Idle surge (mostly in Park/Neutral)
01-25-2016, 06:36 PM
#81
Just tried statesmans base tune and it's worse, now the car surges even cold and by the time it gets warm it won't run without throttle input (I did put the "correct" IFR table from the spreadsheet into it, apparently the version of my tune he modified was one which had the old guestimate table in it which overestimated the flow at the upper end of the table.
I pedaled it around long enough to get a little VE adjustment which didn't change very much from where it was.
I can't even do a rafig because it just surges hard a few times then dies.
Is that any kind of clue as to where to look next? The quick VE touch up put LTFT in the 1% to -2% range at light cruise. There is about a 2% variance bank to bank. Car still drives around fine but can't idle at all in P/N or gear.
Don't want to mess with much until results have been reviewed for ideas.
I pedaled it around long enough to get a little VE adjustment which didn't change very much from where it was.
I can't even do a rafig because it just surges hard a few times then dies.
Is that any kind of clue as to where to look next? The quick VE touch up put LTFT in the 1% to -2% range at light cruise. There is about a 2% variance bank to bank. Car still drives around fine but can't idle at all in P/N or gear.
Don't want to mess with much until results have been reviewed for ideas.
01-25-2016, 07:45 PM
#84
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
This really sucks for you, and I'm really sorry it's still ongoing. Here is a bit of an unorthodox suggestion, based on re-reading the entire thread.
it seems to me that you had the best overall luck when your IAC counts were near 20 at warm idle - back on 12/9/15. It may not matter what the car "should" need, but what it actually seems to want. Maybe go back to that tune as well before you locked in your idle to open loop only. Having the blade open more should at least prevent the stalling. Hell, I've seen some people running IAC counts of 5 at warm idle and ONLY using the IAC as an air ADDER with no capability to subtract. If it idles fast, it ends up cutting timing.
After getting your TB back to that point, look at your airflow modes and oxygen sensor voltage tables. It's really strange, but basically, there is a table that divides your airflow by g/sec into "modes" ranging from 0-16. Then there is another table that tells the computer the target oxygen sensor voltage for each airflow mode. You're idling at, say 1.2 lb/min, which is 9.1 g/sec. Now, with the idle surging, figure 6 to 13 is probably fair game?
In that table, set the airflow mode to "2" for 12 g/sec and lower. Then set the target oxygen sensor voltages for airflow mode 2 to 100mV for both banks. 451mV is stoich. Put it back in closed loop and let the O2's trim it, but this will aim for about 15.5 AFR. it will start rich and then trim its way down. If it trims VERY negative, you might have to adjust your MAF and VE and re-do it a few times.
I wish I weren't speaking HPT vs EFILive, cause this probably makes no sense. It would all be under "Open and closed loop" if this were HPT.
I've done myself way wrong before by doing changes on top of changes on top of changes, and the tune simply drifted way too far. Went back to a last known good tune to get rid of all my changes and start over, but do nothing that didn't help.
it seems to me that you had the best overall luck when your IAC counts were near 20 at warm idle - back on 12/9/15. It may not matter what the car "should" need, but what it actually seems to want. Maybe go back to that tune as well before you locked in your idle to open loop only. Having the blade open more should at least prevent the stalling. Hell, I've seen some people running IAC counts of 5 at warm idle and ONLY using the IAC as an air ADDER with no capability to subtract. If it idles fast, it ends up cutting timing.
After getting your TB back to that point, look at your airflow modes and oxygen sensor voltage tables. It's really strange, but basically, there is a table that divides your airflow by g/sec into "modes" ranging from 0-16. Then there is another table that tells the computer the target oxygen sensor voltage for each airflow mode. You're idling at, say 1.2 lb/min, which is 9.1 g/sec. Now, with the idle surging, figure 6 to 13 is probably fair game?
In that table, set the airflow mode to "2" for 12 g/sec and lower. Then set the target oxygen sensor voltages for airflow mode 2 to 100mV for both banks. 451mV is stoich. Put it back in closed loop and let the O2's trim it, but this will aim for about 15.5 AFR. it will start rich and then trim its way down. If it trims VERY negative, you might have to adjust your MAF and VE and re-do it a few times.
I wish I weren't speaking HPT vs EFILive, cause this probably makes no sense. It would all be under "Open and closed loop" if this were HPT.
I've done myself way wrong before by doing changes on top of changes on top of changes, and the tune simply drifted way too far. Went back to a last known good tune to get rid of all my changes and start over, but do nothing that didn't help.
