1990 No Crank

[SAHall]

I am experiencing a no start on my 1990 ZR-1 with 16,000 miles. The car has power, but the starter does not crank. I don’t think it’s the vats system or the clutch switch. When I turn the ignition to start and push the clutch pedal down the starter does not engage, but the gauge shows a small voltage drop when the clutch switch is activating.

The battery is new and I tried starting with a battery booster just in case it was a power issue. No change.

While it may not be related, the vacuum pump is also making an unusual grinding or clicking noise when the key is first engaged.

Any advice. Is it the starter? Hope not.


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[lfalzarano]

Do a search on DNS “Does Not Start”

My experience has been if the battery has the right CCA and is new - DNS doesn’t show up. This condition is more prevalent in a hot climate also.

Other members more experienced than me will chime it and guide you.


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[Ccmano]

The vacuum pump should cycle on and off making that noise. If it doesn’t turn off for at least a few seconds you have a vacuum leak in the Secondary circuit.

As mentioned do a search on “No start”, not uncommon. Also check the stickies under the “Solutions” thread. Lots of good info. It’s most likely the starter solenoid contacts. There is also a mod to add a relay on 90’s to help that situation.
H

[lfalzarano]

It will push start if you are in a jam! It bypasses every issue[emoji108]


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[SAHall]

Thanks for the input. I will take a look. The vacuum pump turns on for a few seconds and then turns off-but it sounds different than it normally does-more of a clicking or grinding noise. Probably a different problem unrelated to the no crank.


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[Ccmano]

Originally Posted by SAHall

Thanks for the input. I will take a look. The vacuum pump turns on for a few seconds and then turns off-but it sounds different than it normally does-more of a clicking or grinding noise. Probably a different problem unrelated to the no crank.


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Yes, no relation to the no crank.
H

[A26B]

Originally Posted by SAHall

............ When I turn the ignition to start and push the clutch pedal down the starter does not engage, but the gauge shows a small voltage drop when the clutch switch is activating......................

The 1990 does not have a relay in the starter loop. Consequently, when you turn the ignition switch to start BEFORE depressing the clutch pedal, the full voltage arcs across the contacts in the clutch safety switch, which damages the contacts, ultimately to the point of failure. This is the reasoning behind installation of a relay in the starter circuit.

The correct way to start is to depress the clutch pedal fully BEFORE turning the ignition switch to start. This way, the contacts are engaged before the voltage is applied.

I would suggest you bypass the clutch safety switch, only as a test to verify the switch.

[SAHall]

Originally Posted by A26B

The 1990 does not have a relay in the starter loop. Consequently, when you turn the ignition switch to start BEFORE depressing the clutch pedal, the full voltage arcs across the contacts in the clutch safety switch, which damages the contacts, ultimately to the point of failure. This is the reasoning behind installation of a relay in the starter circuit.



The correct way to start is to depress the clutch pedal fully BEFORE turning the ignition switch to start. This way, the contacts are engaged before the voltage is applied.



I would suggest you bypass the clutch safety switch, only as a test to verify the switch.

Thanks for the input. I will give that a shot.


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[Paul Workman]

You mentioned the voltage gauge reacted slightly to turning the ignition switch. That could mean the starter solenoid is activated, but the high current contacts inside of the starter may need to be replace; a common problem with the Denso starters (with 20-30k miles).

Replacement contacts are easy for a DIY project, once the starter is removed, and cost under $10 for a kit with just the copper contact lugs. (NOTE: Some kits include a new armature and contact ring (attached). I caution you that the thrust pins on some replacement armatures are too short, resulting in the pinion gear not fully engaging with the ring gear. However, the copper contact ring can be resurfaced with a little emory cloth - and the armature reused, no problem!))

[SAHall]

Originally Posted by Paul Workman

You mentioned the voltage gauge reacted slightly to turning the ignition switch. That could mean the starter solenoid is activated, but the high current contacts inside of the starter may need to be replace; a common problem with the Denso starters (with 20-30k miles).



Replacement contacts are easy for a DIY project, once the starter is removed, and cost under $10 for a kit with just the copper contact lugs. (NOTE: Some kits include a new armature and contact ring (attached). I caution you that the thrust pins on some replacement armatures are too short, resulting in the pinion gear not fully engaging with the ring gear. However, the copper contact ring can be resurfaced with a little emory cloth - and the armature reused, no problem!))

Thanks for the advice and information. I will run this down.


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