3800 electrical questions (Page 2/3)
olejoedad APR 02, 11:14 AM
The PCM is the computer that controls the drivetrain.

I think Frenchrafe meant to say Powertrain Control Module...

It can be mounted in the stock Fiero ECM location.

[This message has been edited by olejoedad (edited 04-02-2020).]

longjonsilver APR 02, 11:34 AM

quote
Originally posted by olejoedad:
The PCM is the computer that controls the drivetrain.
It can be mounted in the stock Fiero ECM location.



OK, i call that the computer. i understand that a new chip will need to be burned. That chip is located in the PCM no? i have read a lot of threads on the 3800 and i can't seem to find how the wires get from the engine compartment thru the firewall to the PCM. i know that you use the C500 and C203 connectors from the Fiero and that the C500 is on the firewall (at least it is on my 84), but the PCM of the 2002 GP
has these huge connectors. What am i missing?

Connectors


PCM

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Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

olejoedad APR 02, 03:34 PM

quote
Originally posted by longjonsilver:


OK, i call that the computer. i understand that a new chip will need to be burned. That chip is located in the PCM no? i have read a lot of threads on the 3800 and i can't seem to find how the wires get from the engine compartment thru the firewall to the PCM. i know that you use the C500 and C203 connectors from the Fiero and that the C500 is on the firewall (at least it is on my 84), but the PCM of the 2002 GP
has these huge connectors. What am i missing?

Connectors


PCM






1. I would relocate the C500 to the location us d in the 85-88 model years.
2. I would add a Battery Junction Terminal in the 85-88 location.
3. The PCM does not use a replaceable 'chip'. The PCM is reprogrammable. I recommend Ryan at Sinister Performance.
4. The plugs for the PCM, the C-203, and the ALDL will fit through the square cutout in the firewall above the PCM mounting area. They go through the driver side cutout, and there is a plastic housing that captures the wires and seals the cutout.
longjonsilver APR 02, 06:08 PM

quote
Originally posted by olejoedad:
1. I would relocate the C500 to the location us d in the 85-88 model years.
2. I would add a Battery Junction Terminal in the 85-88 location.
3. The PCM does not use a replaceable 'chip'. The PCM is reprogrammable. I recommend Ryan at Sinister Performance.
4. The plugs for the PCM, the C-203, and the ALDL will fit through the square cutout in the firewall above the PCM mounting area. They go through the driver side cutout, and there is a plastic housing that captures the wires and seals the cutout.



1. Why should i relocate the C500?
2. With my Duke i have tied in all the hot wires together - the starter, the battery and the alternator. The battery is in the front under the passenger headlight.
3. i have already contacted Ryan, he says he needs the number on the PCM, and that is why i have carefully taped down the sticker on it as it was coming loose. He also needs to know what exactly i am installing or removing from my swap - mods and what not. He will not ship internationally, so i will have to have him ship the PCM to my brothers house so i can pick it up this summer at a wedding.
4. The ALDL is the thing that you short out to read the codes no? i thot that with OBD2 i didn't need the ALDL - tho, in the rush to pull the motor, i forgot to search for the OBC2 connector - i guess i can pull one at the scrap. i pulled a C-203 at the scrap so i can make the harness while my car is still on the road - less downtime. i found the C-203 in the center console, i guess i have to push it thru the firewall when i am finished with the harness.

Thanks olejoedad for taking the time to answer my stupid questions. i've been doing lotsa reading these last cuppla years, but some things are still not real clear. One thing at a time - i've got a year to get ready for the swap and the more i can do before swapping, the faster and easier it will be.


------------------
Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

phonedawgz APR 02, 09:17 PM
1 - Because the 84 location of C500 will interfere with the valve cover. Swing it over as far as possible towards the passengers side.

2 - Having all those wires screwed to the starter and having the engine move around all the time can cause problems. Many times those wires come loose on 84s. Pontiac moved the power distribution up for all engines in 85 for a reason.

