LQ4 LSXRT 102 FAST TB tuning issue
05-11-2014, 08:48 AM
#1
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
LQ4 LSXRT 102 FAST TB tuning issue I just finished my LQ4 swap in an old Nova and had it tuned yesterday. Its an LQ4 with CNC ported 243 heads, 228r 114 cam,LSXRT intake and a FAST 102 throttle body. Tuner warned me that the TB is really to large for my application and finicky to tune. We spent a long time working the just on idle stability and such and sometimes the idle will hang ( TPS and counts show TB closed) Some times on start up it idles perfectly @ 60 counts other times it take 90 or 100 to keep it idling. IAC responds like it should. Anyway after hours of tweeking and a few quick pulls on the Dyno it was running and driving very well( made 411 to the wheels through a A4) I trailer is home and fire it up in the trailer to unload and it fires right up and idles perfectly but as soon as I drop it in gear it stalls. So I fire it up and I can hear the IAC is open do to my intake and as long as I can hear it hissing it stalls when going into gear. If I let it run until I can hear the IAC closing down it goes right into gear perfectly. I basicity just put in the garage it had been a long day. I will be driving it this week to get an idea of what its doing.
So anybody have any ideas why is stalls going into gear clod?
TIA
So anybody have any ideas why is stalls going into gear clod?
TIA
05-12-2014, 01:02 PM
#2
I just finished my LQ4 swap in an old Nova and had it tuned yesterday. Its an LQ4 with CNC ported 243 heads, 228r 114 cam,LSXRT intake and a FAST 102 throttle body. Tuner warned me that the TB is really to large for my application and finicky to tune. We spent a long time working the just on idle stability and such and sometimes the idle will hang ( TPS and counts show TB closed) Some times on start up it idles perfectly @ 60 counts other times it take 90 or 100 to keep it idling. IAC responds like it should. Anyway after hours of tweeking and a few quick pulls on the Dyno it was running and driving very well( made 411 to the wheels through a A4) I trailer is home and fire it up in the trailer to unload and it fires right up and idles perfectly but as soon as I drop it in gear it stalls. So I fire it up and I can hear the IAC is open do to my intake and as long as I can hear it hissing it stalls when going into gear. If I let it run until I can hear the IAC closing down it goes right into gear perfectly. I basicity just put in the garage it had been a long day. I will be driving it this week to get an idea of what its doing.
So anybody have any ideas why is stalls going into gear clod?
TIA
So anybody have any ideas why is stalls going into gear clod?
TIA
05-13-2014, 09:00 PM
#4
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
the 102's can work and drive very well I've done quite a few of them.....it sounds like you may have either far too much air commanded at cold idle and its going lean and stalling or the opposite, theres not enough air at cold idle to keep it running with the load of being in gear....do you know what the AFR at cold idle when it stalls??
04-22-2016, 07:39 PM
#7
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
I have not gotten it resolved, we had very poor injector data for the injectors I chose and my tuner believes that is playing into the issue. I have a new set of injectors ready to go in and head back to the tuner my work schedule and his are not working well together. Was you LSXRT purchased new or used?
Trending Topics
07-17-2016, 10:27 PM
#8
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
Well I spent the day with my tuner yesterday and replaced the injectors with Deatschwerks 42 lb injectors with solid injector data. It has made huge improvements with tweaking of the tune and IAC parameters changed to make it more responsive. Never stalls going into reverse and Idle quality is better but now it stalls when A/C is on one out of 10 or more at a stop light. Rpm flares up and IAC tries to catch it and then it slows way down timing ramps up to try to save it then it stalls. Starts right back up fine. Really frustrating We have 20 plus hours in this plus 3 trips to the dyno to make sure WOT and shift points are correct. Anybody have any ideas? Idle is commanded up 50 rpm with AC on.
07-19-2016, 07:30 PM
#10
I have daily driven a LSXrt with the FAST 102mm. It's a bitch to get right.
1. Make absolutely sure your idle AFR is correct. If you're cammed, you're going to get a false lean reading, but that's another story.
2. Timing. In park and in drive must be very close to each other.
3. IAC. I made mine bigger with a dremel and moved the effective area per count over to compensate for the lower airflow. This is a recent change and the jury is still out on how it works out.
