AM27S181PC 1982 EPROM for Crossfire Injection
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Racer
Joined: Mar 2013
Posts: 462
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AM27S181PC 1982 EPROM for Crossfire Injection
Does anyone know of an affordable PROM Programmer for that chip? I've been looking everywhere and not one of the newer USB type Zif socket programmers support it. It is an old Bipolar EPROM, still available, but not of much use without a programmer to support it...
The chip is a 1KX8, a really tiny sized memory by today's standards. But it was enough for the 1982 Crossfire Injection system.
My particular concern is the VE table, and the fact that fuels have changed since 1982, notably now including 10% (or more?) ethanol. Not necessarily a bad thing, but the calibration of the 82 Corvette in the VE table was based upon fuels available in 1982. Today it seems to be a tad lean for those parts of the VE table that have mid to high revolutions with low manifold vacuum (open throttle plates). I.e., the engine under load as in climbing a hill.
After going the distance with throttle body balancing, a 1985 fuel pump and so on, the car generally performs well but still has the famous crossfire stumble under load. And when the car is in limp home mode, that doesn't happen (fuel economy drops from ~20MPG to around 14MPG, indicating a much richer mixture). So the VE table entries seem suspect under closed loop operation, again, with the car under load.
I've located and purchased some blank AM27S181PC chips, but can't find a programmer for them. I'm hoping to download the bin file in my factory chip, find the suspect VE entries, tweak them a bit, program and try out a new slightly richer calibration for the under load portions of the VE table. And iterate to get it just right. As much as possible, with all pollution controls in place and functioning. I like clean air as much as good performance...
Of course, this will go nowhere without a suitable PROM Programmer, and I'm not spending $2K for a Xeltek programmer I may only need a few times.
Any help with this would be appreciated!
The chip is a 1KX8, a really tiny sized memory by today's standards. But it was enough for the 1982 Crossfire Injection system.
My particular concern is the VE table, and the fact that fuels have changed since 1982, notably now including 10% (or more?) ethanol. Not necessarily a bad thing, but the calibration of the 82 Corvette in the VE table was based upon fuels available in 1982. Today it seems to be a tad lean for those parts of the VE table that have mid to high revolutions with low manifold vacuum (open throttle plates). I.e., the engine under load as in climbing a hill.
After going the distance with throttle body balancing, a 1985 fuel pump and so on, the car generally performs well but still has the famous crossfire stumble under load. And when the car is in limp home mode, that doesn't happen (fuel economy drops from ~20MPG to around 14MPG, indicating a much richer mixture). So the VE table entries seem suspect under closed loop operation, again, with the car under load.
I've located and purchased some blank AM27S181PC chips, but can't find a programmer for them. I'm hoping to download the bin file in my factory chip, find the suspect VE entries, tweak them a bit, program and try out a new slightly richer calibration for the under load portions of the VE table. And iterate to get it just right. As much as possible, with all pollution controls in place and functioning. I like clean air as much as good performance...
Of course, this will go nowhere without a suitable PROM Programmer, and I'm not spending $2K for a Xeltek programmer I may only need a few times.
Any help with this would be appreciated!
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