Humble guy still have E85 cold star problem

[rduester]

I want to start off with an apology to you guys that have tried to help me. I did not mean to come across as unwilling to accept your help. Right at the moment I need to make the best out of what I have. I have had the truck running and starting great at -20 on gas two years ago. Now on E85 it is kicking my ass.
I know I had some things that have to be corrected, I replaced the alternator and battery so the voltage issue has been corrected. At this point I am asking for help with two things.
One, my ECT sensor, I have replaced with three different ones and they all read 20-25 degrees higher than ambient. I have checked everything I could think of even the wiring ECM by watching the scanner and disconnecting the sensor ( -40 ) and jumping it ( 304 ) so I believe it maybe a problem with the ECM. would like a second opinion or some other input.
Two, on startup while cranking and until open loop it is commanding an EQ of 2.0 and unless I give at least 50 percent throttle it won't stay running till open loop when the temp outside gets below 50/55 degrees. That is for the most part on the first start of the day. After that I only have a problem if it sits for over 8/9 hrs. I have no idea what to change to lean that out. To me it seems odd that it is exactly 2.0 and not some other odd number.
I know my injector data is not correct but I did get it from someone online that said they " had their set flow tested" I know that not all injectors are the same but OE injectors don't all flow exactly the same and they work.
I know that I am just going to end up with a somewhat jacked up tune. But so far I have taught myself what little I know and I would like to continue to learn more and would welcome the opportunity to do so with all of your help.

And yes, Blindsquirrel I will b getting better injectors with good data at some point, I just have to do what i can with what I have for now.

[gtstorey]

Have you checked the resistance of the ECT sensor and compared it to the entire circuit at the ECM? Do all of you different sensors have the same resistance at the same temperature? Are they sourced from different places to ensure that you aren't getting a miss-listed sensor that doesn't have the correct resistance for you vehicle? Have you checked the service manual to see if it has a resistance to temp chart to check the sensor against?

[rduester]

I have checked the sensor the was in the truck and three diffrent ones. Two AC Delcos and One Standard and they all are within limits in resistance charts. And I have done the standard check for the wiring from the sensor to the ECM and it checks out. I don't what to look at now. I am at the point of replacing the ECM or tuning around the offset.

[rduester]

And as far as the being rich problem I am looking for anything specifically retaliated to the alcohol tables. Well at least I hope that is where the problem is.

[gtstorey]

I have checked the sensor the was in the truck and three diffrent ones. Two AC Delcos and One Standard and they all are within limits in resistance charts. And I have done the standard check for the wiring from the sensor to the ECM and it checks out. I don't what to look at now. I am at the point of replacing the ECM or tuning around the offset.

Sounds like an ECM problem to me or bad ECM/Sensor matchup. Not sure how well you can tune around the "offset", have you confirmed the temp reading is correct after warm up or that the offset is the same?

[blindsquirrel]

Verify ECT in a different scan tool.

Also, one of the cardinal rules of diagnostics is, 'fix the obvious problems first', as in, before you go chasing ghosts down a rabbit hole, and if this thing still has the FAST injectors in it, well, the ECT behavior might not have anything at all to do with the problem you're trying to solve.

[gtstorey]

Verify ECT in a different scan tool.

Also, one of the cardinal rules of diagnostics is, 'fix the obvious problems first', as in, before you go chasing ghosts down a rabbit hole, and if this thing still has the FAST injectors in it, well, the ECT behavior might not have anything at all to do with the problem you're trying to solve.

I probably shouldn't assumed that the vehicle has an ECT readout/gauge that is matching HPT.

[blindsquirrel]

I once saw an Autel read out a P0115 on a Cadillac. There is no P0115. Tech2 read it correctly as P0116. That kind of thing, and sensors that read different from one scan tool to the next and from global OBD to mfg-specific...

