Going lean after start.

[cwathne]

OK. I know of another possible issue, but I don't have a great explanation as to why the "fix" works, but it works for me. If I crank the car in cold weather with just the key and don't touch the throttle after it has cranked, I would get a similar lean spike when the After Start Enrichment ends and it enters Closed Loop (runs fine during After Start Enrichment and Open Loop). Either it would stall or simply the CL Comp would jump way up due to the very lean reading. I have a big cam and think that when the car first starts up it has a bit of a misfire which shows up as lean. If I just blip the throttle one time I think it gets all cylinders firing and the CL Comp goes back to nearly 0 and the AFR is at target. I don't have this issue at all in warm weather.

Probably a very specific issue to my setup, but maybe give it a try. Once the car starts, just give the throttle a blip to get the RPM above about 1500 and see what happens.

Yeah, I kinda have the same thing which bugs me. My setup is 467 with 240°/246° @ .050 cam. Hot idle is around 900 RPM. And cold start only manages like 1100 ish cold (50°F). If the ICF would have been larger we could have set it to start at a higher RPM (IAC parked) and let it decay, and that would probably make all cylinders get going so the AFR reading would be correct.

What I'm chasing now in this case is the perfect After Start Enrichment % and Decay Rate. Along with Coolant Temperature Enrichment and AFR Offset. Right now I'm at the point were when it first starts, it seems to fire on all 8, but it's really delicate on the AFR before I start to misfire on 1 or 2 cylinders. Then throws off the AFR reading and you have to feather the throttle to get them back. Or wait around a minute for them to settle back in. Getting closer and closer it to making it cold start like I want it.

[thecowwatcher]

Hmm, I see what you mean. Something is messed up now for sure. Any changes I attempt to make to my Mar 22 20 Config File won't load back on to the handheld. I keep getting an error when I try to upload them to the ECU. Luckily I can still download and upload the original Config File though. None of the files appeared corrupt on my laptop but the Mar 22 20CE, but only after I opened the zipped version I attached here.

Initially I just wanted to tweak what I had, but now I seem to have created some real problems for myself. I've attached another version of my original Config File now as a test, and another strange startup datalog I made with it.

I'm just now seeing this. I'll review the Config File and datalog and post an update.

Update: Still odd that after a 34 second datalog your CTS didn't move once. It's either really cold or you have a very efficient cooling system. Either way I don't think your engine wants to idle at 600. I'd still step it up to at the very least 700 RPM and simplify your Base Timing and Target AFR tables. Set all of your Target AFR to 14.0 and your Base Timing table to 25° and we can troubleshoot the cold starts. Also, after the engine has set all night check the ambient air temperature with the CTS before you start it. If it's 65°F out and your CTS is reads 100°F then there's the issue.

[78 C10]

I've played around a lot in the last week or so. Solved the issue with my Config Files getting corrupted and not loading by clearing the SD card and reinstalling all the firmware. Happened again yesterday though, so I went through all that once more. Maybe I've got an SD card going bad. I'm trying to get comfortable with using the USB direct to my laptop to avoid that link now.

Since the last datalog and Config File posted I've simplified my timing table some to be more conventional. Also changed all the IAC settings to be similar to a range Danny posted that I stumbled upon somewhere. Fiddled with the Cranking Fuel and other starting tables as well. I'm happy enough with the starting side of things for now.

Still getting lean waves at idle and low speed driving that are my new focus. Read some stuff about TPS vs AE Blanking values that may apply, but haven't seen much effect from changing that. I've got this at 13 now which may have helped a little. My plan is to drive it as is a few more days then Transfer Learning To Base again and smooth the Fuel Graph and see where I'm at.

Regarding the CTS, I still don't believe there's an issue. I'm in south Florida and the truck sits in the garage overnight and stays pretty warm. Around 100°F is what it reads on the typical morning now with IAT around 80°F. Maybe it reads a little high, but it doesn't seem to stick there.

