Can an '84 ECM be tuned?
10-23-2014, 04:58 PM
#1
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Can an '84 ECM be tuned?
Can I get my 84 c4 ecm tuned to run effectively with a new 383 swapped into it? Or do I need to purchase an aftermarket ECM?
10-23-2014, 07:04 PM
#4
Race Director
I have never had one die by hooking my scanner up to it. Kinda 'pulling someone's leg'.
The ECM is not the fastest...but my question is ...is the Cross-Fire set-up going to be used????
DUB
The ECM is not the fastest...but my question is ...is the Cross-Fire set-up going to be used????
DUB
10-24-2014, 07:11 PM
#6
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Ben73, Great to see you still active on here!
That seems like a bit of an exaggeration.
According to "69427" on this forum, it CAN be tuned and he's done it. PM him and he can probably give you more facts about it than guys who haven't done it.
That seems like a bit of an exaggeration. According to "69427" on this forum, it CAN be tuned and he's done it. PM him and he can probably give you more facts about it than guys who haven't done it.
The '84 ECM isn't as bad as a lot of people say, but it does have limitations that later GM/aftermarket controllers don't have.
I've run my stock '84 ECM (with modified calibration PROM contents) for several years with the current turbocharged 355 engine, and had no problems. However, I'm looking to bump up the boost a bit more in the future, and there's just not the flexibility with this ECM that would allow me to not have to worry about damaging the engine due to insufficient calibration/software capability. So, I'm in the process of moving to a later TBI ECM.
The stock ECM will work fine for most engines. The problem is that the calibration code that needs to be changed to work with these modified engines is not readily available (I was in the right place at the right time to get the software info I needed so I could modify the cal tables to get my engine to run well under boost).
I've run my stock '84 ECM (with modified calibration PROM contents) for several years with the current turbocharged 355 engine, and had no problems. However, I'm looking to bump up the boost a bit more in the future, and there's just not the flexibility with this ECM that would allow me to not have to worry about damaging the engine due to insufficient calibration/software capability. So, I'm in the process of moving to a later TBI ECM.
The stock ECM will work fine for most engines. The problem is that the calibration code that needs to be changed to work with these modified engines is not readily available (I was in the right place at the right time to get the software info I needed so I could modify the cal tables to get my engine to run well under boost).
Last edited by Tom400CFI; 10-24-2014 at 08:02 PM.
10-25-2014, 07:42 PM
#7
Drifting
No user end software has ever been written for the 1984? Most swap to the 1227746 88 thru 92 TBI ECM to control the CFI.
10-26-2014, 01:03 AM
#8
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..and that's not true. There were others who hacked the '84 ECM back on the CFI Vault when it was up. Since that site is now MIA, I can't post a link to those threads anymore, unfortunately. I'm not saying that is the best way to go about things, but apparently it can be done, and we have a forum member right here who has done it, and may be able to help.
Instead of telling the OP that something can't be done, that someone here has done...why don't we let the OP know the options and then he can learn about those and decide?
Last edited by Tom400CFI; 10-26-2014 at 01:06 AM.
10-26-2014, 04:13 AM
#9
Hi Tom,
I come and go
I'm getting back into my Vette after a few years of disinterest.. I have spent the last two days getting it up and running again. Just waiting for anew master cylinder to arrive now.
The 84 ECM can be tuned, I've done it.
Matt Harris did a bit of work hacking the ECM on the old CFI Vault 10 years ago, but never completed it.
The hardest part is finding an old eprom that will still take a new burn. From memory they were 2516's?? Pretty hard to find in usable condition today.
I used to use an adaptor to repin a 2732 to suit, but even they are now near unobtainable...
I come and go
I'm getting back into my Vette after a few years of disinterest.. I have spent the last two days getting it up and running again. Just waiting for anew master cylinder to arrive now.The 84 ECM can be tuned, I've done it.
Matt Harris did a bit of work hacking the ECM on the old CFI Vault 10 years ago, but never completed it.
The hardest part is finding an old eprom that will still take a new burn. From memory they were 2516's?? Pretty hard to find in usable condition today.
I used to use an adaptor to repin a 2732 to suit, but even they are now near unobtainable...
10-26-2014, 11:55 AM
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10-26-2014, 06:57 PM
#12
Drifting
A 2 hour re pin to a 1227746 with a 28 pin chip adapter and newer software and EEPROM's can be used. Trying to find stone age chips using ultra violet light erasure, and software that needs a DOS prompt just seems futile, but too each their own.
10-26-2014, 07:05 PM
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WOAH WOAH WOAH!!!!! I love all the ranting and replies but I simply wanted to know if I could tune my ECM to a 383 motor and still keep the crossfire injection? If not do I need to machine the ports? And what else? Lol
10-27-2014, 09:51 AM
#14
Team Owner
Pro Mechanic
There are several options to run a 383 both with "Crossfire" and also with the stock ECM. Ben73 (above) and as mentioned earlier, 69427 can both give you first hand experience w/the stock ECM.
As Mr Willtys has advocated, you can use a newer ECM, or virtually any stand alone system to control the CFI or some facsimile thereof.
Others won't agree with this method, but I was able to get a 400 running very well using the stock ECM and chip (tune), by mechanical tuning methods only. The object is to "Feed it what it wants". What ever method you choose to accomplish that, if you can figure out how to make it work, it can work.
What are your goals? What is your budget?
I'd say that w/o a doubt, you need to port your intake runners. The stock 350 couldn't get enough air w/the stock intake...a 383 will be even more choked. You need to port it.
.
As Mr Willtys has advocated, you can use a newer ECM, or virtually any stand alone system to control the CFI or some facsimile thereof.
Others won't agree with this method, but I was able to get a 400 running very well using the stock ECM and chip (tune), by mechanical tuning methods only. The object is to "Feed it what it wants". What ever method you choose to accomplish that, if you can figure out how to make it work, it can work.
What are your goals? What is your budget?
I'd say that w/o a doubt, you need to port your intake runners. The stock 350 couldn't get enough air w/the stock intake...a 383 will be even more choked. You need to port it.
.
Last edited by Tom400CFI; 10-27-2014 at 10:14 AM.