LT5 Ignition Systems Question??? - Page 4 - ZR-1 Net Registry Forums

Tyler Townsley · 03-01-2011

Quote:

Originally Posted by -=Jeff=-

Moates stuff is readily available but how/where do we get Tod Ps definition file that was mentioned?

On this board you will be timed out so do long posts in notepad and paste it in the message.
OK. On the def files by Tod. He has hundreds of hours in reverse engineering the GM calibration code. It has several HUNDRED different calibration points. I have the GM listing in english of the calibration but both of us are rather guarded in release of the information. I would email Tod directly about his TDFs. He might point you to specific points you are looking for.
Tuning software for OBD I
In addition to Tunercat:
http://www.tunercat.com/
there is Tunerpro:
http://tunerpro.net/v5whatsnew.htm
Moats stuff is here:
http://www.moates.net/
The above is for those who choose to stay stock ecm/ignition. For those who want to stray and REALLY want to get into DIY EFI there is the following:
BE PREPAIRED TO INVEST SOME TIME IN READING.
http://www.bgsoflex.com/megasquirt.html
http://www.diyautotune.com/
I know there are several commercial systems out there but they are beyond my pocketbook.

The iginition side of the tuning software is pretty straightforward but there are some real gotchas in the fuel side due to the way the calibration handles the fuel for the dual injectors.

Unless you are a real glutton for work the stock system is more than able to contend with normal to modded motors.

Tyler

XfireZ51 · 03-01-2011

LT5_Ignition,

Need to ask if the ICM shuts down if it doesn't see coil current. As this is what we were thinking is the issue.

LT5 Ignition · 03-02-2011

After looking at this thread more carefully I can see there is a lot of knowledge on engine controls. I can see it will take awhile for me to catch up. My hobbies are sailing, skiing, woodworking, etc. It's about time I did something engine related after work except running a chainsaw !!

The Ignition module should not shut down if it does not see coil current. It does have current limiting control much like a Gen3 LSx coil driver that is built into the individual coil. One reason for not allowing a shut down is that it would be a harsh penalty for the failure mode of one loose coil connector or failed primary coil winding. Letting the customer run on 6 cylinders is usually better than none for a short time. A way to test this idea is to unplug one coil while the engine is idling. Probably not much room to do that! But I am curios and do not have my own LT5.

Side note: There are little energy losses in clean spark plug wires. The exhaust spark on a DIS is a greater loss. I agree with the writers saying you should not see a difference between a coil per cylinder or a DIS system on a stock LT5. Wet, salty wires contribute to loss of peak secondary voltage necessary for very cold starts or WOT transients but I can imagine that ZR1 owners keep their wires clean and do not start much below freezing.

I would like to discuss some of the other questions later.

LGAFF · 03-02-2011

Ran across this guy looking for parts.....

Hi Lee, sorry about slow reply
I would think it easy to convert
the only issue I see is driving 16 injectors, but I believe most reasonable aftermarket systems will drive 16.
The ignition is quite easy, as it has the std GM 4 wire interface to ecu, which I why I chose it
Also , so does the Cadillac Northstar, but this has a different trigger setup, the LT5 is easier.
There is a program called Big Stuff 3 which I have used on Big Block Ford which uses individual coils same as Gen 3
This will drive 16 injectors.
Depending on what your application is, if you are still using it in Corvette, I would stick with what you have.
It is simple, and the only trouble you should ever have is the ignition module itself.
The coils are dime a dozen, pickups are common and basic, so I would buy spare modules if they are getting rare
I dont know much about the ecu with these, but would be surprised if someone like Tuner Cat or TunerPro dont do software for them to retune them if you hve made mods
I would love one of these in my 32.......

Regards
Al Gibbs
www.kalmaker.com.au

XfireZ51 · 03-02-2011

LT5_Ignition,

"...I agree with the writers saying you should not see a difference between a coil per cylinder or a DIS system on a _stock_ LT5."

Interesting comment and I note you underlined the word stock. Why would you say there would be no discernible difference on a stock motor, and secondly would you have a sense on the power level where the Gen3 ignition would have an impact?

I can understand the IM continuing to operate with 1 or even 2 coils going out but what if it sensed ALL four coils out?

carter200 · 03-10-2011

Quote:

Originally Posted by LGAFF

The coils are dime a dozen, pickups are common and basic, so I would buy spare modules.

