C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1987 C4 Security Problem

Thread Tools
 
Search this Thread
 
Old 12-31-2007, 12:42 PM
  #1  
phade
Intermediate
Thread Starter
 
phade's Avatar
 
Member Since: Nov 2007
Location: Las Vegas Nevada
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Default 1987 C4 Security Problem

Ok, My key has failed to turn off the security since i bought the car a few months ago. Car ran ok though. Found it was gettin way too much fuel due to the bad fuel regulator-maybe thats why it ran? Anyway, the car stopped running so i replaced the fuel pump-but it doesnt seem to be working properly. Any one know how to permanently disable or bypass the security system? Also-----wheres te damn fuse panel???Think I might have a bad fuel pump relay, because the fuel pump is only priming for a second or 2 when ignition first comes on"sometimes". HELP?
Old 12-31-2007, 01:54 PM
  #2  
Bob CTS
Race Director
 
Bob CTS's Avatar
 
Member Since: Jun 2005
Location: Lenoir City TN
Posts: 17,640
Likes: 0
Received 0 Likes on 0 Posts
St. Jude Donor '08-'09-'10-'11

Default

Fuses are in the passenger side door jam

Is the security light blinking or on (can not remember which) when trying to start?

The fuel pump will only energize for ~two seconds when the key is turned to acc.

To disable the security you need to know your VATS code and install the bypass or buy a resistor of that value and install at the base of the steering column.

It might also help if you purchase the service manual.
Old 12-31-2007, 05:57 PM
  #3  
phade
Intermediate
Thread Starter
 
phade's Avatar
 
Member Since: Nov 2007
Location: Las Vegas Nevada
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Default

I know I know---service manual. Im just not loaded enough yet-lol. I have a 73 Charger that I am trying to fix as my daily driver, so every lil dollar is important right now. I found the problem with the pump-the damn manual had me hook it up WRONG. It was pumping backwards-lol! The car runs great now-ther than some heavy white "lean" smelling smoke on warm up-not teary eyed-it smells like its burning good. Damn electronic cars are a pain in the ***. I bought this car for my son to sport in High School. I learned on old school carbs man, these sensors and computers are killin me! I had to disconnect the horns because the security system was actually going off, but the car will drive....???
Old 12-31-2007, 07:42 PM
  #4  
Bob CTS
Race Director
 
Bob CTS's Avatar
 
Member Since: Jun 2005
Location: Lenoir City TN
Posts: 17,640
Likes: 0
Received 0 Likes on 0 Posts
St. Jude Donor '08-'09-'10-'11

Default

Glad you got it fixed.

Yeah I know all about the electronics and sensors, just multiply by a zillion for my C5. Check your doors out that was causing the alarm to trigger on my 86. I had problems with the key cylinder as well as the switch that arms the alarm when locked.
Old 01-09-2008, 10:15 PM
  #5  
phade
Intermediate
Thread Starter
 
phade's Avatar
 
Member Since: Nov 2007
Location: Las Vegas Nevada
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Default

nyone know the timing degree and idle speed?
Old 01-10-2008, 08:25 AM
  #6  
rick lambert
Le Mans Master
 
rick lambert's Avatar
 
Member Since: Oct 2003
Location: seattle WA
Posts: 6,130
Likes: 0
Received 1 Like on 1 Post

Default

Stock timing is 6* BTDC, you need to disconnect the EST, it's a single wire close to the wiper motor..it just unplugs, set the timing and reconnect. Don't mess with the idle, should be around 650-700 when at operating temp. if the idel is irratic it will probably come down to the IAC being carboned up.

As far as the alarm goes....make sure your key lock on the door is straight up and down when the key is removed, alot of guys have found this to be the problem. I ended up going with an after market alarm with remote functions....keyless door entry, hatch release etc.
Got it at BestBuy, they did the install.....not bad $$$ and they did a very professional job.
Old 01-10-2008, 10:11 PM
  #7  
phade
Intermediate
Thread Starter
 
phade's Avatar
 
Member Since: Nov 2007
Location: Las Vegas Nevada
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks a bunch. The Alarm works again, but the cockpit lights shut off on me the other night. I tapped the dash and they came back on-maybe a loose plug or wire? Also, is that idle speed in park or in gear?
Old 01-11-2008, 09:57 AM
  #8  
rick lambert
Le Mans Master
 
rick lambert's Avatar
 
Member Since: Oct 2003
Location: seattle WA
Posts: 6,130
Likes: 0
Received 1 Like on 1 Post

Default

Mines 700 RPM in park, 650 in gear. Also, alot of guys put the car in gear (automatic) to time it, but I haven't.
Old 01-12-2008, 08:47 PM
  #9  
phade
Intermediate
Thread Starter
 
phade's Avatar
 
Member Since: Nov 2007
Location: Las Vegas Nevada
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Default

Sorry, a few more questions:
6 degrees + or - ? Also, do i unplug that unit while running or stopped?
Old 11-03-2023, 06:23 PM
  #10  
SMM_DREW
Advanced
 
SMM_DREW's Avatar
 
Member Since: Jul 2023
Posts: 63
Received 5 Likes on 4 Posts
Default Reviving this thread - Security problem on my 1987

Originally Posted by Bob CTS
Fuses are in the passenger side door jam

Is the security light blinking or on (can not remember which) when trying to start?

The fuel pump will only energize for ~two seconds when the key is turned to acc.

To disable the security you need to know your VATS code and install the bypass or buy a resistor of that value and install at the base of the steering column.

It might also help if you purchase the service manual.
hi Bob, I have an 1987 corvette. I have some aftermarket security system “prestige” or some crap. Terrible! Pulls current from my battery and for some reason the fuel pump won’t kick on now when I turn the key, what steps should I take to disable the security system fully so I can start my car?

Get notified of new replies

To 1987 C4 Security Problem




Quick Reply: 1987 C4 Security Problem



All times are GMT -4. The time now is 10:06 PM.