84 Crossfire Renegade Manifold Dynoed
#21
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The interesting thing to me is the big dip in tq and hp at 4200 rpm on the first pull, then moves up by 200 rpm and is less severe on the second pull, and then moves up farther and is much less severe on the 3rd
The dyno tech said it was probably just some sort of anomaly in the timing or something, but honestly its probably the first time this block has been revved past 4,200 since 1988. Could be something freeing itself up... the injectors cleaning themselves from flowing that much or something...
The dyno tech said it was probably just some sort of anomaly in the timing or something, but honestly its probably the first time this block has been revved past 4,200 since 1988. Could be something freeing itself up... the injectors cleaning themselves from flowing that much or something...
I'm guessing that is the "adaptive strategy" and the long term fuel trim is doing it's job. And this would be more pronounced/noticeable if the ECM was recently powered down. A lot of drag racers notice this as their time slips improve after a recent battery disconnect even though the engine becomes hotter after each run.
Will it fully correct your lean problem? No! I highly doubt that as the data blocks in the fuel map table need to be replaced/upgraded.
Good luck and let us know what works. Please.
#22
Melting Slicks
I'm guessing that is the "adaptive strategy" and the long term fuel trim is doing it's job. And this would be more pronounced/noticeable if the ECM was recently powered down. A lot of drag racers notice this as their time slips improve after a recent battery disconnect even though the engine becomes hotter after each run.
Will it fully correct your lean problem? No! I highly doubt that as the data blocks in the fuel map table need to be replaced/upgraded.
Good luck and let us know what works. Please.
Will it fully correct your lean problem? No! I highly doubt that as the data blocks in the fuel map table need to be replaced/upgraded.
Good luck and let us know what works. Please.
It also has a SA main table and SA extended table and that's it. The VE table is not a short or long term table like the much newer ECM/PCM (90s) that you are referring to. Jus sayin'. I'm very familiar with all the ECMs mentioned. By unplugging the ECM on a CFI, it only resets the IACs and will need to relearn idle, it does not reset any VE or SA table.
The OP is talking about early 80s CFI, not late model Camaro/Corvette.
Last edited by Buccaneer; 10-20-2016 at 10:43 PM.
#23
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Well I'm not going to say your wrong as I have never looked at software and fuel maps for an L83 ECM. But I have looked at the data log for someone having problems with his CFI and I recall seeing short term trim data and long term trim data. And IIRC I observed closed loop and open loop operation. As you describe it there would be no closed loop operation and only open loop operation with fueling control by ROM tables.
What I'm saying is you have to have some adaptive learning to have closed loop operation determined by the O2 senor. Or else what am I missing??
What I'm saying is you have to have some adaptive learning to have closed loop operation determined by the O2 senor. Or else what am I missing??
#24
Melting Slicks
Well I'm not going to say your wrong as I have never looked at software and fuel maps for an L83 ECM. But I have looked at the data log for someone having problems with his CFI and I recall seeing short term trim data and long term trim data. And IIRC I observed closed loop and open loop operation. As you describe it there would be no closed loop operation and only open loop operation with fueling control by ROM tables.
What I'm saying is you have to have some adaptive learning to have closed loop operation determined by the O2 senor. Or else what am I missing??
What I'm saying is you have to have some adaptive learning to have closed loop operation determined by the O2 senor. Or else what am I missing??
So let's start here...
But I have looked at the data log for someone having problems with his CFI and I recall seeing short term trim data and long term trim data. And IIRC I observed closed loop and open loop operation
Next...
What I'm saying is you have to have some adaptive learning to have closed loop operation determined by the O2 senor. Or else what am I missing??
Anyway, the 82 ECM was never fully hacked as it were, nor the 83 that I'm aware of. The 84 was hacked enough to make provisions and we used to produce the performance chips for the 84 only. One reason we stopped was it was extremely hard to find the correct chips for us to burn and when we could find them or the prices were very high since they were somewhat rare. Also the failure rate was rather high and not worth the time and effort to create them. BTW: Those 84 chips were actually the same chips that were in commercial arcade game machines.
Last edited by Buccaneer; 10-21-2016 at 07:18 AM.
