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| 4.9L Intermittent PCM issue (Page 3/3) |
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sanderson231
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FEB 13, 06:08 PM
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| quote | Originally posted by Mickey_Moose:
Ok, files have been uploaded here: https://drive.google.com/dr...Pxgyb?usp=share_link
They are in the \EPROM files\4.9l directory. Sorry I don't remember the specifics of the files other than the names that there are called. But includes both Rockcrawl and Stickpony images - you will have to load them into Tunercat and verify if the VATS has been disabled as I don't recall which had.
Stickpony was the go to person after Rockcrawl seemingly left the Fiero scene.
These are for the 2240 PCM (pre-94).
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I did look at the files you posted with Tunercat. The two stock calibrations opened OK. The four files that were edited all gave checksum errors. However I noticed in the text documentation that the checksum error (code 51) had been disabled in the switch table. Therefore I am assuming that files were edited without a tool that would recalcuate the check sum and that the files are not corrupt. I'll proceed with caution and try one out int the car.
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Mickey_Moose
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FEB 14, 02:38 PM
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| quote | Originally posted by sanderson231:
I did look at the files you posted with Tunercat. The two stock calibrations opened OK. The four files that were edited all gave checksum errors. However I noticed in the text documentation that the checksum error (code 51) had been disabled in the switch table. Therefore I am assuming that files were edited without a tool that would recalcuate the check sum and that the files are not corrupt. I'll proceed with caution and try one out int the car. |
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Sorry, I cannot help on how they were originally edited, but the BIN files are as I dumped them using my programmer - however this was also years ago and maybe the files have been corrupted since then sitting on my hard drive? The text files are what I documented as to what the changes were at the time, so one can always create a new file.
The difference between the 2 Stickpony files is 1 was for a 4 speed car and the other was from a 5 speed car - no ideal if there are actual differences other than maybe the PPM calculation for different sized tires. But I have no ideal which one is which. lol
The Rockcrawl file was for the same 5 speed car.
The 4th file - I do not recall what car that was for...[This message has been edited by Mickey_Moose (edited 02-14-2023).]
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sanderson231
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FEB 14, 05:19 PM
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From what I have heard if I open the bin file with Tunercat and then save it back to my hard drive, Tunercat will recalulate a new checksum. So that the next time it is opened Tunercat will not give a checksum error. I have a couple of spare PCMs so I'm going to give it a whirl betting that the checksum error is just an artifact of the programmer that created the file. ------------------
formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged
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Neils88
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FEB 14, 10:08 PM
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It's been a while, but I recall that if you are connecting the Fiero 5 speed VSS to the Caddy PCM, you may need to swap the VSS wires (purple and yellow). Without the swap, mine kept stalling everytime I pushed in the clutch and came to a stop.
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sanderson231
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FEB 16, 12:27 PM
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| quote | Originally posted by Mickey_Moose:
The difference between the 2 Stickpony files is 1 was for a 4 speed car and the other was from a 5 speed car - no ideal if there are actual differences other than maybe the PPM calculation for different sized tires. But I have no ideal which one is which. lol
The Rockcrawl file was for the same 5 speed car.
The 4th file - I do not recall what car that was for...
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The key difference between the Stickpony and Rockcrawl file is the ignitiontiming advance. Rockcrawl stuck with stock timing. Stickpony advanced the timing at high MAP and high rpm's. For example the stock timing at 100 kPa and 4800 rpm is 35.9 degrees. Stickpony increased it to 41.1 degrees. I think that these values are delta timing i.e. the actual timing is the 8 degrees base timing in the distributor plus the value in the PROM. We don't know if Stickpony did this based on dyno results or it was just wishful thinking that more advance would make more power. 49 degrees of advance at 4800 rpm and 100 kPa seems like a lot.------------------
formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged
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