Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 51 of 51 FirstFirst ... 41464748495051
Results 751 to 765 of 765

Thread: DIY LTCC or similar system for LT1s

  1. #751
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Quote Originally Posted by kur4o View Post
    I did one start with some idling till warmed up.
    Are you meaning with engine running from all 8 cop coils, or some other testing configuration?

    Quote Originally Posted by kur4o View Post
    Started within 1 second of cranking.
    This is not what I would call a good description of an LT-1 starting. I've had one somewhat "sketchy" start since moving to the 0.9.40 release. Otherwise it's been great, but with maybe 90 degrees more crank rotation. I actually logged it and can see the EST line arming / going high and then firing before the first cylinder would have fired (but wasn't because no dwell). I might do a pass-through thing for this to get fire sooner because the issue is going to be flooding the engine before any spark is delivered. But I think you have some other issues. A full second of cranking is very long for a healthy LT-1.

    Quote Originally Posted by kur4o View Post
    Will do more tests of random cranking.
    My suggestion would be not to worry a bunch right now about trying to make it break during startup with random "trickery". Unless your perception of 1 second (1000 milliseconds) is a lot different than mine, you have some other start related issue that's obviously happening with your stock ignition system also. You said it here "Started on the second try which is not unusual on my setup".

    I may be completely out to lunch here, but I think your injector flow constant is way off in left field. I would like to say you can trust me but I can't. What I can say is that after about a year of trying to extrapolate my IFC by way of trim numbers and then settling on where I'm at now, it hasn't started this well since I put my Multec injectors in the storage tote.

    Quote Originally Posted by kur4o View Post
    On light throttle change I feel very little hesitation, On hard throttle change no hesitation at all.
    Let's revisit this after you answer my first question.

  2. #752
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    1,042
    All 8 coils hooked up for the test.
    There were total of 12 led events before it fired off and I got a led on second or third crank TDC which is pretty good.

    It only takes some time to fire up only on first start, after it have been sitting for some time[First cold start]. I suspect fueling since I was seeing coil firing on the leds. After the first start it fires off almost immediately[0.3s range]. After it get soaked on the first short try. It fires off immediately on the second try. I might play with FIC constant or first prime pulse.

  3. #753
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Quote Originally Posted by kur4o View Post
    It only takes some time to fire up only on first start, after it have been sitting for some time[First cold start]. I suspect fueling since I was seeing coil firing...
    I personally think you have a badly leaking injector, fuel pressure regulator, or bad check valve in your fuel pump. But it could be anything. Unfortunately without having known perfect fuel injector data, it's going to be very difficult to surmise where the problem is.

    Whatever the case, for the benefit of everyone else watching this thread, kur4o sent me a PM of a video of his start attempt. Out of respect for his privacy I'm not going to share it. But I do plan to go over it frame by frame. My initial impression is that I have no reason to doubt it. So I think we have a winner!

    kur4o let me know via PM how I can get the prize to you and in what form you would like it (if other than 100 USD).

    More importantly let me know how it goes when you try to re-start it after cool-down, etc.

    I think I'm going to go start mine if only for amusement purposes. My neighbor already refers to it as "the engine" so what harm could come of some more punishment of their aural senses?

  4. #754
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Here's another release.

    Code:
    0.9.41 - 9/22/2020
    
    Removed all references to arduino digitalRead() and digitalWrite()
    
    Added EST passthrough in EST rising edge interrupt handler for faster first dwell
    
    Increased MAP vs RPM multipliers slightly in cruising range
    I've driven this about 275 miles without major incident. Mileage on the last fill-up was 24.3 mpg, which was somewhat surprising since I haven't exactly been babying the go pedal. Cold starts have been a little slobbery, but the ambient temp has been dramatically lower in the mornings the past week or two. Then this morning it set a DTC43 when starting, which cleared on it's own after a few seconds of runtime.

    I was somewhat concerned with this DTC when I hooked up my laptop to see what it was, because eehack has a description of "ESC Failure" for it. But EagleMark's original thread [here] describes it as a "Knock Sensor (KS) Circuit". So not sure what to make of this. I haven't seen the CEL light with the engine running in around 2 years. I didn't even think the '95s were equipped to sense a disconnected knock sensor circuit??? Would love to have a better description of what this DTC trigger conditions are but haven't been able to locate where these live in the 2000+ pages of the FSM. Whatever the case I'll report back if it reoccurs.

