3500 engine management

[nfswift]

Ok, so the plan with the swap was to keep it simple harness wise and use a 7730 spliced into my Fiero, run a 3.1L code, datalog it, and tune the tables/maps to run the LX9s (3500) needs. Merlott is currently running this to my knowledge and it worked until he had mechanical failure.

But recently I spoke to another Fiero owner who said he is running his 3400 swap on a camarobird OBD 1.5 ECU because it has provisions for his SFI/DIS crank trigger as well as knock and various other sensor inputs and said it runs beautifully and that it was very "plug and play".

Looking at the 7730 I will need a external trigger/sensor and lots of tuning to begin with, I can only wish I was attempting something more "plug and play".

To my knowledge the 3500 crank trigger is a different style than the 3400/3.4 anyways (if the 3400/3.4 are the same to begin with), and I'd need an external trigger either way? But still, which ECU would make this LESS of a pain in my neck, this is my first swap and I'm SWAMPED.

I thought OBD 1.5 was very UGLY to tune?? Is it a better option for me?
Tuning gods?

Help?

[ForcedFirebird]

Your 7730 will run the DIS. You will need coil packs and ICM from an earlier 660, the 3500 coils won't work to my knowledge.

Forget the OBD 1.5, that's what is holding a lot of 3.4 Fbodies from making any serious mods.

[Superdave]

OBD1.5 is junk, it's not "plug and play" it's more like "plug and hope".

tuning for the 3500 using the OBD1 setup isn't too hard at all, i may even have something that'll give you a head start.

[nfswift]

I'm not positive but I think the external crank trigger will allow use of the stock coil packs, if not... find coil packs from a f-body 3.4 and swap them. What about the SFI though? Isn't that run off a cam sensor?

And the injector harness? Will the 3500 rig run off an OBD 1 ECU?

Sorry for all the questions, but I've gotta get this stuff in order, the engine is here, I'm picking it up this week (eeeek).

And superdave... do tell, PM me?

[Joseph Upson]

I'm not positive but I think the external crank trigger will allow use of the stock coil packs, if not... find coil packs from a f-body 3.4 and swap them. What about the SFI though? Isn't that run off a cam sensor?

And the injector harness? Will the 3500 rig run off an OBD 1 ECU?

Sorry for all the questions, but I've gotta get this stuff in order, the engine is here, I'm picking it up this week (eeeek).

And superdave... do tell, PM me?

The questions are okay and the guys here are pretty good about helping out. You really should be on the Fiero forum where this has been done as well as other swaps very similar;3100 and 3400. It doesn't matter whether the crank trigger is internal or external as long as it is 7x and properly notched the ignition module and coils will not know the difference.

To my knowledge there is no simpler approach to engine management in this scenario than the well traveled 730 ecm. You don't graft a wiring harness with it, you follow the instructions in the 730 thread on the Fiero forum and relocate the harness pins to the appropriate location in the ecm plugs and add a few missing wires, along with matching plugs for the engine end. You don't need SFI however to use it will complicate things by requiring more tedious wiring modifications due to the need for a different ecm. The 730 has readily available programming hardware and programs, and it is much faster than the Fieros ecm.

[nfswift]

Not to offend any of the Pennocks crowd, but what I'm doing with this 3500 swap is over the heads of 80% of the members over there.
Not to mention the ratio of replies to views is VERY poor compared to even a small forum like 60*V6 or Full Throttle V6. I tend to go to Real Fiero Tech with tech questions for this precise reason, as crazy as that sounds.

I know of one 3400 swap on Pennocks and one 3500 swap. The rest of the info there is unrelated, aside from 7730 information, repinning diagrams etc. nobody has much experience with aluminum head 606s.

I'm simply trying to confirm what kind of external triggers (SFI/cam, crank/DIS coils) etc. I might need, and weather I'll have to dick around with the injector harness or not (converting it to work with a return style pump will be neccassary obviously).

Also the 7730 is the ECU that allows 3.4 swappers to go both DIS and SFI, so a new ECU is not needed to go SFI. If I'm taking the trouble to stay DIS with the 3500 I may as well trouble myself for SFI too, as the engine runs it stock.

[IsaacHayes]

Dont use the firebird obd1.5 94-95 PCM. they are un-tuneable and is a waste of time.

The 7730 will allow you to tune and will run the 3500 no problem. You won't be running SFI it will be MPFI but the motor doesn't care. Just leave the Cam sensor disconnected. You will have DIS with the 7730 and will need the external crank sensor since the 3500 uses a new setup that none of the older ECMs can understand. You can't use the 3500 coil pack because it's different and has all 3coils and the ICM built as one and runs differently. Use the ICM and coils from a FWD 2.8,3.1,3100,3400 as those are all the same.

The 7730 DOES NOT run SFI. SFI started in 1994 and 94-95 ECMs are not editable, and 96+ is OBDII which is a lot more complicated and costly swap. All SFI does is fire each injector for each cylinder at a time instead of MPFI where it fires one side of the motor at a time. SFI doesn't even operate past a certain RPM anyways it reverts back to batch fire..

For the fuel return, get a 3100 or 3400 fuel rail with FPR. It has a return and will fit under the 3500 plenum with a little clearanceing of the plenum TB neck and cocking of the FPR. Or get the FPR spacer from the store here.

[Superdave]

here is some good info on running a 3500 with an OBD1 setup..

http://www.v6z24.com/jbodyforum/3500-swap-details-t98567.html

[nfswift]

Ah ok, I was under the impression that mileage (and power to a lesser degree) really did improve with SFI though. I can live without it.

I'll probably just junk yard it for fuel rail bits.

The throttle body is another issue I'll be looking into soon...

Thanks for the reading Superdave

[nfswift]

Any idea if there were any conclusions about that 3.5L Shortstar TB Superdave??
And using some old injs/rail sounds iffy to me, I'd like to run those #24 TDCs to make sure I'm not maxing out but those engines are RRAARRRE around here. Can you actually run the #19 3400s without going lean? How ugly is rewiring the inj harness to get 3400s play nice with a Multech 1 ECU?