4. Throttle cracker and follower both took SO MUCH tweaking to get it from surging at low speed-sudden throttle movements.
5. Run the RussK idle air config many, many times - this is absolutely most important after getting your idle VE correct. http://www.hptuners.com/forum/showthread.php?30362-Russ-k-s-adaptive-idle-config&styleid=4
Edited to correct the reference to RussK instead of rinkrat. See below for a link to rinkrats tutorial.
1. Make absolutely sure your idle AFR is correct. If you're cammed, you're going to get a false lean reading, but that's another story.
2. Timing. In park and in drive must be very close to each other.
3. IAC. I made mine bigger with a dremel and moved the effective area per count over to compensate for the lower airflow. This is a recent change and the jury is still out on how it works out.
4. Throttle cracker and follower both took SO MUCH tweaking to get it from surging at low speed-sudden throttle movements.
5. Run the RussK idle air config many, many times - this is absolutely most important after getting your idle VE correct. http://www.hptuners.com/forum/showthread.php?30362-Russ-k-s-adaptive-idle-config&styleid=4
Edited to correct the reference to RussK instead of rinkrat. See below for a link to rinkrats tutorial.
Last edited by 1970camaroRS; 07-20-2016 at 05:22 PM.
07-19-2016, 09:44 PM
#11
The only experience I've had with FAST TB's was one of their original 90mm ones. It was a piece of ****. The blade would hang so badly that I tried heavier return springs to the point of being totally unusable. It got replaced with a Nick Williams TB. Are you sure the actual throttle blade is returning fully every time you let off the throttle? I think their engineers spend so much time on the intake manifolds that they just have a random helper monkey make the throttle bodies.
07-19-2016, 10:13 PM
#12
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
The only experience I've had with FAST TB's was one of their original 90mm ones. It was a piece of ****. The blade would hang so badly that I tried heavier return springs to the point of being totally unusable. It got replaced with a Nick Williams TB. Are you sure the actual throttle blade is returning fully every time you let off the throttle? I think their engineers spend so much time on the intake manifolds that they just have a random helper monkey make the throttle bodies.
07-19-2016, 10:30 PM
#13
On The Tree
Thread Starter
iTrader: (5)
Join Date: Aug 2009
Posts: 149
Likes: 0
Received 0 Likes
on
0 Posts
I have daily driven a LSXrt with the FAST 102mm. It's a bitch to get right.
1. Make absolutely sure your idle AFR is correct. If you're cammed, you're going to get a false lean reading, but that's another story.
2. Timing. In park and in drive must be very close to each other.
3. IAC. I made mine bigger with a dremel and moved the effective area per count over to compensate for the lower airflow. This is a recent change and the jury is still out on how it works out.
4. Throttle cracker and follower both took SO MUCH tweaking to get it from surging at low speed-sudden throttle movements.
5. Run the rinkrat idle air config many, many times - this is absolutely most important after getting your idle VE correct.
1. Make absolutely sure your idle AFR is correct. If you're cammed, you're going to get a false lean reading, but that's another story.
2. Timing. In park and in drive must be very close to each other.
3. IAC. I made mine bigger with a dremel and moved the effective area per count over to compensate for the lower airflow. This is a recent change and the jury is still out on how it works out.
4. Throttle cracker and follower both took SO MUCH tweaking to get it from surging at low speed-sudden throttle movements.
5. Run the rinkrat idle air config many, many times - this is absolutely most important after getting your idle VE correct.
07-20-2016, 08:02 AM
#14
TECH Senior Member
07-20-2016, 08:55 AM
#16
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,836 Likes
on
1,145 Posts
in google, just type "hptuners how to idle tuning LS1 rinkrat". it'll come up. If you try to search for it inside of HPT website, it doesn't always come up.
07-20-2016, 12:56 PM
#17
TECH Senior Member
07-20-2016, 05:14 PM
#19
Funny, my brain hiccups and I reference rinkrat on accident when I meant to say "use the russK idle config" and it turns into a positive helpful tip. Yes, the rinkrat idle tuning post of at HPT was and is incredibly valuable in dialing in any idle with a good sized cam...with or without that FAST 102mm and the undersized IAC passages.