01-25-2016, 08:09 PM
#86
Since I don't have EFILive... are you running closed loop? It seems like you are. You have to tune the O2s... sort of like what Darth is suggesting (I'd just set the switchpoints to 300mV if you want to run closed loop - it's a hack way of tuning but who cares it works) or run OL at idle like me and don't worry with it. Big cams dump a ton of fuel and the O2s still keep adding fuel at idle. So it becomes a continuous loop of pig rich tail chasing.
01-26-2016, 04:22 AM
#88
With Bi-DI controls you should be able to eliminate the problem if it was caused by a rich condition by turning your AFR way up. By disconnecting your brake booster and the idle getting better, I would think it was an air problem. Try opening your throttle blade up to were it idles and your IAC doesn't have control anymore and see what it does.
01-26-2016, 05:33 AM
#89
Staging Lane
Join Date: Nov 2015
Posts: 96
Likes: 0
Received 0 Likes
on
0 Posts
Okay, I finally figured out what the problem is... your engine is choking at idle.
I thought it was odd that my base tune made your surge worse... that shouldn't have happened. One of the changes I made in that tune was to the IAC effective area table and I bumped up the desired airflow to compensate, but I didn't bump it up enough. That made your engine choke even more at idle. The idle airflow corrections tables should have easily taken care of that, but they didn't... so I went into your tune to have a look at your airflow corrections settings. What I found was the direct airflow correction and learned airflow correction were both disabled. You had no airflow correction at all. You only had spark correction trying to keep the idle stable, which is too much to ask when airflow is insufficient.
I've made a new base tune for you. This one has everything set up properly and will work well.
I thought it was odd that my base tune made your surge worse... that shouldn't have happened. One of the changes I made in that tune was to the IAC effective area table and I bumped up the desired airflow to compensate, but I didn't bump it up enough. That made your engine choke even more at idle. The idle airflow corrections tables should have easily taken care of that, but they didn't... so I went into your tune to have a look at your airflow corrections settings. What I found was the direct airflow correction and learned airflow correction were both disabled. You had no airflow correction at all. You only had spark correction trying to keep the idle stable, which is too much to ask when airflow is insufficient.
I've made a new base tune for you. This one has everything set up properly and will work well.
01-26-2016, 06:49 AM
#90
On The Tree
pretty much exactly the same here, changes at times, most of the time does not surge to bad in gear, but out after warm its like a blown alcohol car...now have over 2' snow not much happening !!!!
01-26-2016, 08:39 AM
#91
Okay, I finally figured out what the problem is... your engine is choking at idle.
I thought it was odd that my base tune made your surge worse... that shouldn't have happened. One of the changes I made in that tune was to the IAC effective area table and I bumped up the desired airflow to compensate, but I didn't bump it up enough. That made your engine choke even more at idle. The idle airflow corrections tables should have easily taken care of that, but they didn't... so I went into your tune to have a look at your airflow corrections settings. What I found was the direct airflow correction and learned airflow correction were both disabled. You had no airflow correction at all. You only had spark correction trying to keep the idle stable, which is too much to ask when airflow is insufficient.
I've made a new base tune for you. This one has everything set up properly and will work well.
I thought it was odd that my base tune made your surge worse... that shouldn't have happened. One of the changes I made in that tune was to the IAC effective area table and I bumped up the desired airflow to compensate, but I didn't bump it up enough. That made your engine choke even more at idle. The idle airflow corrections tables should have easily taken care of that, but they didn't... so I went into your tune to have a look at your airflow corrections settings. What I found was the direct airflow correction and learned airflow correction were both disabled. You had no airflow correction at all. You only had spark correction trying to keep the idle stable, which is too much to ask when airflow is insufficient.
I've made a new base tune for you. This one has everything set up properly and will work well.
And yes, the tune is already an open loop tune and was working fine...until I replaced the injector orings one of which was almost certainly a vacuum leak. Would explain why the problem started then if it no longer was receiving enough air to idle correctly.
But I do not understand why manually moving the IAC counts higher wouldn't have helped? Could the IAC itself be damaged?
I'll start with trying the tune you posted and go from there. If it will at least stable out enough to perform a RAFIG and/or let me adjust DVT controls without stalling out it should help fine tune everything.
01-26-2016, 11:46 AM
#92
Awesome! I will try it after work today and get a log as well. Is there anything specific you would like logged or will a typical default plus IAC and wideband reading be sufficient?
And yes, the tune is already an open loop tune and was working fine...until I replaced the injector orings one of which was almost certainly a vacuum leak. Would explain why the problem started then if it no longer was receiving enough air to idle correctly.