#26
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So I got a chance to look this up and your right Buc the L83 cars/ECM's did not have adaptive strategy . Adaptive strategy wasn't used until somewhere in 1985 and the L89.
I still want to learn how the closed loop adjusts fuel using the tables. I don't have any software to look at let alone an L83 to data log but I am interested as there are plenty of low mileage '84 vetts on the market and I really like the old school GEN I blocks to. Your RENEGADE intake really enables performance for these cars.
No argument here Buc, just sorting things out.
I still want to learn how the closed loop adjusts fuel using the tables. I don't have any software to look at let alone an L83 to data log but I am interested as there are plenty of low mileage '84 vetts on the market and I really like the old school GEN I blocks to. Your RENEGADE intake really enables performance for these cars.
No argument here Buc, just sorting things out.
#27
Melting Slicks
So I got a chance to look this up and your right Buc the L83 cars/ECM's did not have adaptive strategy . Adaptive strategy wasn't used until somewhere in 1985 and the L89.
I still want to learn how the closed loop adjusts fuel using the tables. I don't have any software to look at let alone an L83 to data log but I am interested as there are plenty of low mileage '84 vetts on the market and I really like the old school GEN I blocks to. Your RENEGADE intake really enables performance for these cars.
No argument here Buc, just sorting things out.
I still want to learn how the closed loop adjusts fuel using the tables. I don't have any software to look at let alone an L83 to data log but I am interested as there are plenty of low mileage '84 vetts on the market and I really like the old school GEN I blocks to. Your RENEGADE intake really enables performance for these cars.
No argument here Buc, just sorting things out.
So, have you ever looked at TunerPro R/T? It is a great app for what it does with the early ECMs. It is different than the other app's out there used for the newer/late model cars in how it displays both VE/SA tables. I happen to like TunerPro only because I have been using it so long and percentages work better for me in my head to work with.
The settings that you need to have the ECM use and control VE correctly in CLOSED loop is vast as you already know. I don't know exactly where to start on that subject since it gets real deep fast.
The ECM settings are not as granular as the later model ECMs. Hence you still have power left on the table at the end of the day of tuning. All you can do is get it close to what A/F you want at idle, cruise and WOT and that's why a heated WB 02 sensor is essential for any tuning and a stock narrow band 02 will not work. You will constantly chase you backside with a NB.
Since the tables are not adaptive and static, you get what you get from each cell by virtue of a percentage and what the 02 is seeing and sending the voltage to the ECM and then trying to maintain that A/F commanded at the RPM. There are soo many variables in this entire process it makes your head spin. Lots of chances to get it wrong and "prang" a motor. The GM manual does have some info on this, but it's definitely in its simplest form.
My best advice on this is... Some of the best, if not the BEST info you can find on this subject on the web can be found on ThirdGen site, http://www.thirdgen.org/forums/tech-boards/ in the DFI and ECM and TBI section. Also, IMO "Rbob" is the most knowledgeable person there to ask. He is a plethora of CFI info dealing with tuning and TunerPro. I'm sure there are others as well. I think that http://www.dynamicefi.com/ also still has some good info on his site too. I could also post a portion of my low VE table if you want to take a peek.
Last edited by Buccaneer; 10-22-2016 at 04:44 AM.
#28
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Thread Starter
Buccaneer, that'd be really great if you could. Ive been mulling over doing an ecm swap to the 7747 ecm pretty hard since ive heard the 84 ecm is "untunable," and ive heard you need a tune to get the most out a set of aftermarket headers.
Since im a college student that is foolish and full of energy but not quite broke, I was thinking of also doing the Tremec TKO-500 swap from Kiesler engineering this summer, but ive heard you need some changes to your computer to go from auto to manual.
regardless, it looks like ive got a lot of reading ahead of me to understand ecm tuning.
Since im a college student that is foolish and full of energy but not quite broke, I was thinking of also doing the Tremec TKO-500 swap from Kiesler engineering this summer, but ive heard you need some changes to your computer to go from auto to manual.
regardless, it looks like ive got a lot of reading ahead of me to understand ecm tuning.
