SCCA RX7 RACER

Hi All

The engine is running really smooth at an idle at this time. Best in the whole time I have been using the Mega Squirt.

I am running MS1 on a V3 board with the pull up resistor. I am using the 24 wheel with the two teeth missing opposite each other.
Settings are:

Wheel Decoder Base Teeth 12
2nd Trigger Enable OFF
Missing Teeth -1

Trigger A 1
Trigger A Return 3
Trigger B 7
Trigger B Return 9

Dual Dizzy Mode Normal
Wheel Decoder Routine 024s9stye

Spark Settings

Trigger Angle 60
Trigger Angle Addition 0
Crank Timing Trigger Return
Crank Advance Angle 0
Hold Ignition 0
Fixed Angle -10
Trim Angle (Deg) 0

Timing Map set at 3 Deg. BTDC for 1000 RPM all the way up the chart (Top to Bottom vacuum columns)
Timing Map set at 10 Deg. BTDC for 2500 RPM all the way up the chart (Top to Bottom)
Timing Map set at 26 Deg. BTDC for 5500 RPM to 9000 RPM all the way up the chart (Top to Bottom)

With the above setting and with the motor at an idle of 1500 RPM (Large street port for racing) Water Temp 185, AFR around 12.3 to 12.5. All is good. This is what is happening.

Spark advance on the Lap Top shows 5.1 BTDC which makes cense since it is up from the 1000 and between the 1000 and 2500 RPM. But the timing light on number one leading is showing off the crank pulley the spark plug firing at 2.5 ATDC a difference of about 7.5 degrees. Also at High RPM where total advance should be at 26 Deg I only get about 18 Deg of timing with the light off the pulley marks. Again a difference of about 8 degrees. What am I doing wrong to have these discrepancies?



Thanks in Advance
Kim

SCCA RX7 RACER

I am finding that the spark for # 1 Leading is now working but has a small miss once in a while. Also # 2 Leading is cutting out then coming back to life. Could this be connected to my timing off issue?

Note All new plugs wires and swapped out coils from another car that was running fine.

Kim

Aaron Cake

iTrader: (1)

You may see a miss every once in a while just due to the nature of the engine. I've never seen a rotary which doesn't miss at low RPMs sometimes which will cause timing to jump for a second.

As for trailing, what is your idle speed? Remember MS1 doesn't fire trailing below 1000 RPM.

Did you ever set static timing? Set fixed angle to -5, them move the CAS until the pointer lines up with the leading mark. Then set fixed angle back to -10. Yes, there may be a degree or two difference because the CAS has some slop and MS1 timing calculations are only to the degree. Plus they run as a loop in the main program so are subject to some jitter.

SCCA RX7 RACER

Hi Aaron

Timing is set bang on to -5 static yes I am on -10 and because of the trailing not firing below 1000 I always set my idle at 1500 (Large street port poor idle qualities). This engine is in my EP race car.

I have tried to adjust the timing with more advance as it is running just for testing purposes but as I add in say + 10 deg of timing the mark with the timing light stays at 2 ATDC. I would think at my idle speed the light should show the changes I am making on the lap top. AFR changes can be made I see LC1 and hear them as the engine is running so the fuel end is working.

It is not wiring or the hardware on the car I do not run junk to burn my self. Last Season the car set track records in my area so the MS was working as it should.

I would love to solve this problem if it is simple enough. I started another tread about getting a MS3X unit if all attempts to fix this one fails.

Kim

Aaron Cake

iTrader: (1)

OK, so you are saying that timing adjustments in the table don't change the timing at the pulley?

Have you tried another timing light?

There's really nothing to say about timing on the MS1. With the CAS lined up, the ECU will command the timing in the table unless it is locked. Can you post your MSQ? Perhaps a short datalog of the problem?

SCCA RX7 RACER

I looked at the DB37 connection and it was 100%. But during my inspection I notice my fire bottle bracket has come loose and banged in to the MS box on the floor beside it under braking at the race track. The box was bent by about 1/8 to 3/16th of an inch. The V3 board's DB37 plug is attached to the end plate and the V3 board it must have been damaged. When I put it together and back in the car now I have nothing in the spark out put. Before I had great spark, then it would cut out, jump back in and now dead. I looks like this on is done.

I placed an order with DIY Tune for a Pro 3 unit but by mistake clicked on the MSIII order tab. Thinking Mega Squirt III was the part number for the latest Pro 3 unit. I just counted down in order from I to II to III and thought it was the one. I ordered the 3 Bar sensor and plug as well from there other page. This was Friday then over night I did more reading about what I purchased (MS3X) thinking it was the Pro3 and went what the F##k. Sh*t. I e-mailed them Saturday in the morning to up grade the order to the Pro 3 unit. I hope I caught it in time. If not I will see if it can be returned and get the Pro 3 unit.

Kim