DIY LTCC or similar system for LT1s

[kur4o]

Just did some test run with the new firmware. No issues and running strong. Didn`t push it much. Did some fine tuning to get rid of some lean conditions.

It looks like the most important table for maf tuning is the so called maf pump shot coefficient. I came up with some really weird settings with real time control and now the car runs 100 times better on part throttle take off. Pulls really strong now.

I will do some write up how it works, and how I set it up. Even the wideband almost frozen and stopped jumping around.


I still have no definite answer how to set the multispark.

There are 3 scalars we need. Some 2d pulses vs rpm. Or 3 ranges 0-1000rpm 3pulses 1000-2000 range 2 pulses, above 2000-1 pulse.
Min burn time. The time the coil will discharge. And dwell time based on the pulse count or rpm count.
Also enable at crank only, at run only or always.

Not sure will there be any benefit of waste spark setup. So you fire each coil twice on a full crank rev.

[syntaxterror]

Outstanding work! I have one question with coding could this work on a obd1 v6 ?
Thanks Joe

[spfautsch]

Not in it's current form. The controller firmware is completely dependent on the opti signaling.

It's possible that it could be made to work once a time-based mode is added, but I've had little time to work on this lately and I'm staring at another transmission rebuild project in my garage now - this time a 4t45e.

[syntaxterror]

Do you still have any boards left to sell? Just something to tinker with.

[spfautsch]

Dozens

Un-assembled kits $25 - extensive soldering required but all through-hole components
Assembled + tested board $75 - soldering required to connect wiring, 1-week lead time, small orders only pls

Price includes domestic shipping via USPS. International orders add $7.50

PM'd you my paypal address if interested

[kur4o]

but I've had little time to work on this lately and I'm staring at another transmission rebuild project in my garage now - this time a 4t45e.

I hope some video how to guide will be made this time.

Meanwhile is it possible for the latest firmware to introduce some delay or lag at crank time. I think it is too subjective feeling, but the earlier version seemed a little fresher on cranking.

[spfautsch]

I hope some video how to guide will be made this time.

You wouldn't want to watch 18 hours of me slogging through this in the July heat. I'm hoping this is a simple case of one molded piston that's disintegrated, but that doesn't make the project any less involved. While I have the powertrain out I'm going to replace the timing chain guides and a leaky valve cover seal. Also, GM used what I would call "biodegradable" wire loom during this era (2008 Pontiac G6) - it literally crumbles when you touch it so I'll probably replace a bunch of that while it's easy to get to.

Meanwhile is it possible for the latest firmware to introduce some delay or lag at crank time. I think it is too subjective feeling, but the earlier version seemed a little fresher on cranking.

Yes, you're not imagining it - I've had a couple "funky" hot / warm starts, and a couple instances of the erratic dwell lookup. Ironically, I think I figured out what the issue is this morning during warmup (i.e. when it switches to the high temp coolant table). I probably won't have time to find the exact problem for a few days but I'll do my best.

[spfautsch]

Just wanted to drop in with an update - I did manage to log a bad start the day after my last message. I've yet to completely figure out what might have happened. Seems unrelated to any recent changes. I also logged a fairly long crank this morning but haven't had a chance to pick that apart at all.

Have been unable to log the erratic dwell I mentioned during temp transition, but I think I know what's going on so I might straighten that out. The logic to switch from table 0 to table 1 is somewhat sloppy so I'll shore that up when I get a chance.

Still have the innards of a 4t45e strewn about my garage so probably won't get into firmware changes until that machine is back on the road.

[kur4o]

Hi spfautsch,

Is there any recent firmware to test. I want to use latest and greatest. I am trying to figure some weird fueling issues and want to rule out any spark issues[The car does feel a bit like a spark retarded] and AFR drops from time to time to 13.8-14. It is really intermitten. Once works great[rock solid afr at 14.8-15.2], than after some heat soak it runs like crap and AFR jumps like crap. I suspect a bad injector but might be some coil issue too[].