PFF - Pennock's Fiero Forum, PDA Edition

Donor Parts / Harness for Series III 3.8 SC Swap? (Page 1/1)

UP86GT

JUL 02, 09:09 AM

Hello all, been awhile but I have been busy collecting swap parts and still putting miles on the old 183k plus 2.8. The subject vehicle is a 1986 GT fast back, currently with I believe the original 2.8 V6 and 4 speed M17.

What I have come up with so far is the following:

2004 Grand Prix GTP Comp G - Complete Donor
(Series III though not Series II)

2001 Pontiac Sunfire - Complete Donor
This was a last minute decision to go F23 5 speed while I’m at it. Guy didn’t want to screw with pulling the trans for me got got the whole thing just as cheap. Just more labor on my end.. Has about 125k miles. Ran on starting fluid.

Fiero Rog Engine mount, Flywheel, Upper Dog Bone and Tensioner, mount, Lower Alternator bracket
(Think I have to call Roger and get mounts for the F23 on the way now)

Where I am at now is I found a guy that was willing to pull the engine and harness and parts I need in exchange for the rest of the car since I have been low on time for side projects lately. I am hoping to go today and pick it up but want to make sure I have everything I need off the 2004 grand prix before I give away the rest.

Do I just need the engine harness from firewall forward or anything that runs through the firewall? He already has all the engine harness, fusebox, ECM loose and labeled on that side but didn’t know if there was anything else needed.

Also got thinking today.. Is it even possible or how much of the Series III harness can I use? Do I need to source a Series II harness and I am pretty sure I do need a Series II ECM from somewhere.

I want to go cable operated TB of course for ease of installation and cost. Haven’t decided yet on old Grand Prix TB or N*. Thinking time is right and its probably worth going Northstar TB since tuning will be needed anyways and parts look pretty cheap.

Thanks for any help guys and girls!

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1986 Fiero GT
2.8 V6 4 Speed
176k+ Miles

Dennis LaGrua

JUL 02, 01:10 PM

Easiest way to swap a series III 3800SC engine into a Fiero is to use the 2000- up N* TB and run it with a 1996 -2003 GT PCM. The PCM will need reprogramming to adjust to the larger air flow and to have the automatic codes and several other codes deleted. Not hard to do if you have the HP Tuners editor software and interface box,

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

UP86GT

JUL 03, 10:04 AM

Thanks for the information Dennis. That is the route I was thinking I would end up going.

Will any GT PCM from those years work or does it have to be off a supercharged 3800 in those year of Grand Prix?

Also do I have to have a Engine harness or any other harness from that year Grand Prix or will my harness work?

I may try to do the harness work myself, just haven’t looked into it much yet. How I understand it, it’s basically de-pinning both the Fiero and Grand Prix harnesses and making into one to connect to Fiero vehicle side and Grand Prix PCM. I know not as easy as it sounds and I have done something similar before on a V8 S10 swap.

Thanks again for the help!

UP86GT

JUL 05, 10:02 AM

So I guess the question is has anybody here used a series 3 harness before on a cable TB swap or should I/do I need to source a Series II harness?

Also does anyone have James Browns phone number they could PM me? I don’t use facebook and tried to PM him here and email him but I am not sure he visits this site still or has the same registered email.

Thanks again!

Dennis LaGrua

JUL 05, 12:19 PM

quote

Originally posted by UP86GT:

Thanks for the information Dennis. That is the route I was thinking I would end up going.

Will any GT PCM from those years work or does it have to be off a supercharged 3800 in those year of Grand Prix?

Also do I have to have a Engine harness or any other harness from that year Grand Prix or will my harness work?

I may try to do the harness work myself, just haven’t looked into it much yet. How I understand it, it’s basically de-pinning both the Fiero and Grand Prix harnesses and making into one to connect to Fiero vehicle side and Grand Prix PCM. I know not as easy as it sounds and I have done something similar before on a V8 S10 swap.

Thanks again for the help!

Whatever harness you start with you will have to change connectors. The series III 3800 engines use EV6 fuel injector connectors while the series II engines use EV1 connectors. The 96-03 PCM's and the 04-up PCM's also use different connectors. The 3800 NA and 3800SC harnesses are identical but for one wire for the boost bypass valve that can be eliminated by hooking up the bypass directly. If you buy the right tool for removing connector pins then a wire by wire assembly of a new harness can be successfully done but with a manual trans all of the auto codes need to be deleted from the program with an editor.

UP86GT

JUL 11, 11:06 AM

Thanks for the information Dennis.

I’m thinking I might try to use my 04 Series III harness out of the donor car if I do the work myself. My thoughts are if I can find the 96-03 GT or GTP donor car in a junk yard I could grab the PCM and the connectors and leave a foot or so of wire just in case.. Although I figure I am going to depin the 96-03 plugs and use my series III wires and click them back in the PCM plug hopefully?

I will start looking for a Northstar TB and adapter plate probably from ZZP. I still have to look into what is used for a cable.

I may contact ZZP and see if the can do the tuning and remove codes and automatic stuff and bypass security. Anyone know if they can do this? I see they sell tunes for engine swap cars so.. maybe?

Thanks again Dennis!

cam-a-lot

JUL 11, 08:28 PM

Talk to Ryan from Sinister to help with your tune

Are you sure FieroRog makes F23 mounts? I asked him recently , and he said he does not make them