Recently a friend of mine brought me his Fiero to have a swap done. He had a very high mileage stock 2.8 and 125-C and wanted me to swap in a lower mileage 2.8 and 440-T4 OD transmission. Not content with sticking with the stock 2.8 ECM, I convinced him to swap out ECMs during the swap as well. In short, it was an excellent choice!
The ECM that was used in this swap was the 1227730 unit which was used in many 1987-92 era GM cars. For this application, I elected to use the $88 code mask programming which was designed to be used in a 1990-92 Camaro/Firebird 3.1. The Camaro/Firebird 3.1 is very similar to the stock Fiero 2.8 including it's use of a distributor and iron-heads. With that being said, there were some significant differences between the two systems...
The 7730 ECM running $88 code mask does NOT use or need the 7th injector (cold start). The 7730 ECM controls the coolant fan relay directly. The 7730 ECM will interface with stock Fiero 2.8 ECM wiring harness. (although some modifications will be needed) The 7730 ECM uses a knock sensor. The 7730 ECM interfaces directly with the speed sensor which means changes can be made in the programming to calibrate the speedo without having to change out the plastic gears on the VSS sensor itself. The 7730 ECM running the $88 code mask will NOT work with the stock Fiero 2.8 EGR valve. It is designed to work with the digital EGR valve used in the early-mid 90's era GM V6 cars. I went ahead and designed an adapter plate and had another Fiero friend make one up so we could use the digital EGR valve on the stock Fiero 2.8 y-pipe.
The biggest advantage to using the 7730 ECM in a Fiero application is not only more tunable options in the programming, but the drivability and response time of the engine improved significantly. Gone was the unstable idle characteristics of the stock 2.8 which some have said existed from the factory. Gone was the high idle flare upon startup. We quickly found out that using the 7730 ECM system on the stock 2.8 greatly improved it's drivability as well as throttle response and performance characteristics. Believe it or not, using the newer computer, even this stock 2.8 ran and acted like a new engine found in today's new cars! And because the 7th injector, fan switches, and vacuum-controlled EGR valve were no longer required, it also allowed us to clean up the wiring and vacuum lines on the stock 2.8 engine as well...
I think this is one of the most worthwhile upgrades for a stock (or even modded) 2.8. Obviously, it can also be used on 3.1 and 3.4 OHV swaps. Although if you are swapping in a newer 3.1 or 3.4 that has provisions for the DIS ignition system, I would recommend using the DIS as well. The 7730 ECM will work with the DIS ignition system if you use a different code mask (programming).
-ryan
------------------ power corrupts. absolute power corrupts absolutely. Custom Computer Tuning | Engine Conversions | Turbocharging | www.gmtuners.com
IP: Logged
02:26 PM
PFF
System Bot
darkhorizon Member
Posts: 12279 From: Flint Michigan Registered: Jan 2006
Great project, I am sure alot of guys running 2.8's would love this. I was always confused by the fan switch, and the cold start injector, nice to see them gone i bet!
IP: Logged
04:31 PM
kwagner Member
Posts: 4258 From: Pittsburgh, PA Registered: Apr 2005
Anything that gets rid of some of the clutter of the engine bay, and increases engine responsiveness, is a good thing Since the ECU is designed for a 3.1 in the case of the one you used, was any reprogramming necessary (changing fuel maps)? Edit: one more question. How did you block off the vacuum line that goes between the egr solenoid and the throttle body?
[This message has been edited by kwagner (edited 01-09-2007).]
IP: Logged
05:55 PM
88White3.4GT Member
Posts: 1604 From: Hayward, CA Registered: Dec 2003
It seems to me that this ought to resolve, once and for all, that old argument as to whether multec type injectors will work in a Fiero motor. (Some folks maintain that they won't.) Since the 7730 was designed to drive multecs, it'll also take care of that "issue". I have been thinking about a 7730, ever since I read about this the other day.
Any chance on having the EGR plates made up?
IP: Logged
09:08 PM
Jan 10th, 2007
Fierofreak00 Member
Posts: 4221 From: Martville, NY USA Registered: Jun 2001
It seems to me that this ought to resolve, once and for all, that old argument as to whether multec type injectors will work in a Fiero motor. (Some folks maintain that they won't.) Since the 7730 was designed to drive multecs, it'll also take care of that "issue". I have been thinking about a 7730, ever since I read about this the other day.
