Crank ISC duty cycle

[CJK440]

Copying over the BSK cells to MBT (reduced the values) killed the flare. So much that I had to go put the ISC Duty cycle table back to stock to get it to start.

 

[03Steve]

There you go.

 

[04torchred]

Copying over the BSK cells to MBT (reduced the values) killed the flare. So much that I had to go put the ISC Duty cycle table back to stock to get it to start.

Sorry to dig this old thread up, but I am having a very similar issue on start up. Car has the TPS set to 0.9 volts(key on engine off), throttle blade has been opened up to allow the IAC duty cycle to be around 0.26-0.3 when warm. Car idles well at 800-850rpm when at operating temp.

But same problem as original poster. Cold start it fires up and then dies unless I add throttle input. Same thing happens with a restart if I shut the car down between 60*F up to around 150*F. It fires, flares up to 2000rpm and then rpms fall and it dies unless I stab the throttle a bit. Then it revs up again and steadies out on its own and idles just fine.

So far I have zero'd out the base fuel table cold enrichment decay time table. Seemed to have helped some as I dont need to pedal input as much to get it to steady out.

I just found this thread so I am going to try logging the spark source tonight and see what I can find.

Any thing you can share on what finally ironed out your tune would be great. This same setup with a smaller MAF (JLT 110mm, now has a 123mm crusher MAF) has started fine with a tune from Lund Racing so I must just be missing something on my tune. WOT fueling is good, I just have an ever so slight part throttle stumble at low rpms when you stab the gas a bit, but I am sure I just need to mess with some transient fueling after. That issue only seems to happen on the first stab, don't notice it if you stab again quickly.

 

[03cobra#2]

Just some ideas: the crank isc is during start up, so that's the initial start / fire up. I would look at a table that adds additional rpm at start up. Also make sure you are not going right into closed loop to give your 02's time to heat up. Just some ideas.

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[04torchred]

From 3 logs I grabbed yesterday it appears to hold a nice start and idle following the start if I am remaining on idle source 9. When it switches to idle source 1 my rpms immediately fall and the idle starts to surge or stall.

When its in idle source 9 its holding around 15 degrees as its warming up and then between 18-21 degrees of timing as a range. As soon as it hits spark source 1 it drops to spark as low as 5 at times.

My open loop flag field appears to just stay on zero which seems wrong. The Open loop timer is giving me a value, one log had 63 seconds.

Wideband A/F on the cold start is showing mid 10's to mid 11's.

Seems like the spark is some of my issue with it not wanting to stay running.

In livelink it shows the spark source values, but does anyone know what tables those actually reference in PRP?

I don't know what Spark Source 9 is - Idle Feedback (is this your MBT table or Borderline?)
Spark Source 1 - Base (none of the values in my borderline table or MBT spark go this low at the load ranges I am showing at idle)

More info. My Throttle position absolute at idle is 169, at a coolant temp of 76*F its showing Idle air duty cycle at 0.60 and integrator is calling for varying amounts(0.05 up to 0.23)

 

[03cobra#2]

Couple quick things. Monitor your STFT's. If they stay fixed you are in open loop. After the car warms up and runs a bit you should go to closed loop and the STFT's should bounce around a bit. That's a easy to tell of you are in open vs closed loop. For the Spark source codes, source 9 is what you want at idle, that will refrence your idle spark settings. Spark source 1 is going to reference the borderline / MBT table.

I would make sure your car is up to full operating temp before you start logging and trying to dissect logs. Once you figure the idle ironed out at warm operating temp, then turn your attention to your cold starts / idle if you are still having a problem.

 

[04torchred]

Couple quick things. Monitor your STFT's. If they stay fixed you are in open loop. After the car warms up and runs a bit you should go to closed loop and the STFT's should bounce around a bit. That's a easy to tell of you are in open vs closed loop. For the Spark source codes, source 9 is what you want at idle, that will refrence your idle spark settings. Spark source 1 is going to reference the borderline / MBT table.

