Key question
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Burning Brakes
Joined: Dec 2006
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From: Tyrone PA
Key question
I had pcmforless deactivate my VATS when they did my tune. Can I now use a regular GM blank key and have an extra key made or do I still need to get a blank key with the chip in it and have it cut? If I still need the key with the chip, anyone know where I can get a blank at a decent price???
- 1986 Original Owner -
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From: North Yorkshire, England
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This may not be correct, but would be easy to correct if not. What I mean is, go out and get yourself a couple of normal (cheap no resistor) blanks cut and try. You may find the engine will not crank. This is because the VATS deactivation that pcmforless did in their tune, defeated the Fuel Enable portion of the VATS. The Start Enable function may still be under VATS Module control if this was not defeated. pcmforless would have needed the car for this and I expect you just received a reprogrammed PROM from them. If the new no resistor keys result in a no crank situation, this can easily be defeated through a Start Enable Relay bypass. All you do is remove the Relay and install a jumper wire between the Relay Socket pins E (Yellow wire) and A (Green/White Stripe wire). The Relay is behind the DIC.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Good point Ray, I assumed too much.
If the VATS is turned off in the prom, does that send ground back to VATS module and then onto the start enable relay ??
What is the purpose of the VATS on/off in the bin, if it only enables/disables injectors. Why turn it off then ??
If the VATS is turned off in the prom, does that send ground back to VATS module and then onto the start enable relay ??
What is the purpose of the VATS on/off in the bin, if it only enables/disables injectors. Why turn it off then ??
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Wouldn't turning off the injectors keep the car from being push-started like you would do for a manual tranny car? You could "hot-wire" the car but if the injectors are not powered, it stil won't start.
- 1986 Original Owner -
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From: North Yorkshire, England
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To answer your first question, no. The VATS module outputs a square wave signal to the ECM as Cranking Fuel Enable and a ground to the Start Enable Relay. Nothing goes from the ECM to the VATS Module. Subtracting 10h from the PROM value at address $0014 will cause the ECM to ignore the square wave signal from the VATS Module on pin B6 and allow fuel at all times.
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
I realize VATS controls the injectors and crank enable. I assumed people had it turned off because they were having a previous problem with it and turning it off would allow both crank and fuel. It's actually only turning off half of the VATS features so you still have to bypass the enable relay to really turn it off. Why not just fix the problem, seems like the same amount of work. 
I'll be leaving mine on.
I'll be leaving mine on.
- 1986 Original Owner -
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From: North Yorkshire, England
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When VATS started acting up about 10 years ago, I repaired it. I just like things to work as intended. In a pinch, a bypass is a good idea, but for me, I'd rather make it work. I do admit to having bypassed the Clutch Start Switch though. I hate having to get in the car to crank her over when I'm working on her.
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Thread Starter
Burning Brakes
Joined: Dec 2006
Posts: 936
Likes: 2
From: Tyrone PA
This may not be correct, but would be easy to correct if not. What I mean is, go out and get yourself a couple of normal (cheap no resistor) blanks cut and try. You may find the engine will not crank. This is because the VATS deactivation that pcmforless did in their tune, defeated the Fuel Enable portion of the VATS. The Start Enable function may still be under VATS Module control if this was not defeated. pcmforless would have needed the car for this and I expect you just received a reprogrammed PROM from them. If the new no resistor keys result in a no crank situation, this can easily be defeated through a Start Enable Relay bypass. All you do is remove the Relay and install a jumper wire between the Relay Socket pins E (Yellow wire) and A (Green/White Stripe wire). The Relay is behind the DIC.
- 1986 Original Owner -
Joined: Apr 1999
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From: North Yorkshire, England
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Thread Starter
Burning Brakes
Joined: Dec 2006
Posts: 936
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From: Tyrone PA
Thanks so much for your help. You were exactly right. I got a key made, but the blank's shaft was a hair shorter than my stock key with the chip. I had to cut the key "head" back some with a grinder to make the shaft longer. Then it turned the ignition over but no crank. I pulled the plug out of the relay and made a jumper wire with male ends to plug into E and A. Works great, car started right up!!! Thanks again for all your help, saved me a TON on buying key blanks!!!!