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Thread: AdmiralSenn (Adam S.) #3416 "Christine" Megasquirt conversion

  1. #21
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

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    Quote Originally Posted by AdmiralSenn View Post
    Not exactly. The shielded wire is your tach input. Gray/slate is the same wire as coil negative. For full spark control you'd tap the shielded wire into your VR wires from the distributor, and run pin 36 to the gray/slate (or direct to the coil).

    Owen, I know you're running VR too. I just remember feeling like I was nuts, being the only one who did it that way. It was so long ago, though, I don't really remember. I vaguely remember advising somebody on it during their conversion, maybe it was yours - it was on the .com site.

    Anyway, it doesn't matter who came up with it, I don't know why I even mentioned it. >_<

    Any piercing insights into my hunting problem? I'll log on from the laptop shortly and upload the log.
    Okay, so I would have to add another wire; thanks! And that was me you advised on it

    So the pin 36 talk was confusing me a bit, as I am running the relay board. I just looked it up; that corresponds to an igntion output port on the relay board. So in this case, once I have fueling going and tuned in the spring, I think I will go ahead with spark. Don't have a welder though, so will need to find someone to tack down the weights for me. Plus, I'd get to learn how to install a distributor.
    Last edited by opethmike; 11-02-2011 at 04:57 PM.
    -Mike
    1981 DeLorean, heads/cams/exhaust, EFI
    1999 Corvette, heads/cam/exhaust, 440 BHP
    2005 Elise, stock
    2016 Chevy Cruze

  2. #22
    Back to the Omnipresent! Spittybug's Avatar
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    Adam, I'll look at your files when you post. I have found it to be critical that all the cells sitting in the idle area be very close to one another on VE and advance (AFR too if you have given it authority). If there is any discrepancies you start creating oscillations as it gets more fuel, RPM goes up, moves to a different cell, etc...... lock 'em all down if in doubt. The optimizer is the biggest culprit for changing them. I exclude all my idle cells when tuning with autotune.
    Owen
    Tour the country and visit breweries through the eyes of our two puppy dogs. http://www.twobrewdogs.com
    Help us spread the word! @twobrewdogs on Twitter, twobrewdogs on Facebook.

  3. #23
    Senior Member AdmiralSenn's Avatar
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    Friggin' finally... 97Kb is not much room for a datalog!

    You'll see the oscillations clearly in this log, they start immediately after a restart. Note that I did NOT touch the throttle and have not adjusted anything at all except for initial req_fuel and other absolute necessities prior to starting - I hadn't even opened the VE table except to make sure it looked vaguely sane.

    MSL: http://www.mediafire.com/?uno278cf9mg0unn
    MSQ: http://www.mediafire.com/?1o93imb2xgcrs6z

    It's very possible the VE table is totally off since I haven't dialed it in yet, but I'm honestly not sure exactly what to adjust there because when it idled on this table without oscillating, it idled REALLY nicely. :shrug:

    I haven't even started tuning on this file since it's brand new as of yesterday. Autotune and the optimizer have never even seen this table.

    It did this before on the old code too, but it was somewhat more violent when it did.

    Also, I hadn't even considered just tying the distributor arms down... maybe I will experiment with that tomorrow night if I have time - I do have plenty of ways to secure them nice and tightly. Have you uploaded your advance maps yet? I'm 100% lost on ignition control so far so I will definitely need your settings to start with, and will probably leave them as is for a good long while. What did you set the base timing at (i.e. without MS advancing or retarding what would your timing be)?

    EDIT: Yes, I see how much variation there is now. Not sure if I should tinker with the bins or not. I'm shooting to idle at 850-900 RPM.
    Last edited by AdmiralSenn; 11-02-2011 at 05:14 PM.
    Aka Adam S, aka Adam Wright
    1981 DMC-12 #3416, mothballed in preparation for motor swap
    2006 Volvo S60R

  4. #24
    Back to the Omnipresent! Spittybug's Avatar
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    Your file shows you are using a narrow band 02 sensor. (Basic menu, EGO control). True or is that just one of those oddities about MS where some of the menu items change back? Try disabling any AFR authority until you get the hunt resolved. Try making your advance as consistent as possible too.

