Car dies, won't idle - HPT Log included
09-05-2006, 09:48 PM
#1
On The Tree
Thread Starter
Join Date: Apr 2005
Location: Austin, Tx
Posts: 144
Likes: 0
Received 0 Likes
on
0 Posts
Car dies, won't idle - HPT Log included Hey guys, I'm swapping a 2000 LS1 in my 91Z with a T56. Its got ARE Stage 1 Heads, a TR 224/224 114 cam, and LT Headers.
I've run the car a couple times for short periods of time and it would idle fine and sounded nice and crisp if I gave it some gas. Here is a video of it shortly after I got it all installed.
This weekend I needed to break in my rear end, and finally get the engine up to temp for the first time to test the fans and whatnot. So I started it up and it idled fine for awhile, and then it started surging, and eventually died. So I restarted it and it just would not hold an idle unless I gave it about 1000 RPM, but it sounded a little less crisp than normal, and seemed a little sluggish to respond to the pedal. So I ended up putting some washers on the throttle body idle stop to hold the idle up to continue breaking in the rear, with the washers holding the TB blades open a little it was at about 1000 RPM and surging from 1300-500 give or take.
The car has a completely stock tune except for VATs, AIR, and EGR disabled. I also have the rear 2 o2s turned off as I only have 2 on the car.
Here is the HPTuners log file.
Any help or advice is greatly appreciated.
I've run the car a couple times for short periods of time and it would idle fine and sounded nice and crisp if I gave it some gas. Here is a video of it shortly after I got it all installed.
This weekend I needed to break in my rear end, and finally get the engine up to temp for the first time to test the fans and whatnot. So I started it up and it idled fine for awhile, and then it started surging, and eventually died. So I restarted it and it just would not hold an idle unless I gave it about 1000 RPM, but it sounded a little less crisp than normal, and seemed a little sluggish to respond to the pedal. So I ended up putting some washers on the throttle body idle stop to hold the idle up to continue breaking in the rear, with the washers holding the TB blades open a little it was at about 1000 RPM and surging from 1300-500 give or take.
The car has a completely stock tune except for VATs, AIR, and EGR disabled. I also have the rear 2 o2s turned off as I only have 2 on the car.
Here is the HPTuners log file.
Any help or advice is greatly appreciated.
09-06-2006, 09:36 AM
#2
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
You need to dial in your Base Running Airflow. Check the stickies on idle tuning. One thing I noticed with surging at idle is it's usually due to the IAC having too much control. Drop about 20% or so out of the idle airflow correction tables and see if that helps if the idle tuning guide doesn't get you there all the way.
09-06-2006, 12:33 PM
#3
On The Tree
Thread Starter
Join Date: Apr 2005
Location: Austin, Tx
Posts: 144
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for help, I did notice the sticky's about idle, but I wasnt sure if it applied since it seemed to idle just fine before I idled it for 30 minutes. I was looking at my HPT log a little last night, and it seems like my "o2 b1" moves alot less than "o2 b2", I wonder if my left o2 sensor has gone bad? Its practically brand new though.
Also, my "LT B2" is red while the "LT B1" doesnt' appear to be doing anything, what does that mean?
Also, my "LT B2" is red while the "LT B1" doesnt' appear to be doing anything, what does that mean?
09-06-2006, 01:06 PM
#4
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like your fuel trims aren't balanced, which could also be a cause for idle issues. If the O2 sensors are not working properly, the PCM can't adjust appropriately to keep the fueling at a 14.7:1AFR. If the PCM sees an O2 constantly reading a low voltage, it thinks that side is lean (whether it is or not) and adds fuel. If the voltage never increases, the PCM will keep dumping in fuel until it reaches its allowed limit. If this happens only on one side of the motor, then idle issues come a runnin'.
09-06-2006, 01:12 PM
#5
TECH Enthusiast
iTrader: (3)
Join Date: Aug 2005
Location: Castle Rock, CO
Posts: 597
Likes: 0
Received 0 Likes
on
0 Posts
another odd thing is the TPS is at 5. Now I dont know thats a problem for sure, but its something to look at it. Either recalibrating your TPS range, or pointing again towards the base running airflow problem.
09-06-2006, 02:00 PM
#6
On The Tree
Thread Starter
Join Date: Apr 2005
Location: Austin, Tx
Posts: 144
Likes: 0
Received 0 Likes
on
0 Posts
Sorry about confusing you there Steel, that is actually a couple of washers in the throttle body to keep the car running. I had said in the first post I was breaking in my rear end, so I needed to let it idle in 2nd for about 30 minutes. About 10 minutes into the run it would no longer idle, so I had to put washers in to bring the RPM up enough to let it stay running.
SSpd, you know, the left o2 was always at a very low number, it would blip up just a tiny bit ever now and then, but overall it stayed at 0-ish...I'm thinking that might be part of the problem.
I thought maybe a wire for the left o2 burned through, but it does put some signal out occasionally, and I have a o2 gauge on my pillar and it was showing very lean for most of the run....at one point however the gauge went black so I thought the wire was dead, but it came back on the next time I started the car, so I guess it was just way out of range for the gauge
SSpd, you know, the left o2 was always at a very low number, it would blip up just a tiny bit ever now and then, but overall it stayed at 0-ish...I'm thinking that might be part of the problem.
I thought maybe a wire for the left o2 burned through, but it does put some signal out occasionally, and I have a o2 gauge on my pillar and it was showing very lean for most of the run....at one point however the gauge went black so I thought the wire was dead, but it came back on the next time I started the car, so I guess it was just way out of range for the gauge
09-06-2006, 02:56 PM
#7
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
You might want to try some C5 rear NBO2 sensors. They have a stronger heating element and have been known to cure some of the lazy O2 symptoms people notice with longtube headers. Check the search below for more info...
https://ls1tech.com/forums/search.php?searchid=3881406
There's over 100 different threads in there from the last 6 months.
Between the O2's and dialing in the idle with the Base Running Airflow (as seen in the stickies), I'd say you should be able to fix that idle issue fairly easily. Good luck and happy reading.
https://ls1tech.com/forums/search.php?searchid=3881406
There's over 100 different threads in there from the last 6 months.
Between the O2's and dialing in the idle with the Base Running Airflow (as seen in the stickies), I'd say you should be able to fix that idle issue fairly easily. Good luck and happy reading. Last edited by SSpdDmon; 09-06-2006 at 03:02 PM.