Any chance on having the EGR plates made up?
Ryan , I'm in for the adapter for the egr if you think you can get it done. I pulled the one for the firebird that I got the ecm from, but I don't think I can make it work without modifing it alot (it will look like like crap). I'm in this for the long haul, this is such a great idea and I want to make it all work seemlessly. -Jason
It certainly sounds like it has Excellent potential for my 2.8 Turbo car. I'm waiting for the details to spill out as well. I've already asked my yard supplier to look for the ECM.
Thanks! Nice work!!!
IP: Logged
01:19 PM
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
Wow, so many questions...lets see if I can answer them all...
Tuning - Believe it or not there were quite a few changes required to the 3.1 programming to get it to work with the Fiero 2.8. It seems as though the stock Fiero 2.8 wanted a little more fuel and a little more timing than what was programmed for the 3.1 F-body engine. Although, some of that might be a result of the headers used on this engine as well as the bored out throttle body.
EGR Vacuum Connections - Vacuum caps were used to block off un-needed vac ports. I also installed late model GM electronic cruise control on this engine which allowed the removal of the vac reservoir and hard lines. The EVAP system did require the addition of a computer-controlled EVAP solenoid and some rerouting of vacuum lines for it.
ECM Wiring Changes - The 7730 ECM uses the same type of connectors as the stock Fiero 2.8 ECM. The only difference is the 7730 ECM uses a 3rd connector (yellow) and requires 2 additional grounds and some additional wiring circuits for the knock sensor, fan relay control, EGR, EVAP solenoid, and VSS input. All told, I only had to run 6 additional wires out to the engine from the computer to cover for these circuits. Everything else was able to be hooked up using existing circuits in the stock 2.8 harness. The 7730 ECM also mounts inside the Fiero using a stock, early 4cyl ECM mounting tray.
Multec Injectors - Multec injectors WILL work in a Fiero 2.8, even with the stock computer. There are different types of multec injectors tho. There are peak-and-hold type, which were only used in the Quad 4 as far as I know. There were high-imp type 12ohm units used in later model engines. And there were high-imp type 16ohm units used in late 80's, early 90's GM engines. The latter are a direct-replacement for stock Fiero injectors. In fact, I have seen the multec units in 88 Fiero 2.8's so that should be proof enough they do work. Of course the only thing one needs to watch out for is injector size. I believe the stock Fiero 2.8 injectors flow about 15 lb/hr. I think the multec's used in 3.1 V6's flow about 16 or 17lb/hr. Of course if you use a larger injector in your stock 2.8, you will need the chip reprogrammed to compensate.
EGR Plates - I have a design sitting on paper for the adapter. The one that was made for this project was made out of 1/2" thick aluminum. The most difficult part of the design is the passage that has to be bored into the surface that the DIG EGR mounts to in order to connect the 3-ports on the DIG EGR with the passage that leads to the EGR tube that feeds the intake. Therefore, some sort of mill would need to be used to make this plate. I would be willing to share my designs with anyone wishing to have a EGR plate made for their needs. PM me if interested.
EGR Usage - Of course, if you don't have emissions testing in your area, you don't need to hook up the EGR. It can be disabled in the chip programming.
Turbo Applications - While this computer could work in a turbo application, I think you would be better off using a 1227749 ECM running the $58 code mask (GMC Syclone/Typhoon 4.3 Turbo) modified to work in a Fiero 2.8 distributor application. If your engine has provisions for DIS ignition, I would suggest installing DIS and then using the 7730/7727 ECM running $8F code (Turbo Grand Prix 3.1)
-ryan
IP: Logged
02:03 PM
FieroVin Member
Posts: 951 From: Raleigh, NC, USA Registered: May 2005
What engines does the 7730 run? If I install it to run my 2.8 stock engine. Can I get it reprogrammed to run a 3.4L with a distributor or a DIS (forced induction later)? How about a 3400 with forced induction later? How about a 3800SC Series II or III? Not sure which upgrade to do. I have two Fieros. An 86 SE that has some ignition issue, but runs (trouble shooting in progress. Hope to God the ECM is not the issue.) I have an 88 awaiting my choice of engine replacements as I spun a bearing racing on a course with a lot of turns; some short and some long sweepers. Both are currently 125c automatics. Will upgrade to one of the current electronically controlled autos at time of engine upgrade for both.
