Hi all

I have read the other postings and have a similar problem but with a small difference. This system is on my 13b street port race car. After the car warms up the car runs great (Coolant temperature at170 to 195). The idle is fine, the AFR good at all rpm and loads, great power, no dead spots all the way to 9000RPM. Last race took pole and first place with the Mega Squirt system (Works fine).

At this time I have no logs to post but I will describe how it starts and may be some one has worked through the same problem. Please note race engine no extras on it such as pollution controls BAC, vacuum throttle actuators and so on. This is not an electrical or mechanical problem strictly cold start tuning issue.

START UP PROCEDURE

Turn on power, turn on ignition, turn on fuel pump, hit starter button. Air temp and engine 65 (Not very cold)

Cranks for two to three then starts and runs for two seconds and dies. As if I hit the kill switch.

To restart each time I wait two seconds and only hit the start button. Every time it catches and starts perfectly as fast as I hit the start button. It idles smooth at 1200 RPM with AFR of about 12.7 to 12.9 then dies with a quick shut down.

On every restart it catches and idles good but dies after more time has passed. First start idles 2 seconds, second start idles 2 seconds, third start idles 3 seconds, forth start idled 5 seconds, fifth start idle 8 to 10 seconds, sixth start idles 15 seconds, seventh start it runs for 20 to 30 seconds then dies. Then after about 10 push button starts it could idle for about 1 minute then it dies. Then after about the time frame of idling for about1 minute on the next restart it idle all the way up to 195 degrees.

Now you have an idea of what is happening. I just do not understand why it starts so well and idles so well then shuts down as if someone came along and turned it off.

It is not the cold cranking set up because it all ways catches and idles. It is not the AFR Table 1 at the idle section because when it is up and running after the starting issue it idles with12.7 to 12.9 until it quits.

What could it be? See attachments

SCCA RX7 RACER

 

Your warmup enrichments below 160 degrees should be greater than 100. It dies after the afterstart enrichment expires. I expect that a log would show that it leans out then dies (if your wideband O2 sensor reads during startup - mine always resets during cranking so it doesn't give valid readings for 10-20 seconds).

Glad to hear it's going well on track.

 

Marty I will try what you have mentioned tomorrow morning at my shop it will be stone cold and it makes sense. Yes it does lean out just like some one has turned off the fuel. I can only see it on my AFR gauge on the longer cold start just before it dies. You are also right about the wide band giving me no information on the first million starts. That is why I find it had to trouble shoot my problem.

I hope you car is doing well on track as well. I have up graded my transmission for a turbo to a stock one with Miata gears and switch from Toyo RA1 to Hoosier R6 radials. I am allowed to run slicks but so far I have been doing well on the R6 radials (First time this season).

I hope I can post positive results tomorrow night about my cold start issues.

SCCA RX7 RACER

 

Thanks for your help I tested the cold start this morning and backed it up with one at the end of the day. A little rich right now but after one start and stall it catches and warms up to 185 no stalling. The numbers that I used for others that want to know are -40 160, -20 160, 0 160, 20 160, 40 160, 60 120, 80 115, 100 110, 130 100, 160 100.

Thanks again
Ready for the track!!!