1985 No Start- Anti-Theft? Electrical?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
1985 No Start- Anti-Theft? Electrical?
Bought a 1985 Vette last February for dirt cheap. Spun Rod Bearing. I proceeded to rebuild motor, and turn crank.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Last edited by Hobbitrabbit; Nov 25, 2015 at 01:10 PM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
it sounds like you have multiple problems. Codes?
Security light and interior lights staying on shorted door jam switches, tamper switches on door lock cylinders shorted or out of place.
No start if engine turns over it's not normally a security issue. No pulse to turn on injectors with what your describing ignition module or ecm. I would lean more to ignition module. Get a FSM if you don't have one your going to need it
Security light and interior lights staying on shorted door jam switches, tamper switches on door lock cylinders shorted or out of place.
No start if engine turns over it's not normally a security issue. No pulse to turn on injectors with what your describing ignition module or ecm. I would lean more to ignition module. Get a FSM if you don't have one your going to need it
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
it sounds like you have multiple problems. Codes?
Security light and interior lights staying on shorted door jam switches, tamper switches on door lock cylinders shorted or out of place.
No start if engine turns over it's not normally a security issue. No pulse to turn on injectors with what your describing ignition module or ecm. I would lean more to ignition module. Get a FSM if you don't have one your going to need it
Security light and interior lights staying on shorted door jam switches, tamper switches on door lock cylinders shorted or out of place.
No start if engine turns over it's not normally a security issue. No pulse to turn on injectors with what your describing ignition module or ecm. I would lean more to ignition module. Get a FSM if you don't have one your going to need it
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
FSM factory service manual both books. You can get flash codes using (ALDL) computer plug under dash.
https://www.corvetteforum.com/forums...ps-w-pics.html
https://www.corvetteforum.com/forums...ps-w-pics.html
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
FSM factory service manual both books. You can get flash codes using (ALDL) computer plug under dash.
https://www.corvetteforum.com/forums...ps-w-pics.html
https://www.corvetteforum.com/forums...ps-w-pics.html
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
Bought a 1985 Vette last February for dirt cheap. Spun Rod Bearing. I proceeded to rebuild motor, and turn crank.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
The paperclip connect it to the top tight terminals and turn ignition on and count the number of times the check engine light flashes, for example 3 flashes pause 4 flashes that is code 34.
type it into google and it will say what is out of spec.
Your fuel pressure should be around 32-38 psi, does the pressure bleed of to zero? could be a sign of a leaking injector.
the pressure should stay up when the ignition is turned off and fuel pump is off, the fuel pump could be at fault or the pulsation damper leaking.
use a simple multimeter and measure the injector connector voltage as someone cranks the car, each will momentarily show 12 volts.
The fuel injectors are pulsed by the ecm, they batch fire all of one side together. Do not pull the connectors off by the wiring harness they are fragile.
The throttle position sensor should be set to 0.54 volts dc at idle (top two wires)
should be a simple problem either injector or fuel pump..
Good luck
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Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Hi
The paperclip connect it to the top tight terminals and turn ignition on and count the number of times the check engine light flashes, for example 3 flashes pause 4 flashes that is code 34.
type it into google and it will say what is out of spec.
Your fuel pressure should be around 32-38 psi, does the pressure bleed of to zero? could be a sign of a leaking injector.
the pressure should stay up when the ignition is turned off and fuel pump is off, the fuel pump could be at fault or the pulsation damper leaking.
use a simple multimeter and measure the injector connector voltage as someone cranks the car, each will momentarily show 12 volts.
The fuel injectors are pulsed by the ecm, they batch fire all of one side together. Do not pull the connectors off by the wiring harness they are fragile.
The throttle position sensor should be set to 0.54 volts dc at idle (top two wires)
should be a simple problem either injector or fuel pump..
Good luck
The paperclip connect it to the top tight terminals and turn ignition on and count the number of times the check engine light flashes, for example 3 flashes pause 4 flashes that is code 34.
type it into google and it will say what is out of spec.
