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  Topic Review (Newest First)
06-04-2020 09:29 AM
FergiesJeep so i was under the jeep last week and noticed some moisture around my high pressure fuel line next to the tank where the rubber hose goes into the steel next to the cross member it had a lot of dry rot and had been seeping fuel, was waiting for the weekend to replace it well the jeep decided it was not going to wait. went for a drive yesterday and was smelling fuel really bad pulled over and it was pouring out so got it back to the house dropped the tank and replace the line. finger crossed that I was loosing a gallon+ each tank.
05-28-2020 06:28 PM
cobra30689
Quote:
Originally Posted by 1project2many View Post

The "half-assed misfire at idle" is a GM thing and it tends to be worse on engines with bore size 4" or larger. I believe it is due to cylinders not completely emptying of exhaust on the exhaust stroke. As the closed loop system drives fuel from rich to lean the combination of leaner mixture plus inert exhaust in the cylinder causes a misfire. In this condition you might feel a stumble or shake very briefly but it will quiclkly disappear as the ecm drives the mixture from lean back to rich. It can often be reduced with tuning by adjusting the lean limit richer and by setting stoich or the O2 crossing point to a slightly rich value.
My LS1 Camaro is notorious for this, and it comes and goes as it pleases. Hardly a peep from the misfire counters either, and the one or two times it registers it doesn't even remain in history. I've accepted it as normal and moved on......

I presume the 4.8 LR4 going in my YJ will do the same.
05-28-2020 05:40 PM
1project2many
Quote:
I can't find either of those apps in the google play store...
Thanks for letting me know. Next time I will include links. LSDroid is being developed independently. I know there is a dedicated webpage at http://ls-droid.com/ . There is also a facebook page and there are a number of users and a lot of discussion on gearhead-efi.com as well as other sites. You will need to sign up for an account to post or download on gearhead-efi. Tunerpro is a Windows based app. Tunerpro can be downloaded from https://www.tunerpro.net/ . It's technically a pay for app at $35 and it's well worth the $$ but the evaluation period never expires. I honestly don't know if it can be run in an emulator on Android but I do see folks talking about logging data with it on a phone or tablet. Definition files for the LS are also on gearhead-efi but may also be on other sites.

gearhead-efi link: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?7676-Free-LS1-Tuning-Software-(all-you-need-is-TunerPro)

There are some videos about LSDroid on Youtube that might be interesting as well.
https://www.youtube.com/results?search_query=lsdroid

Full disclosure: I use a professional tuning package for my OBDII tuning so I have never used LSDroid. I have used Tunerpro for some OBDI tuning and for logging. It is a great tool.
05-28-2020 05:22 PM
Waternut
Quote:
Originally Posted by 1project2many View Post
There is free LS tuning software available. LSDroid allows uploading and downloading of the vehicle calibration while Tunerpro allows one to log OBDII data and make changes to the calibration using a pc.
I can't find either of those apps in the google play store...
05-28-2020 05:17 PM
1project2many
Quote:
I'm actually more concerned with coils. There seems to be a lot more debate as to when coils fail and how they fail. Some claim they go bad and you can feel them if you know what it's supposed to be but won't throw a code. Others claim that a single misfire will throw a code even when the coilpack is still good. I've also read a lot of things saying coils should be replaced between 100k-200k miles while some claim to fail at 50k and others claim over 300k on the originals. My LS engine does have a stutter at certain speeds that won't throw codes or anything useful but it definitely feels like a misfire. Feels like someone is tapping the brakes for a split second while driving some days. I have a scan tool that does live information but it doesn't log it and I will definitely get in a accident if I try to run 45-55mph in my Jeep while staring at multiple inputs on a screen.
The computer is programmed to watch for changes in crank speed. It knows the crank should speed up each time the spark plug fires. If the crank does not speed up sufficiently it's counted as a misfire. Each misfire is added to a misfire counter. If the misfire counter increments quickly enough the ecm determines there is a problem. The ecm is programmed not to look for misfires under certain conditions such as a cold engine when the fuel is harder to light, or at idle in some vehicles, or possibly when A/C is active at low engine speeds. Because of these rules it is possible for misfire codes to occur when a coil is good and able to deliver enough spark. Insufficient combustion due to incorrect fuel delivery or low compression can be flagged as a misfire. OTOH it can be hard to make comparisons based on internet data if you don't have the complete story. If the vehicle is operated under conditions where the misfire counter is not incremented the ecm may never set a code. Or if the engine and calibration are from a heavy vehicle it may be programmed not to set individual cylinder misfire codes. It can be hard to know whaich data to filter out. Most GM vehicles will display misfire counter data but if not, there is a way using Mode $06 data if your reader allows it.

As a tech and a shop manager I can tell you from a customer service standpoint that most customers would rather not gamble on changing one coil on a vehicle with high mileage. The thinking is that if one coil failed the rest are close behind. I also know that most DIY guys are willing to save $$ and will replace only the coil they know is bad. I believe this is what leads to the range of recommendations found on the internet. In my experience Ford coils are more likely to fail in rapid succession than GM coils so we usually replace all Ford coils on a high mileage engine but replace a single failed coil on the LS family.
05-28-2020 11:23 AM
Siva283
Quote:
Originally Posted by Waternut View Post
I'm less concerned with injectors. I would think if 1-2 injectors were spraying funny, the fuel trims would be inconsistent. That and new injectors are stupid expensive. There are bucket loads of aftermarket injectors but reviews are 50% positive at best which doesn't inspire confidence in the quality.

