Security light and no start


#1

i have a 93 firebird. it has a new engine ,starter and battery. fuse under hood is good. turn switch lights work as usual . any ideas???


#2

Is this an aftermarket security system? If it is…it will have to be removed. Since you say you have a new engine…the computer is probably not recognizing the new lump of metal that has been attached to it. You will need to contact an independent mechanic and explain to them what is happening.


#3

If this is the factory system, try a new key made from the VIN by a dealer.


#4

Your key should have a chip on it? Either the chip on the key is missing/broken or else you’re losing contact with the computer that reads the chip.

If you have a second key, try starting with that first.


#5
If this is the factory system, try a new key made from the VIN by a dealer.

GM wasn’t using a smart key in 93. If it turns the ignition then it works.


#6

GM began using a resistor in the key shaft that is verified by a module in the left kick panel during the late 1980’s. If there is a problem with the key or the wiring to the lock cylinder the vehicle won’t start.


#7
GM began using a resistor in the key shaft that is verified by a module in the left kick panel during the late 1980's. If there is a problem with the key or the wiring to the lock cylinder the vehicle won't start.

HMM…that’s new to me. In fact the local hardware stores says they can make any GM key prior to 1993.


#8

There are 13 different resistor on those old systems so it is a matter being able to identify the key and having the inventory.


#9

Very common failure with VATS of that era- tiny wires going to lock cylinder work harden and break off after decades of use…Good news is it is the simplest system to defeat. Measure key chip resistor value. Locate pair of yellow wires running down column to first connector, insert equivalent resistance 1/8W (or larger) film resistor across connector leading away from ignition switch.


#10

when we droped engine in someone tried to steal the car. we had to by pass the vats. and I no longer have the chip key. garage that done the work is no longer around and obviously im not that great on ignitions . is there a way to find the resistance without the key.


#11

I’m not familiar with that technology, but I’d guess you could just probe that resistor pellet with an ohm meter, using pointed probes. You’ll have to experiment to see where to place the probes, maybe one side of the key to the other, or there’s two separate spots on the same side of the pellet. Look at it with a magnifying glass. The ignition switch would have to provide the same function, probes contacting the pellet somehow, for the computer to be able to measure the pellet resistance.


#12

we had to by pass the vats.

Do you recall how that was done?
The typical way is what I have described above. Maybe, someone jammed a resistor into the harness connection and it has now come loose/fallen out. You could start looking from either end although the column side is more accessible IMO.

Eliminating the VATS module altogether is quite difficult. It produces an output waveform that the ECM expects to see. Far easier to fake out the VATS module than the ECM…