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Discussion Starter #1
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

Feel free to ask any more tech info, didnt want to clutter the post too much more
 

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Why not try finding the correct ECU on ebay or car-part.com?

A quick search for 16168625 on ebay turned up 200ish results. I didn't parse through it looking for s10.

Or since it sounds like you aren't above fudging things, maybe find a non-W vin ECU?
 

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Discussion Starter #3
Why not try finding the correct ECU on ebay or car-part.com?

A quick search for 16168625 on ebay turned up 200ish results. I didn't parse through it looking for s10.

Or since it sounds like you aren't above fudging things, maybe find a non-W vin ECU?
locating a 16168625, isnt an issue. that pcm was used on several models. its finding one that has the correct eprom program for a manual trans with this engine.
The pcm has to match the engine. they verify part number when doing the inspection.
 

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I have literally spent 100s of hours on this very thing, including a VIN number generation spread sheet ran through comp nine VIN verification when you could run unlimited RPO build searches or VIN numbers.

There are 3 model 4.3 CPI manual trans applications that I was able to 100% confirm

1994 ZR2 S10 silver PCM in cab, emissions code 81TMU federal
1995 ZR2 S10 black VCM-A federal emissions
1995 SS Sonoma black VCM-A emisions code 81YBS california emissions, read the small print on the bottom of the pictured label and you will see certified for sale in californis

I have actually located several of these in real life however only one had california emissions. You are looking for a truck with the following build RPOs

L35-4.3 CPI
M50-manual trans 5 speed
NN5-emission override, california emissions system, federal offset vehicle
YF5-california emission certification

On comp nine you can run a search by putting in RPOs and it tells you how many were built that way, I think there were like 300 that had the 4 build codes listed. If you find one you can run the vin and it will verify the L35, M50, NN5 and YF5

The 1995 4.3 CPI VCM-A is a one year unique piece, google it. It will not wire up to your current motor, ignition, emissions purge and most sensors, but primarily because of the ignition.
It can be quickly identified by the distributor having horizontal spark plug wires, it utilizes a crank trigger and cam sensor and is the OBD1.5 transitional computer when GM was moving to obd2

PM me and I can give you my phone number, the 4.3 CPI 5 speed VCM-a is a very unique limited application

If you compare the TMU federal and the YBS california the difference is on the purge federal is vac operated calif is computer controlled
 

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here is an old ebay add from 2010

1995 ZR2, 4.3 CPI, 5 SPEED BUT FEDERAL EMISSIONS
YOU CAN RUN THE VIN (NOTE THE "W" DESIGNATION IN THE 8TH DIGIT FOR CPI) AND SEE THE RPOS
 

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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.
Not sure if it’ll help you, but they did put manual trans in Astro vans. Rare, but available as I’ve driven one. So, can you tell the ref it’s a 4.3 from an stick shift Astro? If it doesn’t ask on the scanner you should be home free.

Ninja edit: Never-mind, after some googling 89 was the last year for stick shift Astro, probably won’t help your 94.
 

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Discussion Starter #8
BINGO

I got to thinking that I remembered a 1994 california carb certified chassis configuration with the 4.3 CPI and 5 speed.
I dusted off my paper files and found a note for two executive orders. I looked them up on the CARB page for On-Road New Vehicle & Engine Certification Program

EO A-6-644
https://ww3.arb.ca.gov/msprog/onroad/cert/pcldtmdv/1994/gm_ldt_a0060644_4d3_0.pdf

EO P-6-80
https://ww3.arb.ca.gov/msprog/onroad/cert/pcldtmdv/1994/gm_ldt_p0060080_4d3_5.pdf
1994 ZR2 S10 silver PCM in cab, emissions code 81TMU federal

This is what im most interested in. REF was actually ok with a federal emission swap since the base vehicle wasnt california as long as there is documentation the swap came from a fed truck.
just need to know what the ecm and prom number will be especially since its the standard obd1 just like the current one i have
 

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1994/S10/4X4/L35/MY2


BDCM
EPROM-16185117
PCM-16156647
PROM ID-5424
SCAN ID-5525 (matches EO A-6-644)
4.3 CPI--L35
MAN 5speed--MY2
 

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This should work too, looks like you can still source both the eprom and ecm

BHRL
EPROM--16195908
ECM--16196392
SCAN ID--5945 (matches EO A-6-664)
L35--4.3CPI
MAN 5 SPEED--MY2
 

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I may have a spare mt 4.3 ecu I can check my swap is ca legal and is a 92 4.3cpi
 

