Diagnosing Idle Issues
Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
Diagnosing Idle Issues Finally got my LS swap running again after about a year. Last year, I had all the machine work done and completely rebuilt it and had it running on a stand. Over the last year, I have put the motor in the swap vehicle, completely reworked the harness, swapped out the factory intake for a TBSS, upgraded to 50 lb nnbs injectors, and reused the old 78 mm nbs throttle body via an adapter plate.
Couple questions - first, I cannot get it to idle on its own without around 10% throttle input (read through a scan tool). Once you give it some throttle, it runs decently but seems to run pretty rich. The only tuning that has been done was VATS removal from Brendan at LT1 swap, just so I could get it to run on the stand last year. This was before I changed out the manifold and injectors. Additionally, today I noticed the TB adapter plate I had did not have the relief cut in it for the IAC. I plan on ordering the correct one, but in the meantime, I cut a relief in my current one and it did not seem to really do much. I confirmed my IAC is working properly.
So, how can I get this thing to idle? I know the tune way out of whack now for the current manifold/injectors, but I figured it should at least idle or run somewhat? Should I send the computer out to get tuned for the current manifold/injectors, then reassess the issue?
Also, I am currently running no O2 or MAF, because I was just wanting to do a test start on it. Hoping you guys can point me in the right direction.
Thanks
Couple questions - first, I cannot get it to idle on its own without around 10% throttle input (read through a scan tool). Once you give it some throttle, it runs decently but seems to run pretty rich. The only tuning that has been done was VATS removal from Brendan at LT1 swap, just so I could get it to run on the stand last year. This was before I changed out the manifold and injectors. Additionally, today I noticed the TB adapter plate I had did not have the relief cut in it for the IAC. I plan on ordering the correct one, but in the meantime, I cut a relief in my current one and it did not seem to really do much. I confirmed my IAC is working properly.
So, how can I get this thing to idle? I know the tune way out of whack now for the current manifold/injectors, but I figured it should at least idle or run somewhat? Should I send the computer out to get tuned for the current manifold/injectors, then reassess the issue?
Also, I am currently running no O2 or MAF, because I was just wanting to do a test start on it. Hoping you guys can point me in the right direction.
Thanks
Teching In
Joined: Jan 2014
Posts: 36
Likes: 13
I’m going off the statement that VATS is the only tuning, and assuming you don’t have HP Tuners. You need to get it tuned before starting it again, larger injectors without tuning can wash down the cylinders. I would guess you don’t know if the PCM was tuned for the throttle body your running as well. Fuel and air have to be close for it to idle without intervention.
Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
I’m going off the statement that VATS is the only tuning, and assuming you don’t have HP Tuners. You need to get it tuned before starting it again, larger injectors without tuning can wash down the cylinders. I would guess you don’t know if the PCM was tuned for the throttle body your running as well. Fuel and air have to be close for it to idle without intervention.
I live in California so there’s not a whole lot of options in my area as far as tuning goes.
Teching In
Joined: Jan 2014
Posts: 36
Likes: 13
I feel you on the tuner situation. I’m in MS, three hours plus from the nearest tuner worth a darn. I did have mine Dyno tuned. WOT was good, but driveability was bad. I ended up buying HP tuners. No one will spend more time getting it right than you will. Remote tune is ok to get it running, but to get decent manners on the street and performance at WOT, it will need a full tune by you or someone you hire. If you decide to dive into the tuning world, there are a ton of resources available on here and hptuners forum.
Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
I feel you on the tuner situation. I’m in MS, three hours plus from the nearest tuner worth a darn. I did have mine Dyno tuned. WOT was good, but driveability was bad. I ended up buying HP tuners. No one will spend more time getting it right than you will. Remote tune is ok to get it running, but to get decent manners on the street and performance at WOT, it will need a full tune by you or someone you hire. If you decide to dive into the tuning world, there are a ton of resources available on here and hptuners forum.
does anyone have any tuner recs? I know many have used brenden from LT1 swap but I’m open to any recommendations. Also, does anyone know of any good tuners in California? I’m located in the Bay Area.
tia
TECH Fanatic
Joined: Jan 2018
Posts: 1,059
Likes: 198
It's running rich because the new injectors flow a lot more fuel than the stock ones. That probably also explains the need for extra throttle to keep it idling.
