My project has been down for 1 year this month and I'm just now finding out about RBob passing. He was always very helpful with all my newbe questions. Maybe someone here can help me out? I am currently running the EBL flash ll and upgrading from TBI to port injection. Does anyone know what needs to be done to the computer side in order to run 6 injectors on a 44727? I was prepared to send it in to RBob (RIP) for his assistance. Thanks guys!
From this thread: https://www.gearhead-efi.com/Fuel-In...-TBI-QuestionsOriginally Posted by JLee1423
The stock TBI ECM will drive:
2 TBI injectors, 1 on each driver
4 port saturated injectors, 2 on each driver (in parallel)
4 port peak-and-hold injectors, 2 on each driver (in parallel)
6 port saturated injectors, 3 on each driver (in parallel)
8 port saturated injectors, 4 on each driver* (only if the injector resistance is greater then 14 ohms) (in parallel)
* saturated port injectors range from 12 to 17 ohms. FMS/Bosch are typically in the 12 ohm range. AC Delco/Delphi are typically in the 16 ohm range.
*A simple modification to the TBI ECM will allow any 8 port saturated injectors, 4 on each driver (in parallel). This mod is required for saturated injectors in the 12-14 ohm range.
With the 4-injector upgrade (a Dynamic EFI exclusive) the TBI ECM will drive:
4 TBI injectors, 2 on each driver (in parallel)
6 port saturated injectors, 3 on each driver (in parallel)
6 port peak-and-hold injectors, 3 on each driver (in parallel). Not exactly correct as-is, this can be changed to suit if a user is running a 6 cylinder with PnH port injectors.
8 port saturated injectors, 4 on each driver (in parallel)
8 port peak-and-hold injectors, 4 on each driver (in parallel)
Yes, thank you, I understand the capabilities of the ebl. But what he (RBob) mentions is to do a six injector upgrade actual modification to the ebl hardware needs to be performed (port mod) I was really asking if there's anybody in the forum that may have knowledge on the procedure that needs to be done to the ECU or can actually do the modification to the ebl themselves.
The ecm in stock form will control 6 pfi high impedance injectors. No modification is needed.
There is a "port fuel mod" that some folks do to the 7427 memcal. I am not aware of a 44727 ecm so I do not know if this mod applies.
I'm sure the ECU you mentioned is the one I have the EBL installed on. I just mistaken the #.Thank you for your response, this is what I've read about In the past. I currently have an EBL flash ll and using TunerPro to tune. I'm installing a marine intake with vortec heads on my tbi block and need a way to control the port style injectors. I was ready to send RBob my EBL in order to install the port mod in it. Is there a way I could do this myself or do you know anyone that could help modify my current EBL? I'm also open to buy a used EBL with port mod previously installed. Thanks again.
I found this information on Thridgen.org
Maybe a Thridgen member has the ability to help. RBob was very active on Thridgen.org
For those that want to use an EBL Flash system with their high performance multi-port fuel injection can now have the injectors firing in batch mode. The Port Mod changes the injector firing to once per engine revolution and is available for either a 6 or 8 cylinder engine (4 cylinder engines do not require the Port Mod).
Yes, I'm trying to find out how to modify my EBL so it will operate port style injectors. It was a proprietary service he offered (port mod). But now with his passing I'm trying to find out how to modify the ebl myself or hire someone to modify it for me. I'm a member of thirdgen also. RBob recommended me to join this site as well.
It's possible Bob was using a version of the memcal modification that is talked about in the zip file here:
https://www.gearhead-efi.com/Fuel-In...ull=1#post2855
Yes, that's what Dave w just said. It's exactly what I was looking for. If I don't find one that already has the port mod then I'll have to mod it myself or enlist someone else's services to do so. Hopefully someone will just trade my EBL for there's but anywho, thanks guys. I'm probably going to start a new thread about using the 749 ECU in order to have a back up plan.
The 749 is not so different from the 7427 except that it cannot control an electronic transmission. The PFI memcal modification could be considered a DIY project, and it's good for learning.
I’m wondering why not try using the EBL with 6 saturated (port) injectors?
Edelbrock used to sell a MPFI conversion system (part # 3505 for example), using saturated injectors for a stock TBI computer.
The EBL computer would likely use the injector driver from the original TBI computer.
I would agree the port modification would be nice, not necessary for 6 saturated injectors.
I would also agree the EBL computer has many features and benefits a factory TBI computer doesn’t have to provide a successful tune.
I'm thinking the same thing. I'm horrible with anything electrical unless I have a step by step guide so this EBL has been a blessing with my turbo TBI 4.3. RBob states in his overview of the ebl as needing the port mod to utilize 8 saturated injectors. I'm sure that has something to do with resistance. I'm going to keep moving forward and try the ebl with 6 saturated injectors and see how she does and report back.
They did. I believe I have one of their calibrations from a 454 swap. They didn't even change the injector firing strategy. This was talked about on the old GMECM mailing list, and folks were amazed that Edelbrock had failed to make significant tuning changes. But that was years ago and we didn't have anywhere near the amount of technical information we have today.Edelbrock used to sell a MPFI conversion system (part # 3505 for example), using saturated injectors for a stock TBI computer.
It looks like Bob's modification is really about firing the injectors in batch mode. This is what the memcal port modifications does. Bob showed a small board with two chips... potentially he has moved memcal circuitry into the ecm.RBob states in his overview of the ebl as needing the port mod to utilize 8 saturated injectors.
https://web.archive.org/web/20240527...BL_PortMod.php
Maybe I'm just totally confused now. I purchased the ebl flash ll for my 4.3 v6 TBI turbo project and it worked great! But I'm upgrading to a marine intake that uses 6 high impedance injectors. Will my EBL be able to control these injectors or will I need the port mod?
I vaguely remember that discussion as I was subscribed to that mailing list in the late '90s. I seem to recall wiring 1-4-6-7 on one driver and 2-3-5-8 on the other. I changed directions to using the '7730 for my L29 intake and abandoned the thoughts of Edelbrocks multi-port. I sorta remember there was a hand drawn schematic hosted at one of the sites for the port mod but gonna require some digging...
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