[This message has been edited by Knight (edited 01-11-2007).]
IP: Logged
02:32 AM
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
Those are the only ones I can think of right now. I do know for sure this ECM will not directly work with a 3800 or 3800 SC engine or any other Buick V6. The way the ignition timing and crank sensor signals are set up in the Buick engines are buick-specific and won't work with the "Chevy" 7730 ECM.
The 7730 ECM is virtually identical to the 1227727 ECM (which was used in the W-body cars) concerning board hardware; the only real difference between the two was the 7727 unit was designed as a weather-sealed unit so it could be placed in the engine compartment and the 7730 is not weather-sealed so it must be placed in a dry location such as inside the car.
That 2.0L. Is that the one in the late '80s Sunfire and Cavalier? How different are the 3.1 and Carmaro 3.4 compared to the 3100 and 3400. Were the 7730/7727 used on the aluminum headed 3.1?
IP: Logged
03:00 AM
F-I-E-R-O Member
Posts: 8410 From: Endwell, NY Registered: Jan 2005
The 7730 ECM also mounts inside the Fiero using a stock, early 4cyl ECM mounting tray.
Actually it's the 87-88 4 Cyl tray. But yea, In all reality, you could provide a "kit" with the third connector, explicit wiring instructions, the speedo adaptor circuit, the EGR and Fan and Knock sensor whip's, an ECM and a chip, burnt to match, and if a 3.4 engine is installed (or any engine with the crank sensor) an adaptor cable from the Distributor to the DIS (they use almost the same wiring anyway, just a different connector).
I've done this swap myself too, but I never went all the way to insure that all pieces of the puzzle were in place, So I never had good results.
One more little thing to add... it is possible, though it would need a lot of tuning, to run the 3.4 DOHC with exactly this configuration, and make it so it's compatible with boost. And it can be done with what is mostly a 2.8 Fiero harness!
IP: Logged
07:57 AM
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
That 2.0L. Is that the one in the late '80s Sunfire and Cavalier? How different are the 3.1 and Carmaro 3.4 compared to the 3100 and 3400. Were the 7730/7727 used on the aluminum headed 3.1?
The 7730/7727 ECMs were used with the aluminum-headed 2.8's and 3.1's. The 7730 was used with the iron-head 3.1 in 90-92 Camaros and Firebirds.
The 3100 and 3400 engines have aluminum heads and roller camshafts. All 3400's, and later models of the 3100's had roller rocker arms. The "standard" aluminum-headed 2.8's and 3.1's did NOT have roller cams nor roller rocker arms. The 90-92 Camaro 3.1 is virtually identical to the Fiero 2.8; iron heads, standard flat-tappet cams and non-roller rocker arms. The 93-95 Camaro 3.4 SFI had iron heads and also did not have roller cams or roller rocker arms BUT it was set up for DIS ignition.
The 1st generation aluminum head 3.1 made about 135-140 rated hp. The Camaro 3.4 SFI V6 only made 160hp. The 3100 made 160-175hp depending on year. The 3400 made 170-185hp depending on vehicle.
I'm getting excited at the possibility of putting a 3.4 or a 3400 with 4-speed auto. I want to upgrade my current ECM in my 86 2.8. and place an upgrade engine /transmission in my engineless 88.
IP: Logged
12:14 PM
PhatMax Member
Posts: 562 From: Peotone, IL. USA Registered: Apr 2006
I third that. Either for a kit to use a 7730 that is already obtained or to buy a 7730 or similar already modified with needed items to plug and play with instuctions and with option of EGR "kit".
Hey Darth! Good work. Now I know what I need to do with my 3.1 stroker. My son recently junked an 89 GP with a 3.1 so I guess I'll go to the yard and yank the ecm and tranny along with the DIS & egr. One thing that has constantly driven me nuts is the hunting idle on the damn thing. Sounds like this might be a good cure. Still won't be as much fun as my dohc 3.4 though.