2b - Make sure your battery's negative wire connects to the block and not to the frame. If it connects to the frame also and your frame to engine strap comes loose your wiring harness's small wires will become the battery cable. Then when you got to start it those wires will heat up red hot. They will short other wires in your harness.

3 - Ryan is good.

4 - Yes you will want an OBD2 connector. The smart move is to extend it and put it up front under the dash like a normal car. Makes it much easier to plug in your OBD2 scan tool. That or put a blue tooth OBD2 adapter on the connector under the console and just leave it on all the time.
longjonsilver APR 03, 05:41 AM

quote
Originally posted by phonedawgz:

1 - Because the 84 location of C500 will interfere with the valve cover. Swing it over as far as possible towards the passengers side.

Will do, right now it as far over to the drivers side as possible.


quote
2 - Having all those wires screwed to the starter and having the engine move around all the time can cause problems.


i have only one hot to the starter, and thats from the battery. i made my own sort of hot harness tying the others together. i didn't know at the time that later Fieroz had a Battery Junction Terminal and so i pulled one off a Lincoln. Then i decided not to use it but rather make my own by soldering copper wire together. i have a friend that has two parts cars. i will look for one. Thanks

quote

2b - Make sure your battery's negative wire connects to the block and not to the frame.


It does both. The heavy gauge goes from my front battery directly to the block, and the 10 gauge goes to the frame. i have added grounds other places (thanks Ogre for the tip)


quote
4 - Yes you will want an OBD2 connector. The smart move is to extend it and put it up front under the dash like a normal car. Makes it much easier to plug in your OBD2 scan tool.


My ALDL is not under the console. i rerouted it behind the seat. i don't know where i will put the OBD2 connector, but i know it won't be under the console or in the engine compartment

Question: do i wire in the OBD2 connector to the ALDL wires? i haven't seen a discussion of how to wire it.

thanks
jon

------------------
Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

olejoedad APR 03, 07:41 AM
You will need to construct a new engine wiring harness for your engine swap.

In effect, the harness will use the OBD2 PCM and ALDL (it's called DLC in OBD2 for Diagnostic Link Connector), and hook to the Fiero chassis electrical connections using the Fiero connectors.
darbysan APR 03, 11:20 AM
THe ECM can be mounted in the engine compartment( it is in the GP). Mine is located just behind the driver, where the Fuel pump relay is located. If you got the whole wiring harness, including the fuse box, then it is almost a drop in ( fuse box where the battery was located). Only a couple of wires need to go through the firewall to the c203, a couple go to the C500. You can also use the Electronic Cruise control from the GP.

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'87 GT , '00 3800 Series II SC, 4t65e, Vue Power Steering. (SOLD)

longjonsilver APR 03, 11:38 AM

quote
Originally posted by darbysan:
If you got the whole wiring harness, including the fuse box, then it is almost a drop in ( fuse box where the battery was located).



In spite of me saying "don't cut any wires" my buddy cut the fuse box out of the harness. But i hauled it home anyway.

i think i will do what Darkhorizon was talking about here:

http://www.fiero.nl/forum/A...0315-2-074653-2.html

use the wiring harness as it is, get the car running, and then modify the harness for beauty and simplicity.

Step at a time, for a newbie swapper like me.

jon

------------------
Astronomy says we will find a coded signal from outer space. Then we'll KNOW that life exists there, for coded signals aren't by chance.

Biology says there are coded genetic signals in every cell, but we KNOW that no intelligence created life.

I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

phonedawgz APR 03, 12:26 PM
The OBD2 connector needs four wires. Pin 2 (Purple) is data and runs to the PCM. Pin 4 (Black) is chassis ground. Pin 5 (Black/White) is ECM ground. Pin 16 (Orange) is constant +12v.

Does your wife know you are doing a 3800 swap in her kitchen?

[This message has been edited by phonedawgz (edited 04-03-2020).]