My 4.3 swap has been in and running great for years, but I rolled the truck did a full rebuild and made the mistake of trying to make this thing legit instead of paying for under the table smogs anymore...
Big mistake. Anyone with input will be greatly appreciated.
Quick rundown.
85 pickup
engine is a 93 4.3 CPI vin"w"
Trans is w56
Stock GM eprom is flashed to not turn out codes for manual swap
The REF refuses to sign off on it because the 92-93 vin W CPI engine appears to never have been backed by a manual trans.
2 different ref locations looked at it.
One said he would sign off on it if the scanner he uses will accept the option of manual transmission, but when he does it the scanner doesn't read the computer properly. if you select automatic when using an s--10 or Blazer, if you use the astro van it wont prompt for manual/auto option but of course there was never a Manual trans Astro van.
There is a spreadsheet floating around the net that shows eprom catch codes that indicate it could possibly exist with the same base computer that i currently have.
I was able to track down one of these but it appears it still looks like an auto program. (BMUR)
when I install in in my current ecu it throws auto trans codes as an astro, and run as an s-10 manual it shows communication error. Same as my current one.
I have not been able to find any other of the 7 eprom's from this list anywhere, and after the one I have not working am unsure if the others will work or satisfy Ref's requirements.
If I cant get this thing figured out, I'm either going to have to swap to a newer truck/engine setup, or install an auto (going to shorten my trans length by about 1/2" and mess up driveshafts and trans cross-member dimensions)
Prog ID BCC Year Release Date Eprom ECM Prom ID Scan ID Platform Engine Disp. Trans Trans Type
BMUR 1993 34498 16210986 16168625 987 975 S1 L35 4.3 MAN
BMUS 1993 34498 16210989 16168625 990 985 S1 L35 4.3 MAN
BMXP 1993 34498 16211362 16168625 1363 1365 S1 L35 4.3 MAN
BUZD 1993 35277 16239323 16168625 9323 9301 L1 L35 4.3 MAN
BUZF 1993 35277 16239338 16168625 9238 9311 M1 L35 4.3 MAN
BUZH 1993 35277 16239347 16168625 9347 9321 L1 L35 4.3 MAN
BUZJ 1993 35277 16239362 16168625 9362 9331 M1 L35 4.3 MAN
BUZK 1993 35277 16239376 16168625 9376 9341 S1 L35 4.3 MAN
current ecu and prom setup is:
BBNX 1993 33717 16179746 16168625 9747 9601 S1 L35 4.3 AUTO
