I have been trying to fix my no-start 86 corvette, I trouble shot it the best I can but I am at the end of my rope! The problem is every once in a while my car wont start. I by-passed the vats with the proper resister, checked the neutral safety switch, replaced the starter relay in the dash and still have same problem. What is weird about my problem is it seems every time it rains or is damp and humid my car wont start. But when the air is dry or sunny out it starts, Could something in the starter system be causing this? Also can a interment dash problem also cause this (sometimes dash lights up other times no)

 

Could be a voltage leak in the ignition system- coil, coil wire or ?? The dash light issue might have something to do with it if it happens at the same time the car won't start. Try testing for spark when it won't start by pulling a plug wire and laying it near a grounded part of the car to see if you have spark when cranking.

 

Sounds like a spark issue - coil, wires or ICM. On HEI ignition systems, make sure you have a spark plug plugged into the wire when checking for spark or you can damage your module.

 

ICM ?, maybe I should replace rotor, distrubator, ignition coil.

 

ICM= ignition control module which is under the rotor. I wouldn't just start throwing parts at it. If it was me, I would pull the cap, rotor, coil and ICM, inspect for cracks with a magnifying glass and put everything back together with a new coating of dielectric silicone (which is designed to keep moisture out). That'll cost you about $8 and an hours worth of time.

 

I will try that, and thx.....

 

are you saying it will not crank? or it cranks and will not start?

 

What it is doing is when I try to start the car nothing happins no, starter click, no rotation nothing, turn key and it is dead.

 

ok real fast test when the car will not start take a test light to see if you have voltage on the large lug of the starter if you do then have someone in the car turn the key to crank while you hold the test light to the s term on the starter it should light if it does you have a bad starter if it does not you need to to see why you are loosing voltage there. My quess is starter. Just a quess

 

OK, that's some valuable information you left out of your original post....

Do you have dash lights when you turn the key forward and try to start? Check your battery cables on both ends and connections, test your starter as Hooked said, or remove the starter and have it tested at a parts store.

 

Yes I have dash lights but that is it.

 

When you try and start your car, do your dash lights dim? If they do, look at your starter as the culprit and test it.

If the dash lights don't dim at all during start, the problem is probably a bad connection or an open in the starting circuit.

Hooked's idea will tell you if you are getting power to the starter solenoid the way you're supposed to. And if you are, it's probably the solenoid or starter.

--you could also try giving the starter a whack with a hammer

 

When it won't crank, measure the battey terminal voltage when someone hits crank position. The battery voltage must not fall below 9.0 volts or you have bad battery cable connections, battery is discharged or the battery is at the end of its life. Remove battery cables (neg first) and clean the cable lugs, bolts, and battery terminals and replace the cables (neg last). You can tell the battery state of charge by measuring the no load battery voltage, 12.0 volts and below, discharged, charge the battery up overnight with a battery charger. 12.9 volts and above, fully charged and linear in between. If the battery is ok and no cranking, check for voltage between the neg battery cable and the engine block when ign is in crank position, it should be very small, if large 1v or more, you have a poor ground connection on your neg battery cable. Also check the wire that goes from the battery cable ground to the left head. If all ok, then check for tight nut on the large cable connection to the starter and also check the voltage on this terminal in crank position, it should also be the battery voltage and not lower than 9.0 volts (starter cranking). Check for 12 v on the s terminal on the starter, this is the starter solenoid wire and if no 12v there, the starter does nothing. If no 12v, then go backwards in the system, check for 12v on the clutch safety switch bypass wire, check for 12v on the start enable relay contacts, check for 12v on the ign sw start contacts.

 

[QUOTE=jfb;1575150293]When it won't crank, measure the battey terminal voltage when someone hits crank position. The battery voltage must not fall below 9.0 volts or you have bad battery cable connections, battery is discharged or the battery is at the end of its life. Remove battery cables (neg first) and clean the cable lugs, bolts, and battery terminals and replace the cables (neg last). You can tell the battery state of charge by measuring the no load battery voltage, 12.0 volts and below, discharged, charge the battery up overnight with a battery charger. 12.9 volts and above, fully charged and linear in between. If the battery is ok and no cranking, check for voltage between the neg battery cable and the engine block when ign is in crank position, it should be very small, if large 1v or more, you have a poor ground connection on your neg battery cable. Also check the wire that goes from the battery cable ground to the left head. If all ok, then check for tight nut on the large cable connection to the starter and also check the voltage on this terminal in crank position, it should also be the battery voltage and not lower than 9.0 volts (starter cranking). Check for 12 v on the s terminal on the starter, this is the starter solenoid wire and if no 12v there, the starter does nothing. If no 12v, then go backwards in the system, check for 12v on the clutch safety switch bypass wire, check for 12v on the start enable relay contacts, check for 12v on the ign sw start contacts (all tests with the ign sw in crank position).QUOTE]