ECM Upgrade (Page 1/2)
Yellow-88 MAY 20, 10:11 AM
Hello

The time has come to seriously consider a ECM upgrade. I'll keep the distributor and welcome the digital EGR. I'm just looking for better response and drivability.
The engine is a stock 2.8 with 5 speed gearbox. From what I've learned, I need a readily available 7730 ECM. The prom should be from a 89 Chevy Beretta 5 speed.
I think the prom part number is GM 16148340. Am I on the right track?

Thank you.

Yellow-88
82-T/A [At Work] MAY 20, 12:08 PM

quote
Originally posted by Yellow-88:

Hello

The time has come to seriously consider a ECM upgrade. I'll keep the distributor and welcome the digital EGR. I'm just looking for better response and drivability.
The engine is a stock 2.8 with 5 speed gearbox. From what I've learned, I need a readily available 7730 ECM. The prom should be from a 89 Chevy Beretta 5 speed.
I think the prom part number is GM 16148340. Am I on the right track?

Thank you.

Yellow-88




I've not yet swapped out ANY ECMs... other than replacing stock for stock and my experience in burning PROMs from days past.

But I've done a ton of research, and of course... I have opinions!


My personal opinion is that probably the "best" solution for reliability and improvement in performance and drivability is to upgrade to a MicroSquirt system. If you want to keep your distributor (like I'm doing), then you'll also want to make use of an MSD 6EFI box. The MSD 6EFI is used to convert the single from analog to digital (if I remember correctly), and of course... also provides a whole host of other benefits including multiple spark discharge (which itself improves idle and higher RPM performance). Anyway, the MicroSquirt system operates at a much higher baud rate than any of the older GM ECMs, including the 7730 and responds much more quickly to changing conditions. It can also make use of the digital EGR... but more importantly, allows you to convert from a Multi-Port Fuel Injection system, to a Sequential-Port Fuel Injection system. This has several advantages, including better idle, improved and lowered emissions, lowered fuel consumption, and improved horsepower in the low-to-mid RPMs (it has no effect, good or bad, in the higher RPMs). Note, you don't have to change anything... but you will be replacing the entire engine wiring harness (with a new harness).

This is the link to the MicroSquirt System: https://www.diyautotune.com...foot-wiring-harness/
This is the link to the MSD 6EFI Controller: https://www.summitracing.com/parts/msd-6415

Couple of things... the first is that if your engine does not run well now, then it won't run well with a new ECM. A new ECM doesn't really "fix" problems... so make sure your car runs as good as it can in stock form before attempting to replace the ECM. Assing your car does run appropriately... there are a TON of benefits you can expect by going with the MicroSquirt:

- Improved Idle (disables cold start injector)
- Improved fuel economy
- Improved horsepower everywhere
- Improved (reduced) emissions
- Improved drivability (better throttle response, etc.)

Another nice thing about the Fiero, for what it's worth, is that the gauges (except for the shift light), all totally work independently from the ECM. This means that they get all of their signals directly from specific sensors on the engine that, while they may ALSO feed the ECM (some of them), they are independent and will continue to work regardless of what ECM you put in there.

EDIT: When you're doing all this, consider replacing your factory ignition coil with an aftermarket (higher spark output one). They're cheap... like ~$50 for a higher output one. One of the problems is that in the upper RPMs, the factory coil is unable to produce the necessary spark / charge in order to support necessary combustion in the higher rpms. Like... above 4,500 rpms you start to see a loss in performance. I'll say this, people see improved performance JUST by swapping out the ignition coil... engine continues to pull hard in the upper RPMs. https://www.fierostore.com/.../Detail.aspx?s=51065


EDIT 2: MicroSquirt won't do SFI... you'd have to get the MegaSquirt 3. I'm planning on doing this swap (after I know everything else is working), but I'm going to be using the Fast EZ-EFI 2.0 system.

[This message has been edited by 82-T/A [At Work] (edited 05-20-2024).]

olejoedad MAY 20, 01:31 PM
Get everything else on your drivetrain in tip top shape before looking at the ECU.
2.8's are very sensitive to timing.
A properly tuned and maintained drivetrain provides crisp performance, but a different ECU on a not so well tuned and maintained engine is a waste of time and money.

While you're at it, check and restore all of the grounds on the drivetrain, and add an extra ground to the chassis.
You might be surprised at the results.
Yellow-88 MAY 20, 05:05 PM
Hi

Yes, I understand that basic tuning and maintenance is key to a smooth running engine. Perhaps because I grew up with multi carbureted British Sports cars, I've become spoiled to that "feel". Right out of the box, Fieros feel clumsy and sluggish by comparison. A higher sample rate and no EGR solenoid is enough for me. As I understand it, the 7730 samples at 120 per second. One and a half seconds is like being on the wrong drug.

Yes, the micro squirt system is nice. Perhaps someone would consider putting together a plug & play kit. You'd sell a couple of hundred.

