Has anyone used an aftermarket ECM with a 4.9 swap?
I've been looking into that as well. A while ago Jon Lagler (Rockcrawl) experimented with the 730 ECM to control his 4.9L Cadillac engine in his Fiero. He got the engine to run but there was no provision to control the idle air control motor and I don't believe that he ever got it right . We've heard reports of poor mileage on that vehicle as well. Jon is now no longer into Fieros and sold out years ago. I would advise sticking with the 740 ECM. It does everything that the 730 and aftermarket units do plus it controls the idle, so what benefit can we expect to get from changing it?. Now if we could use OBD2 engine management; I would go for that ,but again controlling the idle would be a chore. Now if a custom intake was developed that would accept say a N* throttle body w its IAC then the path to a PCM might be available.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I've got a 7730 that I'm going to try to adapt to my 4.9 w/ Allante intake. Will probably be using an LS throttle body. (One of the 4.9 gurus was talking about producing an adapter, I think. IF it's still in the works.) That's one of the biggest issues I have with both the 4.9 and the Allante. The goofy ISC motor. That, and the Caddy PCM was never offered with a manual trans configuration. (My 7730 is going to think it's talking to a 305 Chevy TPI.)
I setup a 4.9 running the 7730 using a 305 TPI 5 speed memcal/prom with a truck TBI throttle body (and normal IAC) and some appropriate knock sensors back in 2008.
Normally, the EGR valve placement doesn't allow the truck TBI as the IAC and EGR need the same space.
The trick is:
Flipping the throttle body 180 so the IAC points to the front of the car (simple 1/4" aluminum spacer).
Raising the EGR valve 1/2" with a simple spacer as well.
Modify the cable pull cam on the throttle body (I used the cam from a 2.8 and welded it to the truck TB).
Installing some compatible knock sensors - have to do some digging, long since forgot which ones
Once you do these items, then it tunes (and runs) just like a 305 TPI car with the 7730 ecm with none of the caddy ecm/idle control issues.
Another option would be reach out to EFI Connection and see if they can adapt one of their 24X conversions to the 4.9 so you can use the 411 LS1 ecm (and tuning). https://www.eficonnection.com/
I used one of their kits on a SBC install and it worked quite well. The fuel/spark table resolution and ecm calcualtion speed from the 7730 to the 411 (and again for the E40/E67) is night/day.
[This message has been edited by fieroguru (edited 07-04-2021).]
They also stock connectors, pins, and wire. I have been poking around, looking for a source. These guys prices don't seem to be any more ridiculous than most other sources that I've found, and it's a pretty good bet they've got everything needed. (Unless guru knows of a better source, this is the first "one stop shop" I've found.)
[This message has been edited by Raydar (edited 07-05-2021).]
I've been looking into that as well. A while ago Jon Lagler (Rockcrawl) experimented with the 730 ECM to control his 4.9L Cadillac engine in his Fiero. He got the engine to run but there was no provision to control the idle air control motor and I don't believe that he ever got it right . We've heard reports of poor mileage on that vehicle as well. Jon is now no longer into Fieros and sold out years ago. I would advise sticking with the 740 ECM. It does everything that the 730 and aftermarket units do plus it controls the idle, so what benefit can we expect to get from changing it?. Now if we could use OBD2 engine management; I would go for that ,but again controlling the idle would be a chore. Now if a custom intake was developed that would accept say a N* throttle body w its IAC then the path to a PCM might be available.
Jon used the PFI 4.9 manifold with a custom built throttle neck and TPI/LT1 style throttle body. I've never heard of it "not running right"
These pics are from a clone site of Jon's old FieroAddiction site.
I have converted to aftermarket ecu. I would highly encourage it as you can tune it yourself, you are not limited to the fuel/timing maps of a 1990s vehicle. You can also delete all the emissions garbage they put on these engines.
The 4.9L Cadiilac V8's are still inexpensive engines so in my view it becomes hard to justify an aftermarket ECU setup. The market now has self tuning ECU's but they would require a custom manifold to work. To answer the question, anything can be done if you have the cash and the time to get it done. Megasquirt can work but again the IAC can only be controlled by the Cadillac ECM. For automatic setups, you'd also need to add a separate trans controller. As for our friend Will , I assume that he has seen and heard Jon's engines. I have and when they were revved the miss and popping/spitting noise was very noticeable. Also ask those who ran his tunes if they had satisfactory results. If you wish to sight an example of a prime running 4.9L engine; Pete from Canada (PBJ) ran in the 12's with his Turbo 4.9L with his wife at the wheel. That ET makes sense as boosting can overcome many of the shortcomings of the 4.9L's small head ports. I believe Pete ran the Cadillac ECM.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by Dennis LaGrua: A while ago Jon Lagler (Rockcrawl) experimented with the 730 ECM to control his 4.9L Cadillac engine in his Fiero. He got the engine to run but there was no provision to control the idle air control motor and I don't believe that he ever got it right . We've heard reports of poor mileage on that vehicle as well.
quote
Originally posted by Dennis LaGrua: If you wish to sight an example of a prime running 4.9L engine; Pete from Canada (PBJ) ran in the 12's with his Turbo 4.9L with his wife at the wheel. That ET makes sense as boosting can overcome many of the shortcomings of the 4.9L's small head ports. I believe Pete ran the Cadillac ECM.