    Still haven't heard anything further from kur4o - hoping everything's well. I'd like to get you your prize money and hopefully try to see if we can further investigate the light acceleration stumble you mentioned. That is, if your rig is still in running order...
    Attached Files Attached Files

  5. #755
    Fuel Injected!
    Join Date
    Jul 2019
    Location
    Orange, CA
    Posts
    339
    Quote Originally Posted by spfautsch View Post
    Here's another release.

    Code:
    0.9.41 - 9/22/2020
    
    Removed all references to arduino digitalRead() and digitalWrite()
    
    Added EST passthrough in EST rising edge interrupt handler for faster first dwell
    
    Increased MAP vs RPM multipliers slightly in cruising range
    I've driven this about 275 miles without major incident. Mileage on the last fill-up was 24.3 mpg, which was somewhat surprising since I haven't exactly been babying the go pedal. Cold starts have been a little slobbery, but the ambient temp has been dramatically lower in the mornings the past week or two. Then this morning it set a DTC43 when starting, which cleared on it's own after a few seconds of runtime.

    I was somewhat concerned with this DTC when I hooked up my laptop to see what it was, because eehack has a description of "ESC Failure" for it. But EagleMark's original thread [here] describes it as a "Knock Sensor (KS) Circuit". So not sure what to make of this. I haven't seen the CEL light with the engine running in around 2 years. I didn't even think the '95s were equipped to sense a disconnected knock sensor circuit??? Would love to have a better description of what this DTC trigger conditions are but haven't been able to locate where these live in the 2000+ pages of the FSM. Whatever the case I'll report back if it reoccurs.

    Still haven't heard anything further from kur4o - hoping everything's well. I'd like to get you your prize money and hopefully try to see if we can further investigate the light acceleration stumble you mentioned. That is, if your rig is still in running order...
    As someone who owns a '95 and had that CEL himself, yes, they're wired the same way as all the older C4s (which is why the knock sensor part number is shared until 1996). The knock sensor on our cars has a resistor inside the sensor that the PCM uses to detect whether the sensor is physically present. When this resistor inevitably breaks or fails to be in the correct range, it triggers DTC 43. But this doesn't mean the sensor failed--it just means the resistor is no longer in spec. You can fix it by replacing the sensor, but I just disabled the DTC in my BIN since I could see in EEHack that the sensors were still working perfectly fine.
    1994 Corvette (Automatic)
    1995 Corvette (Manual)

  6. #756
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Thanks for the clarification. I remember reading something about the resistor for checking the circuit continuity but have a growing amount of information to keep track of and waning motivation to search thoroughly. Whatever the case I found it odd that the DTC cleared itself almost immediately, and these are 3 year old AC Delco O.E. sensors.

    Since the last couple revisions I've had a couple attempts that didn't start on the first try, most recently a hot re-start this afternoon. These were both instances where I cranked around 1400-1800 milliseconds and then let off because it was obviously not going to run without intervention (I did not try opening the throttle). It felt like it hit on a few cylinders and then flooded (or possibly underfueled). Second, relatively long crank started and felt pretty normal once running. I'm going to try catching a log of one of these in hopes of finding the cause.

  7. #757
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Here's another updated release. Made a minor modification to the dwell pass-through logic on first fire.

    Since the last post I had one cold restart (naturally wasn't logging it) where it felt like a coil fired waaaaaaay before commanded spark advance (i.e. it sounded like the engine briefly came to a dead stop after a couple compression strokes, and then immediately started and ran perfectly for the next 57 miles). Hoping this change resolves that in the rare occasion it might re-occur.

    I'm once again making a concerted effort to log the controller with every start to capture every bit of data possible. It seems like once running things are near perfect, as witnessed by the average fuel economy of around 23 mpg over the last 5-6 fill-ups. Aside from some A/C related surge and a bit of closed throttle bucking in 1st through 3rd that I've mentioned ad-nauseum, it seems like my tune is pretty decent and I want to believe none of my drive-ability issues are related to the ignition system. Due to my retarded brother-in-law the test mule has once again been pressed into daily driver service so I'm getting more test data than I normally would this time of year. Apologies to those who have an actual learning disability.