Yellow-88
Jeffdylanproctor MAY 20, 09:34 PM

quote
Originally posted by Yellow-88:

The engine is a stock 2.8 with 5 speed gearbox. From what I've learned, I need a readily available 7730 ECM. The prom should be from a 89 Chevy Beretta 5 speed.
I think the prom part number is GM 16148340. Am I on the right track?

Thank you.

Yellow-88





I'd like some confirmation if these part numbers are a plug and play swap on a Fiero 2.8 (mine's an 1986 gt)
pmbrunelle MAY 20, 09:58 PM

quote
Originally posted by Yellow-88:
As I understand it, the 7730 samples at 120 per second.




quote
Originally posted by Yellow-88:
One and a half seconds is like being on the wrong drug.



I think that you are referring to the frequency of the data on the ALCL connector.

Internally within the stock ECM, the calculations are performed at a much higher frequency (fast enough) than once every one and a half seconds.

The slow data broadcast to the outside world does not mean the ECM is inadequate for running the engine.

********************************************************************************

My general opinion about different ECUs is that the engine only cares about spark timing, fuel mixture, and a few other minor outputs.

For good driveability, the ECU doesn't matter; it's all about the calibration inside the ECU.
82-T/A [At Work] MAY 21, 10:56 AM

quote
Originally posted by Yellow-88:
Hi

Yes, I understand that basic tuning and maintenance is key to a smooth running engine. Perhaps because I grew up with multi carbureted British Sports cars, I've become spoiled to that "feel". Right out of the box, Fieros feel clumsy and sluggish by comparison. A higher sample rate and no EGR solenoid is enough for me. As I understand it, the 7730 samples at 120 per second. One and a half seconds is like being on the wrong drug.

Yes, the micro squirt system is nice. Perhaps someone would consider putting together a plug & play kit. You'd sell a couple of hundred.

Yellow-88




Just for full disclosure... I'm not insisting you get the MicroSquirt, just stating it as an option. It's a pretty solid system that's used in dozens of aftermarket systems. I'd even point out that I'm not actually using it in my own system... I'm going with a $1,600 FAST EZ-EFI 2.0 system that I bought last year that does auto-learning (basically... auto-adjusts the fuel map for optimal learning in all conditions). You can still manually adjust all settings, including the fuel map, but it gets you there ~95% of the way, which basically solves all of the issues and concerns that you have.

I'd point out that it's almost comical that I'm recommending the MicroSquirt, simply because I've taken so much **** over the years by recommending anything other than the MegaSquirt line of products. There's an entire thread on ThirdGen.Org where the moderator (at the time) locked the thread, and went on a screed about how the MegaSquirt was the best thing since the birth of Jesus Christ. There's a similar thread here too. So it's almost Stockholmish that I'd even suggest it. I only mention it because there's a lot of support and tools for it to really optimize your system, and it's inexpensive (under $400 for everything). You SHOULD replace your engine harness since it's already ~35 years old... but not necessary. You could simply make an adaptor. Either way... you have options.

I respect Joe a lot, and he really knows his stuff. But the idea of having some dude sit in my car, possibly even drive it, and do some manual tuning seems to me very "old fashioned." Perhaps it's because I work in AI, and know there's better ways to do this. But more than anything, I don't want some dude sitting in my car, and I certainly don't want to pay some dude to sit in my car... or that I'd have to rely on some dude to optimize my car.

The 7730 is awesome, lots of people have swapped to it, but it's no more a plug and play solution than any of the other options, as far as I know. I THINK (someone correct me if I'm wrong), you still have to re-do the pin-outs for the ECM and harness.

I like the MicroSquirt simply because it's so well documented, and there's so much software out there to update your fuel maps. You literally "reflash" the fuel map, rather than having to burn an old fashioned EPROM.





Either way, don't get discouraged... there's a lot of options out there, and the 7730 isn't a bad one.
Yellow-88 MAY 21, 11:16 AM
Hi

Like I said earlier, you should consider putting together a Micro Squirt plug & play kit complete with a map tuned to a stock 2.8 V6. Plug & play means literally pull out the old system and plug in the new one. I'm sure you could sell several "kits". The price tag would be the only snag for regular people.

Yellow-88
82-T/A [At Work] MAY 21, 11:30 AM

quote
Originally posted by Yellow-88:
Hi

Like I said earlier, you should consider putting together a Micro Squirt plug & play kit complete with a map tuned to a stock 2.8 V6. Plug & play means literally pull out the old system and plug in the new one. I'm sure you could sell several "kits". The price tag would be the only snag for regular people.

Yellow-88



Someone should... but not me. I don't have the time, and my time is too expensive to be building kits for other people. :/
Yellow-88 MAY 23, 01:10 PM

quote
Originally posted by 82-T/A [At Work]:


Someone should... but not me. I don't have the time, and my time is too expensive to be building kits for other people. :/



Just wondering. Have you actually done one for yourself? What do you charge for your time?

Yellow-88