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Discussion Starter · #1 ·
Over the years I’ve just about replaced everything on my Elco
Wondering if this could be a hidden problem?
What would be the symptoms would it show on Check Engine Light?
Would car still run?
Anyone replace one? Why?
Thx
 

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Discussion Starter · #3 ·
They can but if you had issues I'd imagine you would be getting some kind of error code reported via the check engine light. What issues are you seeing exactly?
High voltage on TPS replacing ECM have thoughts about Prom Chip if they go bad, never heard anyone mention it.
It is 36 y.o. Part. Trying to cover all bases.
Thx.
 

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What kinds of specific problems are you referring to in your posting above? What symptoms are you experiencing? When and under what situations/conditions do these symptoms appear? When a CEL comes on, what do you do? Did you check for any codes and what codes did you find?

If you share that kind of information with us rather than asking about replacing parts, then the members will be able to help with diagnosing and be way more helpful to you as well as others in solving issues.
 

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1978 Elcamino base 305
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Prom's, PCM's of that era do not typically have "wear items" in them that degrade over time.
If you have no codes (other than 12, all clear) you should be OK.
There are codes associated with prom and memory issues that would foretell of issues and failures.
Temperature, Moisture, Voltage (both high or low), Clean Supply B+ and good Ground -- all factors in life of these units. Solder joints from thermo- cycling were an issue long ago but at 35+ years old this would have manifested itself long ago. The fact that GM was smart enough to put them in the cab rather than the engine compartment helps alot.
Modern unit that have "drivers" in them to actuate motors and injector are another story.
Old school TV, Radio etc have electrolytic capacitors in them that do degrade but nothing to worry about for you.
 

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Discussion Starter · #6 ·
What kinds of specific problems are you referring to in your posting above? What symptoms are you experiencing? When and under what situations/conditions do these symptoms appear? When a CEL comes on, what do you do? Did you check for any codes and what codes did you find?

If you share that kind of information with us rather than asking about replacing parts, then the members will be able to help with diagnosing and be way more helpful to you as well as others in solving issues.
I got code 21, one time. Checked again I get No codes. Tested TPS got high voltage on blue 417. Tested wiring good. says ECM issue..,,CEL reads 12,
Ordered remanufactured ECM from Cardone AP. Can’t read info on Prom chip. Don’t want to take it apart
 

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Anything can and will go bad.
 
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