    Your VE values in the block between 40% and 1100rpm varies between 26 and 39. I would believe that to give you some oscillation as it will constantly be getting different fueling. I only vary mine by a few, say ~4 over the same range. I also set my table up to give me very fine control; 10-35% 5% increments, 40-100% in 10% increments. The RPM axis goes: 500,700,900,1100,1300,1500,2000,2500,3000,3500,400 0,4500,5000. Remember, these are just "points on a line" so Megasquirt interpolates between them and past 5000. By doing this I can be fine tuning the idle area where little changes make a meaningful difference to the engine, and have "close enough" in those areas that the optimizer is going to play with and that only has transient hits as the car accelerates or decelerates through them.
    Owen
    Tour the country and visit breweries through the eyes of our two puppy dogs. http://www.twobrewdogs.com
    Help us spread the word! @twobrewdogs on Twitter, twobrewdogs on Facebook.

  5. #25
    Senior Member AdmiralSenn's Avatar
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    Yeah, I have an LC-1. TS just decided to ignore the wideband settings I configured for some reason.

    I didn't realize that I forgot to disable EGO control... it's been too long since I did some of this.

    I guess I should take my vacuum advance off completely for now then, and monkey with the VE table. Apparently the generated table isn't even REMOTELY close to making sense. I'll just open up DARCOM's and compare values.

    I'm not really sure what I should do with the RPM bins. I'd really like to define the upper limits of the engine's range so that when I start playing with the nitrous oxide system it doesn't have to guess at proper fueling - blowing up this motor is not on my to-do list. Granted that it's a wet system with extra fuel injected anyway, but even so. I'll probably bump up the 500 bin to closer to my idle speed rather than sacrifice the top end. I think that's what I did on my pre-fire tune and it idled just fine.

    I now have a bunch of work to do tomorrow outside the DMC world so I may not get back to this until Saturday or so.
    Aka Adam S, aka Adam Wright
    1981 DMC-12 #3416, mothballed in preparation for motor swap
    2006 Volvo S60R

  6. #26
    Senior Member AdmiralSenn's Avatar
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    EDIT: Owen, thanks for posting your VE table. I was able to get a good sense of some sane VE numbers from looking at it. The advance table will be coming in handy very soon, too.

    Some solid progress tonight, although I'm chickening out before I start tinkering with the ignition system. I'm just on the edge of "I'm sure that fuel smell is nothing dangerous" levels of tiredness. Figured I'd stop before something really dumb happens.

    Part of the reason I keep asking impossibly dumb questions about basic tuning is that I got REALLY lucky on my first ever tune. I got a pretty much rock solid idle my first try and the generated VE table didn't need much tuning, so I never really got very far into the fundamentals of setting this stuff up correctly. But I'm learning!

    I flattened out the VE table to the mid-30's range by trial and error and adjusted the bottom two RPM bins to something that makes a little more sense - 700 and 900 RPM. This smoothed out the idle hunt completely. I also dropped the upper third of the table down by about 10% and smoothed it into the rest, which should keep things a little more sane. I was seeing VEs in the 80-90 range at about 3000 RPM and ~60% load. Not quite normal even for a modded engine.

    After tweaking the map until I was satisfied, I started to disconnect the vacuum advance and accidentally pulled the hose off the butterflies instead of the T junction I put in. Grumbling, I pulled the throttle/w pipe assembly off and found a leaking water pump pipe (apparently I didn't quite tighten that clamp as much as I thought) and a crumpled, slightly blackened W pipe gasket on the plenum that feeds the passenger side. I need to get some proper meaty gasket material and replace it, but fixing the huge vacuum leak on this side toned down my idle popping and stumbling significantly.

    It's always something simple. I am optimistic that replacing those gaskets with something squishier and thicker will almost completely resolve the instability of my idle. The "popping" I thought was an exhaust leak was actually a misfire - I could feel the gap in the exhaust stream with my hand.

    See my "solididle" log for tonight's results. It stays almost perfectly still on a single VE intersection. The RPM still fluctuates a bit but it's more "normal" vibrations (probably the vacuum leak) rather than that sickening sine wave pattern. The engine is also WAY quieter now, which is good - I'm at about 80% of the quality of idle I had on my previous tune now.

    Also, in a fit of scientific curiosity, I decided to find the absolute lowest speed my engine will run at. See "stupidlowidle".

    A few things on this attempt. First of all I was able to get the engine down in the 370-400 RPM range (again I'm on the OEM manifold). It was actually reasonably smooth considering that it was running so slowly. However, I had to OPEN the throttles significantly to accomplish this (and adjust the distributor excruciatingly slowly), and look at the MAP readings compared to my regular idle. From playing with that it's pretty clear that this is a horribly inefficient engine speed to run at, and required a lot of fiddling to get it to operate. The alternator is basically not doing anything at this point. The log is too short to show it clearly but the voltage was dropping noticeably. This should be obvious to anyone who knows how an alternator works but I figured I'd mention it anyway just in case.

