Newbie question , re; mem-cal compatability; TBI to MPFI ??

Need an info byte or 2 ; I have 2 ECM's , both #16197427 , from different fuel systems , one MPFI , the other TBI . Will moving the mem-cal from the TBI unit to the MPFI unit be successful ? I'm installing an M20 Muncie in my 55 Chevy and the engine is from a 95 Astro V6 Vortec with MPFI and auto trans , so I need to modify the mem-cal to lose the auto trans inputs . I'm figuring just a mem-cal swap should get me closer , then do a tune from there ; does that sound reasonable ? I'm ordering the Moates hardware to tune it anyways , but thought this might be a bit more my speed , as long as the TBI chip will work with MPFI . It doesn't sense fuel pressures , and they're both the same year ECM's , just wondering.....Be safe...Bob.

The PCM is the same, the Memcals are different. For a 4.3L Vortec manual I would use the 4.3L Auto Memcal or find a 4.3L manual memcal or burn a 4.3L manual bin to chip on G2 adapter for starters.

Lots of differances in chips, mostly IAC logic between auto and manual.

There are hardware modifications need to make the 16197427 MEMCAL run MPFI, there's also a PCM modification, that I don't recall the specifics of, that might cause issues to use that PCM in a TBI application again.

Where did the MPFI 16197427 PCM come from?

Other than the cyl select portion of the MPFI MEMCAL, the rest of the LHM and RDF should be the same, or similar. It would be a waste of time to try to use that MEMCAL in a TBI application IMO.

Best place to start is modifying a bin for running a manual, or start with a known manual bin for that ECM and code.

Quote:

---

Originally Posted by Six_Shooter

There are hardware modifications need to make the 16197427 MEMCAL run MPFI, there's also a PCM modification, that I don't recall the specifics of, that might cause issues to use that PCM in a TBI application again.

Where did the MPFI 16197427 PCM come from?

Other than the cyl select portion of the MPFI MEMCAL, the rest of the LHM and RDF should be the same, or similar. It would be a waste of time to try to use that MEMCAL in a TBI application IMO.

Best place to start is modifying a bin for running a manual, or start with a known manual bin for that ECM and code.

---

The MPFI 16197427 ECM came with the 95 Astro 4.3 engine (auto trans) , and I bought another 16197427 ECM from a 95 S10 with a 4.3 TBI engine and manual trans. . The 2 mem-cals won't just switch ? I'm just trying to find an easier way to dump the auto trans inputs , as I'm swapping the V6 into my 55 Chevy with a Muncie 4-speed. Be safe...Bob.

I'm not aware of any MPFI applications using the '7427 from the factory. I know it was a surprise when people discovered the ability and the flag in the code years ago. Maybe you're thinking CPI? I thought those used a different PCM though.

Once you program an EPROM with a manual bin, what the original EPROM (on the MEMCAL) was programmed for no longer matters. There are no trans controls in the LHM RFD side of the MEMCAL.

Quote:

---

Originally Posted by Six_Shooter

I'm not aware of any MPFI applications using the '7427 from the factory. I know it was a surprise when people discovered the ability and the flag in the code years ago. Maybe you're thinking CPI? I thought those used a different PCM though.

Once you program an EPROM with a manual bin, what the original EPROM (on the MEMCAL) was programmed for no longer matters. There are no trans controls in the LHM RFD side of the MEMCAL.

---

I've used the wrong system name ? The 95 Astro GM service manual # GMT/95-M/L-1 calls this fuel system "Central Multiport Fuel Injection" :I have no idea what your CPI might stand for ; Canadian Pittsburgh Industries , a glass company ? I thought the MPFI stood for MultiPort Fuel Injection ; there are so many abbreviated ,bastardized short forms thrown around , no wonder we get lost . Memcals get called Proms , then chips , then back to Memcals ; I can't speak this language I guess . The ECM I'm using is a 16197427 from a 95 Astro van 4.3 V6 with an auto trans ; this engine is now in my 55 Chevy and the question was , can I use the Memcal(Prom) from a manual shift 16197427 ECM out of a 95 S10 manual shift 4.3 V6 with TBI fuel system ? I don't know how to ask the question more specifically ; am I just stupid ? It's been a long , hot day , and I've had enough; I'll try and figure this all out tomorrow morning . Be safe...Bob.

Quote:

---

Originally Posted by Six_Shooter

I'm not aware of any MPFI applications using the '7427 from the factory. I know it was a surprise when people discovered the ability and the flag in the code years ago. Maybe you're thinking CPI? I thought those used a different PCM though.

Once you program an EPROM with a manual bin, what the original EPROM (on the MEMCAL) was programmed for no longer matters. There are no trans controls in the LHM RFD side of the MEMCAL.

---

Can't find CPI in the list of Acronyms and abbreviations ; this "Central MultiPort Fuel Injection" system was factory on 95 Astro van 4.3 engines. Am I just calling it the wrong name ? This is quite confusing ; glad I don't have hair to pull out . Be safe...Bob.

CPI = central port injection. that would be the correct pcm for that engine.

Quote:

---

Originally Posted by PJG1173

CPI = central port injection. that would be the correct pcm for that engine.

---

Thanks for the courtesy of a reply ; so I should call my 95-4.3 Astro fuel system "CPI" , even though GM named it Central Multiport Fuel Injection(CMFI) ? It's the one with the leaky spider and little plastic lines to the 6 injectors . I just want to be sure of the nomenclature ; so many parts and pieces are slang-named or misnamed , it's confusing to the neophyte wannabe tuner . I wonder how many have been scared off by this confusing detail . First clue is many members signing up , and zero posts . I'm no quitter , so need to know what system we're all talking about ; TBI is pretty self-explanatory , but the rest is a mystery and not in the index of abbreviations . Be safe...Bob.

JeepsandGuns did start a EFI dictionary to go along with an abbreviation list I had, but it will be a work in progress forever to keep up.

http://www.gearhead-efi.com/gm-ecm-p...ictionary.html

Quote:

---

Originally Posted by EagleMark

JeepsandGuns did start a EFI dictionary to go along with an abbreviation list I had, but it will be a work in progress forever to keep up.

http://www.gearhead-efi.com/gm-ecm-p...ictionary.html

---

I read a ton of posts , both here and the Moates site , but I still don't know what to call my FI system when asking a specific question . The system is 1995 Astro 4.3 Vortec ; GM calls it Central Multiport Fuel Injection ; what do you guys call this system ? I can't imagine what Tuner support will be like , based on the results of this one question. Be safe...Bob.

CMFI is the official name for the system by GM and CPI is the street name most people use. They are referring to the same thing.

The PCM are compatible. If they weren't they would have different part numbers. Just swap the MEMCAL and everything will be good.

93, he's wanting to use the CPI MEMCAL, to run TBI, because it has a mechanical or manual trans.

Using that MEMCAL will only complicate what he's trying to do.

[QUOTE=Six_Shooter;11257]93, he's wanting to use the CPI MEMCAL, to run TBI, because it has a mechanical or manual trans.
Thanks 93 and sixshooter ; I'm trying to ask about just switching mem-cals from auto to manual . I originally named my system MPFI , but what I've learned so far is , it's called CPI here . Okay , I've got a 95 Astro 4.3 Vortec engine with CPI and 16197427 ECM ; can I just switch chips from auto to manual trans , and would a manual trans TBI chip work to run my TPI ? Are the TBI and TPI manual chips interchangeable ? Be safe...Bob.

Oops, sorry I missed that. Your absolutely right. OP will need to get a 4.3 TBI Manual MEMCAL. Trying to use the CPI one is way too much trouble.