Suggested swap for a fiero

[neophile_17]

I'm an EE too. The wiring doesn't bother me so much as trying to integrate all of the extra modules that have to be present (ABS, radio, gauge cluster). Many of these can probably be programmed out but I haven't seen anyone do it yet. Re-pinning the Fiero harness to accommodate a 7730 ECM is straight forward and buying a tune from WOT-tech put me on the road faster and better tuned than if I had tackled it. The OBD2 ECMs obviously have more features but aren't completely hacked and have additional costs associated.

Other things to consider. Some have more money into their 6-speed than I have into my entire swap. How many miles will it take to make up the cost difference vs the Getrag you have? I like my Muncie for back roads and on track, it's not a great highway cruiser. Muncies are supposedly easy to rebuild and I'll be finding out this summer.

Good luck with your research.

~sam

[sdad]

Sam, I'd like to expand the discussion on the wiring harness. If I understand you correctly, you have a 3400 in a Fiero? If so, and the 4 speed you have is from the original, your Fiero is a 1984?

[ericjon262]

the muncie was offered up to 1986, the 84 case isn't designed very well, and is very weak.

[sdad]

ericjon262, is that 3.5 in a Fiero? Comments?

[ericjon262]

It's about 1/2 way there, I've got the engine and trans on the cradle, and I am planning on test fitting everything this weekend, so I can mock up my shift cables and turbo. I'm also swapping to a F23 5 speed from and automatic.

[ericjon262]

here's a link to my build thread.

http://60degreev6.com/forum/showthread.php/49241-262-s-85-Fiero-SE-LX9-F23-swap-thread-lots-of-pics

[sdad]

ericjon262, why the 3.5? Availability is an allowable answer btw. Where'd the turbo come from?

[neophile_17]

Yes I have a 3400 which started out in my street car and got moved to our budget race car. I'll be getting another 3400 for the street car in the next month. I have the 85 v6 4 speed that came with the car. Installing a 7730 ECM in a Fiero requires removing the pins from the stock ECM connectors and inserting them into the 7730 connectors. You can do this with a large paper clip and some patience. A couple extra wires need to be added for the injector grounds. There's an excel sheet over at www.gmtuners.com/files/Fiero_V6_to_7730_DIS.pdf but having the diagrams from a 7730 car can help make sense of what is described there. If you buy your chip from WOT-tech tell them if your ECM input comes from the speed sensor or the gauge. The pulses per mile are different by a factor of 2 and I was getting fuel cut at 75mph instead of 150mph, which was my fault. There are some other harness changes that are needed to make everything hook up to a 3400 but it's straight forward if you're a 'wire guy'.

~sam

[ericjon262]

ericjon262, why the 3.5? Availability is an allowable answer btw. Where'd the turbo come from?

Better heads. you make power in your heads, also, I bought it cheaper than I could buy a 3400. the turbo is an EBay special GT35.

[Kaiju Senso]

I wish I saw this thread earlier! I also have a 3400 in my 86 Fiero GT with the 4 speed Muncie. It is actually a 2005 LNJ motor from an Equinox. Why? because I got it for free with ridiculously low miles. It does take a bit more work to deal with the electronics, and I went with OBDII. I decided to revert back to the return style fuel rail and upper intake with throttle body from an LA1 and also had to add an External 7x crank trigger and 24x sensor with a harmonic balance from the LA1. If I swap another 3400 into a Fiero, I'll stick with the LA1 for simplicity but this engine was too nice to pass up. Drove the car a few thousand miles so far but had to drop it out again because of a Transmission leak. Also decided to add some goodies (Cam, injectors, pushrods, and springs) so the car should be that much more fun when it's back together. To me the wiring was no problem. I'm an ME by the way.

Good luck to you, it'll be a fun project.