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  1. #1
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    LH2.2 tweaking diary

    So I've been reading up on how LH2.2 works. EcuProject forums have pointed me in the right direction, so from there I set out. I'm delving into old magic, folks. LH2.2 was abandoned by Bosch in 1989. I plan to take apart an ECU, re-program a chip, and put said chip back in the ECU and have the car run, hopefully better than before. A few have gone before me, but my ventures into LH2.2 programming will be the best-documented on the internet. This will be my official log of what happens to me, if anybody is listening.

    I'm not one of those lucky folks with a 900 T16 to drive around and soup up. Instead, I have a lowly N/A 16v, but I'm working on this project with a friend who does own a T16, and will be contributing the Turbo side of this LH2.2 puzzle.

    To start out: a little vocab.

    EPROM: The chip in an LH2.2 ECU is this funny kind of chip called EPROM. EPROM stands for erasable programmable read only memory. It's erasable by UV light, it turns out. So the chip at the heart of the ECU has a quartz window in it that is normally covered by a sticker. The LH2.2 chip has a standard number 2732. This I found out through extensive googling. You can get 2732 chips on Ebay for very cheap.

    BIN File: The file on the chip, that tells the ECU what to do. These are 4 somethings large. I think 4kb? Very small. Near as I can tell, the BIN stands for BINary. This file contains a fuel map that takes load/airmass and rpm information as input and outputs the amount of fuel that goes into the engine. It also contains a table of acceleration enrichment values, warm-up enrichment values, warm-up idle values, acceleration enrichment values, and full-throttle values. It's quite simple.

    So, I need to get the BIN file off of the chip and onto the computer, so I can modify it. Then I need to erase the chip, and put the BIN file back on the chip.

    More on that in a little while.
    Echo! Is anybody listening?

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  2. #2
    Mike
    Moderator Shazam's Avatar
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    Saab(s)
    1973 96
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    Wow... that sounds cool. We do have a "Blog" function if you find that fits your needs better than the regular forum. Keep us updated!

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  3. #3
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    I normally do everything off of my Macbook, because it allows me to do multilingual work better than does a PC. Accent key combinations stay constant across multiple applications. I found two LH editors on ECUProject, but unfortunately they both work off of PCs.

    Enter the White Box:
    64k RAM, 200mhz Pentium Pro, 6gb HDD. What a screamer!

    It was originally running Win95, but my computer-geek friend (the one with the T16) says that 2000 is a lot better. Can read flash drives and modern DLL files and stuff. I got a copy of Windows 2000 and put it on...and she boots!

    Now for software: There are two editors. One is more used among the (small) LH tuning community This one is called LH22edit10. The other one is Weird but may prove useful. It is named "lheditor". First one was made by some crazy Swede who calls himself Ragnar on Saabnet. Second one came from someplace? I'm going to try and attach files of these, since they're all over the internet and nobody seems to ever mention copyright, so I assume they're freeware. Since I can't seem to attach these files to a forum thread, I am going to stick my neck out and say that anybody who wishes to get a copy can PM me.

    I'm running LH22edit10 now. Here is a pretty picture of a map!
    Name:  lhmap2.jpg
Views: 1684
Size:  137.2 KB

    And here is a pretty picture of the other tab, with values for warmup enrichment, idle, accel enrichment, a rev limit value, and a "control constant" that has to do with injector pulse.
    Name:  lhmap3.jpg
Views: 1661
Size:  69.1 KB

    In addition, I have lots of BIN files, which I found from this site. There are more on ECUProject, but you must be a member. Again, PM and I'll send you everything in a zip file of goodness.

