is pressed, passing current directly to the starter solenoid in the 90-92 MY cars, and to a relay (to handle the current) in the 93-95 MY cars. But, the issue is the current drawn by the starter solenoid is several amperes and the clutch safety switch contacts are eroded by the arching (primarily when the key is turned to start before the clutch pedal switch is closed).

This problem was alleviated in the 93-95 MY cars by placing a relay between the clutch switch and the starter solenoid current. And, by inserting a relay in the path between the clutch safety switch and routing the solenoid current path through the relay, it essentially upgrades the 90-92 cars to the 93-95 circuit design and all but eliminates that particular issue.

Regardless of MY, all of the Denso starters have an internal (solenoid) relay that bridges 100s of amperes of battery current (carried in that "00" copper cable) to the starter windings. Every time the starter solenoid is activated, there is significant arching between the contacts bridging the battery to the starter windings.
Fortunately, overhaul kits for the Denso starter are only around $10 for the contacts, and maybe a piece of emery cloth to polish out the pitting on the bridge ring.

NOTE: There are also kits which include a new solenoid armature/plunger assembly. However, the length of the plunger is critically important that it is neither too long or short or the pinion to ring gear mating is compromised and excessive wear can result!! So, I recommend simply getting the contact kit and shine up the bridge ring with the emery cloth and not compromise the pinion/ring gear mating. And, for what it's worth, my solenoid contacts had to be replaced at 45k miles. (And, I chose to bypass that nanny clutch switch all together!)

Pictured are schematics for the 90-92 clutch circuit upgrade (relay) as well as diagrams from the FSM showing the current flows and values for the 90-92 and the 93-95 clutch circuits. (Note the clutch safety switch is isolated from the direct solenoid current path in the 93-95 MY cars. And, then you can see how the insertion of a relay behind the battery to upgrade the 90-92 cars to reduce/eliminate the arching due to the high starter solenoid current draw (see the STICKY notes for details)

[mlipmd]

If you find the clutch switch underneath the DS dash, can you not just disconnect the wiring plug leading to it and just jump or short out the 2 purple and yellow wires in that connection leading to the switch, eliminating that safety switch? The worst that will happen is that the car will start even if the clutch is not depressed, but everyone who drives a stick shift steps on the clutch and knows this anyway. That seems like an easy way to resolve this issue without tapping into the wiring harness and installing more relays.

[conesare2seconds]

I may have missed what year your car is, but know that something like the purple wire mod has already been done by GM on the later cars. If you have a 93-95 especially, the starter may just be on the way out or the solenoid needs reconditioning. I had all the DNS symptoms on a 94 and Marc found a unique failure mode related to an improper water pump replacement. The starter was ruined by a coolant leak.

[mlipmd]

My car is a '90, #545. The "mod" I am thinking about is just jumping a wire between the purple and yellow in the female connector that goes into the clutch safety switch under the dash, thereby just removing the switch from the circuit. There would be no clutch switch.

[tccrab]

I may have missed what year your car is, but know that something like the purple wire mod has already been done by GM on the later cars. If you have a 93-95 especially, the starter may just be on the way out or the solenoid needs reconditioning. I had all the DNS symptoms on a 94 and Marc found a unique failure mode related to an improper water pump replacement. The starter was ruined by a coolant leak.


Most bizarre!!!
I guess the leak coming from the water pump was being blown under plenum by the air coming from the fan.
Had to have been a pretty big leak for the coolant to make it to the starter before it evaporated.

Was there any exterior evidence of the leak, like drips on the garage floor after the car was parked?



His car is a '90.


'Crabs

[mlipmd]

I understand how heat changes electrical resistance so maybe explain how the switch would fail, but why does it get hot? It's only on momentarily for a sec. or two 'till the engine starts, but does that arcing heat it up so much it fails? And why would it work again after 1/2 hr. or more of cooling off? When it fails the contacts are apart, no connection, if they were fused together by the heat and arcing it would be constantly on. And the current going through there is only to energize the starter solenoid, not to engage the starter motor itself. This makes no sense to me so somebody enlighten me why this is.

[mlipmd]

I've used my car a few times since the last No Start and it works/starts flawlessly now every time, like it did before. How do you find and fix an intermittent problem like this? Having a car that you never know if it will start again each time you park somewhere is worse than leaving it sit in the driveway and knowing it will never start.
Maybe I'll just bypass the CSS and hope that solves the issue but you still don't know if that's the problem unless the years go by and it never happens again.