[rduester]

Update, I confirmed temps. The ECT temp matches the truck gage temp, the ECT temp is 20-25 higher than outside temp after sitting long enough to cool to ambient temp.
Above information verified with another scanner and certified temp gauges from work.
And as far as the injectors I know they will be hinderance to getting my tune on point, I am just looking to get a usable MAF tune for now. I had a good tune one on gas that started great at temps from-20 up. And the truck ran good, no stumble or other problems. I just had to pull a little to much timing around the torque peak and I was leaving to much on the table. I also had some knock on tip in. That is why I went to E85 and I wanted to learn how to do it.
Everything went fine when I did so. Dropped in the injectors, installed flex fuel sensor, drained and refilled with E85 and loaded a flex fuel tune I made from bits and pieces I got from other flex fuel tunes. After priming the system it started and for the most part ran OK, only had to make changes two or three times to get it to run and drive good. I will admit I got real lucky. I am in no way, shape or form any kind of tuner. HELL I even took it the local track that afternoon for a test and tune and ran at least stock to just over stock numbers with it, didn't get but three passes to do any changes.
I know that I will probably never get the thing to switch from E85 to gas correctly like it should, I would like to. I could just switch back to gas for the winter but that won't teach me anything about E85 cold starts.
And like I said before, I don't know what else to try with my ECT.
And in the E40 ECM what tables control the alcohol cold start enrichment?
Any and all help is more then welcome. Thank you.

[Fast4.7]

ECT will only be fairly close to ambient after hours of soaking in ambient temps. I like to verify sensor readings after an overnight soaking. Overnight my CTS, IAT and Trans temp are within a few degrees of each other.

My P59 starts well on Gas or E85.

[rduester]

I have verified temps my ECM - ambient and IAT are within a couple degrees of actual ambient air temps. My CTS sensor is 20-25 higher. My E40 ECM and 4L70 transmission has no transmission temp pid.

[blindsquirrel]

Well it for sure has the sensor for it.

screenshot.28-10-2022 15.29.18.png

[rduester]

I found it, I had to have my laptop in the truck and the scanner active to see it. Thank you.

[rduester]

I have been working on some of the problems with my truck and it is much better now. I am still having trouble with the temp sensors and I know that is not helping matters.
I made a changed my fuel tables to match a 2011 Silverado 6.2 flex fuel truck and I still had problems with it commanding double stoich at start up till closed loop. It seemed is if nothing I did made any difference. I finally went to a different forum to look for some help and someone there suggested that I do write complete. Did a write complete and first time it failed about 80% of the way done with the tranny controller ( I found out a while back that if I don't write to both I will soft brick/fail my ECM and have to do the ground the ECM thing and start over ) and had to rewrite the tranny controller. After that the double stoich problem cleared up. Now it starts up! OK, maybe not the best. I need to work on the lower end of my VE table after the changes I made to my tune.
Now my problem is what do I do with the damn temp sensors? If you look at the logs starting at 8 seconds in both logs show that the ambiant, intake and actual air temps all are within 1 or 2 degrees of each other. But my tranny and ECT are much higher and the colder it gets the wider the spread. My gage temp inside matches the ECT sensor. I have used other scanners to read the temp sensors and I get the same results. Any ideas? At this point I am thinking it is in the ECM. If so I will just have to tune around it I don't want to replace it as it works well otherwise.

[SiriusC1024]

20 degree difference isn't going to cause the problems you are having.

- Put closed loop enables back to stock. They shouldn't ever be that low.
- Put catalyst heating back to stock.

Ethanol burns much slower at lower temperatures. You're running e85 without running ethanol-optimized spark advance. I see the AFR scaling for ethanol, but you're missing the e85 spark table. If you want this to work you need to install an e85 compatible OS. If you don't want to do that then you could wing it and manually enter a spark table that would work.

[rduester]

Thanks SiriusC1024 for the input.

I have it going into closed loop early for now so I can work on my cold start problem then I will work on my VE table.
As for the catalyst heating it is not needed I am not running cats.

I have both flex and alcohol tables in spark area of my tune and alcohol in the fuel area. I just don't have anything in them right now. Stock tune flex fuel was disabled and all related tables zeroed out. That being said, that was why I started this thread, I need help with my tune.

My current tune has it starting well around 60% Ethanol and down to 30 degrees it still starts ok at 25 maybe a bit sketchy.
My last log this morning it had a struggle, 2 try's and started on the third one. It was also around 17 degrees outside.

I know my fueling needs work but the changes made have helped. What other fueling changes might/will help?
What spark tables need filled populated to get this thing to start? I don't want to do anything that is going to have an effect on it outside of starting or warmup.

[rduester]

Sorry forgot to post this mornings log.

[eXo3901]

This ran before e85?

I have it going into closed loop early for now so I can work on my cold start problem then I will work on my VE table.

This is backwards and makes no sense to me.