#29
Burning Brakes
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2021 C4 of the Year - Modified Finalist
I saw this thread over on Gearheads EFI forum and thought it might have some helpful info for what you are doing. Hope it helps. http://www.gearhead-efi.com/Fuel-Inj...rs-please-help
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rorrapalooza (10-22-2016)
#30
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Buccaneer, that'd be really great if you could. Ive been mulling over doing an ecm swap to the 7747 ecm pretty hard since ive heard the 84 ecm is "untunable," and ive heard you need a tune to get the most out a set of aftermarket headers.
Since im a college student that is foolish and full of energy but not quite broke, I was thinking of also doing the Tremec TKO-500 swap from Kiesler engineering this summer, but ive heard you need some changes to your computer to go from auto to manual.
regardless, it looks like ive got a lot of reading ahead of me to understand ecm tuning.
Since im a college student that is foolish and full of energy but not quite broke, I was thinking of also doing the Tremec TKO-500 swap from Kiesler engineering this summer, but ive heard you need some changes to your computer to go from auto to manual.
regardless, it looks like ive got a lot of reading ahead of me to understand ecm tuning.
I guess I'm not understanding this as keisler has gone out of business and SST bought their assets.
Something along of C4 owners overlook for a manual overdrive is a ZF6 swap from a later model C4 (1988-1996). I believe all the correct parts will swap w/o modification. The ZF6 is a very strong trans though kinda heavy. FORD put a lot of the ZF5 trans in their pickups but I can imagine quite the headache to convert to fit the sbc - but they are strong andcheap.
IMOP, if you're in school spend your valuable time on book study and use cars just for transportation. Unless you have the time to support a major hobby along with the funds it's gonna drag you down and quickly become a burden rather than any fun at all.
#31
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Thread Starter
Sorry, I meant silver sport transmissions
The zf6 is temping, but from what I saw they were expensive unless maybe I could find one out of wreck. I drove my dads 2013 grand sport and found 6 speeds to be one too many for me after daily driving a 5 speed for a few years, but maybe I could get used to it.
Don't worry about my grades too much, I stay focused during the school year, and since I stay focused I get enough scholarship money back to support a hobby or two. I just think that with the career field I'm going into (military), I wont be able to find time to do a full auto-manual conversion until several years after I graduate, unless I can do it over one of my summer breaks.
The zf6 is temping, but from what I saw they were expensive unless maybe I could find one out of wreck. I drove my dads 2013 grand sport and found 6 speeds to be one too many for me after daily driving a 5 speed for a few years, but maybe I could get used to it.
Don't worry about my grades too much, I stay focused during the school year, and since I stay focused I get enough scholarship money back to support a hobby or two. I just think that with the career field I'm going into (military), I wont be able to find time to do a full auto-manual conversion until several years after I graduate, unless I can do it over one of my summer breaks.
#32
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Glad you found the info on the CF ECM. Honestly, I didn't think they did that in 85, I thought it was later they started using that adaptive strategy system only because they were still using TBI in late 80s and early 90s.
So, have you ever looked at TunerPro R/T? It is a great app for what it does with the early ECMs. It is different than the other app's out there used for the newer/late model cars in how it displays both VE/SA tables. I happen to like TunerPro only because I have been using it so long and percentages work better for me in my head to work with.
The settings that you need to have the ECM use and control VE correctly in CLOSED loop is vast as you already know. I don't know exactly where to start on that subject since it gets real deep fast.
The ECM settings are not as granular as the later model ECMs. Hence you still have power left on the table at the end of the day of tuning. All you can do is get it close to what A/F you want at idle, cruise and WOT and that's why a heated WB 02 sensor is essential for any tuning and a stock narrow band 02 will not work. You will constantly chase you backside with a NB.
Since the tables are not adaptive and static, you get what you get from each cell by virtue of a percentage and what the 02 is seeing and sending the voltage to the ECM and then trying to maintain that A/F commanded at the RPM. There are soo many variables in this entire process it makes your head spin. Lots of chances to get it wrong and "prang" a motor. The GM manual does have some info on this, but it's definitely in its simplest form.
My best advice on this is... Some of the best, if not the BEST info you can find on this subject on the web can be found on ThirdGen site, http://www.thirdgen.org/forums/tech-boards/ in the DFI and ECM and TBI section. Also, IMO "Rbob" is the most knowledgeable person there to ask. He is a plethora of CFI info dealing with tuning and TunerPro. I'm sure there are others as well. I think that http://www.dynamicefi.com/ also still has some good info on his site too. I could also post a portion of my low VE table if you want to take a peek.
