Idle trouble again.
Idle trouble again. I'm trying to get a big cam (250*) to idle and having trouble. I just noticed that I am seeing 80 kPa MAP at 1200 RPM idle. That seems way to high to me. Anyone have any experience with this?
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
That may well be the case.
You can use bidirectional controls to adjust spark and afr to minimise your idle map.
Then flash in the settings. You might need more spark. Or perhaps its the best you are going to get.
You will also need to dial in your desired airflow as crazycam says. 14 might be ok, but you really need to log stit and ltit's to see what they want to do to airflow.
My little 220 went from a stock 38kpa to only 40kpa.
You can use bidirectional controls to adjust spark and afr to minimise your idle map.
Then flash in the settings. You might need more spark. Or perhaps its the best you are going to get.
You will also need to dial in your desired airflow as crazycam says. 14 might be ok, but you really need to log stit and ltit's to see what they want to do to airflow.
My little 220 went from a stock 38kpa to only 40kpa.
Originally Posted by DVCrazyCamTAWs6
make sure your airflow decay is set, set airflows to 14.00
I have:
Idle->General->Desired Airflow (which is RAF with HPT I think), which is 8.6 g/s in the normal ECT range for in gear and 0 for P/N
Idle->Start-up->Startup Friction Airflow Decay, which is 0.05 g/s in the normal ECT range
Idle->Throttle Cracker->Throttle Cracker Decay Rate, which is 0.1 g/s below 12 MPH
Idle->Throttle Cracker->Throttle Cracker Decay Delay, which is 0 sec below 12 MPH
Idle->Throttle Follower->Throttle Follower Decay Rate in Gear, which is 0 below 12 MPH
Idle->Throttle Follower->Throttle Follower Decay Rate in P/N, which is 0 below 12 MPH
Idle->Throttle Follower->Throttle Follower Decay Delay in Gear, which starts at 3 sec at 0 MPH and tapers off
Idle->Throttle Follower->Throttle Follower Decay Delay in P/N, which is 0 at all speeds
None of these have look like what you are talking about.
cylair is running about 0.2 g/s and the MAF is running about 13 g/s. STIT starts around 3.0 and trails off to 0.2 g/s
IAC ramps from 70s to 250 while the idle stays in the 1100 to 1200 range. This also makes no sense. It is like the idle air bleed has no ahthority.
Thanks for the help.
Originally Posted by ringram
That may well be the case.
You can use bidirectional controls to adjust spark and afr to minimise your idle map.
Then flash in the settings. You might need more spark. Or perhaps its the best you are going to get.
You will also need to dial in your desired airflow as crazycam says. 14 might be ok, but you really need to log stit and ltit's to see what they want to do to airflow.
My little 220 went from a stock 38kpa to only 40kpa.
You can use bidirectional controls to adjust spark and afr to minimise your idle map.
Then flash in the settings. You might need more spark. Or perhaps its the best you are going to get.
You will also need to dial in your desired airflow as crazycam says. 14 might be ok, but you really need to log stit and ltit's to see what they want to do to airflow.
My little 220 went from a stock 38kpa to only 40kpa.
More info in the post above.
Thanks for the help
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
Ok so maybe you need a little more air from cold, but not when warm. with efi you can use a calc pid called rafpn and rafig which are for in gear and neutral. Just make a map to record these pids against ect and copy and add the difference to your raf/desired air table.
Thats that bit, the next part you really need to let it idle by itself and change afr and spark, use the bidirectional controls to do this and try and get it smooth and happy, you then might be able to drop idle speed down as well. You want it as lean as possible, but retaining good manners. The air will have sorted the idle air part out. Though a 250 IAC count is quite a bit. You might want to adjust your throttle stop to let more air through and zero your TPS count.
Mind you with a cam that big your 0.006 numbers are likely over 300 degrees so its a nice challenge to sort out idle.
Oh I assume you are running in speed density for this? If not then I suggest you might want to see what SD does as reversion can mess with the maf. Try the stickies on the efilive forum too.
Forget follower and cracker for now, they are used when coming to a stop and driving off from idle, worry about those later once you have static idle sorted.
I think the main thing is to play with the bidirectional controls and see what works best.
Thats that bit, the next part you really need to let it idle by itself and change afr and spark, use the bidirectional controls to do this and try and get it smooth and happy, you then might be able to drop idle speed down as well. You want it as lean as possible, but retaining good manners. The air will have sorted the idle air part out. Though a 250 IAC count is quite a bit. You might want to adjust your throttle stop to let more air through and zero your TPS count.
Mind you with a cam that big your 0.006 numbers are likely over 300 degrees so its a nice challenge to sort out idle.
Oh I assume you are running in speed density for this? If not then I suggest you might want to see what SD does as reversion can mess with the maf. Try the stickies on the efilive forum too.
Forget follower and cracker for now, they are used when coming to a stop and driving off from idle, worry about those later once you have static idle sorted.
I think the main thing is to play with the bidirectional controls and see what works best.
Originally Posted by ringram
Ok so maybe you need a little more air from cold, but not when warm. with efi you can use a calc pid called rafpn and rafig which are for in gear and neutral. Just make a map to record these pids against ect and copy and add the difference to your raf/desired air table.
Thats that bit, the next part you really need to let it idle by itself and change afr and spark, use the bidirectional controls to do this and try and get it smooth and happy, you then might be able to drop idle speed down as well. You want it as lean as possible, but retaining good manners. The air will have sorted the idle air part out. Though a 250 IAC count is quite a bit. You might want to adjust your throttle stop to let more air through and zero your TPS count.
The IAC behavior is just bizzarre. I will try to attach a screen shot for you. It did seem to help when I put an o-ring on the IAC motor I will also try my other TB, but I have to run out and get a pipe plug and tap the TB first.
Mind you with a cam that big your 0.006 numbers are likely over 300 degrees so its a nice challenge to sort out idle.
Oh I assume you are running in speed density for this? If not then I suggest you might want to see what SD does as reversion can mess with the maf. Try the stickies on the efilive forum too.
Forget follower and cracker for now, they are used when coming to a stop and driving off from idle, worry about those later once you have static idle sorted.
I think the main thing is to play with the bidirectional controls and see what works best.
I have attached the last two logs. I hope this site has enough sense to show thumbnails ...
Last edited by critter; Jun 2, 2009 at 07:52 AM.
