LT5 Ignition Systems Question???

[todesengel]

Originally Posted by Tyler Townsley

Sorry if I was a bit short. These posts are read by a lot of people who do not have a grasp on the correct terminology and it was more an attempt to keep it straight in thier minds. I agree with your assement of MAF vs MAP.

Tyler

Tyler, no apology needed. I can see where my post may have created confusion. We are all on here to learn, and share. I have a LOT left to learn, and do not mind being corrected when I am outright wrong, or just need simple correction.

[LT5 Ignition]

Hey is there a time limit for once you start writing? I just wrote about 5 paragraphs trying to help answer some of the questions and when I hit submit it said I was logged out and I lost the message.

Here is a shorter version:
If someone wanted to go to a coil per cylinder system like a Gen3 small block LS1, here are some challenges I can think of. The LT5 ECM is designed to receive a 4 ppr digital input REF for engine position sensing. It outputs a single 4 ppr EST signal that is pulse width controlled for coil on time (Dwell time) and phased for spark timing control. The ignition module is the go between that receives the 9 tooth VR signal and creates the REF signal.
It also receives the EST signal and splits it into 4 coil primary current drivers.

The Gen3 small block ECM receives a digital crank position signal and outputs 8 separate EST signals directly to Coils with internal drivers.

[LGAFF]

I think it is an internet setting on your computer....I recall a similiar issue

[ScottZ95ZR1]

Originally Posted by LT5 Ignition

Hey is there a time limit for once you start writing? I just wrote about 5 paragraphs trying to help answer some of the questions and when I hit submit it said I was logged out and I lost the message.

Happens to me often. When you are presented with the message stating you've been logged out, if you immediately enter your login information and log back in your message will post and won't be lost. But, if you hit your browser's back button your post will be lost. I've found that to be the case for me, anyway.

[Blue Flame Restorations]

Glad to have you involved, Ron!! Is it even possible to update the igntiion system by using a module compatible with a crank positioning sensor?

[LT5 Ignition]

Thanks,
Some more ignition stuff:
I believe the 1990 LT5 engine was released prior to Northstar. One difference between Ignition modules. Northstar ignition used 2 VR crank sensors with 24 pulses (or was it 32 ?) per revolution rather than the 1 sensor and 9 pulses of LT5.

The ignition module uses suface mount components and is potted. Than a lid is sealed over. Typical sealing of igniton modules of the time not designed to be serviced. A serious electronics expert may want to try. Another thing it contains is a Motorola processor with EEPROM. If it lost its memory I do not know what one would do.
the whole module was made by Motorola who supplied it to Delco Remy who supplied it to the Chevrolet group. It does have a back up mode that allows ignition output if communication is lost from the ECM.

I would be happy to help discuss some after market system ideas such as MSD?
I'll check back Wed.

[LGAFF]

Any comment on the trigger system that was used on the two bentley motors?

Here is a note on internet settings, be sure to check remember me...and
check cookies settings:

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[XfireZ51]

LT5,

The approach that I took in adapting LSx coils was to try using the IM as the sequencer. Rather than have the IM actually fire the coil through ground signal, we built a circuit that converted the ground into the triggering signal used for the LSx coils. I built separate power and ground circuits for the LSx coils. They suck up quite a bit more power than is provided LT-5 coils. Each side of LSx coils needs a 20amp fuse. I was using the 2nd gen LSx truck coils which are the ones all the C6 guys rave about due to the 120k volt spark it throws.The motor would "start" but I suspect that the IM could not complete the timing "hand-off" after reaching the 400rpm threshold. I was able to achieve a Start to On transition several times with the 1st gen truck coils I had. The first time it ran, I found that I had two of the coils reversed in terms of sequence causing it to run rough. Once the coil sequence was corrected, motor started and idled smoothly but then came to a halt after blowing the 10amp fuse in the secondary injector circuit which powers the LT-5 coils.
I then built harnesses to completely separate the power and ground circuits for the LSx coils from the LT-5 circuit. In this configuration, the motor would only Start but not transition to On.

[-=Jeff=-]

Originally Posted by Tyler Townsley

The ecm code is not just modified l98 code, it is far more flexible and with Tod Ps definition files there is no need for any other ecm system up to about 600 rwhp.

With Moats tuning aids and current software you can tune on the fly.

Tyler

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

[XfireZ51]

Jeff,

And just to expand on your point, there are multiple def files for the LT-5 that differ year to year. Even within each year, there is a mid-year mod made to each def file. Gotta know which one you're using or the motor starts to run funny if at all. I once mistakenly saved my cal using the $D0 mask but the cal was actually formatted for the $D0A mask. Car ran but very rich.