ls1 wont start or stay running, runs with throttle???? help!
08-14-2021, 05:08 PM
#21
[QUOTE=reidtk;20373352] What???? What sensors did you change? Why are you changing sensors? What diagnostic data drove you to change sensors??
You may be on to something here.. The STICK trans tune will have less BRAF because there is less of a drag on the engine when idling.. Going to an automatic trans with a torque converter is going to require BRAF changes as the engine will *most likely* need more idle air. You can start by scanning the engine on a cold start with the IDLE CONFIG by RUSS K and see what the engine is actually wanting to idle.. Since you are already stating the engine will not start without a little throttle pedal.. I'd start by turning the throttle blade screw in at least 1/4 turn to open the blade a little bit, and then do the idle config. OR... alternatley.. just highlight the columns for 176 and lower (as you said it idles when hot so no need to adjust the HOT columns at this time) on the BRAF table and multiply by 1.10 which will add 10%. Burn that in and then try to start it to see if will idle. Have your scanner recording your cold start attempt so that if it does idle, you can get good data to put into the BRAF table after the engine gets up to operating temp.
Keep in mind a 224 cam is going to require quite a bit LESS fueling in the 400-800-1200 columns.. If the engine was not tuned for this cam previously... You may want to reduce the 400 column by 20%, 800 column by 18%, and the 1200 column by 15%.. IF this engine was already tuned for this cam-DO NOT CHANGE ANY OF THE FUELING TABLES YET and just focus on the BRAF table... A cold start while data logging with a wideband O2 could save you a lot of trouble.... Unless... Like me... You have a wideband that will NOT give accurate data until the vehicle has been driven at least 15 minutes and gotten the O2 sensor up to full temp.. .My AEM wideband is TRASH until the car is as hot as it can get with the fans running, at thermostat operating temp.. Seriously... anything less than 15 minutes of drive time gives TRASH data that if you make changes to the tune based off of... you will be CREATING problems not solving them...[/QUOTE
]
Just changed the sensors and went for the first start huge back fire. I don’t know what it is at this point smh.
Keep in mind a 224 cam is going to require quite a bit LESS fueling in the 400-800-1200 columns.. If the engine was not tuned for this cam previously... You may want to reduce the 400 column by 20%, 800 column by 18%, and the 1200 column by 15%.. IF this engine was already tuned for this cam-DO NOT CHANGE ANY OF THE FUELING TABLES YET and just focus on the BRAF table... A cold start while data logging with a wideband O2 could save you a lot of trouble.... Unless... Like me... You have a wideband that will NOT give accurate data until the vehicle has been driven at least 15 minutes and gotten the O2 sensor up to full temp.. .My AEM wideband is TRASH until the car is as hot as it can get with the fans running, at thermostat operating temp.. Seriously... anything less than 15 minutes of drive time gives TRASH data that if you make changes to the tune based off of... you will be CREATING problems not solving them...[/QUOTE
]
Just changed the sensors and went for the first start huge back fire. I don’t know what it is at this point smh.
08-14-2021, 05:45 PM
#22
Teching In
Join Date: Aug 2021
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
08-15-2021, 07:17 AM
#23
just changing the IAC should not have caused a back fire. I was asking above why you just threw an IAC on it... Did you scan it, or data log the vehicle and something was revealed that pushed you in that direction? Or, was it a "hope and prayer" change? backfiring is usually a lean condition, or crank position, or cam position, issue (timing).. Or, you've got an injector leaking down and when you went to start it again it lit off the dripped fuel. Will the vehicle still start if you give it a little throttle? Did you update the BRAF table with the %'s I mentioned above? Do you have HP Tuners? Have a good scanner?
08-15-2021, 11:23 AM
#24
Teching In
Join Date: Aug 2021
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
just changing the IAC should not have caused a back fire. I was asking above why you just threw an IAC on it... Did you scan it, or data log the vehicle and something was revealed that pushed you in that direction? Or, was it a "hope and prayer" change? backfiring is usually a lean condition, or crank position, or cam position, issue (timing).. Or, you've got an injector leaking down and when you went to start it again it lit off the dripped fuel. Will the vehicle still start if you give it a little throttle? Did you update the BRAF table with the %'s I mentioned above? Do you have HP Tuners? Have a good scanner?
