Citroen GSA 1129

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Jaan
MegaSquirt Newbie
Posts: 4
Joined: Wed Jun 24, 2009 12:03 am

Citroen GSA 1129

Post by Jaan »

I have been aware of MS for ages, but when I visit the success story pages I often found long lists of dream motors being assembled, but no descriptions of how things were actually running or being tuned. The few that were running alluded to a long learning curve.

I converted this car from carb to a Throttle body injection, & used a brain from a 3cylinder GEO Metro. Using a jimstim 1.3 I queried the brain & hacked into it with a soldering iron & some old guitar amplifier parts. It has been a daily driver that way for about a year & a half. Huge improvement in torque & power. Depending on how I set it up mileage was the original 25 MPG US gal, sometimes 30mpg, & down to 21 mpg when I had a sensor failure.

So I dove in & bought an MS last week. What did I learn ?

1: The manuals are tough to read online: http://www.megamanual.com/mtabcon.htm Better retention when printed out & read with a highlighter.

2: A Stimulator is essential to make sense of the tuning program. Build one of those first.

3: The Megasquirt works fine. Using it's built in suggestion tools I came up with a VE table & a REQ fuel. It fired up instantly & ran as well as with the GEO computer after 3 minutes of changing the REQ fuel around.

4: Doing everything at once can make you crazy. I know we all want ignition control, turbo, nitrous & whale sounds at the same time, but start with fuel only, then add ignition.

5: An MS 1 with 8x8 tables is still a great tool. You can always update later, & the simplicity is good for keeping confusion down.

6: This thing is running well without autotune or an oxygen sensor. Don't be afraid, just go for it.

& there you have it. When I graft in an O2 sensor I'll make another post of findings.

Here's to the B& G Fan club.

Jaan Hjorth
eddinsmoto.com
Jaan
MegaSquirt Newbie
Posts: 4
Joined: Wed Jun 24, 2009 12:03 am

Re: Citroen GSA 1129

Post by Jaan »

Ok, it's been about a year. The MS runs faultlessly. I put an O2 sensor in & figured out how to use autotune. Tried many different VE tables & they all run great. Mileage is a constant 30Miles per US gallon in my mixed driving & I live at the top of a giant hill. In the flatlands I'm sure it would be even better. Didn't get around to MS controlled ignition yet. Maybe I'll build another one with multiport & ignition some day. In the meantime, the MS works exactly as I had hoped. Thanks to all involved !

JH.
Jaan
MegaSquirt Newbie
Posts: 4
Joined: Wed Jun 24, 2009 12:03 am

Re: Citroen GSA 1129

Post by Jaan »

Started another conversion, this time using MSII & ignition. Started with the Ignition first & good thing. It wouldn'r run, I learned a few things: A V3.57 surface mount board does not always have the (Q16) transistor to drive an ignition installed. Also, jumpering is involved on a V3.57 though I don't recall seeing that in any manual

Runs much better with the ignition than previously with a stock distributor, Why ? Better dwell controll ? Who knows.

Anyway, on to multiport injection. & MSII
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