Hey all,

Well it's time for my annual help request I was hoping there is a wiring guru out there that can help me with a couple of questions I have.

Here's the background: 84 (I know not the greatest choice, but you use what you have) swapping a DOHC from a 96 Monte Carlo. Going to use megasquirt to control it (well that's what I have in my mind). I'm using the C130D alternator (it was easier to route the belt) in place of the the 10SI alternator.


#1. The 10SI had a + terminal and 2 smaller spade terminals 1 and 2. 1 the smaller wire goes to the charging light. 2 splits and goes to the C500 block (engine control side). The + (Main) terminal has a wire to the + post of the battery and a fusible link that connects to the other bulkhead connector (single wire). The C130D has + terminal and a 4 connector (SFLP). The L (3rd position) should go to the charging light (if my internet research is correct). I also read that the SF connectors can go to the lug below the C500. Problem is that the wire gauge is much smaller on the SFLP connector. Can I just use the single L and tie the C500 wires to the starter main terminal (see next question) to get the power I need or does the C130 need a feedback over the SF connectors that go to the C500 block.

Here's question #2. Since the 84 doesn't have a power distro block I was thinking of using the the starter as the distro block. Originally the 96 Monte motor (C130D alternator) has the + alternator wire going to a terminal block (fusible link) and then back out to the main bulkhead connector (again fusible link). What I'm thinking is run the C130D main wire to the starter, then tie the C500 red wires to the other fusible link that comes back out of the starter. The final result is that the batt + cable, alternator + cable, C500 power wires all tie into the main lug on the starter. Will this cause problems? From what I'm seeing with either car's original layout that point is all the same electrically????

Final question. Up on the firewall there is a single brown and white wire that goes to the other bulkhead connector (not C500) and appears to be tied to the ALCL connecor and also splits into two different (brown and white) wires that I believe go to the SES light. There has never been anything connected to that single wire in the engine compartment since I got the car. The SES light never was on. What is the purpose of that single wire connector?

Hope this all made sense and thanks in advance for your thoughts.

Cheers,
Steven

Any thoughts anyone?
Bump

Move the battery to the front and get a power distribution block from a early 90's caddy and run all the power from there. I used the alternator the came with my 96 DOHC, I used the ECM from a 97 Monte Carlo (has more memory )

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC OBD II
88 Formula/GT 4.9 Allante Intake (My Baby)

You can get all kinds of different aftermarket Dist. Blocks. Try looking up some of the Audio terminals if you want something that looks a little better.







I would use one of these over the starter. If you get corrosion or oil etc on the connection... It's better to just have a block for your connections, or splice the main feed.

Thanks for you thoughts. Hadn't thought about the corrosion/oil issue.

I thought the OBD II ECM would be more difficult to tie in to the fiero. Good on ya for getting that working.

Steven

Especially if you plan on keeping the engine stock, I don't see much benefit in using MegaSquirt...

quote Originally posted by pmbrunelle: Especially if you plan on keeping the engine stock, I don't see much benefit in using MegaSquirt...

Agreed, and you'll have nightmares tuning it properly. MegaSquirt will be beneftical if your planning on doing something more than cams / exhaust on the stock tune. A factory ECM will compensate for quite a few things,

Fieroking,

Could I pick your brain on how you merged the ECM into your Fiero? Since I'm using a manual trans was thinking it would be more difficult to merge the OBD II into my car. This leads to questions about the 4k trans signal, pass key, rev limiter etc. Any ideas on where to find the ECM pinouts on-line? Thanks again for your inputs.

Cheers,
Steven

I have all the wiring diagrams for the 97 Monte Carlo. I used HP Tuners software to turn off the VATS, Disable the Auto trans signals. I have a FWD manual trans in my 85se it has the 24k ppm output that the ECM uses to drive the speedo (I also have a 95 Grand Am dash). However the 4K ppm signal can be split and fed to the ecm so that the ecm sees a signal when the car is moving. As far as the wiring most of the signals that the Fiero needs are available, it's just a matter of building the blended harness.

Hope this helps a little

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC OBD II
88 Formula/GT 4.9 Allante Intake (My Baby)

Joe,

This sounds very intriguing. Looking at the 96 harness there aren't that many wires (whole fear factor driving the MS). If most of the ECM connections are just plugged in like normal.... well might be worth a shot.
From the sounds of it the 4k signal from VSS will be enough for the ECM (i.e. just tap the pink wire and take to the ECM) and drive the Fiero speedo too (probably too oversimplified by me).
Though the 97 is a different ECM (more memory) do you know if the pinouts are the same? Should be able to figure the power and grounds out by tracing the 72 wires, but would be nice be able to confirm.

Thanks,
Steve

Do you want to run the obd2 ecm? You can run the 94-95 obd1.5 ecm on the 96-97 engine or you can also run the obd1 ecm on the 96-97 but it will be speed density

Erik,

No requirement to run OBD II, it's just what I have on hand from the donor (96 Monte carlo). Was looking at the DOHC site and they were pretty comprehensive on the OBD I conversion.

Steve