08-20-2021, 08:09 AM
#25
So changing the IAC did not help at all.. That would have been my guess too. That's why I was asking what pushed you to change it. I thought maybe you did some data logging, or other diagnostic testing, that pointed you in that direction.
Do you have anyone near you with HP Tuners? Someone that is more knowledgeable with LS engines that can help you? Not idling can be a couple things... but you can pretty much narrow it down to 2 main things... 1. Not enough air getting into the engine. 2. Incorrect fueling due to fueling tables not being tuned correctly. #1 Could be incorrect BRAF settings. A thottle blade that is not opened far enough. Or some combination of the two. #2 Could be the VE table, and/or MAF tables are off. There is also an OPEN LOOP fueling table that factors in a cold start.. Again, datalogging is going to be necessary to get the tune dialed in.
Here is a link to some Youtube videos that may get you onto the right track.
https://www.youtube.com/results?sear...ap+idle+tuning
This one is specific to DBC cars;
Good luck!
Do you have anyone near you with HP Tuners? Someone that is more knowledgeable with LS engines that can help you? Not idling can be a couple things... but you can pretty much narrow it down to 2 main things... 1. Not enough air getting into the engine. 2. Incorrect fueling due to fueling tables not being tuned correctly. #1 Could be incorrect BRAF settings. A thottle blade that is not opened far enough. Or some combination of the two. #2 Could be the VE table, and/or MAF tables are off. There is also an OPEN LOOP fueling table that factors in a cold start.. Again, datalogging is going to be necessary to get the tune dialed in.
Here is a link to some Youtube videos that may get you onto the right track.
https://www.youtube.com/results?sear...ap+idle+tuning
This one is specific to DBC cars;
Good luck!
09-22-2022, 11:47 AM
#26
Teching In
Join Date: Sep 2022
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
it was a hope and pray I can send you video of what the car is doing because nothing popped up on the scanner and crank position good and cam position both new. The car will only start if foot is on gas and I have to keep my foot on it to idle it and once I release car dies .
I'm having the same problem. Did you ever figure out what it was? I have a stock 5.3 with a stock 5.3 ECU with a cable throttle. It will not idle unless I help it. When it warms up, it seems to start idling. Fuel pressure good, changed MAF, IAC, TBS, cleaned throttle body. EVAP disconnected and EGR plugged. I have HP tuners, but I don't want to go through and re-configure the idle tables unless I have to. The thing should run with a completely stock ECU.
When you install a new IAC, MAF or TBS, do you need to calibrate them?
Thanks in advance.
09-23-2022, 07:31 AM
#29
does the TPS read 0% when your foot is off the gas?
09-23-2022, 10:12 AM
#30
Teching In
Join Date: Sep 2022
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for your response.
I cannot get a reading in HP tuners for the TPS. I tried setting up a generic channel to get the reading, but I still don't get any data for TPS when I am logging. I am probably doing it wrong in HP tuners.
I installed a new TPS sensor, still nothing.
I am using a stock harness.
I tested and am getting 5V from the ECU at the sensor plug.
I also tested the stock TPS sensor using a multimeter and it is working.
I cannot get a reading in HP tuners for the TPS. I tried setting up a generic channel to get the reading, but I still don't get any data for TPS when I am logging. I am probably doing it wrong in HP tuners.
I installed a new TPS sensor, still nothing.
I am using a stock harness.
I tested and am getting 5V from the ECU at the sensor plug.
I also tested the stock TPS sensor using a multimeter and it is working.
09-23-2022, 11:58 AM
#31
can you use a generic OBD dongle to check tps and/or tps voltage?
09-23-2022, 08:20 PM
#34
In Hp Tuners scanner you can easily log TPS % and voltage to see if it is sitting at 0 with your foot off the gas pedal. You can also do a TPS re-learn by simply unplugging the TPS wire connector, then turn the ignition switch to the "RUN" position and let it sit for about 10 seconds. Then, turn the ignition off, and reconnect the TPS connector. That should re-set it. Keep in mind that the voltage needs to be less than .75V with your foot off the gas in order for the idle parameters to work correctly.
The situation where the idle does not want to come back down after you rev the engine... if the Ve table, and MAF calibration, are correct, then you could look at Throttle Cracker values.. You can actually log throttle cracker air to see if this is contributing to the slow return to idle. The other thing that can cause a high/higher idle that slowly returns to your desired idle speed (as set in the tune) is BRAF values that are incorrect.