    Normally I wouldn't even bother to share these findings, but I recall some discussion on the .com site (I think it was in one of the many carb threads, not sure) of the disadvantages of the stock manifold and/or the smoothness of the idle at lower engine speeds. I think this shows pretty clearly how bad of an idea this is - certainly from a fuel efficiency standpoint and probably from an emissions standpoint as well. There's a reason the factory bumped us up to 900 RPM!

    Anyway. From playing with the engine all night I think I'm basically ready to start road tuning. Even with acceleration enrichment turned off I can rev the engine pretty hard and it barely murmurs - prior to these fixes it would hesitate for half a second before screaming ahead. I was unable to get the engine to stall or behave strangely otherwise despite anything I tried, so the open road shouldn't pose much of a problem now.

    I'm making a junkyard run tomorrow and will be keeping my eyes peeled for a proper idle motor. If the Volvos that I usually scavenge from are still there I should be able to set up idle control by Sunday.
    Attached Files
    Aka Adam S, aka Adam Wright
    1981 DMC-12 #3416, mothballed in preparation for motor swap
    2006 Volvo S60R

  7. #27
    Back to the Omnipresent! Spittybug's Avatar
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    Looking much better. A couple of points to consider;
    • Your TPS is showing 14 at idle, so I think you need to calibrate. It should be zero. Probably occurred when you cracked the butterflies.
    • Running too low an RPM not only hurts your alternator, but oil pump too!!! You need to stick with >700 in my opinion.
    • The ranges on your MAPdot and TPSdot are pretty narrow and that's good. It will help you when you get to acceleration enhancement. My TPSdot is still kind of noisy (interference on wires or unclean 5v supply, I need to diagnose more...) and this means I have to have a higher threshold or I get random acceleration boost.


    Keep in mind when you autotune it that you should drive reasonably and not hop on it. Otherwise it will try and give you fuel values that are too high (and should be accommodated via acceleration enhancement).

    I'm off to see my daughter at OU this weekend and see us whip up on A&M. I'll take the laptop with me and check on your progress!
    Owen
    Tour the country and visit breweries through the eyes of our two puppy dogs. http://www.twobrewdogs.com
    Help us spread the word! @twobrewdogs on Twitter, twobrewdogs on Facebook.

  8. #28
    Senior Member AdmiralSenn's Avatar
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    Well, my TPS is disconnected as the sensor itself is actually dead. I just set the flood clear threshold to 100% and ignore it. Similarly the thresholds for mapDOT and tpsDOT are set high enough to entirely disable AE, and the balance for that is set to 100% MAP.

    This will change when I get the TPS sensor replaced, so I'll have to put in settings that actually make sense...

    And yeah, I forgot about the oil pump being affected. Like I said, it's an AWFUL idea and I'm not really sure why anyone ever advocated it as a good thing.

    As soon as I get my bumper back I'll take it out on a back road and update this thread. I am REALLY looking forward to driving her again!
    Aka Adam S, aka Adam Wright
    1981 DMC-12 #3416, mothballed in preparation for motor swap
    2006 Volvo S60R

  9. #29
    Senior Member AdmiralSenn's Avatar
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    Zoom zoom...

    Drove her around today. She's actually pretty well set for power, though there's an alarming rattle on hard acceleration - sounds like I'm in too high of a gear, even in first. It could almost pass for engine knock but I can't imagine that I'm seeing that with the way I have my advance set up. (Yeah yeah, I probably shouldn't have accelerated hard the first time out.... >_> sue me)

    A few days of doodling and tuning and I'll start my ignition control project. Still have to grab and install an idle motor too. Currently idling right around 1000-1100 RPM but I'd like it to be lower off the throttle.
    Aka Adam S, aka Adam Wright
    1981 DMC-12 #3416, mothballed in preparation for motor swap
    2006 Volvo S60R

  10. #30
    Not a DeLorean Guru
    Join Date:  May 2011

    Location:  Rochester, NY

    Posts:    1,989

    My VIN:    01049

    I've decided to stick with the stock idle speed motor. I have a GM IAC + the housing block for that diyautotune sells, if you're interested. PM if you'd like, and we can work out a deal.
    -Mike
    1981 DeLorean, heads/cams/exhaust, EFI
    1999 Corvette, heads/cam/exhaust, 440 BHP
    2005 Elise, stock
    2016 Chevy Cruze

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