    Anyway, after about 10 starts with this revision there's nothing to report. Over the next couple commutes the plan is to see how far I can stretch economy. This was my intention after the last fill-up, but a 15 mile interstate parking lot snarl made that an exercise in futility.

    I've been hearing from kur4o via PM and things sound promising. When he's convinced it's mediocre, I'll be elated - over the moon.
    Attached Files Attached Files

  8. #758
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    1,042
    Finally have some time to update the thread.

    New caps installed and new firmware loaded. Still using 0.9.40 version. Starts every time without issues. I also went for some long drive logs.

    Car feels great. Overall better throttle response and much nicer low and mid range. Some of the low rpms, high load drone disappeared. Did some moderate wot pulls, but not hard enough to make some impressions. Still fighting with some mechanical lifter problems.

    I feel some nice double platinum or iridium plugs will make it even nicer.

    Here is the official video of the last drive with coils running the engine.
    https://drive.google.com/file/d/1zr5...ew?usp=sharing

    Ignore the coils attachment. It is still on testing fixture.

    Also some eehack logs with the COP drives.


    As a last note I want to Thank you for putting such an enormous R&D time, developing the controller. It is really amazing that it works so good.

    The car feels so much better. Too bad I didn`t have enough time recently to conduct more tests. Some fine tuning of the dwell times, spark advance and trying some other plugs will make it even better.

    I will contact you via pm about the reward.
    I also want to do some more videos, so people can get more confident about the quaility of the work being done. I guess the best place to put them will be on some video sharing sites.

    It is still too advanced for the average Joe but some install guides with a list of the needed parts will unleash demand.

    This is to be considered the best mod on par with ls1 injectors patch.

    As a side note project I might get access to a spark plug pressure chamber to test some dwell settings.
    Attached Files Attached Files

  9. #759
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Quote Originally Posted by kur4o View Post
    I feel some nice double platinum or iridium plugs will make it even nicer.
    I ended up running Denso IT16TT (4713) based on their cleaner (bright blue) spark pattern compared to the OE double platinum AC Delcos.

    Quote Originally Posted by kur4o View Post
    As a last note I want to Thank you for putting such an enormous R&D time, developing the controller. It is really amazing that it works so good.
    Thanks for the kind comments, but much more importantly a huge thanks for investing the time, money and faith to test this on your own hardware. I was really worried for a while there, but I'll sleep better knowing it has your blessings. Be sure to PM me for the prize money.

    Quote Originally Posted by kur4o View Post
    I also want to do some more videos ... I guess the best place to put them will be on some video sharing sites.
    Anything you'd want to do in that regard would be great. My next 3-6 months are looking to be fairly busy so I'll have limited time to spend with hands-on stuff when not at work. Needing to rebuild a 4L60E that's getting ready to drop 3rd / 4th in my wife's daily driver, among numerous other (non-fun) projects.

    Quote Originally Posted by kur4o View Post
    It is still too advanced for the average Joe but some install guides with a list of the needed parts will unleash demand.
    I'm not necessarily interested in "unleashing" demand. In my eyes there's no way to make this a commercially viable product either assembled ready to install, or in kit form. The amount of time it takes to count the parts out, if I were to pay someone minimum wage to do it, would dictate price be triple ($75) just for an un-assembled circuit board kit. Building harnesses, assembling the board and packaging in some kind of case would inflate the price to well beyond obscene.

    My intention was to start an assembly and installation guide with accompanying pictures, but I simply hate writing documentation. I will try to suck it up and get going with this. My only other immediate plans are to work on a limp mode in the event of a loss of the high res signal. I'd like to get those two items accomplished this winter, along with building a more formal support forum and info and ordering pages.

    Another low-priority item I'd like to tackle is acquiring one of the coils being used on the newer LT-1/LT-2 platforms and develop a dwell map for them. Unfortunately it looks like these use yet another connector.

    message-editor%2F1571683903820-2020-chevrolet-corvette-stingray-engine-100.jpg

    Beyond that, I have no immediate plans to forcefully grow the project. I'll continue to support it but my hope is that some of you who have kits will try them, like the results and subsequently develop your own installation methods in order to offer these services to others who are less comfortable tackling a project of this nature.