[Matt B]

Another member of the brotherhood has described a method he found grinding a small slot into the rear cover to avoid hot air getting trapped and thereby blocking the plunger.

Adding a relay is a very common measure to boost the power of old car headlamps. Instead of squeezing your amps through yards of old wires, rotten switches and corroded connectors you pull the energy directly from the battery through a highly efficient relay. And here I think is the major benefit to the relay mod: more punch to the plunger to unfreeze it when needed.



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[mlipmd]

If I understand all this correctly adding another relay does not remove the CSS from the circuit. There would be no power to the purple wire if the switch does not work. If you want to take power from the purple wire to trigger a relay to power the starter solenoid directly off the battery rather than trigger the starter relay from the purple wire itself, there seems to me to be little advantage to that. Extra relay or not, you need a properly functioning or bypassed CSS if you want power to the purple wire.
Matt B - are you talking about hot air being trapped inside the starter relay? Have you ever seen the inside of one of those? There's no chance of air blocking the movement of the piston holding the copper disc or bar from moving inside of that can. The whole thing just floats in there, no blockage or entrapment of air can occur in there.
And the problem with my No Start is not with the starter relay or the starter, it is that no juice makes it up to there in the first place. The purple wire is dead because the CSS is not working, and an extra relay would add nothing. I know it's the CSS because there is no sound, no clicking, no nothing, on turning the ignition key on. And then, later it works fine (?).

[Young1]

Right of passage plenum pull. Polish the solenoid contacts with a die grinder stone in a battery drill. Reassemble. Good for another 40 k miles.

[conesare2seconds]

Hi there. Yes, coolant was migrating underneath the plenum and got to the starter. Marc hadn?t seen it before. Whomever replaced the water pump made an RTV gasket that didn?t allow the bolts to be torqued to spec, as I recall the explanation. I never found coolant on the garage floor before the pump was re-sealed and the starter replaced.

[Matt B]

Matt B - are you talking about hot air being trapped inside the starter relay? Have you ever seen the inside of one of those?

No... As stated that wasn't my thoughts but posted by a member. It's in this threat http://www.zr1.net/forum/showthread.php?t=10321 picture is linked on the last page.
And you are right - if the CCS is not functioning a relay will help nothing. Swap it out and see if it ultimately resolves the issue. Easy fixes are the best!

[Paul Workman]

If you find the clutch switch underneath the DS dash, can you not just disconnect the wiring plug leading to it and just jump or short out the 2 purple and yellow wires in that connection leading to the switch, eliminating that safety switch? The worst that will happen is that the car will start even if the clutch is not depressed, but everyone who drives a stick shift steps on the clutch and knows this anyway. That seems like an easy way to resolve this issue without tapping into the wiring harness and installing more relays.

Yes, you are correct. Note the alternative (jumper) method in the relay diagram showing the very jumper you describe.) The jumper bridges that clutch (nanny) switch (which is exactly what I did to mine - and I totally agree w/ your statement regarding ppl pressing the clutch on manual trans cars B4 turning the switch!)

AND!! There was an occasion where my wife's Z ran out of gas, but was able to coast to the entrance to the gas station. By putting it in 1st gear and merely hitting the start switch, w/o that nanny clutch switch, we were able to dive the car to the gas pump using the starter! That clutch switch removes the option of moving the car a short bit when the engine doesn't start. (It has come in handy several times over the years - speaking from personal experience!)

HOWEVER.... None of this bypass/relay stuff has any affect on the starter's (internal) solenoid switch. Those contacts are a significant contributor to the infamous "DNS" issue - an issue related to the Denso starters et all and NOT limited to the ZR-1s by any means!

[KPW]

Another vote for solenoid contacts, I?ve had similar issues as you describe, but not since I pulled the plenum and shined up those contacts. I had been dragging my feet on that as the solution, but in the end it was quite effective.

Big confidence boost to trust the car will start after dinner [emoji6]


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[mlipmd]

Has anyone done the relay mod underneath the DS dash panel? It may be easler to access the purple wire under there where it is exposed instead of digging it out somewhere in the wire loom and the relay could be tucked in under there out of the weather and heat. You just have to maybe run a pos. 10 gauge wire through the firewall to that area.

[32VALVS]

I fought the hot no start (with solenoid click) condition in my '92 this spring.

