Witch, if any, get swapped over to the 7730?

The 1227730 ECMs use a removable mem-cal. The mem-cal is a device that contains the PROM chip, CAL-PAK chips, and the knock sensor interface circuit - all on one removable device.

The stock Fiero ECMs use separate removable PROM and CAL-PAK chips which cannot be used in a 7730 ECM.

If you are doing a 7730 ECM upgrade in a Fiero, you'll need a stock V6 mem-cal from a 7730 or 7727 ECM to use with that ECM as well.

-ryan

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Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

Ok. I must be on the right track then. It's a 7730 that I bought off another member here that was running a 3.4 with it. I hooked it up and it runs out alright, but idle is unpredictable. I'm going to fill out the request form on your site and start from scratch. I'm trying to run a slightly modded 2.8 with it. He must have had a five speed because the shift light lights at crazy times and lights when I'm running my top (fourth) gear.

Ryan...
This is kind of a continuation of a conversation on our club forum.
What would happen with this conversion if the engine is still running the stock (pintle type) injectors?
If it's good elsewhere, but idles badly, it is my belief that the stock injectors are contributing to the problem, since the 7730 mostly "talks to" disk type injectors. (I understand that accommodation can be made. Just speaking in general terms.)

What are your thoughts? (I've beat this largely to death in a couple of places. If I'm off base, I'll be quiet.)

Thanks.

[This message has been edited by Raydar (edited 03-23-2015).]

Raydar, keep going and play this out. I'm curious too about pintle vs disk injectors and the 7730. It's a valid question. I've seen videos where different style injectors handle pressures differently. I'm not sure any of that matters with batch firing, but....well....I take that back. Atomization should be MORE critical when batch firing, so the injection hangs in the air longer. Right?

I'm not sure what the differences are - or why. I just know that they're there. The pintle injectors "fire" differently from the disc injectors. The particular ECMs that run those injectors have characteristics that complement those injectors. I don't think it's one ECM over another. More just the tune that's in the ECM. At least one person, here, has modified the Fiero tune to "correctly" operate disc injectors.
I have to believe that the 7730 tune can be tweaked to run the Fiero injectors. (Not that I would know how.) I just wonder if that's the most expedient way to accomplish what you want.

7730 ECMs were used from the factory with pintle type injectors in all sorts of applications prior to GM switching to the disc type Multec injectors in the late 80's/early 90's. I don't think the pintle/disc type injector differences are the cause of the idle problems some guys are having.

The main thing you should be aware of while using the 7730 ECM is the fact that it is much more sensitive to engine changes (performance mods) and issues (bad sensors and such) than the stock Fiero ECM is. The stock Fiero ECM has proven to be much more forgiving to such variables.

Most stock 7730 V6 chip tunes are going to calculate idle fuel based on IAC position, RPM, and MAP (vacuum). It uses these readings to calculate engine air flow (at idle), and if you are using that 7730 ECM/tune on an engine that is different than what it was programmed for, it won't run right and certainly won't idle right.

Okay. Cool. Thanks for the info.

I'm learning a lot every day. This forum is awesome!