See ya
Murf
IP: Logged
05:10 PM
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
Hey Darth! Good work. Now I know what I need to do with my 3.1 stroker. My son recently junked an 89 GP with a 3.1 so I guess I'll go to the yard and yank the ecm and tranny along with the DIS & egr. One thing that has constantly driven me nuts is the hunting idle on the damn thing. Sounds like this might be a good cure. Still won't be as much fun as my dohc 3.4 though.
See ya
Murf
Just remember that 7727 that was used in the 89 GP uses different type wiring terminals than what the 7730/stock Fiero 2.8 harness uses so extra work would be required to use a 7727 ECM vs. just getting a 7730 ECM.
As for the KIT question, I will look into it, but to be quite honest, I don't think there is going to be an easy plug-and-play solution. For one thing, there isn't much room in the stock ECM location in the Fiero for a conversion harness with connectors for both the new ECM and the Fiero harness. I could probably put together a repinning and wiring instruction sheet and post it on my website for download but anyone wishing to do this conversion would need to obtain their own 7730 ECM and connectors (with some wiring) and then do the necessary wiring and repinning work themselves. Unless of course they were willing to bring the car to my shop in which case I could do the conversion for a nominal fee.
[This message has been edited by Darth Fiero (edited 01-11-2007).]
IP: Logged
07:32 PM
oliver2245 Member
Posts: 38 From: Cape Coral,Fl 33909 Registered: Dec 2006
Hey, no cold start injector?? Awesome idea! I'd LOVE to see this turned into a "kit" as well. For those of us with practically zero car computer experience.
Ryan, have you got any experience with flex fuel ECM's? I'm wondering what automakers are using these days. I know GM uses a fuel composition sensor too.
IP: Logged
11:35 PM
Jan 12th, 2007
PhatMax Member
Posts: 562 From: Peotone, IL. USA Registered: Apr 2006
Originally posted by F-I-E-R-O: I'd be willing to pay for beggining to end instructions on completing this project!
I would consider purchasing a kit for my 1986 2.8 with 4-speed that has the updated ECM , EGR bracket, pins and connectors with a project instruction manual with exact part numbers for the EGR and knock sensor.
Sure like the idea of improved performance from the cold idle stand point. This sounds like once you have it all installed that you would never have to fuss with again.
Ryan, has your customers gas mileage and or emissions improved? Any comments from your customer that you can pass along to us please?
Outstanding post!
------------------ jetman Silver 86 SE 2M6 4-speed, with "check wallet light"
Ryan, has your customers gas mileage and or emissions improved? Any comments from your customer that you can pass along to us please?
The owner picked up the car and drove it straight home to Michigan and put it into storage until spring. He did call and tell me that, according to his digital fuel gauge and mileage calculations, he got 35 mpg on the trip. Remember, that's using the 4-speed auto OD trans making the engine only turn about 2200rpm @ 70mph. So it's hard to say whether or not the ECM swap contributed to increased fuel economy or not. I can tell you that the 7730 running the $88 code mask DOES have highway mode fuel (lean cruise).
IP: Logged
12:47 PM
Darth Fiero Member
Posts: 5921 From: Waterloo, Indiana Registered: Oct 2002
The one I had made looks similar to that but I don't think they are the same. The one you have pictured appears to be meant for use only on 3100 and 3400 engines and doesn't mention anything about using a stock Fiero Y-pipe. The adapter I designed and had made bolts tot he stock Fiero EGR block/y-pipe and allows a digital EGR to be bolted onto it.
Hey, no cold start injector?? Awesome idea! I'd LOVE to see this turned into a "kit" as well. For those of us with practically zero car computer experience.
Forget it, dude. You even look at the emissions system on an California car wrong and you'll fail smog. Much as this upgrade would probably help emissions, it'll never fly in this state.
I was wondering. What would be a cost estimate of this upgrade. Even better would be a parts/supplies list with estimated prices off to the side. Also, Darth, would you be willing to modify a 7730 with the necessary wires & connectors (with extra long wiring to cut to fit) if I sent one to you and how much would you charge. Also, each time I upgrade my engine, how do I modify the ECM software or do I need to send it back to you. If I do need to send it back to you for reprogramming, what info would you need to properly tune it. Oh yeah...how much besides shipping would you charge for reprogramming each time?
[This message has been edited by Knight (edited 01-12-2007).]
