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-   -   4.3l.Electrical ? (https://www.pirate4x4.com/forum/jeep-willys/2352170-4-3l-electrical.html)

AZ Wheelin 07-05-2016 07:37 PM

4.3l.Electrical ?
 
Bought a 95 Chevy S10 Blazer complete and running to swap over the 4.3l into my Flatty. Complete truck cost me $450. I can do basic electric work, but swapping efi is a new one to me, so this will be a learning experience for sure.

Pulled the motor already, and pulled the entire harness out today, minus the obvious unneeded circuts (power windows, locks, stereo)

Ran across two boxes, both look like they could be the computer, so are there two? One was located in the kick panel on the pass. Side and the other slightly larger was under the firewall near the ac parts inside the cab.

I know I need the computer (ECU?) for the CPI motor, I was just expecting a single unit. Not sure what both are for.

I'm saving everything untill I hear it running in the Jeep, just in case I accidentally send something I need to the scrapper.

Thanks.

a3dhunter 07-05-2016 08:12 PM

If there is a black box with one multipin connector, that's the brake module.
I sent my harness to Jims Performance last week to get trimmed and ECM programmed.

AZ Wheelin 07-06-2016 06:07 PM

The ones I pulled are both tin cases.

Do I need to get the ecu programmed?

Mike-M 07-06-2016 08:42 PM

If I recall, late '94 and all of '95 had a mix of OBD1 and OBD2 shit in there and no one will want to touch your wiring harness with a 10 foot poll. I hope Im wrong.

v6toy4x 07-06-2016 09:05 PM

Quote:

Originally Posted by Mike-M (Post 37432018)
If I recall, late '94 and all of '95 had a mix of OBD1 and OBD2 shit in there and no one will want to touch your wiring harness with a 10 foot poll. I hope Im wrong.

Close, all 94 are old school OBDI with the silver ECU in the cab. The 95s were mixed OBDI and a partial OBDII sometimes referred to OBD1.5. They had the ECU under the hood and are technically called a VCM-A, with the A designation for the partial OBD1.5.

The OBD1.5s have horizontal wires at the distributor, crank sensor and cam sensor along with a ten bolt plastic timing cover.

You will have a hard time getting anyone to deal with the OBD1.5 stuff. However changing out the distributor and coil to the 94 stuff and you can get it to run on the early style ECU which most anyone can do.

v6toy4x 07-06-2016 09:12 PM

2 Attachment(s)
1995 vcm-A

v6toy4x 07-06-2016 09:13 PM

1 Attachment(s)
1994 pcm

MrWillys 07-07-2016 07:50 AM

I show both 94 and 95 being the same and are 16196395 or 16197427 PCM and are the $ODA definition if it is CPI. If it is not CPI it is the $OD definition and uses a different broadcast code.
This may help you.

http://scotthansen.net/BCCLookup.pdf

You would only need a reflash if it has VATS or you want to make changes. See www.tunercat.com and click on ECM definition to learn more about what you have.

v6toy4x 07-07-2016 08:00 AM

2 Attachment(s)
Quote:

Originally Posted by MrWillys (Post 37436034)
I show both 94 and 95 being the same and are 16196395 or 16197427 PCM and are the $ODA definition if it is CPI. If it is not CPI it is the $OD definition and uses a different broadcast code.
This may help you.

http://scotthansen.net/BCCLookup.pdf

95s used the above AND the 16193495 (OBD1.5 VCM-A) used only one year and only this application.

It is easy to identify which you have, do the spark plug wires enter the cap vertically or horizontally?

Vertical and you have one of the above mentioned
Horizontal and you have the redheaded step child!

crazybluerider 07-07-2016 08:08 AM

Quote:

Originally Posted by v6toy4x (Post 37432234)
Close, all 94 are old school OBDI with the silver ECU in the cab. The 95s were mixed OBDI and a partial OBDII sometimes referred to OBD1.5. They had the ECU under the hood and are technically called a VCM-A, with the A designation for the partial OBD1.5.

The OBD1.5s have horizontal wires at the distributor, crank sensor and cam sensor along with a ten bolt plastic timing cover.

You will have a hard time getting anyone to deal with the OBD1.5 stuff. However changing out the distributor and coil to the 94 stuff and you can get it to run on the early style ECU which most anyone can do.

You will also need knock sensors. I swapped an OBD1.5 back to OBD 1 and chased a runability issue for a couple weeks that turned out to be knock sensors. The OBD1.5 stuff uses a knock sensor with a much higher resistance number.

I stole the ditrib, coil, ECU and drac out of a junk yard s-10 and should have stole the knock sensors as well. I then paired that with a Howell harness. Easy peasy. Just leave the crank sensor unplugged it is unneeded. The older stuff used the distrib for engine speed.