I would make sure your car is up to full operating temp before you start logging and trying to dissect logs. Once you figure the idle ironed out at warm operating temp, then turn your attention to your cold starts / idle if you are still having a problem.

Thanks for the info. The car will idle really well for me. Warm or cold it idles well.

My big problem is getting it to start nicely when cold without having to add throttle input to save it from stalling. That is my big issue I am trying to sort out now. It seemed like it was too rich at first, I had to give it a lot of throttle input to keep the car running when cold. I zero'd out the Base Fuel Table Cold Enrichment Decay Time.

Maybe that is the wrong table? Should I have zero'd the Base Fuel Table Enleanment when Cold table?

Either way reducing the table I did to 0 across the board helped the amount of pedalling I had to give it on a cold start to keep the car running and AF does look not so rich. However its still 10 AFR when first started but gets closer to 14 on my wideband in less time.

What I noticed on a log was its idling fine off Spark Source 9, but at spots in the log it will start to switch to Spark Source 1 and that seems to cause grief to the cold idle/cold start. Not sure of this issue.

I just took my bottom 2 rows (0.15 load and 0.25 load from in the 40's for spark down to 30) of my MBT spark table and going to try another start. This might fix the flare, but not sure if its going to fix the spark source switch from 9 to 1 at idle.

Any ideas on the cold start and having to pedal it? Also the spark source randomly switching?

 

[03cobra#2]

Thanks for the info. The car will idle really well for me. Warm or cold it idles well.

My big problem is getting it to start nicely when cold without having to add throttle input to save it from stalling. That is my big issue I am trying to sort out now. It seemed like it was too rich at first, I had to give it a lot of throttle input to keep the car running when cold. I zero'd out the Base Fuel Table Cold Enrichment Decay Time.

Maybe that is the wrong table? Should I have zero'd the Base Fuel Table Enleanment when Cold table?

Either way reducing the table I did to 0 across the board helped the amount of pedalling I had to give it on a cold start to keep the car running and AF does look not so rich. However its still 10 AFR when first started but gets closer to 14 on my wideband in less time.

What I noticed on a log was its idling fine off Spark Source 9, but at spots in the log it will start to switch to Spark Source 1 and that seems to cause grief to the cold idle/cold start. Not sure of this issue.

I just took my bottom 2 rows (0.15 load and 0.25 load from in the 40's for spark down to 30) of my MBT spark table and going to try another start. This might fix the flare, but not sure if its going to fix the spark source switch from 9 to 1 at idle.

Any ideas on the cold start and having to pedal it? Also the spark source randomly switching?

So cold fuel enrichment is for after the car is started. Crank lambda table is what is used to adjust fueling at startup. Also you may need to add air during cranking. Can't remember the table but you could look at that too.

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[Lou02stang]

Thanks for the info. The car will idle really well for me. Warm or cold it idles well.

My big problem is getting it to start nicely when cold without having to add throttle input to save it from stalling. That is my big issue I am trying to sort out now. It seemed like it was too rich at first, I had to give it a lot of throttle input to keep the car running when cold. I zero'd out the Base Fuel Table Cold Enrichment Decay Time.

Maybe that is the wrong table? Should I have zero'd the Base Fuel Table Enleanment when Cold table?

Either way reducing the table I did to 0 across the board helped the amount of pedalling I had to give it on a cold start to keep the car running and AF does look not so rich. However its still 10 AFR when first started but gets closer to 14 on my wideband in less time.

What I noticed on a log was its idling fine off Spark Source 9, but at spots in the log it will start to switch to Spark Source 1 and that seems to cause grief to the cold idle/cold start. Not sure of this issue.

I just took my bottom 2 rows (0.15 load and 0.25 load from in the 40's for spark down to 30) of my MBT spark table and going to try another start. This might fix the flare, but not sure if its going to fix the spark source switch from 9 to 1 at idle.

Any ideas on the cold start and having to pedal it? Also the spark source randomly switching?

Any updates to this i am having the same issue with spark source at idle changing from 9 to 1