    Quote Originally Posted by kur4o View Post
    This is to be considered the best mod on par with ls1 injectors patch.
    I may give that a whirl now that I know the ignition controller isn't the cause of my tuning difficulties.

    Quote Originally Posted by kur4o View Post
    As a side note project I might get access to a spark plug pressure chamber to test some dwell settings.
    That sounds great. I have no doubt there can be improvements made to the dwell tables I developed last winter - if there's anything I can do to help let me know.

  10. #760
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    1,042
    The more miles I put on the COP system the better it gets. Last time I completely forotten that the system is present. It has a driving experience completely as stock, with beefed up spark.
    You can be sure that the reward will be spent wise on testing equipment.
    Big thanks for the support.

    The weather is getting worse and more time will be spend when it gets warmer here.

    I think that lt1 coils are the same as yours other than being square. They have the same step up driver and use identical dwell tables.
    Found some pregapped iridiums that might work well. ac delco 41-101. I will give them a try. Also scored a used set of a double platinum 41-985 that are fine wire, and looks good, but nowhere to be found new. It ill be either new design coming or are discontinued in favor of the iridiums.

    I also figured that runing evap system on idle improves it tremendously. CLosed loop gets pig rich and can`t compensate for now. I will try to dial in some of transition fueling tables. It needs to increase the boil time to compensate for the colder heads.

    Some winter patching will include figuring out the transition tables and make a patch the will enable evap on idle and work in closed loop or something like that.

  11. #761
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Thanks for the update - I'm happy that you're happy!

    On the plugs, the double fine-wire iridiums easily demonstrated the cleanest spark in free air with the exception of plain copper. Honestly, anything and everything had a cleaner looking spark in free air than the the ACD double platinum "puck" style plugs. The spark jumped around the platinum in dozens of smaller spark showers, and the overall color was more orange than blue.

    Looking at what rock auto shows for cross reference those newer square coils appear to be referred to generically as D510C with a GM / ACD part # of 12619161. If I get a chance this winter I'll pick one up and perform temperature and voltage sweeps to get a dwell map.

    Interesting stuff you've found on the evap system. It's got me wondering if there would be a simple way (thinking electric water pump) to switch the reverse flow system back to cooling the block first. Hmmm...

    I'm almost done with the 4l60e build for the family truckster. Not looking forward to dropping the xfer case and trans out on the garage floor, but desperate times call for desperate measures. I have made a small amount of progress on an assembly / installation manual for this project, but as I mentioned previously writing documentation is less entertaining than the aforementioned transmission swap on the cold concrete floor.

  12. #762
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    1,042
    If you switch the polarity of the pump it migth start working backwards. but the propellers are not designed for a reversed flow. There are other unknowns too. There is no cross-water passage in the intake. It is the flow passage within the pump that points fluid tp heads first. I am not sure how hard will be to retrofit regular SBC waterpump. Than it might work. You will lose the extra advance, cooler heads give. The only drawback of the revese flow system is fuel evaporation. I will test warmer thermostat. What helps best is not the overall coolant temp, but the heatsoacked heads. I guess the heads run good 10-20 degrees less than the block. That is why the coolant gauge on f-bodies always runs much lower the pcm measured temp.

    Why not run some PWM relay to slow down the coolant flow, at warmup and at highway cruise to regulate temp above thermostat rating. Some inelligent control algorythm will be needed. You will extend the life of alternator too.

    I am sure if we play with the transient fuel tables some improvement can be made. Leaving more fuel soacked heads. Another issues that is not discussed is the spary pattern of the injectors. Those ls1 style injectors can spay sideways and the fuel not hitting hot intake valve. I didn`t check mine, they might contribute to the crap run.
    I think the stockers have a cone spray, at the correct angle. I might try bumping fuel pressure to see if that helps too. Hope the pump survives 3.5-4 bar at idle for the test.

    If you have the time you can command open loop and turn on the evap. Watch for map drop. If it drops a healthy 4-5 points than a evap patch is on high priority list.

    I am interested to measure spark duration for the same coil with plugs with different materials. If the resistance is great it is likely the discharge time to last longer. The platinum with dot pluck should always discharge around the dot pluck since copper have less resistance. Is it made on purpose. I have seen heavily worned plugs. The copper core was rounded around the pluck. That dot might be just for longetivity combined with the less resistance of copper. Also the color of the spark can give some clues but the spectrum must be linked with the energy output. Only pressure chamber will sort good and bad plugs. At least 12-16 bars to simulate cylinder chamber.