Where are these modules sold? Thanks.........

Blue Flame Restorations · 03-10-2011

I just bought an extra module off Ebay. I'll probably buy a few more over time just to make sure I have extras.

carter200 · 03-10-2011

Quote:

Originally Posted by Blue Flame Restorations

I just bought an extra module off Ebay. I'll probably buy a few more over time just to make sure I have extras.

What wording would one use to look one of these up on Ebay?

Blue Flame Restorations · 03-10-2011

Quote:

Originally Posted by carter200

What wording would one use to look one of these up on Ebay?

I just typed in "ZR1 module" and found more than one at the time. About two weeks ago.

LGAFF · 03-10-2011

I picked up one for $76

03-01-2011	#32
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,696	Re: LT5 Ignition Systems Question??? LT5_Ignition, Need to ask if the ICM shuts down if it doesn't see coil current. As this is what we were thinking is the issue.

03-02-2011	#33
LT5 Ignition Join Date: Feb 2011 Location: Sterling Heights, MI Posts: 11	Re: LT5 Ignition Systems Question??? After looking at this thread more carefully I can see there is a lot of knowledge on engine controls. I can see it will take awhile for me to catch up. My hobbies are sailing, skiing, woodworking, etc. It's about time I did something engine related after work except running a chainsaw !! The Ignition module should not shut down if it does not see coil current. It does have current limiting control much like a Gen3 LSx coil driver that is built into the individual coil. One reason for not allowing a shut down is that it would be a harsh penalty for the failure mode of one loose coil connector or failed primary coil winding. Letting the customer run on 6 cylinders is usually better than none for a short time. A way to test this idea is to unplug one coil while the engine is idling. Probably not much room to do that! But I am curios and do not have my own LT5. Side note: There are little energy losses in clean spark plug wires. The exhaust spark on a DIS is a greater loss. I agree with the writers saying you should not see a difference between a coil per cylinder or a DIS system on a stock LT5. Wet, salty wires contribute to loss of peak secondary voltage necessary for very cold starts or WOT transients but I can imagine that ZR1 owners keep their wires clean and do not start much below freezing. I would like to discuss some of the other questions later.

03-02-2011	#34
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: LT5 Ignition Systems Question??? Ran across this guy looking for parts..... Hi Lee, sorry about slow reply I would think it easy to convert the only issue I see is driving 16 injectors, but I believe most reasonable aftermarket systems will drive 16. The ignition is quite easy, as it has the std GM 4 wire interface to ecu, which I why I chose it Also , so does the Cadillac Northstar, but this has a different trigger setup, the LT5 is easier. There is a program called Big Stuff 3 which I have used on Big Block Ford which uses individual coils same as Gen 3 This will drive 16 injectors. Depending on what your application is, if you are still using it in Corvette, I would stick with what you have. It is simple, and the only trouble you should ever have is the ignition module itself. The coils are dime a dozen, pickups are common and basic, so I would buy spare modules if they are getting rare I dont know much about the ecu with these, but would be surprised if someone like Tuner Cat or TunerPro dont do software for them to retune them if you hve made mods I would love one of these in my 32....... Regards Al Gibbs www.kalmaker.com.au __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

03-02-2011	#35
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,696	Re: LT5 Ignition Systems Question??? LT5_Ignition, "...I agree with the writers saying you should not see a difference between a coil per cylinder or a DIS system on a _stock_ LT5." Interesting comment and I note you underlined the word stock. Why would you say there would be no discernible difference on a stock motor, and secondly would you have a sense on the power level where the Gen3 ignition would have an impact? I can understand the IM continuing to operate with 1 or even 2 coils going out but what if it sensed ALL four coils out? Last edited by XfireZ51; 03-02-2011 at 11:14 PM.

03-10-2011	#37
Blue Flame Restorations Join Date: Feb 2010 Location: Pendleton, IN Posts: 3,904	Re: LT5 Ignition Systems Question??? I just bought an extra module off Ebay. I'll probably buy a few more over time just to make sure I have extras. __________________ 1988 KOH Prototype EX5023 sold 1990 ZR-1 #444 Convertible 1990 ZR-1 Black #966 1991 ZR-1 Quazar Blue #296 1957 Duntov SS Project