Working on my wiring harness for the 3800SC swap. Donor car was a '95 Riviera. Got the entire wiring harness from the vehicle, so lots of extra wire. Spent the last 5 days buzzing out the harness, tracing wires, etc. Also spent a lot of time online confirming stuff that wasn't clear. Came down to just a few questions that I know someone here can help with!

1) Riviera harness has a large connector in the engine bay connecting the engine to the ECM. Very convenient, and I plan on using it. I want to locate it where the battery was located ( already moved battery to front). Any issues with locating it there ( such as water?). If not there, where else would you suggest.

2) Coil pack going in same battery area. I know this has been done many times, so I don't expect any issues???

3) 3 wires were missing from the ECM connectors that I would like to use. Want to know if I can just use some of the "extra" wires from the ECM, and re-pin to these missing locations:
a) RB1 BRN Alternator Charge warning lamp control - goes to B3 of C500 connector
b) RB10 Dk GRN Engine Hot warning lamp control - goes to D3 of D500 connector
c) WD7 Lt BLU Performance shift switch input Goes to switch, then to ground to enable performance mode for shifting

4) WD14 Dk Blue Theft Deterrent Fuel Enable. Info suggests to ignore, that it can be programmed out in ECM. I will be deleting VATS in ECM- does this take care of this issue. Wiring diagrams in Buick Manual indicate that this might "go to ground", but not sure it it should just be grounded permanently.

NOTE: I have the capability to re-program and burn chips, although I believe that these "features" should already be there. Please let me know if there is something else in the programming I need address for these issues.

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'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) 4t60e.

Are you using the 1995 PCM?
I have heard that they are a bit fussy to flash. I haven't seen any files for 1994 or 1995. 1994 still used a memcal. The 1995, I think was ODB1.5
Also 3800 PCMs from around 1992-1996 like to see the temp light control and most likely the alternator light control or will give a quad driver code. I had to connect the temp light in mine.
The sport shift can be connected, but may not be enabled in your bin. I'm using a 1993 PCM and it also had that line. Mitchel manuals only showed that enabled on Bonneville SSEi though it used the same PCMs as the Buicks.
The VATS will have to be programmed out or it won,t stay running. You will be able to ignore that line if it is edited out. Most of the VATS fuel inable lines get a 30hz or 50hz signal from the BCM or VATS module. If you can't get it edited, there are VATS signal generators, to "fool" the PCM by sending a 30/50hz signal to that line.

[This message has been edited by cmechmann (edited 11-09-2015).]

1994-95 3800 FWD PCMs are what many people refer to as the "OBD1.5" PCMs. This same computer was used for both 1994 and 1995 model years. In 1994, it was used with the L27 3800 Series 1 vin L V6 and L67 3800 Series 1 SC vin 1 V6. In 1995, it was used with these two engines + the (then new) L36 3800 Series 2 N/A vin K V6. These computers used a short style removable mem-cal (which only contained the PROM chip and knock sensor interface circuitry). 1994-95 Buick Regals used the same type of computer except it had a different, water-sealed case and different connectors.

1995 F-body L36 applications actually used the same OBD2 PCM that was used in 1996. These were flash-based PCMs just like everything else OBD2.

quote Originally posted by darbysan: Working on my wiring harness for the 3800SC swap. Donor car was a '95 Riviera. Got the entire wiring harness from the vehicle, so lots of extra wire. Spent the last 5 days buzzing out the harness, tracing wires, etc. Also spent a lot of time online confirming stuff that wasn't clear. Came down to just a few questions that I know someone here can help with! 1) Riviera harness has a large connector in the engine bay connecting the engine to the ECM. Very convenient, and I plan on using it. I want to locate it where the battery was located ( already moved battery to front). Any issues with locating it there ( such as water?). If not there, where else would you suggest.

Just make sure water can't get into it. If there is any doubt you can seal it, fill it with dielectric grease.

quote 2) Coil pack going in same battery area. I know this has been done many times, so I don't expect any issues???

Mount a rubber flap over it to keep water from being able to directly drop onto it.

quote 3) 3 wires were missing from the ECM connectors that I would like to use. Want to know if I can just use some of the "extra" wires from the ECM, and re-pin to these missing locations: a) RB1 BRN Alternator Charge warning lamp control - goes to B3 of C500 connector b) RB10 Dk GRN Engine Hot warning lamp control - goes to D3 of D500 connector c) WD7 Lt BLU Performance shift switch input Goes to switch, then to ground to enable performance mode for shifting

Yes, you can pull wires and terminals out of other connector locations you aren't using and use them for these purposes. However, in order to enable performance shift mode, you cannot just ground that wire. You must install a 348 ohm resistor between this wire and ground to enable performance shift. Most of the later OBD2 PCMs simply have this wire grounded to enable performance shift.

quote 4) WD14 Dk Blue Theft Deterrent Fuel Enable. Info suggests to ignore, that it can be programmed out in ECM. I will be deleting VATS in ECM- does this take care of this issue. Wiring diagrams in Buick Manual indicate that this might "go to ground", but not sure it it should just be grounded permanently.

This PCM requires a PASSKEY II signal which I believe is 50hz, unless you have it disabled in a custom tune.

quote NOTE: I have the capability to re-program and burn chips, although I believe that these "features" should already be there. Please let me know if there is something else in the programming I need address for these issues.

Disable DTC's 626, 629, 571, 573, 599, 619 & 670 for most swap applications utilizing a 4T60-E trans. Don't forget to uncheck the "VATS Select" option as well (to disable VATS). If you are not using an EGR, A/C, the Boost Solenoid - more will need to be disabled and changed in the tune.

-ryan

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More is more. Less is not enough.

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

[This message has been edited by Darth Fiero (edited 11-09-2015).]

Thanks Chris, Ryan. This helps a lot. I am using the 95 "1.5" ECM. Just figured it would be easier. I downloaded the stock bin from the computer, so I am starting with a known working bin, and will only change a few things other than those mentioned above( fan on temps, for example). I was able to open this in Tunerpro RT, and was also able to log on to the running donor before I took it apart, and got downloads of performance data streams ( so I know that part works too!). I even bought an Ostrich emulator to play with, since I can use it on both of my toys. Gonna try programming the ECM, and if I run into problems, then my backup plan is to have Ryan try and program it. Trouble with being an engineer, you want to try and do everything yourself if you can

Thanks again for all the help. Slowly but steadily getting there...

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'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) 4t60e.

quote Originally posted by darbysan: Thanks again for all the help. Slowly but steadily getting there...

No problem, let me know if you have any other questions.