$EE / LT1 Injector Swap Running Rich

**spfautsch** · 08-08-2017

Search me...

I generally don't like putzing around with things I don't (believe) I fully EDIT: (change fully to vaguely) understand but I'm going to make an exception here as I can't imagine it can hurt anything. Notice the qualifier "believe"? If it would have been left up to me to conquer the disassembly and mapping of $EE we'd all be stuck using carburetors.

I have two bins ready to test when I get home. In one I scaled the BPW by 60% and have loaded the factory prime pulse table values. In the other I scaled it to give as much resolution as I believe is possible given the range of pulsewidths I've determined I should need. I'll be astonished if the second one starts at all, and not surprised if the first doesn't either.

EDIT2: One thing that really has me intrigued is what clocking the processors run at. The 1.5625 scalar has me confounded and I'd love to know how it was determined.

**spfautsch** · 08-08-2017

Well I ripped the big band-aid off first - flashed the most radical change first with BPW of 8600 / 0x2198. Cold start was great. Warm restart on par with I had yesterday after scaling the table raw by hand. I'll report back in a few days when / if I have a chance to tweak further.

**kur4o** · 08-13-2017

I have some insight how to get good feedback of injector pulswidth.
When you reached operating temperature remove injectors fuse and log with eehack during cranking. You will get very good reading of injector pulswidth and see if changes you made have any effect.

**spfautsch** · 08-21-2017

Thanks for the suggestion - I may give it a try if all else fails resolving the 60C restart issue. Other than the scenario where the engine has been hot and left to cool 3+ hours, it's starting perfectly. I think it's close to being too lean to start at all now.

If I can't find "perfection" through trial and error I might resort to wiring the ECT sensor line to a potentiometer along with your suggestion to help find the "magic" pulsewidth.

**spfautsch** · 08-27-2017

I don't think I'm going to tick this one off as a victory, but it's certainly better now than I was able to get to before changing the Base Prime Pulsewidth at 0x2680 and rescaling the whole Prime Pulsewidth table.

It's very odd, I can't reproduce the sluggish start unless:

1) I get the car to temp by running (hard or for a long drive) 160F thermostat mind you
2) I let it cool without touching it for around 2 hours 40 minutes (at ~85F ambient)

For whatever reason, this gets things into the opposite of a "goldilocks zone" between 135F and 144F where it wants to "meow" to life. It's starting reliabily here now with one crank so I'm going to move on to bigger and better things, but oddly if you start it at this temp and then shut it off within 1-2 seconds it will restart eagerly (presumably because the valves have been warmed). At ECT above 144 or below 135 it seems to roar to life as it did with stock injectors. Even warmer and cooler ECTs (above 146F or below 133F) are much more forgiving of AFR at startup. You have to take a ton of fuel out to get any reaction in these ranges.

So I guess what I've learned is that for a standard displacement 5.7, stick with the smallest injectors possible. Also, don't waste your time or money with chinese knock-offs.

Moving on to finishing the performance computer for tuning WOT power now. Thanks to everyone who contributed! I'm sure there will be more setbacks along the way such as the /other/ exhaust tip cracking, "quacking" and setting off the knock sensors. Thankfully I had enough argon to weld this one up too, regardless I'm going to be sending a strongly worded email to Stainless Works. :-\

**Terminal_Crazy** · 01-01-2018

Originally Posted by spfautsch

For whatever reason, this gets things into the opposite of a "goldilocks zone" between 135F and 144F where it wants to "meow" to life. It's starting reliabily here now with one crank so I'm going to move on to bigger and better things, but oddly if you start it at this temp and then shut it off within 1-2 seconds it will restart eagerly (presumably because the valves have been warmed). At ECT above 144 or below 135 it seems to roar to life as it did with stock injectors. Even warmer and cooler ECTs (above 146F or below 133F) are much more forgiving of AFR at startup. You have to take a ton of fuel out to get any reaction in these ranges.

I just happened to come across this post whilst searching.
This is very similar to my issue with injectors going lean and happened at 49C to 55C. Your temps are around 56C-63C
Scott, could you check your logs to see if the injectors were leaning out at these temps?

Thanks
Mitch

**spfautsch** · 01-02-2018

I would but I don't think I have any logs of bringing the car up to temp at idle with the big injectors. I'll try to make one for you today if I get a chance.

I don't really think my issue is related but it could be. The pulsewidth I ended up at for the 56C row that was giving me the most problems was 2.23ms which I think is a bit higher than where you're seeing your O2s "flatline"?

It's been nasty cold here the last week or so. I've been freezing my behind off working on the diy-ltcc controller with the garage door open so the fumes don't asphyxiate me.