You should probably do a log that includes all of your idle channels, to include throttle cracker air, to see what is happening. Post up a log of a cold start idle up to operating temp. With that info, we can point you in the right direction. Also, a copy of your tune!
The situation where the idle does not want to come back down after you rev the engine... if the Ve table, and MAF calibration, are correct, then you could look at Throttle Cracker values.. You can actually log throttle cracker air to see if this is contributing to the slow return to idle. The other thing that can cause a high/higher idle that slowly returns to your desired idle speed (as set in the tune) is BRAF values that are incorrect.
You should probably do a log that includes all of your idle channels, to include throttle cracker air, to see what is happening. Post up a log of a cold start idle up to operating temp. With that info, we can point you in the right direction. Also, a copy of your tune!
09-25-2022, 10:34 PM
#35
Teching In
Join Date: Sep 2022
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Okay, so I found a solution to my problem. The guy I bought the motor from told me the ECM and MAF were from an 01 Sierra 5.3 he pulled. They got switched around, so he sent me the MAF and ECM that were originally with this motor (02 Yukon 5.3 LM7). I put the MAF on, swapped the ECM and bought another (2) HP tuner tokens to remove the VATS...($100) BOOM. It starts right up, idles (rough), and has great throttle control.
Due to my idle screw tinkering from before... Before I started it with the new ECM, I attempted to put the butterfly idle screw back to stock, but I can't guarantee I got it back to where it was originally. Does anyone know the number of turns to get this thing back to the stock position from the butterfly all the way closed? It idles "rough"... in my case, it wants to lope unless I give it some gas and let it recalibrate. After 5-10 seconds I let it go and it goes into a nice idle. When I shut it off and start it back up again it starts loping again.
Thank you for everyone's help!
Due to my idle screw tinkering from before... Before I started it with the new ECM, I attempted to put the butterfly idle screw back to stock, but I can't guarantee I got it back to where it was originally. Does anyone know the number of turns to get this thing back to the stock position from the butterfly all the way closed? It idles "rough"... in my case, it wants to lope unless I give it some gas and let it recalibrate. After 5-10 seconds I let it go and it goes into a nice idle. When I shut it off and start it back up again it starts loping again.
Thank you for everyone's help!
09-26-2022, 06:34 PM
#36
You said "Does anyone know the number of turns to get this thing back to the stock position from the butterfly all the way closed?" There is no set # of turns that you can just set it back to. Typically, that set screw can be used to dial in your IAC (counts) to where you want them to be. That set point is going to be completely different on every vehicle.
You still have not posted a log or a tune. You are not likely to get many/any responses unless and until you post your tune and a log. You say you "found a solution to your problem" but then go on to say that you are still having idle issues... You need to research the RussK IDLE CONFIG and go through those steps. That *may* get you to a good idle situation where it's not "loping" as you say. How well the IDLE CONFIG works is also going to be dependent on how close your VE table is in the idle areas.. From there, you can then use your butterfly set screw to adjust your IAC counts.. and then start your VE & MAF tuning (or at least logging to see if those tables are accurate).
Throwing on another unknown tune/computer could have solved a problem or two... But it can also burn a hole in a piston top if the VE & MAF tables are way off... Not trying to scare you, but you should be checking this stuff BEFORE you attempt to drive this thing on the road. Do you know for sure that your injector data is correct? Lot's of questions... but no tune and no log..
You still have not posted a log or a tune. You are not likely to get many/any responses unless and until you post your tune and a log. You say you "found a solution to your problem" but then go on to say that you are still having idle issues... You need to research the RussK IDLE CONFIG and go through those steps. That *may* get you to a good idle situation where it's not "loping" as you say. How well the IDLE CONFIG works is also going to be dependent on how close your VE table is in the idle areas.. From there, you can then use your butterfly set screw to adjust your IAC counts.. and then start your VE & MAF tuning (or at least logging to see if those tables are accurate).
Throwing on another unknown tune/computer could have solved a problem or two... But it can also burn a hole in a piston top if the VE & MAF tables are way off... Not trying to scare you, but you should be checking this stuff BEFORE you attempt to drive this thing on the road. Do you know for sure that your injector data is correct? Lot's of questions... but no tune and no log..