But I do not understand why manually moving the IAC counts higher wouldn't have helped? Could the IAC itself be damaged?
I'll start with trying the tune you posted and go from there. If it will at least stable out enough to perform a RAFIG and/or let me adjust DVT controls without stalling out it should help fine tune everything.
And yes, the tune is already an open loop tune and was working fine...until I replaced the injector orings one of which was almost certainly a vacuum leak. Would explain why the problem started then if it no longer was receiving enough air to idle correctly.
But I do not understand why manually moving the IAC counts higher wouldn't have helped? Could the IAC itself be damaged?
I'll start with trying the tune you posted and go from there. If it will at least stable out enough to perform a RAFIG and/or let me adjust DVT controls without stalling out it should help fine tune everything.
01-26-2016, 12:02 PM
#93
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
To answer the question about higher counts, it's sort of the opposite. If your IAC counts are low, you're getting more air. If they are high you're getting less air and the computer is trying to add.
You reach a point of diminishing returns where the IAC opens a lot but doesn't get much more air.
Aftermarket throttles are even worse because the IAC port is smaller. So the computer can command all the air it wants but it doesn't actually get more air.
It's the reason people end up drilling the blade. If your TPS volts are over 0.65 and your IAC is still in the 80's you'll probably want to drill to get it some air
You reach a point of diminishing returns where the IAC opens a lot but doesn't get much more air.
Aftermarket throttles are even worse because the IAC port is smaller. So the computer can command all the air it wants but it doesn't actually get more air.
It's the reason people end up drilling the blade. If your TPS volts are over 0.65 and your IAC is still in the 80's you'll probably want to drill to get it some air
01-26-2016, 06:16 PM
#94
Bleh....better. Car started and came up to temp then surged.
I tried barely adjusting the TB some to open it up and close it. Only effect was if I opened the screw enough IAC was 0 and it idled higher than it was set.
I tried as little throttle input as possible and found it to be LTFT at -12.5% so I tried reducing the VE by that and no go. So I tried 4% less than that and still no go.
Attached are the tune and 3 logs. Last log is a warm start with the adjusted VE.
I tried barely adjusting the TB some to open it up and close it. Only effect was if I opened the screw enough IAC was 0 and it idled higher than it was set.
I tried as little throttle input as possible and found it to be LTFT at -12.5% so I tried reducing the VE by that and no go. So I tried 4% less than that and still no go.
Attached are the tune and 3 logs. Last log is a warm start with the adjusted VE.
01-26-2016, 07:31 PM
#95
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
When you open it just enough to get to zero IAC, kill the motor, unplug the TPS and IAC, key on but don't start for thirty seconds, key off, plug everything back in. That will rezero the TPS in the computer.
Start the car, should idle down. When you adjust the blade position, the TPS needs to be rezeroed or it will read a false 1% at idle.
Tuning for idle is such a pain
Start the car, should idle down. When you adjust the blade position, the TPS needs to be rezeroed or it will read a false 1% at idle.
Tuning for idle is such a pain
01-27-2016, 08:02 AM
#97
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,835 Likes
on
1,145 Posts
01-27-2016, 08:34 AM
#98
Didn't realize the sensors needed unplugged to reset I thought they just needed the key to be cycled a couple times. Going to try that. I will also check the voltage and see where it sits.
For ***** and giggles I might swap the coils from my truck on. A local tuner said he has seen 1 case where the car wasn't idling right but everything else was great...switched coils and it was cured. Longshot but it's easy enough to do.
For ***** and giggles I might swap the coils from my truck on. A local tuner said he has seen 1 case where the car wasn't idling right but everything else was great...switched coils and it was cured. Longshot but it's easy enough to do.
01-27-2016, 09:00 AM
#99
The FAST had a smaller IAC but was open around the blade much moreso than the NW. I had it set at .48V, but the IAC did less to help since the IAC port was more restricted.
Every time you flash the car, it resets them too.
01-27-2016, 09:04 AM
#100
I used to have a Fast 90mm tb and it was hell trying to get the car to run with it even after I tried porting the IAC port.
I bought this Ballistic Speed 92mm and was able to get it to idle fine on the 230/238 cam.
The problem I used to have was the opposite of now...it wouldn't idle for **** cold but once it was warm it was fine.
I bought this Ballistic Speed 92mm and was able to get it to idle fine on the 230/238 cam.
The problem I used to have was the opposite of now...it wouldn't idle for **** cold but once it was warm it was fine.