Your fuel pressure should be around 32-38 psi, does the pressure bleed of to zero? could be a sign of a leaking injector.
the pressure should stay up when the ignition is turned off and fuel pump is off, the fuel pump could be at fault or the pulsation damper leaking.
use a simple multimeter and measure the injector connector voltage as someone cranks the car, each will momentarily show 12 volts.
The fuel injectors are pulsed by the ecm, they batch fire all of one side together. Do not pull the connectors off by the wiring harness they are fragile.
The throttle position sensor should be set to 0.54 volts dc at idle (top two wires)
should be a simple problem either injector or fuel pump..
Good luck
by accidentally attaching the negative battery terminal while the ignition was set to on. So I'm going to test for that this weekend.
Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 276
From: Melbourne, Victoria, Australia
See the starter wiring diagram, the ecm has nothing to do with it.
Most likely the starter solenoid or the starter interrupt relay, now with the wiring diagram you can check where the problem is.
From memory the starter interrupt relay is behind the center information panel, remove the trim panel and the switch/check engine light panel.
Will add the relay location diagram when I get home from work
(is 2:30pm here in Oz)
So check where you have power from the diagram below, the gear selector must be in neutral or park.
The theft deterrent controller grounds the starter interrupt relay, if the security is not disabled with key in door that could be the problem also .
Check the purple wire gets 12 volts when turning the ignition switch to start, if it doesn't check the starter interrupt and theft deterrent .
Last edited by gerardvg; Nov 25, 2015 at 10:31 PM.
Team Owner
Joined: Jul 2004
Posts: 28,495
Likes: 3,298
From: Hartford WI
I'd get a real scanner and not a code reader which is about as useful as the paperclip. You are going to need a scanner sooner or later. If not today, then tomorrow or the day after. Why not today?
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Bought a 1985 Vette last February for dirt cheap. Spun Rod Bearing. I proceeded to rebuild motor, and turn crank.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Car ran and drove great for about 2 months before it started to stall out and die randomly.
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all. Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Team Owner
Joined: Jul 2004
Posts: 28,495
Likes: 3,298
From: Hartford WI
Ever since I got my hands on it, the security system has been on the fritz, lights will stay on in the car until the battery dies- takes 6-8 seconds of turning the starter to start the car. Was somewhat tolerable until it stopped functioning all together. The car would start, run for a short duration of time, then quit, running for shorter and shorter intervals of time, until finally it wouldn't run at all.
Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Every once in awhile the key would refuse to leave the ignition after the transmission (auto) was placed in park as well.
After doing a fuel pressure test and measuring the resistance of the injectors with an ohm meter, I determined that everything was within spec and fuel was being pumped, but NOT injected. I sprayed starting fluid into the intake to test this theory and it would run on starter fluid.
This led me to believe that a security system issue was preventing the fuel from being pumped. However, when I opened up the convenience center, or whatever it's called, and began to test voltage and resistance on each terminal, the car began to decline to turn the starter at all. Electricity is being supplied to the car and everything lights up and turns on. I tried the A-E Pin Starter Interrupt Relay bypass trick, no luck. I pulled the theft deterrent fuse, still no luck.
It is worth noting that the car has an aftermarket stereo that was present when I purchased it. There was no horn relay behind the Convenience Center when I opened it, as well. Someone has, of course, been in there before.
I'm truly at a loss as to how to fix this problem. I've attempted everything I can think of. Any help would be appreciated.
Not sure that the bad cylinder affects that much more.
Can you outline the procedure you used to determine fuel pressure at WOT and whether it holds pressure well?
If you think it is the security system, what is the fuel pressure like when it dies?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Hard starting could be dirty injectors. With a car that old and I'll bet nobody has cleaned the injectors, who knows what shape the injectors are in? That has a big effect on starting. Also, in your vintage, supposedly the 9th injector is there to spray extra fuel during startup to ease the starting. I'd take all of them out, spend some money to clean the 9th one and if the other 8 are Multec, toss them for Bosch III. Could be your pump is old and tired and stops working after it gets too warm? IDK. Check fuel pressure when it is running and at WOT.