The drac is unneeded if you are using a non electric trans, I kept the 4l60e in my swap so I needed the drac to make the trans shift right.

v6toy4x 07-07-2016 08:10 AM

Quote:

Originally Posted by crazybluerider (Post 37436282)
You will also need knock sensors. I swapped an OBD1.5 back to OBD 1 and chased a runability issue for a couple weeks that turned out to be knock sensors. The OBD1.5 stuff uses a knock sensor with a much higher resistance number.

I stole the ditrib, coil, ECU and drac out of a junk yard s-10 and should have stole the knock sensors as well. I then paired that with a Howell harness. Easy peasy. Just leave the crank sensor unplugged it is unneeded. The older stuff used the distrib for engine speed.

The drac is unneeded if you are using a non electric trans, I kept the 4l60e in my swap so I needed the drac to make the trans shift right.

Agreed

MrWillys 07-07-2016 08:27 AM

Quote:

Originally Posted by v6toy4x (Post 37436162)
95s used the above AND the 16193495 (OBD1.5 VCM-A) used only one year and only this application.

It is easy to identify which you have, do the spark plug wires enter the cap vertically or horizontally?

Vertical and you have one of the above mentioned
Horizontal and you have the redheaded step child!

Great post and clears up which he has. I'm a Camaro Corvette OBD1 programmer. I have a BJWN memcal here that is for a 95 4.3. My understanding is GM started OBD1.5 in the 94 Camaro Corvette. My guess would be they transitioned at some point during the 95 model year for the Blazer.

AZ Wheelin 07-07-2016 06:59 PM

Both the box's I pulled looked like the silver one posted, none look like the black one with ribs.

My distributor also looks like a standard distributor.

Can post pics if someone can host

CPI motor.

AZ Wheelin 07-07-2016 07:03 PM

My distributor looks just like the distributor I have on an old donor tbi 4.3l I bought. Same two plugs on the back and all.

AZ Wheelin 07-07-2016 07:07 PM

Data plate on the door says it was made 07 of 95

One box says service 16176557 the other says service 16197427

v6toy4x 07-07-2016 09:21 PM

Quote:

Originally Posted by AZ Wheelin (Post 37444410)
Data plate on the door says it was made 07 of 95

One box says service 16176557 the other says service 16197427

The 16197427 is old school with after market support, not sure about the other can you post some pics

AZ Wheelin 07-07-2016 09:27 PM

I can email you one.

shaggy10000 07-08-2016 07:00 AM

Quote:

Originally Posted by AZ Wheelin (Post 37444410)
Data plate on the door says it was made 07 of 95

One box says service 16176557 the other says service 16197427

IIRC the donor i pulled mine from had a door tag of 95 but the drivetrain was all 94 stuff.

MrWillys 07-08-2016 08:14 AM

The 7427 is the OBD1 PCM used up until 1995 when the change occurred. It has a removable memcal (AKA PROM) that can be reflashed if needed. I can do it and Jim's Performance can do it as well as many others. I would cut the chip out and solder in a newer flash chip. Remove the inspection cover and tell me what is the Alpha code on the silver sticker on the memcal?

AZ Wheelin 07-08-2016 03:47 PM

I can get you that info, but I'm leaving town for a few days, so maybe sun.

Do I still need the other box?

MrWillys 07-08-2016 04:34 PM

Quote:

Originally Posted by AZ Wheelin (Post 37455162)
I can get you that info, but I'm leaving town for a few days, so maybe sun.

Do I still need the other box?

No, use the one you have is just fine. The other would require a crank trigger and get things all screwed up. You were just on the cusp of a major revision.

AZ Wheelin 07-08-2016 07:32 PM

Just to clarify, all I need is the computer labelled 16197427? And not the other mystery computer?

Considering they were both in the vehicle, I figured they were both needed.

What does the other computer thingy mabob do?

MrWillys 07-10-2016 02:27 AM

The 7427 is the PCM for drivetrain control and should be all you need. I'm not an S10 expert but can say my 04 Corvette has several computers and one that controls the security system and other functions. Do you have the key for this truck? Does it have a resistor pellet in it?

AZ Wheelin 07-10-2016 05:12 PM

I didn't get a key with the truck. They drilled it out and used a screwdriver to start it lol. It's a real peach :) but it runs well, all I cared about.

superdooty 07-10-2016 06:26 PM

I purchased a 95 for exactly the same coin, self weeded the harness, that worked for a few years, i just didnt care for the hack look.

I ordered a new harness from Howell recently, money well spent! All they need is a pic of the ecm youll be using, they know what to do from there. Make sure you specify which O2 sensor youll be using!!


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