If your PCM is a P01 or P59 you can fix that yourself with PCM Hammer - http://pcmhammer.org/
Setting up new injectors is not a bad way to get started with tuning. Just getting the flow rate right will improve things a lot, and you can fine-tune the rest little by little if you need to.
If your PCM is a P01 or P59 you can fix that yourself with PCM Hammer - http://pcmhammer.org/
Setting up new injectors is not a bad way to get started with tuning. Just getting the flow rate right will improve things a lot, and you can fine-tune the rest little by little if you need to.
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Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
It's running rich because the new injectors flow a lot more fuel than the stock ones. That probably also explains the need for extra throttle to keep it idling.
If your PCM is a P01 or P59 you can fix that yourself with PCM Hammer - http://pcmhammer.org/
Setting up new injectors is not a bad way to get started with tuning. Just getting the flow rate right will improve things a lot, and you can fine-tune the rest little by little if you need to.
If your PCM is a P01 or P59 you can fix that yourself with PCM Hammer - http://pcmhammer.org/
Setting up new injectors is not a bad way to get started with tuning. Just getting the flow rate right will improve things a lot, and you can fine-tune the rest little by little if you need to.
It looks like LT1 swap only does VATS delete tunes. Does anyone know of any vendors on the forum or elsewhere where I could mail a PCM for a tune to get me up and running? Changes to the motor include cam, milled heads, intake, injectors, etc... nothing too crazy.
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Verdad Gallardo Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
I’m going off the statement that VATS is the only tuning, and assuming you don’t have HP Tuners. You need to get it tuned before starting it again, larger injectors without tuning can wash down the cylinders. I would guess you don’t know if the PCM was tuned for the throttle body your running as well. Fuel and air have to be close for it to idle without intervention.
Teching In
Joined: Jan 2014
Posts: 36
Likes: 13
See this thread. Some of the real experts commented on this one. Same case, heed their advice.
https://ls1tech.com/forums/generatio...built-lq9.html
https://ls1tech.com/forums/generatio...built-lq9.html
Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
See this thread. Some of the real experts commented on this one. Same case, heed their advice.
https://ls1tech.com/forums/generatio...built-lq9.html
https://ls1tech.com/forums/generatio...built-lq9.html
Thinking I will go with LSX power tuning for a mail order tune. Anyone have any experience they can share? From what I've read, they seem like a solid option for mail-order.
Launching!
Joined: May 2023
Posts: 286
Likes: 94
From: AZ
Correct, no tuning other than VATS (and whatever else Brenden did to allow me to run it on a stand). I do not have access to HP tuners. So, would the next logical step be to send the computer off to Brenden again and give him the specs on the new injectors, manifold, and TB? Or am I better off finding someone with hp tuners?
I live in California so there’s not a whole lot of options in my area as far as tuning goes.
I live in California so there’s not a whole lot of options in my area as far as tuning goes.
mail order tunes are really not ideal. you need to get that thing on the dyno and have it tuned RIGHT
goto the Kali section and ask guys what tuner to go to that is closest to your home
Thread Starter
On The Tree
Joined: May 2022
Posts: 139
Likes: 6
From: Morgan Hill, Ca
what ? dude, Kali has some of the best tuners in the nation. it would be VERY easy to find a tuner, and well worth your travels. If you are super far north or something.
mail order tunes are really not ideal. you need to get that thing on the dyno and have it tuned RIGHT
goto the Kali section and ask guys what tuner to go to that is closest to your home
mail order tunes are really not ideal. you need to get that thing on the dyno and have it tuned RIGHT
goto the Kali section and ask guys what tuner to go to that is closest to your home