Moving past the electrical/sensor issues already discussed, I am going to just jot down my thoughts as I look through this tune. Hopefully people correct any incorrect comments I make.
-Cylinder volume does not need to be changed on this platform. I would leave this stock to avoid unknown/unseen issues it may or may not cause.
-Base idle rpm, I would set this back to stock but increase the entire table by 175rpm to match your current rpm. Or at least drop the rpm at a higher temp like factory. Same thoughts on the startup RPM tables. (note that the startup RPM tables are show in Celsius)
-I presume the idle adaptives are modified because of the cam. If it ran before, fine.
-Airflow minimum. I think this could be lowered slightly. Maybe by 5% to start. I just try to have this be slightly less than what the MAF/VE tables show for airflow in their respective idle areas.
-I don't like the startup airflow table. Just seems like to much. Maybe a stock table increased by 30%(multiply by 1.3).
-VE table, let's at least start with a stock table. Then, lower everything under 2,000 rpm by 20%. Then, select everything from 400 to 4,000 rpm and smooth across only the rpm axis 2 or 3 times.
-Cranking VE I would just set the entire thing to 80.

Fuel tab. To much changed here for the amount of information we have. If you choose to apply my comments below for this tab, please know that it follows the "double stoich" method in order to fit the larger injectors into the flow rate table.
-Stoich table needs to be doubled. (see flow rate comment)
-Flow rate table: Since we cannot fit 85lb injectors in this table we need to enter a flowrate that does fit. Assuming I looked at the right injectors, Fast says their 85lb injectors flow 87.8lbs at 58 psi. Assuming you are running 58psi of non-manifold-referenced fuel pressure. Set the flow table to stock values, highlight the whole thing, and multiply it by 1.492. This will put the 0kpa column at 43.9'ish lb/hr, which is half of 87.8lbs. You will need to adjust for fuel pressure if you are not running 58psi, obviously.
-Flow rate multi table, I've never seen anything that suggests this table actually works. Set it all back to 1.000.
-Min inj pulse table seems reasonable if we confirmed it was a limiting issue previously. Always best to test and confirm before blindly changing though. So, if this is limiting our pw and we are still to rich, then we lower it.
-Offset vs inj temp shouldn't be zero'ed but whatever. This can be dealt with later, if it ever becomes an issue. Zero'ed or not, don't bother looking at any data gathered directly after a re-flash. To many virtual/calculated sensors that need to normalize before data is worth looking at.
-Cranking fuel has been lowered which seems backwards to me. With e85 I would expect this table to be increased in the colder areas. Maybe I am wrong? Also note that, to my knowledge, the time axis on this table is "time since shutdown" and I always view this table with the time axis set to "hours".
-IVT terms-AFR terms are values from newer platforms? The applicability of them to this older platform is unknown, to me at least. Set these to stock values 7.92 and divide them by 2 = 3.96. (see flow rate comment)
-Again, the closed loop settings don't make sense for the issue you are trying to fix. We do not want this going into closed loop right away if we are trying to fix a cold start issue. My opinion.
-Open loop tables: you'll have to do the math here, I didn't, but these effect your commanded EQ when in open loop(COLD STARTING). Once everything is warm, EQ would generally calculate out to 1.000.
--Specifically addressing the IVT Gain table, I cannot see how this is helping at all being set to 1.000 entirely.
-Transient tables are changed but were they changed to mask improperly tuned MAF/VE tables with bad injector data or was real work put into these after meticulously tuning the airflow previously with good injector data? I am taking the stance these were changed because the entire thing was tuned with bad injector data. These are a model of actual engine characteristics more than anything in my mind and if they were altered based on the current facts, I cannot imagine they are anywhere close to accurate.
-Spark smoothing is generally disabled.

Right or wrong, these are all things I would be changing or researching. Eliminate the variables as best as possible.

[BigTuner]

Thanks SiriusC1024 for the input.

I have it going into closed loop early for now so I can work on my cold start problem then I will work on my VE table.

Closed loop can only target a lambda of 1.0 with narrowband sensors, if you are forcing it to go to closed loop early you are negating any of your cold start fueling which is normally far richer than 1.0 Lambda and would explain your cold start issues. You usually fix your VE/MAF tables i.e. your fueling before ever looking at your cold start. If your fuel tables are inaccurate how can your cold start fueling ever be accurate, even if you got it to work when you went back and adjusted your VE/MAF all your cold start work would be back at square one.

[rduester]

I do fully understand what was said by both of you. What I don't fully understand is why the thing started and ran good on E85 almost from day one up untill the outside temps got down in the lower 50's and then only on first starts if was sitting for more than 10/12 hours.