09-27-2022, 01:42 PM
#37
Teching In
Join Date: Sep 2022
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Sorry for the delay posting the tune. This is the tune from a Yukon with a 5.3 LM7 with VATS removed. This tune file came from the ECM out of the Yukon which I also have the motor from.
I haven't tried logging the data as you said in your previous message yet, but I should have some time this week.
I haven't tried logging the data as you said in your previous message yet, but I should have some time this week.
09-27-2022, 09:51 PM
#39
Holy cow,.. I just realized that YOU Jvanderwall are the THIRD person posting in this thread about similar issues. Holy crap it's hard to keep up with who I'm responding to. It might behoove you to start a NEW thread-specifically for you so it won't get so muddled up.. With that said..
You said "(02 Yukon 5.3 LM7)" is what you have... and yet the tune you posted is for a 2000... 10th digit of the VIN is a "Y"... So.. Not a BIG deal, but it proves my point that you really MUST log your fuel trims, and MAF curve to be sure that the fueling is spot on BEFORE you start driving it. It might be just fine.. a 2000 5.3L is probably not that different from a 2002.. But why risk it? The tune has DTC's turned ON for EGR stuff... 2000 was the last year for EGR stuff.. If your motor is REALLY an '02 then there should be NO EGR valve, and the passenger side exhaust manifold should not be threaded/plumbed for a connecting line for EGR.. the boss might be there... but it will not be machined. If you find that your pass. side exhaust manifold DOES have the line for the EGR valve, or the EGR valve is present.. then you might have a '00 engine... This stuff is easy to check for. Regardless, you will need to tune out those codes for EGR if you don't have it, or don't plan on running it.
The good news... It does appear to be an all stock tune.. Your not wanting to idle on a cold start could be something simple since it's an all stock tune, on an all stock motor... The easy way to figure this out... LOG IT! I've attached a channel list below... It might not be complete as this is NOT my "tuning" computer, it's just my laptop at home... But that list should give us enough data to at least get you going in the right direction.. Also... As mentioned multiple times in this post above... RUSSK IDLE CONFIG... Find it.. Download it.. READ it.. UNDERSTAND it.. PERFORM it on your vehicle... Then let us know if the cold start idle issue goes away... Have you installed a cold air intake on this engine? Or changed the air inlet in any way? if so... RUSSK IDLE CONFIG is where you need to start. And maybe a NEW post for you? As you have continued on after TWO OTHER people.. I wonder what the record is for "taggers" on an existing post..
You said "(02 Yukon 5.3 LM7)" is what you have... and yet the tune you posted is for a 2000... 10th digit of the VIN is a "Y"... So.. Not a BIG deal, but it proves my point that you really MUST log your fuel trims, and MAF curve to be sure that the fueling is spot on BEFORE you start driving it. It might be just fine.. a 2000 5.3L is probably not that different from a 2002.. But why risk it? The tune has DTC's turned ON for EGR stuff... 2000 was the last year for EGR stuff.. If your motor is REALLY an '02 then there should be NO EGR valve, and the passenger side exhaust manifold should not be threaded/plumbed for a connecting line for EGR.. the boss might be there... but it will not be machined. If you find that your pass. side exhaust manifold DOES have the line for the EGR valve, or the EGR valve is present.. then you might have a '00 engine... This stuff is easy to check for. Regardless, you will need to tune out those codes for EGR if you don't have it, or don't plan on running it.
The good news... It does appear to be an all stock tune.. Your not wanting to idle on a cold start could be something simple since it's an all stock tune, on an all stock motor... The easy way to figure this out... LOG IT! I've attached a channel list below... It might not be complete as this is NOT my "tuning" computer, it's just my laptop at home... But that list should give us enough data to at least get you going in the right direction.. Also... As mentioned multiple times in this post above... RUSSK IDLE CONFIG... Find it.. Download it.. READ it.. UNDERSTAND it.. PERFORM it on your vehicle... Then let us know if the cold start idle issue goes away... Have you installed a cold air intake on this engine? Or changed the air inlet in any way? if so... RUSSK IDLE CONFIG is where you need to start. And maybe a NEW post for you? As you have continued on after TWO OTHER people.. I wonder what the record is for "taggers" on an existing post..
09-27-2022, 11:15 PM
#40
Teching In
Join Date: Sep 2022
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Holy cow,.. I just realized that YOU Jvanderwall are the THIRD person posting in this thread about similar issues. Holy crap it's hard to keep up with who I'm responding to. It might behoove you to start a NEW thread-specifically for you so it won't get so muddled up.. With that said..