Not sure that the bad cylinder affects that much more.
Can you outline the procedure you used to determine fuel pressure at WOT and whether it holds pressure well?
If you think it is the security system, what is the fuel pressure like when it dies?
Not sure that the bad cylinder affects that much more.
Can you outline the procedure you used to determine fuel pressure at WOT and whether it holds pressure well?
If you think it is the security system, what is the fuel pressure like when it dies?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
So just to be clear, you pulled the FPR hose and checked while running? Did you do a WOT run and see if the pump keeps up?
I'd get a real scanner and not a code reader which is about as useful as the paperclip. You are going to need a scanner sooner or later. If not today, then tomorrow or the day after. Why not today?
I'd get a real scanner and not a code reader which is about as useful as the paperclip. You are going to need a scanner sooner or later. If not today, then tomorrow or the day after. Why not today?
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Hi
See the starter wiring diagram, the ecm has nothing to do with it.
Most likely the starter solenoid or the starter interrupt relay, now with the wiring diagram you can check where the problem is.
From memory the starter interrupt relay is behind the center information panel, remove the trim panel and the switch/check engine light panel.
Will add the relay location diagram when I get home from work
(is 2:30pm here in Oz)
So check where you have power from the diagram below, the gear selector must be in neutral or park.
The theft deterrent controller grounds the starter interrupt relay, if the security is not disabled with key in door that could be the problem also .
Check the purple wire gets 12 volts when turning the ignition switch to start, if it doesn't check the starter interrupt and theft deterrent .
See the starter wiring diagram, the ecm has nothing to do with it.
Most likely the starter solenoid or the starter interrupt relay, now with the wiring diagram you can check where the problem is.
From memory the starter interrupt relay is behind the center information panel, remove the trim panel and the switch/check engine light panel.
Will add the relay location diagram when I get home from work
(is 2:30pm here in Oz)
So check where you have power from the diagram below, the gear selector must be in neutral or park.
The theft deterrent controller grounds the starter interrupt relay, if the security is not disabled with key in door that could be the problem also .
Check the purple wire gets 12 volts when turning the ignition switch to start, if it doesn't check the starter interrupt and theft deterrent .
Team Owner
Joined: Jul 2004
Posts: 28,495
Likes: 3,298
From: Hartford WI
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 19
Likes: 0
Hi
The paperclip connect it to the top tight terminals and turn ignition on and count the number of times the check engine light flashes, for example 3 flashes pause 4 flashes that is code 34.
type it into google and it will say what is out of spec.
Your fuel pressure should be around 32-38 psi, does the pressure bleed of to zero? could be a sign of a leaking injector.
the pressure should stay up when the ignition is turned off and fuel pump is off, the fuel pump could be at fault or the pulsation damper leaking.
use a simple multimeter and measure the injector connector voltage as someone cranks the car, each will momentarily show 12 volts.
The fuel injectors are pulsed by the ecm, they batch fire all of one side together. Do not pull the connectors off by the wiring harness they are fragile.
The throttle position sensor should be set to 0.54 volts dc at idle (top two wires)
should be a simple problem either injector or fuel pump..
Good luck
The paperclip connect it to the top tight terminals and turn ignition on and count the number of times the check engine light flashes, for example 3 flashes pause 4 flashes that is code 34.
type it into google and it will say what is out of spec.
Your fuel pressure should be around 32-38 psi, does the pressure bleed of to zero? could be a sign of a leaking injector.
the pressure should stay up when the ignition is turned off and fuel pump is off, the fuel pump could be at fault or the pulsation damper leaking.
use a simple multimeter and measure the injector connector voltage as someone cranks the car, each will momentarily show 12 volts.
The fuel injectors are pulsed by the ecm, they batch fire all of one side together. Do not pull the connectors off by the wiring harness they are fragile.
The throttle position sensor should be set to 0.54 volts dc at idle (top two wires)
should be a simple problem either injector or fuel pump..
Good luck