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Originally posted by PBJ: We went with the 730 ecm before the engine was even turbocharged. 3 years ago when I put in the 4.9 the caddy ecm was not completely hacked like it is now. Also the 730 ecm uses a knock sensor which is ALMOST a must on a higher compression ratio turbo charged engine. To switch from caddy ecm to 730 ecm is very simple and Rockcrawl "owns" the PROM info that we are running, so I would see him to obtain a copy.
Hi, I have a FAST TPI retro fit kit on my 4.9 engine. It uses a custom plenum, an LS throttle body and sensors mounted on an Allante lower intake manifold. Fuel injectors are EV6, 12 hole 24 lb injectors. Uses a wide band o2 sensor mounted to one side of an 180 degree headers and dual exhaust system. The ecm is self learning after a few basic inputs. Quick throttle response, good idle and easy start up. Runs great! Cheers John
Thanks Dennis for confirming (unintentionally) that the 7730 can result in a prime running 4.9 engine!
I was there back then, and always saw Jon at the shows. I spoke with Jon about his projects, heard Jons engine but not Petes and that's what base my comments on. If you want to give up the IAC and you are a master ECM tuner you might make anything work with just about anything else. I believe that Pete may have used the 7730 because there was a split timing table available for running boost and his car was mainly for strip. . I'd sure like to see what these 7730 tunes do at the strip in ET's or on the dyno as compared to running the identical engine with the stock Caddy ECM. Horsepower is simply made with how we control fuel, air and spark. The 740 is tunable just like the 7730 is. In closing we must remember, Forums are for the free and open exchage of ideas and opinions and I just expressed mine about a technical issue. Sadly some people are happier talking about people.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
rusEFI can handle the IAC if you want to keep it. It's all open source, so if you have coding skills you can control just about anything.
Dennis doesn't know the difference between an ISM and an IAC. IAC is a stepper motor. ISM, AIUI works via PWM pushing against the throttle spring. I think GM used the ISM on Cadillacs because by operating on the main throttle blade it theoretically has greater control authority than an IAC and can more completely overcome sudden increases in load from the alternator... e.g. everyone turns their seat heaters on at once and the idle dips less.
I thought that an engine swap was more about getting the block, crankshaft, and heads you wanted.
The peripherals are a sort of non-issue that you're likely to change/adapt when you install the engine in your car.
The reason why I asked about OBD-II is that part of the engine swap project is doing an electronic dash/instrument panel. VERY easy to do with OBD-II, a straight up pain in the ass with OBD-I. Possible, but a lot more work on a gee-whizzy part of the project. Better engine tuning would be a benefit, however.
Hi, I have a FAST TPI retro fit kit on my 4.9 engine. It uses a custom plenum, an LS throttle body and sensors mounted on an Allante lower intake manifold. Fuel injectors are EV6, 12 hole 24 lb injectors. Uses a wide band o2 sensor mounted to one side of an 180 degree headers and dual exhaust system. The ecm is self learning after a few basic inputs. Quick throttle response, good idle and easy start up. Runs great! Cheers John
The FAST Retro system is what I've been planning to use for my next 4.9 Fiero swap. Seems straight forward, but I'm very interested in hearing your thoughts and lessons-learned with it.
Dennis doesn't know the difference between an ISM and an IAC. IAC is a stepper motor. ISM, AIUI works via PWM pushing against the throttle spring. I think GM used the ISM on Cadillacs because by operating on the main throttle blade it theoretically has greater control authority than an IAC and can more completely overcome sudden increases in load from the alternator... e.g. everyone turns their seat heaters on at once and the idle dips less.
Nomenclature doesn't always indicate what a person knows. As a graduate electronic engineer I am very familiar with all types of motors and electronics controls. I am quite familiar with programming, interfaces, I/O have completed 5 engine swaps and do all of my own ECM/PCM tuning. I say again anyone who decides to talk about another forum member is someone severely lacking in character and a total jerk. People need to show off their work and achievements not just shoot their mouth off.
