442 Eprom issue

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airboatgreg

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Oct 2, 2016
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I don't think so but you are thinking about the regular prom. Programmable Read Only Memory. The Eproms were installed so the manufacturer could change the programming at say 15k miles for whatever reasons. The Eprom automatically erased
 

69hurstolds

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Jan 2, 2006
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Let's not forget that the issue is what seemingly is (for now anyway) a benign Code 51 issue. Which has to do with the PROM. I didn't see anything in the CSM troubleshooting chart about an ePROM. Maybe the ePROM is the thing that fuggs up if it's the ECM causing the problem?

Troubleshooting per the CSM is pretty easy. Read below.

If everything checks out and you still get a Code 51, then replace ECM. Which to me, is their way of saying, you're kind of FOOKED at that point.

Just don't install the PROM backwards and turn the key on to energize the ecm or you'll toast the PROM. There's a little notch in one end of the PROM carrier to help guide you. IIRC, I believe the notch goes toward the center of the ECM but make sure if/when you take the cover off to inspect.

Code 51 Troubleshoot pg 1.JPG


Code 51 Troubleshoot pg 2.JPG
 
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JAMES L EUBANK

Apprentice
Feb 18, 2018
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CLARKSBURG, WV
Let's not forget that the issue is what seemingly is (for now anyway) a benign Code 51 issue. Which has to do with the PROM. I didn't see anything in the CSM troubleshooting chart about an ePROM. Maybe the ePROM is the thing that fuggs up if it's the ECM causing the problem?

Troubleshooting per the CSM is pretty easy. Read below.

If everything checks out and you still get a Code 51, then replace ECM. Which to me, is their way of saying, you're kind of FOOKED at that point.

Just don't install the PROM backwards and turn the key on to energize the ecm or you'll toast the PROM. There's a little notch in one end of the PROM carrier to help guide you. IIRC, I believe the notch goes toward the center of the ECM but make sure if/when you take the cover off to inspect.

View attachment 146325

View attachment 146326
As I said before, it seems too operate as if there is nothing wrong. I do not want to dig it out and look at it since it is not my car, but I doubt it was installed backward given how well the car performs. Im guessing an aftermarket chip was put in at some point. If what you said is true, the aftermarket chip might cause the code, but still allow the chip to run everything within programmed parameters. Would that be a good assumption?
 

69hurstolds

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As I said before, it seems too operate as if there is nothing wrong. I do not want to dig it out and look at it since it is not my car, but I doubt it was installed backward given how well the car performs. Im guessing an aftermarket chip was put in at some point. If what you said is true, the aftermarket chip might cause the code, but still allow the chip to run everything within programmed parameters. Would that be a good assumption?
As I stated earlier, I've heard of that happening with some of the Hypertech chips. But it was on Chevy applications. I could see the same thing happening on any OBD1, though. Yes, the prom ran everything fine, except got the 51 code that couldn't be erased permanently.

It was traced down to something to do with the checksum verification of the correct PROM being installed or something to that effect. Basically, the PROM checksum didn't add up like the ECM expected and tossed the code due to that. I doubt they all do that, as I'm sure that kind of issue would have spread like wildfire by now.
 
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JAMES L EUBANK

Apprentice
Feb 18, 2018
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CLARKSBURG, WV
Well then, I am more confused than ever. But, whats the worst case senario here? I may have to get a new ecm? Or, possibly trash the whole ccc system and go with oldschool vacuum assist distributor, etc? The bottom line is how much will it cost to fix versus how much I pay for the car?
 

Ribbedroof

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Jan 4, 2009
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Wellston, OK
Possible that an aftermarket chip was removed, and OE chip reinstalled with a bent or missing pin or not fully installed.

I'd say if it runs as it should, figure out what it's going to cost to replace PROM or ECM/PROM and see if you can live with that.

Not sure how seller justifies that the price is already "discounted", given that these are not late model cars with a large sold database to set a "normal" or book value with.
 
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69hurstolds

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Buy that ebay unit for 75 bucks and plug it in. Everything is there and correct for the application.
 
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Brodewok

Not-quite-so-new-guy
Jan 31, 2021
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Your ECM box should be a 16047963 production, and 1226457 service number. And the PROM for an 85 442 should be an 7987FCH code prom with service replacement number of 16047986.
I have been searching high and low for the part number to the original ecu and prom for a 1983 vin9 hurst. Is there any way you can help me out?
I put the 83 vin9 engine/carburetor into a 82 olds ninety eight. It is running on the ECU for the ninety eight vin Y. It seems to run ok but I want the vin 9 chip. From what I gather the computer part number is the same for each vehicle. I have a brand new ac delco anyhow. It didn't come with a PROM and I can't find the part number anywhere. All I've found is the hypertech and another performance one. If push comes to shove I'll use the stage 1 hypertech but I'd much prefer to find the original. Thank you in advance for your time and sorry for stealing the thread.
 

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
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I have been searching high and low for the part number to the original ecu and prom for a 1983 vin9 hurst. Is there any way you can help me out?
I put the 83 vin9 engine/carburetor into a 82 olds ninety eight. It is running on the ECU for the ninety eight vin Y. It seems to run ok but I want the vin 9 chip. From what I gather the computer part number is the same for each vehicle. I have a brand new ac delco anyhow. It didn't come with a PROM and I can't find the part number anywhere. All I've found is the hypertech and another performance one. If push comes to shove I'll use the stage 1 hypertech but I'd much prefer to find the original. Thank you in advance for your time and sorry for stealing the thread.
PROM for an 83 H/O should be an 2195BPA code prom with service replacement part number of 1226360.

The ECM production box number is 16030223, and the service replacement part number should be 1225450.

Your best bet in finding one is likely buying a complete ECM with PROM already in it for an 83 H/O.
 
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