ecm 3400 automatic to 5 speed ?

[bjornmk1]

can I use a ecm from a 99 3400 with automatic
for my 3400(9 swap in the fiero with a 5 speed gearbox hooked on ?

always thought the ecm works in conjunction with the transmission
on automatic equiped vehicles

thanx guys. bjorn

[IsaacHayes]

It would be a lot of work since you'd have to get a DHP to edit out the transmission codes /etc. Also the ECM would look for a BCM to communicate with and that would cause problems. The stock computer you have you can just burn proms for with adjusted code that's the easiest route.

Swapping to OBDII and using a DHP would be a lot of extra work. If you do go that route then one from an older car that doesn't use CAN or a BCM would be good, like a 96 car with 3100. Then import in the 3400 fuel/spark/etc tables from a 3400 bin.

If you don't want to get into tuning yourself, then ask around for someone to burn you a chip with 3400 stuff. A lot of the Jbody guys swap in the 3400 and it's injectors and FPR and burn chips to run it all smoothly.

[bjornmk1]

maybe the ecm from an 3.1 with dis will work.
my 87 fiero ecm won't work with dis so that rules this one out.

i think the 3.1 ecm should work,it's the same stroke engine and it already works with the dis ignition system.

should I get the 3400 wirings then ?
or can i just use my fiero(gen.1) with some mod. ?

bjorn

[Guest]

I have read that your existing ECM can control teh DIS, but there's some ignition map and settings editing that needs to be done. Specifically the crank angle has to be changed, but not exactly sure how to go about doing that.

The easiet route is as you suggested and use a genII ECM, and start from there.

For the wiring you can use your harness and modify it slightly. IIRC your OEM ECM uses two connectors (same as a '7747), where as the genII ECM (most commonly '7730) uses three connectors. The DIS connectors differ and need to be changed as well, from the connectors to the dizzy.
There will most likely be a few other changes needed, either due to position of sensor/actuators, or due to differing connetors, like the IAC connector I believe is different as well, but matching wire colour for wire colour makes it easy.
You may have to add a wire or two, such as knock sensor wire, if your doesn't curretly have one, but overall, it shouldn't be that difficult to acomplish.

[bjornmk1]

ok..but that sounds like a lot of work all together.
wouldn't it be easier to use a 3400ecmand wiring (75$) and overcome the
automatic issue ?

just my first thoughts.