intermittent problem - car starter dead, no start

[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]

Originally Posted by mlipmd

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]

Originally Posted by 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.

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.