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Old 10-06-2016   #6
merc3065
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Re: 89 gta cranks no start

VATS can cause this.
Couple questions:
Do you have fuel pressure at the fuel rail? If no, check fuel pump, check injectors, check fuel filter.
Fuel pump should be providing 42PSI at the rails. Pressure should be held for at least 15-20 minutes before slowly starting to die down.
If pressure does not hold, check the fuel system for holes or leaks.
If injectors are not firing, check resistance on the injectors, should be 16Ohms off, when cold.
If no pressure, you may have a fuel filter issue, fuel pump relay could be shot, or clogged/damaged fuel filter.

If you have a "security" flashing light on the dash:
Your VATS is malfunctioning.
The injectors will NOT fire.
This could be the ignition cylinder is not reading the key's resistance, the key has damage to the resistor. The wiring to the VATS module behind the dash could be damaged, the VATS module could be damaged.
The starter relay could be damaged or the wiring to the relay could be damaged. The starter relay is located under the upper left driver's side foot well. It's buried in there pretty deep.

MAF will also cause this as well, but it's less likely. You would need to read the MAF reading. If you have a 33 or 34 code on the Check Engine Light, I believe that is a MAF issue? I can't remember been too long...Google is your friend on that one.

However, you can hook up WinALDL and start reading info from the computer to determine what the MAF is doing at key on engine off. It should read somewhere around 9-16gm/s without engine on. Again it's been a long time since I've had mine running, but the numbers should read low. If it is like 255gm/s your MAF is way out of whack...

Throttle position sensor can also cause hard starting, it should read 0.5-0.55V closed and 4.6-5V fully open. If it is anything else other than that, it will throw the fuel/spark curve way off.

Lots of info, but more info from your end is needed.
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