My official Duke to 3400 swap thread (Page 1/2)
Yorgle SEP 10, 01:01 PM
The car: 86 Fiero 2m4 automatic. The plan: depose the Duke and install a 3400sfi/4t65e. The reason: cheap way to double horsepower and gain overdrive.

What I've got: 1) 105 mile 3400sfi and 4t65e from a 2005 Impala ($250)
2) bits of the 3400 wire harness (just the connectors for all of the sensors with about 12" of wire still attached)
3) 2005 Impala ECM and connectors with about 4" of wires

What I'm missing: 1) starter
2) wire harness between ECM connectors and sensors
3) axles
4) air intake

What I've done so far: (Aside from hours of reading and printing info). So far, I've inspected the 3400 and haven't found any obvious oil leaks or missing sensors. I removed the alternator from it's stock location and started making a bracket to relocate it to the lower, opposite side of the engine. Before doing anything else, however, I want to start working on putting a wiring harness together.

Stay tuned for more...
Dennis LaGrua SEP 10, 07:06 PM
Good luck on the swap. One of the guys in our club has the 3400 swap and he loves it. He did say the wiring was a bit tricky though.

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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 "

Yorgle SEP 11, 11:37 AM
Mounting the alternator was surprisingly simple- two of the bolt holes on the side of the 3400 block for the AC bracket line up perfectly with the mounting bolts on the alternator. They even position the alternator so that the pulley is in the correct plane with the rest of the belt pulleys. All that is needed is a small bracket to space the alternator away from the block, and another small bracket to connect the lower alternator bolt to the block. Here is my crude attempt at the upper bracket using a scrap that I found in my misc steel pile and two 10x1.5 flange nuts. Please disregard the nasty appearance of my welds.
[img][/img]
I see a couple of options for the lower mount- there is an 11mm threaded hole on the front of the block close to the alternator mount so I'll probably just make something to connect the dots.
[img][/img]
Yorgle SEP 11, 11:46 AM
I like to keep things simple and with the tensioner in its stock location, what do you guys think about this for the belt routing:
[img][/img]

Maybe I could incorporate a small idler pulley onto my lower alternator mounting bracket to give the belt a little more purchase on the alternator pulley.
[img][/img]

EDIT: must have been asleep when I did this- aside from the fact that the water pump pulley is for the outside of the belt, my routing will spin it backwards. I see now that there must have been a power steering pump or idler pulley above and to the left of the water pump that I'll have to recreate.

[This message has been edited by Yorgle (edited 09-12-2024).]

Yorgle SEP 11, 03:25 PM

quote
Originally posted by Dennis LaGrua:

Good luck on the swap. One of the guys in our club has the 3400 swap and he loves it. He did say the wiring was a bit tricky though.




I think the wiring will be tedious, but not particularly difficult as I will be using the donor Impala ECM, which I plan to mount in the trunk. The stock Fiero ECM can just continue living a useless life inside the console. I'll have to construct a mini-harness to run the VSS, tach, temperature and oil pressure gauge wires forward, or maybe I can just pull them from the existing Duke harness.
ericjon262 SEP 16, 04:17 AM

quote
Originally posted by Yorgle:

I like to keep things simple and with the tensioner in its stock location, what do you guys think about this for the belt routing:
[img][/img]

Maybe I could incorporate a small idler pulley onto my lower alternator mounting bracket to give the belt a little more purchase on the alternator pulley.
[img][/img]

EDIT: must have been asleep when I did this- aside from the fact that the water pump pulley is for the outside of the belt, my routing will spin it backwards. I see now that there must have been a power steering pump or idler pulley above and to the left of the water pump that I'll have to recreate.




try like this.



LX9 3500's have a bolt on idler in the location of the star in applications that use electric power steering. I assume you aren't going to use AC?

Most of the connectors and their terminals are available from Ballenger Motorsports, they offer "connector kits" that I found to be the most reasonably priced when considering the convenience of buying them one at a time and not by the thousand.

https://www.bmotorsports.co...tip7968fgo3atcb0ius6

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

Yorgle SEP 17, 12:19 PM
I mounted an idler pulley as suggested and found a 49" belt that fits. Thanks for the tip. I then changed out intake gaskets and shot some maroon paint on things to pretty it up. Oh, I also swapped the valve covers around so the oil filler will be easier to reach.
[img][/img]

Now it's time to focus on the PCM and getting a harness wired up. My goal is to get the 3400 as close to *ready-to-run" before I drop the Duke from the car. It seems from what I've found in other threads here and on the 60degV6 forum that using the stock 2005 Impala PCM is not a good idea, but I'm not sure why that would be- after all, it ran things just fine in the Impala. I'm guessing there must be some security feature that is problematic. If anyone here has done this swap, I'd love to hear what you did for a PCM.
82-T/A [At Work] SEP 17, 02:56 PM
I'd love to know how you like the performance / behavior of the engine once installed. I loved the 3400 motor in the Grand Ams... and think it should be awesome in the Fiero. It's such a smooth running engine!
ericjon262 SEP 17, 04:19 PM
I personally prefer standalone aftermarket ECU's, but a 3400 can be run off a bunch of different PCM's, and even a '7730 OBD1 ecu. I ran my 3500 with a 3400 PCM before I went megasquirt, it worked, but it was a bit more difficult to tune, and required OBD2 tuning software, which can get expensive. being that you want to run the transmission too though, using the stock Impala PCM is probably a good idea, it will need VAT's turned off, and a few other flags adjusted, but then should run ok with only minor tweaks.

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

Yorgle SEP 18, 10:43 AM

quote
Originally posted by ericjon262:

I personally prefer standalone aftermarket ECU's, but a 3400 can be run off a bunch of different PCM's, and even a '7730 OBD1 ecu. I ran my 3500 with a 3400 PCM before I went megasquirt, it worked, but it was a bit more difficult to tune, and required OBD2 tuning software, which can get expensive. being that you want to run the transmission too though, using the stock Impala PCM is probably a good idea, it will need VAT's turned off, and a few other flags adjusted, but then should run ok with only minor tweaks.




Since I'm leaving the 3400 stock, I'd like to use the Impala PCM if possible. Can you recommend someone who can do the programming tweaks you mentioned?

EDIT: I broke down and ordered a programmed PCM from https://www.wot-tech.com.

[This message has been edited by Yorgle (edited 09-19-2024).]