You said "(02 Yukon 5.3 LM7)" is what you have... and yet the tune you posted is for a 2000... 10th digit of the VIN is a "Y"... So.. Not a BIG deal, but it proves my point that you really MUST log your fuel trims, and MAF curve to be sure that the fueling is spot on BEFORE you start driving it. It might be just fine.. a 2000 5.3L is probably not that different from a 2002.. But why risk it? The tune has DTC's turned ON for EGR stuff... 2000 was the last year for EGR stuff.. If your motor is REALLY an '02 then there should be NO EGR valve, and the passenger side exhaust manifold should not be threaded/plumbed for a connecting line for EGR.. the boss might be there... but it will not be machined. If you find that your pass. side exhaust manifold DOES have the line for the EGR valve, or the EGR valve is present.. then you might have a '00 engine... This stuff is easy to check for. Regardless, you will need to tune out those codes for EGR if you don't have it, or don't plan on running it.
The good news... It does appear to be an all stock tune.. Your not wanting to idle on a cold start could be something simple since it's an all stock tune, on an all stock motor... The easy way to figure this out... LOG IT! I've attached a channel list below... It might not be complete as this is NOT my "tuning" computer, it's just my laptop at home... But that list should give us enough data to at least get you going in the right direction.. Also... As mentioned multiple times in this post above... RUSSK IDLE CONFIG... Find it.. Download it.. READ it.. UNDERSTAND it.. PERFORM it on your vehicle... Then let us know if the cold start idle issue goes away... Have you installed a cold air intake on this engine? Or changed the air inlet in any way? if so... RUSSK IDLE CONFIG is where you need to start. And maybe a NEW post for you? As you have continued on after TWO OTHER people.. I wonder what the record is for "taggers" on an existing post..
You said "(02 Yukon 5.3 LM7)" is what you have... and yet the tune you posted is for a 2000... 10th digit of the VIN is a "Y"... So.. Not a BIG deal, but it proves my point that you really MUST log your fuel trims, and MAF curve to be sure that the fueling is spot on BEFORE you start driving it. It might be just fine.. a 2000 5.3L is probably not that different from a 2002.. But why risk it? The tune has DTC's turned ON for EGR stuff... 2000 was the last year for EGR stuff.. If your motor is REALLY an '02 then there should be NO EGR valve, and the passenger side exhaust manifold should not be threaded/plumbed for a connecting line for EGR.. the boss might be there... but it will not be machined. If you find that your pass. side exhaust manifold DOES have the line for the EGR valve, or the EGR valve is present.. then you might have a '00 engine... This stuff is easy to check for. Regardless, you will need to tune out those codes for EGR if you don't have it, or don't plan on running it.
The good news... It does appear to be an all stock tune.. Your not wanting to idle on a cold start could be something simple since it's an all stock tune, on an all stock motor... The easy way to figure this out... LOG IT! I've attached a channel list below... It might not be complete as this is NOT my "tuning" computer, it's just my laptop at home... But that list should give us enough data to at least get you going in the right direction.. Also... As mentioned multiple times in this post above... RUSSK IDLE CONFIG... Find it.. Download it.. READ it.. UNDERSTAND it.. PERFORM it on your vehicle... Then let us know if the cold start idle issue goes away... Have you installed a cold air intake on this engine? Or changed the air inlet in any way? if so... RUSSK IDLE CONFIG is where you need to start. And maybe a NEW post for you? As you have continued on after TWO OTHER people.. I wonder what the record is for "taggers" on an existing post..
Kawabuggy, I can't thank you enough for being patient with me. I've read many forumns, this is the only one I decided to create an account to post a question. Thank you. I will start a new post after this.
Rest assured, this motor is on the stand and will not go in the car until I can get this sorted out.
On to business... This motor did have an EGR valve. I removed and capped it. (I understand this means I probably have an '00 engine) I will remove the EGR DTC's.
Thank you for the attachment, I will try logging the channels you listed.
Lastly, I did watch the RUSSK video and I understand it, I just didn't want to dive into the tune a make a mistake if there is a simple way to put the butterfly back to it's original position. I did change the intake though - right before the MAF I have a K&N cone air filter.