I had a solid "click" from the solenoid and assumed it must be the battery, it was weak after winter storage. That didn't fix it and left me bump starting in the grocery store parking lot.

New contacts fixed it for a few days. Then back to the clicking no-start.

Hmm...pulled the plenum and put in a new starter. Thought maybe the windings were shorted when hot.

Same problem, stranded at a friend's house until it cooled.

Jumped the wires at the clutch switch and have not had another issue all summer.

The switch measured 0.5 ohms resistance. That's equivalent to 300 feet of 12 AWG copper wire!

The switch had enough voltage/current drop that it actuated the solenoid with enough force to click, but not enough force for the contacts to pass the battery current needed to turn the hot starter.

[mlipmd]

I tried a few times to post this here but keep getting timed out so I'm just copying what I posted on the C4 ZR-1 section of the Corvette Forum.

For those of you that have followed these threads, here's a new better way to fix this problem.
Twice now I got the DNS, both times parked in a shopping area parking lot. Had to wait 30-45 'min. till the car cooled off then it would start right up like it never happened. PIA as well as embarrassing.
I have been reading a lot about this on this and the ZR-1registry forum and the best advice is to modify my '90 to the later '93-95 ignition system by bypassing the CSS and installing a relay to power the starter solenoid.
All of the relay mods talk of finding the purple wire in the wiring loom and cutting it, using the CSS end of the wire to trigger the relay, and the output goes to the other end of the wire, used to power the starter solenoid.Cutting wires is scary, but there is a much easier,better way without cutting any wires.
If you take down the DS dash panel to gain access to the CSS wiring preparing to bypass it, the first thing you will immediately see is the light yellow with ? blue or black stripe wire (wire looks white, so from now on whatever color it really is, I'm calling it "white" because it looks white to me), alongside a purple wire, in a black connector, connected to 2 black wires leading up higher to the CSS above the clutch pedal.
Don't go looking for the CSS itself, it's buried way up underneath the dash and you don't need it for anything.
If you take apart that connector you have the ends of the white wire from the ignition switch and the purple wire leading out to the starter solenoid. If you just want to bypass the CSS, just connect a short jumper wire to the 2 male terminals in that plug. But if you want to do the starter relay mod, why would you want to dig around in a wire loom and look for the purple wire and cut it for your relay connections? You have the end right there.
Very simply, use the white wire to trigger the relay, use the purple wire for the output to the starter solenoid, all by very simply attaching a short jumper wire to each in the male plug in the connector.
So when my 60-80 amp heavy duty relay arrives tomorrow, I am going to plug in a new 12V hot lead to pin 87, the purple lead connected via a short jumper in the connector plug to 30, the white lead (from the ignition switch) via a short jumper in the connector plug to 86, and a ground from somewhere under the dash, to a bolt handy, to 85. Very simple, no searching for a purple wire to cut, less connections, less resistance in the circuit, and much easier. In addition the whole thing is hidden under the dash, out of the weather, out of the heat, out of sight. Also, if I ever want to restore it back to original, all I have to do is pull off a few jumpers and hook it back up the way it was, no repairing cut wires.
The only thing I have to figure out is how to run the 12V hot lead into the cabin. I can enter via the driver's door accordion, poke a small hole in the bottom and then silicone it up, I can enter via the grommet that the hood latch release cables pass through, also poking a hole then siliconing it up, or I can run a lead down in front of the door hinges protecting the wire inside a 1/4"vinyl tubing and lead it right into the cabin. I already checked and there is plenty of room as the door closes and nothing would get squished but that would be pretty unsightly and not very professional.
Tomorrow if I get to this I'll post some pics but this seems to me very much easier and less destructive and easily reversible if you want.
Hopefully after this I'll never have that DNS happen to me again.

[mlipmd]

For a wiring diagram and pics of what I did, go here, post #8.
https://www.corvetteforum.com/forums/c4-zr-1-discussion/4555640-a-better-way-of-fixing-the-dreaded-no-start-problem.html#post1603877386

[Matt B]

Thanks for that. Staying inside the cabin seems useful considering heat an moisture under the hood.
I cut the purple wire during a plenum pull as it's VERY easy to locate inside that remote end branch of the harness. One could even use a matching pigtail to connect the terminal end of the wire to that pigtail instead of the starter connector.
However, precondition is to remove the plenum and dig under the coil base plate.
In any way I like your approach more...

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[karlaw]

Thanks


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