[thecowwatcher]

I have a 700R4 trans and experienced lean spikes while shifting. I have my AE vs TPS RoC at 5.9 and that seemed to have taken the big spike away. Don't be afraid to make large changes to see how it reacts. Keep dialing in the Cold Starts and reviewing the Learn Table and datalogs. I am working on tune adjustment 51 right now, yes that's 51 times I've made adjustments to my Config File. I review it quite often to dial it in just so I'm that much more comfortable with driving it.

[cwathne]

Regarding the CTS, I still don't believe there's an issue. I'm in south Florida and the truck sits in the garage overnight and stays pretty warm. Around 100°F is what it reads on the typical morning now with IAT around 80°F. Maybe it reads a little high, but it doesn't seem to stick there.

When the truck sits for 12-24 hours MAT & CTS should read fairly the same. The CTS that comes with the kit often shows higher temperature then what it really is when cold. And to cold when it's hot. Had the same issue with mine, and lot of others in the forum here as well. I replaced mine with one from ACDelco, Summit Racing website is down right now so I can't get you the part number.

[Danny Cabral]

The Sniper EFI 543-120 CTS has been problematic. My Holley HP/Dominator EFI 534-10 CTS is accurate & reliable.
I've also heard good reports from using a Standard Motor Products TX3, ACDelco 213-928 & Delphi TS10075 CTS.
http://forums.holley.com/showthread....=2760#post2760 (Replacement Sensors For Holley EFI - Auto Parts Store)

Holley EFI Coolant Temperature Sensors: Standard Motor Products TX3, ACDelco 213-928 or Delphi TS10075.

Originally Posted by Danny Cabral Sniper EFI Replacement Sensors - Auto Parts Store CTS Sensor: Standard Motor Products TX3 TPS Sensor: Standard Motor Products TH191 IAC Motor: Standard Motor Products AC416 WBO2 Sensor: Bosch 17025, 0258017025 (LINK/LINK/LINK/LINK) (The Sniper EFI 2 bar MAP sensor is internal with the ECU. The Sniper EFI IAT sensor is a circuit board sensor that measures one throttle bore.) Innovate Motorsports HBX-1 Heat-Sink Bung Extender is great for protecting the WBO2.

[78 C10]

So consensus seems to be my CTS sensor is operating in too "tight" of a range. I can try a new one. Datalogged cold start this morning after the truck sat 10 hours. CTS read 102°F with MAT at 90°F. Thermometer on the garage wall read 75°F. Starts good, but initially rich then a bit lean for awhile. I'll play with the start enrichment tables to get it better later, unless it's related to another problem.

Also attached a datalog of part of my drive to work. It's only a couple miles so it doesn't get into Learn mode, but you can still see the lean spots I get. Plan to drive it more then smooth the fuel table if there are no other suggestions. Thanks all. apr 2 cold start.zip apr 2 drive in.zip Mar 31 20 w13roc.zip

[thecowwatcher]

It won't go in to Learn mode until a Coolant Temperature of 160°F. You need to take it on a nice long drive for it to properly Learn. I see your Learn Table is well populated at this point. You will need to continue to Transfer Learning To Base and smooth out the Base Fuel Table before you can dial in the lean spikes. Transfer Learning To Base with a smooth Base Fuel table may solve most of your cruising issues. I'll still adjust the Target A/F Ratio table. Those 15.5 spots will not be too friendly if you approach those while cruising. On a side note, the cold start looks to be much better.

[GPatrick]

If the supplied coolant temperature sensor is bad, most have read high at lower temperatures and they read low at higher temperatures. Mine read about 30°F high when the engine was cold and about 30°F low at high temperatures. It would rarely indicate above 160°F with a 190°F thermostat, which meant that it wouldn't go into Learn mode. The replacement temperature sensor worked perfectly. If your CTS is bad you shouldn't try to tune around it - replace it and then tune. You may find at start with a good sensor, the cold start compensation will work well. Do a search on CTS problems and you'll find more than a few.