So, have you ever looked at TunerPro R/T? It is a great app for what it does with the early ECMs. It is different than the other app's out there used for the newer/late model cars in how it displays both VE/SA tables. I happen to like TunerPro only because I have been using it so long and percentages work better for me in my head to work with.
The settings that you need to have the ECM use and control VE correctly in CLOSED loop is vast as you already know. I don't know exactly where to start on that subject since it gets real deep fast.
The ECM settings are not as granular as the later model ECMs. Hence you still have power left on the table at the end of the day of tuning. All you can do is get it close to what A/F you want at idle, cruise and WOT and that's why a heated WB 02 sensor is essential for any tuning and a stock narrow band 02 will not work. You will constantly chase you backside with a NB.
Since the tables are not adaptive and static, you get what you get from each cell by virtue of a percentage and what the 02 is seeing and sending the voltage to the ECM and then trying to maintain that A/F commanded at the RPM. There are soo many variables in this entire process it makes your head spin. Lots of chances to get it wrong and "prang" a motor. The GM manual does have some info on this, but it's definitely in its simplest form.
My best advice on this is... Some of the best, if not the BEST info you can find on this subject on the web can be found on ThirdGen site, http://www.thirdgen.org/forums/tech-boards/ in the DFI and ECM and TBI section. Also, IMO "Rbob" is the most knowledgeable person there to ask. He is a plethora of CFI info dealing with tuning and TunerPro. I'm sure there are others as well. I think that http://www.dynamicefi.com/ also still has some good info on his site too. I could also post a portion of my low VE table if you want to take a peek.
Thx for info and I do visit TGO quite a lot. I see the RENEGADE is popular there also.
#33
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Sorry, I meant silver sport transmissions
The zf6 is temping, but from what I saw they were expensive unless maybe I could find one out of wreck. I drove my dads 2013 grand sport and found 6 speeds to be one too many for me after daily driving a 5 speed for a few years, but maybe I could get used to it.
Don't worry about my grades too much, I stay focused during the school year, and since I stay focused I get enough scholarship money back to support a hobby or two. I just think that with the career field I'm going into (military), I wont be able to find time to do a full auto-manual conversion until several years after I graduate, unless I can do it over one of my summer breaks.
The zf6 is temping, but from what I saw they were expensive unless maybe I could find one out of wreck. I drove my dads 2013 grand sport and found 6 speeds to be one too many for me after daily driving a 5 speed for a few years, but maybe I could get used to it.
Don't worry about my grades too much, I stay focused during the school year, and since I stay focused I get enough scholarship money back to support a hobby or two. I just think that with the career field I'm going into (military), I wont be able to find time to do a full auto-manual conversion until several years after I graduate, unless I can do it over one of my summer breaks.
Well I assume you have the 700R4 trans now. It's just that those are fairly cheap or should I say relatively cheap to your other options. For less than $2k for can have a rebuilt (performance rebuild to) 700R4 swapped in 1 day - any day of the week. This will keep you going when you need transportation.
Now the DN 4+3 is the opposite and can dig you into a hole if you need it for transportation. After market swaps can be problematic and most can't be serviced by anyone but you.
It looks like you are mastering tuning your own car now and that will only help you in the long run for using the car for transportation.
Well enough preaching here and good luck with whatever you choose.
Last edited by cardo0; 10-22-2016 at 05:36 PM. Reason: Stupid autocorrect!
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rorrapalooza (10-22-2016)
#34
Melting Slicks
Thx for info and I do visit TGO quite a lot. I see the RENEGADE is popular there also.
Here is my low speed table with 3D graph, enjoy. Sorry, I won't post the high table... kind of top secret, for my build anyway. This is TunerPro R/T early version before version 5. I use this version because I'm the most familiar with this one. The newer version is good, but I didn't want to learn a new app just to finish my tune. Since I'll be changing heads, cam and gear...again, the tuning process never ends. Hopeing to send the car down the track in mid 12s, maybe lower depending on how aggressive I get with the new tune.
Last edited by Buccaneer; 10-22-2016 at 10:10 PM.