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Discussion Starter #12
I may have a spare mt 4.3 ecu I can check my swap is ca legal and is a 92 4.3cpi
interested in what your ecu\prom setup is, and how you went about making the ref happy
 

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I refed mine back in 2007 and I got my ecu from Howell efi didn't seem to have a problem with it back then and my spares missing the chip my have lost it when I moved when I talked with Howell and said I was keeping the r150 trans they sent the correct ecu with chip
 

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Discussion Starter #14
This should work too, looks like you can still source both the eprom and ecm

BHRL
EPROM--16195908
ECM--16196392
SCAN ID--5945 (matches EO A-6-664)
L35--4.3CPI
MAN 5 SPEED--MY2
ECM arrived today, but the plugs are different then the red/blue ones on my current ecu. Ordered the connectors and will look up pinouts tomorrow. Just waiting from the prom to arrive, hopefully it works...

I refed mine back in 2007 and I got my ecu from Howell efi didn't seem to have a problem with it back then and my spares missing the chip my have lost it when I moved when I talked with Howell and said I was keeping the r150 trans they sent the correct ecu with chip
Do you know the PCM number and prom number in your truck that howell set you up with? they seemed lost when I asked them what I needed.
 

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ECM arrived today, but the plugs are different then the red/blue ones on my current ecu. Ordered the connectors and will look up pinouts tomorrow. Just waiting from the prom to arrive, hopefully it works...



Do you know the PCM number and prom number in your truck that howell set you up with? they seemed lost when I asked them what I needed.
2 black plugs as opposed to the red and blue?
It is a carryover from 92-93 most likely because of the 5 speed, I would guess an astro harness from 92 would work close?
 

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on my invoice from Howell its says prom HCPI cal-prom 9293 I would have to tear into my dash to pull my actual ecu
 

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Discussion Starter #18 (Edited)
2 black plugs as opposed to the red and blue?
It is a carryover from 92-93 most likely because of the 5 speed, I would guess an astro harness from 92 would work close?
correct 2 black plugs, a 24/36 pin, or something like that.
Where is this #? SCAN ID--5945 (matches EO A-6-664)
I have the ecu, Eprom arrived today, part# and bcc code match BHRL, read through those carb sheets and didnt see any matching # for what we talked about.

I ordered the plugs and will just re pin them, just need to find the correct wire diagram, none of the 94 stuff i was looking up seemed to look correct.
Ill try looking at 92 stuff.
 

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Comments added in your text below

correct 2 black plugs, a 24/36 pin, or something like that.
Where is this #? SCAN ID--5945 (matches EO A-6-664)
I have the ecu, Eprom arrived today, part# and bcc code match BHRL, read through those carb sheets and didnt see any matching # for what we talked about.

page 8 under ignition number you will see 16195945 that is thE GM part number for the scan ID it is another part number in GMs masterplan of terminology and numbering. Each BCC (prom) has a part number, a prom ID number and a scan ID number, the PROM ID and scan IDs are usually only referenced by the last 4 digits. If you dig deep enough on the web you can find this explanaltion.

If you take the last 4 digits of each one of the ignition numbers you will find a corresponding scan ID

I ordered the plugs and will just re pin them, just need to find the correct wire diagram, none of the 94 stuff i was looking up seemed to look correct.
Ill try looking at 92 stuff.


I believe in 92 GM, for the 4.3 motors anyway, was in the process of switching over to the red and blue connector PCMs. The double black connectors were kind of the left overs. The red and blue connectors for the CPI became very prevalent in 93.

This 5speed application behind a CPI is a very rare bird, its (1994)BHRL with its PCM was the replacment for (1994)BDCM and its PCM 16156647
PCM 16156647
is vintage double black connector from early 90s. I have all the service manuals from GM for 92-95 which will have the pinouts I am not sure how well I can photo them but I could try.

You are in socal, might try a library, I know here in the bay area our local library has a multitude of factory service manuals.

If not you can always buy the gm manuals for your 94 and the 92, that is pretty much what I did.
 

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Discussion Starter #20
According to the BCC lookup spreadsheet, ECM--16196392 was only used with the 94 cpi/manual, nothing else.
I have re pinned based to the black plugs on everything I can find, and believe I have it correct.
the truck will crank but not start.
It appears the computer isnt telling the CPI injector to fire.
I can get the truck to run by manually triggering the injector, or spraying brake clean in the intake.
Im at a loss why its not triggering. any help would be appreciated.

Pin- outs that are better would be huge as I have a feeling its a power/ground signal the computer needs but isnt on the pin-out and needs to go to one of the open connectors.
 
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