1993 corvette auto trans with a no crank condition that is intermittent. this problem pops up after the car sits for a few hours, the battery is fully charged and we have a .030 milliamp draw when the car is off. when the problem occurs the starter does try to start the engine but does not have enough power to crank the engine using the key. if i short the starter with a screwdriver it cranks perfectly.

security light is not on with key in ignition. security light does flash with key out of ignition and door open.

we installed a new starter, battery, and starter enable relay. we also ran a new purple wire from the starter enable relay to the starter solenoid.

when the car will not crank by turning the key it will crank by shorting the 2 terminals on the starter. after doing that it will crank with the key. we have tested both battery cables and they are both good. i have battery voltage at the starter on the battery terminal. ground cable are all perfect grounds.

i have GM service manuals for the car but when i try to test the car is cranking fine and i find no faults. one concern i have is the CCM, it is the ground for the starter enable relay and maybe it is failing in the CCM but i am not sure how to test that.

any advice would be appreciated. we are at our wits end with this car.

also, this morning we had the no crank condition. i had 12 volts on both yellow wires at the starter enable relay when turning the key to the start position, i jumped the yellow wire and purple wire on the plug end with the relay disconnected and the car did not crank. that is why i ran a new purple wire today.

 

When it does not crank.......does the dash light up and no soliniod click or starter turn try your extra key mine did that got a new key made problem solved

 

dash lights up fine, solenoid clicks and starter tries to start engine but doesn't have enough power to turn engine over. if i short the starter with a screwdriver it cranks perfectly.

i just jumped the starter enable relay with a paperclip and had a no crank condition a few times. then it decided to crank just fine. i am leaving the paperclip installed because it rules out the park/neutral safety switch and the CCM ground at the relay.

i am starting to suspect the ignition switch on the column, not where you put your key but the one by your feet.

this is so frustrating to track down because it is intermittent.

 

Key turns the starter on. That big fatty cable going to the starter supplies the amperage to turn the engine.

Headers or exhaust close to starter?
Resistance goes up with heat.

Battery cables (take them off to look for corrosion)

Have the starter checked -

 

car has headers but the problem is when the car is cold. i cleaned the cables at the battery terminals but honestly they were already clean, i see no corrosion.

i just installed a new ignition switch and have the same intermittent no crank condition.

 

Are you sure the battery is good

 

I would check the voltage drop on your positive battery cable to your starter.

 

yes battery is good

 

Then if it's not the soliniod im stumped

 

the only time i was able to that test was when the problem was not occurring and got less that .5 volt drop.

when the no crank problem occurs the engine acts like its trying to turn over but cant. if i immediately go under the car and short the 2 starter terminals it cranks perfectly.

maybe a bad positive battery cable?

 

i dont see how it could be the solenoid because is i short the 2 starter terminals together with a screwdriver it cranks perfectly.

 

if that positive battery cable was bad would i still be able to short the 2 terminals on the starter and have it crank or would that not work?

i was assuming it was something on the solenoid end of the wiring because when i short the starter it cranks just fine. am i wrong in that assumption?

 

The contacts INSIDE the starter solenoid are what make the starter crank. If they are burned or corroded you will get the symptoms you describe.

Shorting the solenoid bypasses the solenoid contacts, which is why it cranks when you do that.

It is possible to replace the solenoid contacts, but that may be more work than you want to do...

 

the GM mini starter has 2 contacts B and S. my car does not crank using the ignition key but if i touch B and S together with a screwdriver it cranks. how is that bypassing the contacts in the solenoid?

i thought if i jumped the 2 contacts at the starter and the starter works it meant the starter and solenoid were good and that i have a voltage supply issue going to the starter.

 

 

please explain to me how using a screwdriver between B and S on the starter bypasses the solenoid contacts please.

 

I have never takeing one apart I just replace them but just like a old ford if they get crudded up will not give enough juice but if you get a good outside contact they fire right up

 

understood. keep in mind the starter is new. i have exactly the same problem after replacing the starter.

i dont see how it could be the solenoid because when i put 12V to the S terminal of the solenoid it cranks perfectly every time. that tells me the starter and solenoid are good.

i feel there is a voltage supply problem to the S terminal of the starter or possibly a ground problem. i checked the battery cables the best i could and even ran a new purple wire to the S terminal from the relay. then i thought i may have a problem with the yellow wire at the really and it gets its power from the ignition switch so i replaced that. i am not sure what else to do.

if i put 12V to the starter solenoid S terminal the car cranks.

 

I agree with your conclusion. If the car cranks fine when you jump B to s you have ruled out all issues with the starting system except the power to the s terminal. My assumption is you must have a large voltage drop to the S terminal causing a low voltage condition at the s terminal. The low voltage means there is a reduced magnetic field in the solenoid and that magnetic field is not closing the contacts in the solenoid with enough force, causing a poor connection in the solenoid. To trouble shoot this measure the voltage at the S terminal while cranking and see what it is, if it is low you will have to trouble shoot the S circuit in the car.

 

Ok I'll buy that did not see new starter thing