  13. #763
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Quote Originally Posted by kur4o View Post
    It is the flow passage within the pump that points fluid tp heads first. I am not sure how hard will be to retrofit regular SBC waterpump.
    The water pump and block are both completely different. The water pump outlet passages go into the block and promptly make a 90 degree bend into the heads.

    lt1asd.jpg

    Quote Originally Posted by kur4o View Post
    Why not run some PWM relay to slow down the coolant flow, at warmup and at highway cruise to regulate temp above thermostat rating. Some inelligent control algorythm will be needed.
    You're a genius.

    Quote Originally Posted by kur4o View Post
    If you have the time you can command open loop and turn on the evap. Watch for map drop. If it drops a healthy 4-5 points than a evap patch is on high priority list.
    I'll give it a shot the next time I start it up. It's been sitting neglected while I've been building the tranny but I put the pan on that last night. Now I'm looking for volunteers to help R & R it - I'll even pony up for a transmission jack!

  14. #764
    Fuel Injected! spfautsch's Avatar
    Join Date
    Apr 2015
    Posts
    674
    Quote Originally Posted by kur4o View Post
    If you have the time you can command open loop and turn on the evap. Watch for map drop. If it drops a healthy 4-5 points than a evap patch is on high priority list.
    Had a chance to start it and let it idle up to temp yesterday afternoon. Unfortunately didn't really see a pronounced relationship between the evap solenoid and MAP, just the IAC counts dropping.



    Apparently the evap solenoid can be commanded in open loop (using steveo's v4.91). I didn't notice until just now but mine went incredibly lean when switched to open loop (wideband also reading 1.16-1.20 lambda - 1.20 being 5v / max lean). I imagine this is because I extrapolated my injector flow targeting E0 fuel but am currently running a fresh tank of E10. Whatever the case, I only turned off the evap solenoid after I let it go back to closed loop and noticed the IAC count was still very low. The two dips in IAC afterwards coincided with the ccp solenoid being commanded on / off with eehack.
    Attached Files Attached Files

  15. #765
    Fuel Injected!
    Join Date
    Mar 2013
    Posts
    1,042
    I suspect you have an air leak in the evap system. Canister, fuel tank, or somewhere in the middle. When you switch on the ccp it doesnt get pig rich at all, It even leans out more. based on blms. When I turn on ccp on at idle it gets pig rich immediately and blm dropping to 108 and closed loop freaks out. In your case the blm jump even higher.
    The ccp is really hard to diagnose, I was running and tuning with stuck open ccp for a year and a half, and didn`t notice the problem. I suspect injectors, fuel pressure, maf, temp compensation for inconsistent tune, but at the end by chance it turns out to be the ccp valve. After fixing it the ind cyl trims were all messed up, including maf table and ve.

    You can turn it on without waiting to get warmed up. I am planning to test some transient fuel tables soon and report back. Now looking for some good description of the system.

    I also scored some document with description of the dwell tables and scalars used with ls1 coils, regarding startup and coil temperature. It is freaking modelling with tons of variables to predict coil temperature, so it is indeed the coil temp related than coolant temp.
    The more intersting one was EGR dwell boost. I will post the list soon.

Similar Threads

  1. Which TBI system is better?
    By KeyAir in forum GM EFI Systems
    Replies: 41
    Last Post: 05-13-2019, 09:39 PM
  2. Hard start 93 LT1 with LTCC Ignition Mod
    By beestoys in forum GM EFI Systems
    Replies: 0
    Last Post: 05-18-2015, 08:58 AM
  3. ABS system?
    By K1500ss4x4 in forum Gear Heads
    Replies: 3
    Last Post: 02-06-2014, 06:21 AM
  4. Vortec EGR System?
    By EagleMark in forum OBDII Tuning
    Replies: 40
    Last Post: 06-02-2013, 10:07 PM
  5. Quicker way to do Spark Hook test on the street for LT1s and others?
    By sherlock9c1 in forum Fuel Injection Writeups Articles and How to New and Old
    Replies: 15
    Last Post: 03-03-2013, 01:52 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •