SCCA RX7 RACER

Hi All.
I have not been at this site for over a year. I have been tuning my E Production Gen 2 race car by trail and error and it seems to be working out. This Mega squirt seems to work all right (Not perfect but OK it may be me). In my class I manage to set new track records with out destroying the motor so this is a testament that it can work (with a lot of work LOL).

In the passed I have been only working on the program at middle to wide open throttle (That’s racing for you) for each track I run on. I have set up the warm up wizard for the cold start and it works ok. So now I am working on slow speed travels through the pits. Here is my problem.

I run a 13B street ported engine, stock throttle body, ported out stock intake runners, 550 primaries and 750 secondary injectors, stock coils, GM sensors, Wide band Lambda sensor, . 2” headers to a single custom 3” exhaust. I use a MS1 with a V3 board with the missing teeth on the CAS. I run off of a map sensor to tune. I have no issues with noise tack, water, air, throttle all are smooth like a baby’s bum (Car runs great on track).

If I bring up my throttle to 2500 RPM from a smooth idle and hold it (Map 45 to 50). The pulse width 1 for the primary injectors cut out like clock work. A time interval of 2 seconds and duration of .373 seconds. It goes from 2.8 to 0 then back to 2.8. At first I thought it was just running rich and cutting out. So I went to the lean extreme but it did not help. Then I went richer and did not help. SO HELP!!! What’s up with this cut out issue? Have some though on this problem and I will send a short data log and my MS program that I have developed to this point in a few hours.
Thanks all and happy tuning.
Kim

muythaibxr

Please post an msq and a datalog.

Thanks,

Ken

SCCA RX7 RACER

Hi All

Wireless is great I'm in my race car real time gathering the information and sending it from the driver seat. Any how I warmed up the engine to 180 and oil at 200. Here is what I have. Take a look and see if anything stands out at you. As I mention before this program works for a street port wide open at a race track with no problems. I no pollution control or anything stripped clean and ported. Use it as a staring point.
Thanks
Kim

SCCA RX7 RACER

I all so use the o29q firmware.

muythaibxr

I'll take a look later if I get a chance after work.

SCCA RX7 RACER

I hope this is some thing that I just missed in a setting some place in my program.
Thanks

renns

Kim,

Decel fuel cut is being triggered, which drops pulse width to zero until your engine speed drops down below 2000 rpm, which is the threshold you have assigned in your setup. You could just turn this feature off completely, or change settings to avoid this issue.

For reference, here's a pic of your present decel fuel cut settings.

muythaibxr

Thanks Renns, I didn't have a chance to look at the settings last night.

Renns is correct though, I usually run decel fuel cut with a MAP value of 28 kPa, and a TPS value 1 or 2 ADC points above my closed-throttle ADC.

Ken

SCCA RX7 RACER

Yes You HIT IT RIGHT ON!!!!
I'm in the car right now and with it off no drop out on the PW1.
Thanks