C4 1986 corvette wont start need help pleas.
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
C4 1986 corvette wont start need help pleas.
Ok so I'm having trouble getting my 86 corvette running. It all started when the car would have trouble starting cold and i was getting a coolant tempter sensor err from the computer. replaced the coolant temp sensor and the error went away but it still had problems starting cold, got it started drove it around the block once parked it and haven't been able to get it started sense. engine would turn over but would not start. car had fuel pressure, spark(seemed kinda week), and while testing compression it stopped turning over completely and when you turn the key nothing happens. So I thought it might be the security system because the security light flashes when you turn the key. SO I read online that you can make a wire with the same resistance of the key and connect it under the dash to bypass the system. that did nothing at all. not sure where to go from here at this point, Anny help would be greatly appreciate.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Can you test the starter off the car to isolate it? Otherwise, there's a good VATS discussion on GIJoe's page: http://www.joestradingpost.com/vats/index.html
Team Owner
Joined: Jan 2003
Posts: 20,333
Likes: 262
From: Summerland B.C. Canada
First thing to check is to see if 12v is making it's way to the small terminal on starter solenoid, during crank.
If it's not, it's time to works backwards to see where the 12v stops.
Auto or manual ?
If it's not, it's time to works backwards to see where the 12v stops.
Auto or manual ?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Measure your battery voltage at the battery terminals, you may just have a discharged battery. 12.0 volts and below, discharged, charge your battery up overnight with a battery charger.
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
Ok first chance ill get ill go test it. and yes the battery is at 12v and its a 3+4 overdrive manual transmission. I would be testing from the terminal in the center of the solenoid shown in this pic correct? 
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Check at the large terminal with the heavy wire on it. You need at least 12v. to ground.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
If no voltage at the purple small terminal wire bypass the starter enable relay and retry.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Melting Slicks
Joined: May 2010
Posts: 2,082
Likes: 3
From: Conowingo Maryland
You need 12 volts on the s term the (small term when key is turned to crank) Is 12 volts you are seeing by using a load tester? The Vats system has nothing to do with the security system and should not light the security light.
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
Yeah those are pretty slick i was looking at them. My problem is I have magnaflo cats that are in the way. But if i can get it up on ramps i should be Ok. Another question though, Should there be a ground wire running off the starter or is it just grounded to the block?
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
It's not as hard as it seems. Just remember to disconnected the battery first before you start.
The starter is heavier than it looks though and you will have to somewhat wrestle with it to fish it out.
The starter is heavier than it looks though and you will have to somewhat wrestle with it to fish it out.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Yeah those are pretty slick i was looking at them. My problem is I have magnaflo cats that are in the way. But if i can get it up on ramps i should be Ok. Another question though, Should there be a ground wire running off the starter or is it just grounded to the block?
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
The thick one is hot at all times. This is the actuall supply to the motor coming directly off the battery positive terminal. And the small solenoid wire (purple) should see battery voltage when the key is cranked in order to close the contacts between thick wire and motor. The starter bolted to the engine block is the ground. If all of this is happening the starter is bad.
If no voltage at the purple small terminal wire bypass the starter enable relay and retry.
If no voltage at the purple small terminal wire bypass the starter enable relay and retry.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Sounds like a VATS glitch. I've had this happen to me.
Open the throttle body and shoot some starter fluid or carb cleaner and crank the car again. If car starts up then dies you fuel injectors probably aren't being pulsed. I would rent a noid light kit from autozone and disconnect fuel injectors to check for injector pulse to verify this. Harbor Freight also sells a kit.
Open the throttle body and shoot some starter fluid or carb cleaner and crank the car again. If car starts up then dies you fuel injectors probably aren't being pulsed. I would rent a noid light kit from autozone and disconnect fuel injectors to check for injector pulse to verify this. Harbor Freight also sells a kit.
Last edited by 86PACER; Oct 20, 2010 at 07:37 PM.
Thread Starter
Heel & Toe
Joined: Aug 2010
Posts: 24
Likes: 0
Sounds like a VATS glitch. I've had this happen to me.
Open the throttle body and shoot some starter fluid or carb cleaner and crank the car again. If car starts up then dies you fuel injectors probably aren't being pulsed. I would rent a noid light kit from autozone and disconnect fuel injectors to check for injector pulse to verify this. Harbor Freight also sells a kit.
Open the throttle body and shoot some starter fluid or carb cleaner and crank the car again. If car starts up then dies you fuel injectors probably aren't being pulsed. I would rent a noid light kit from autozone and disconnect fuel injectors to check for injector pulse to verify this. Harbor Freight also sells a kit.