LA2SD
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- Mar 21, 2013
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1993 Chevy Silverado 5.7L V8 w/ TBI and 4L80E - LA2SD's '93 RCSB
So, I was cruising the other night when my truck died without warning. I went through it the best I could, and tried restarting it, but no luck. I had plenty of gas, but the truck felt like it wasn't getting any fuel.
Towed it home, and re-checked all of my basic connections (e.g. alternator, battery, plug wires, distributor cap, spark, fuses, etc.), double checked to make sure I had fuel, and everything looked fine.
So I moved on to checking DTCs (diagnostic trouble codes) for any possible issues, and the MIL (malfunction indicator lamp) would not flash DTC 12, which is supposed to indicate that the truck's diagnostic system is functioning properly.
According to the shop manual, if DTC 12 doesn't flash, there's either 1) a short 2) an open, or 3) a defective ECM/PROM (engine control module).
I followed the flow chart, which led me to the ECM. The problem is that it could be either the ECM or the PROM that is defective. And based on the flow chart, I won't know which until I replace the ECM.
The ECM was replaced once before by the PO, and I don't want to replace the ECM again if it's actually the PROM. If it's the PROM, I can replace it with a ZIF socket and flash memory.
Before posting up, I read through Putting A Chip In A TBI Truck, which had some great advice on doing just that.
My questions are:
1. Is there a way to test the ECM and PROM separately - without having to buy a refurbished ECM?
2. How does the factory "refurbish" an ECM? Do they simply write a new BIN file to the PROM? Or is it more of an electronics issue, where they use an oscilloscope and specialized knowledge to test for faulty components?
If all they're doing when "refurbishing" an ECM is to write a new BIN file, I could use tuning software to write a new BIN file, and "refurbish" it myself.
So, I was cruising the other night when my truck died without warning. I went through it the best I could, and tried restarting it, but no luck. I had plenty of gas, but the truck felt like it wasn't getting any fuel.
Towed it home, and re-checked all of my basic connections (e.g. alternator, battery, plug wires, distributor cap, spark, fuses, etc.), double checked to make sure I had fuel, and everything looked fine.
So I moved on to checking DTCs (diagnostic trouble codes) for any possible issues, and the MIL (malfunction indicator lamp) would not flash DTC 12, which is supposed to indicate that the truck's diagnostic system is functioning properly.
According to the shop manual, if DTC 12 doesn't flash, there's either 1) a short 2) an open, or 3) a defective ECM/PROM (engine control module).
I followed the flow chart, which led me to the ECM. The problem is that it could be either the ECM or the PROM that is defective. And based on the flow chart, I won't know which until I replace the ECM.
The ECM was replaced once before by the PO, and I don't want to replace the ECM again if it's actually the PROM. If it's the PROM, I can replace it with a ZIF socket and flash memory.
Before posting up, I read through Putting A Chip In A TBI Truck, which had some great advice on doing just that.
My questions are:
1. Is there a way to test the ECM and PROM separately - without having to buy a refurbished ECM?
2. How does the factory "refurbish" an ECM? Do they simply write a new BIN file to the PROM? Or is it more of an electronics issue, where they use an oscilloscope and specialized knowledge to test for faulty components?
If all they're doing when "refurbishing" an ECM is to write a new BIN file, I could use tuning software to write a new BIN file, and "refurbish" it myself.
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