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  4. #4
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    Quote Originally Posted by Shazam View Post
    Wow... that sounds cool. We do have a "Blog" function if you find that fits your needs better than the regular forum. Keep us updated!
    I'll see--if this turns into more than a simple "this is what I did" thread, I'll put it into the blog. As of now, I figured the c900 forum could use some color and I just happened to be doing it. I can link to here from anywhere, so I figured I might as well do it here

    A little background on why I'm doing this: My ECU is funny. It does funny things with warmup and funny things when very hot. After I put in the 89 thermostat and ditched the 82, it's gotten worse. I have a strong suspicion this may be the warmup enrichment or idle speed, or both. The Wikipedia article on EPROM indicates it has a lifespan of approximately 10-20 years. My car's past that by a long shot, so it could very well be an EPROM issue. Senescence, as I like to see it. I always did compare my ECU to a hockey player who's had one too many concussions. Maybe it's better to compare it to an old man with Alzheimer's.

    So I'm not a tuner. But I'm learning to "tune" anyway, just to fix the underlying problem. I figure this will enrich the community, and I'm underemployed, so my time is worth next-to-nothing anyway. Might as well fiddle with ECUs! I will get a turbo engine someday and switch to Trionic 5.5, and then I'll cook with gas. For now, I stay with mostly stock 900 and learn to fix it proper-like.

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    Last edited by euromobile900; 04 September 2010 at 05:49.

  5. #5
    Masterfully Slow Learner SPGreg's Avatar
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    Three SPGs
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    This is interesting! Thanks for doing this. I will be following along.

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  6. #6
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    OK so, I'm ordering some things off of the internet, so I have a way to do this with no risk to my current setup.

    The first thing I need to order is a new (old) ECU, which is coming from eBay. I can get the EPROM chip out of it, and then commence messing with it.

    The second thing I need is the device to mess with the EPROM chip. I have found a few, one of which is fairly affordable. They look fairly techy, like this:

    They usually hook up to a PC only, via parallel (huge! like an old printer) cable, and are driven by .exe drivers, so the White Box should do handsomely!

    Next update will occur when I've gotten the chip flasher and the new ECU. I'll keep you posted!

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    Ask me a question about your c900! I promise I either can answer it or know someone who can

  7. #7
    Saab Fan
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    Saab(s)
    1985 Saab 900 SPG
    Thumbs Up:   0
    Any luck with burning eproms?

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  8. #8
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    Currently my gearbox is having trouble! I need to get that sorted before I'll be back to trying to muck with the ECU.

    That said, I can give you some tuned .bin files if you like! I think I have one around here somewhere for the 34# injectors.

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  9. #9
    Saab Fan
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    1985 Saab 900 SPG
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    I've been through 3 transmissions in under 3 years so I know the trouble. I've done some experimenting with eproms myself and I have made a rough tune for the 34# injectors. Ragnar's editor is a big help but it is still not an easy task to fine tune. My tune works well enough to be driven daily, its a bit rough in spots, but I want to try to dial in the AFR to 12.5:1 to 12:1 at about 20 psi. Problem is it requires so much testing to dial it in I have a feeling I will break my transmission again before I can dial it in. Im not driving it in the winter, but in the spring I'll be spending time experimenting with Megasquirt and LH 2.2 again. Is the tune you have for the 34# injectors from Raul (ECUProject.com • View topic - I relese my tune for LH2.2 34lb/hr inj) or do you have something different? I have Raul's tune but haven't tried it because it requires adjusting the AMM and mine is perfect so I don't want to touch it.

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  10. #10
    Sam Carlson
    Tutorial Bot euromobile900's Avatar
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    Saab(s)
    '90 900 LPT with a flat-nose conversion
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    Yeah, mine's from Raul. Sounds like you know the ECU Project forum better than I do! Too bad Raul is so...well...abrasive. Sounds like he knows a lot.

    Do you know much about adjusting the AMM? I've done a rough adjustment, trying to get it to swing the oxygen sensor voltage up and down at idle, but I am probably off. Of course I don't have access to a CO meter. I hear you can do it by attaching a pulse-ratio meter to some test-connection somewhere. Since a dwell meter is a type of pulse-ratio meter, I think I could probably do this easily if I just knew what pins to put where. Any ideas?

    Thanks!

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    Ask me a question about your c900! I promise I either can answer it or know someone who can

 

 

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