Hello everyone,
To make this as short as possible, I am working on a 2.2L engine off a 1995 Chevy S10 for my senior design project that we are currently trying to finish up (unfortunately, it needs to be finished in order to graduate). We have everything working right but at the moment are not too confident about what is going on with our ignition settings and circuit.
Since this engine is not in a car, we don't have any source of 5v that is not on when the engine is cranking and on when the engine is running as needed for the relay setup I see alot of people using for the IC bypass wire. The way we did it is we ran 5v from the proto area into the pin# 30 circuit since we don't have an FIdle solenoid. This way we ran Pin #30 out to the IC bypass wire on the ignition coil to always have 5v, even during cranking.
Well, using our megasquirt settings, we get the engine to start but it feels like it has a hard time starting. Once it starts (after playing with the throttle while cranking) it runs semi-ok. The next step I read was that we need to set our trigger offset (the one mega squirt displays) to match the value of the timing light by adjusting the trigger offset until the timing light reads the same value of megaTune. Well this is were we have our problem. At 1200rpm, which is what it stays it at the moment, megatune displays a value of 76* of advance on the trigger offset wizard. When we finally play with the trigger offset on megatune, we end up around a value of 56 and it is at this value that our timing light reads 76* of advance and it is "flashing" at TDC on the crank wheel. The problem is, the engine runs way rougher than our initial guess/calculation of 110 trigger offset at this new value of 56. I believe when we compared the timing advance on the stock ECU around 1000 rpm it was something around 20* advance, but will have to double check on this again....
I don't believe this problems we are having have anything to do with our fueling settings but any advice will help, it really seems to be an ignition issue and problem getting this trigger offset correct.
We really need help to sort this out, we are learning as we go and it's a very big plunge for us since this is also everyone's first stand alone experience. If anyone can point out anything they see wrong or offer any advice we would greatly appreciate your help. The following is what we have built on the board itself to help anyone reading this see any other potential mistakes we have made:
This engine uses the 4 cylinder GM DIS system. We have built the board doing the following modifications for this ignition setup:
JS10 to IGN[
OptoIn to TachSelect
TSEL to Optout
XG1 to XG2
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To use the GM DIS module, build your MegaSquirt® as shown in the GM HEI section. To connect the module to MegaSquirt:
* Module pin B or C - white wire - DB37 #36 (V3 main board, ignition output signal pin for V2.2), OK
* Module pin A - tan/black wire - Connect to a bypass relay as shown for the HEI modules, Getting 5V all the time, even during cranking
* Module pin E - purple/white wire - DB37 pin #24 (tach), OK
* Module pin F - red/black wire - ground, OK
* Module separate connector - black/white - ground, OK
* The module also has connections for power (pink), the crank position sensor (yellow & purple), and tach (white).
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And also megaTune is set according to this section I found here: http://www.megamanual.com/ms2/GM_DIS.htm
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Ignition Input Capture - Rising Edge
Cranking trigger - Trigger Rise
Coil Charging Scheme - Standard Coil Charge
Spark Output - Going High (Inverted)
Max Spark Duration - 25ms
Max Dwell Duration - 25ms
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GM I4 DIS & Trigger Offset Settings.
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Re: GM I4 DIS & Trigger Offset Settings.
Still searching for advice..... are we ok leaving the bypass to always recieve 5v or do you guys think that is something that needs to get fixed?