I'm actually more concerned with coils. There seems to be a lot more debate as to when coils fail and how they fail. Some claim they go bad and you can feel them if you know what it's supposed to be but won't throw a code. Others claim that a single misfire will throw a code even when the coilpack is still good. I've also read a lot of things saying coils should be replaced between 100k-200k miles while some claim to fail at 50k and others claim over 300k on the originals. My LS engine does have a stutter at certain speeds that won't throw codes or anything useful but it definitely feels like a misfire. Feels like someone is tapping the brakes for a split second while driving some days. I have a scan tool that does live information but it doesn't log it and I will definitely get in a accident if I try to run 45-55mph in my Jeep while staring at multiple inputs on a screen.
Use your phone to video the tool then watch the video
05-28-2020 11:00 AM
1project2many There is free LS tuning software available. LSDroid allows uploading and downloading of the vehicle calibration while Tunerpro allows one to log OBDII data and make changes to the calibration using a pc.


Injectors generally do not fail or wear out. It is possible for deposits to accumulate in and around the ports causing issues with atomization although most fuel today has sufficient detergent to prevent serious issues. I believe this is the source of recommendations to replace injectors at regular intervals.


The "half-assed misfire at idle" is a GM thing and it tends to be worse on engines with bore size 4" or larger. I believe it is due to cylinders not completely emptying of exhaust on the exhaust stroke. As the closed loop system drives fuel from rich to lean the combination of leaner mixture plus inert exhaust in the cylinder causes a misfire. In this condition you might feel a stumble or shake very briefly but it will quiclkly disappear as the ecm drives the mixture from lean back to rich. It can often be reduced with tuning by adjusting the lean limit richer and by setting stoich or the O2 crossing point to a slightly rich value.


When you are getting steady and regular misfire you should expect to check the ignition system, injector operation, and valve and cylinder head integrity. Our fleet vans tend to have a problem with valves even though we do not abuse them.
05-27-2020 04:32 PM
Waternut
Quote:
Originally Posted by FergiesJeep View Post
I also get a misfire when i am sitting at a stop light and it is occasionally i dont have a fancy reader that can get into much detail just an obd2 code reader and it never logs it. what kind of reader/programmer would you recommend?
The best for us DIY guys would probably be hp tuners. You can log whatever you want and replay everything to see exactly what happened and when. However, that's $400 for just read capability. You'll need another $100 to register your ECU for an LS engine should you decide to make changes. $500 is nearing the cost of a dyno tune so that's a tough pill to swallow for me.

I currently have the Launch CRP129 from Amazon. It's only a reader and costs about $200 but it's capable of reading transmission codes and live timing as well. Just not logging to my knowledge. You can view a lot information that you didn't think was possible. When I was troubleshooting my 4L60E trans, I could look to see what the duty cycle was on the solenoids and if the ECU was commanding them to be on.

Since you're getting misfires at idle, it might be a lot easier to troubleshoot. Mine will only do it at speed.
05-27-2020 02:04 PM
NHfireLJ
Quote:
Originally Posted by FergiesJeep View Post
I also get a misfire when i am sitting at a stop light and it is occasionally i dont have a fancy reader that can get into much detail just an obd2 code reader and it never logs it. what kind of reader/programmer would you recommend?
You need a shop w an active reader....
05-27-2020 10:05 AM
FergiesJeep
Quote:
Originally Posted by Waternut View Post
I'm less concerned with injectors. I would think if 1-2 injectors were spraying funny, the fuel trims would be inconsistent. That and new injectors are stupid expensive. There are bucket loads of aftermarket injectors but reviews are 50% positive at best which doesn't inspire confidence in the quality.

I'm actually more concerned with coils. There seems to be a lot more debate as to when coils fail and how they fail. Some claim they go bad and you can feel them if you know what it's supposed to be but won't throw a code. Others claim that a single misfire will throw a code even when the coilpack is still good. I've also read a lot of things saying coils should be replaced between 100k-200k miles while some claim to fail at 50k and others claim over 300k on the originals. My LS engine does have a stutter at certain speeds that won't throw codes or anything useful but it definitely feels like a misfire. Feels like someone is tapping the brakes for a split second while driving some days. I have a scan tool that does live information but it doesn't log it and I will definitely get in a accident if I try to run 45-55mph in my Jeep while staring at multiple inputs on a screen.



I also get a misfire when i am sitting at a stop light and it is occasionally i dont have a fancy reader that can get into much detail just an obd2 code reader and it never logs it. what kind of reader/programmer would you recommend?
05-27-2020 07:02 AM
Waternut I'm less concerned with injectors. I would think if 1-2 injectors were spraying funny, the fuel trims would be inconsistent. That and new injectors are stupid expensive. There are bucket loads of aftermarket injectors but reviews are 50% positive at best which doesn't inspire confidence in the quality.

I'm actually more concerned with coils. There seems to be a lot more debate as to when coils fail and how they fail. Some claim they go bad and you can feel them if you know what it's supposed to be but won't throw a code. Others claim that a single misfire will throw a code even when the coilpack is still good. I've also read a lot of things saying coils should be replaced between 100k-200k miles while some claim to fail at 50k and others claim over 300k on the originals. My LS engine does have a stutter at certain speeds that won't throw codes or anything useful but it definitely feels like a misfire. Feels like someone is tapping the brakes for a split second while driving some days. I have a scan tool that does live information but it doesn't log it and I will definitely get in a accident if I try to run 45-55mph in my Jeep while staring at multiple inputs on a screen.
05-27-2020 06:57 AM
bruinjeeper My FI's are 25 years old!!
05-27-2020 05:01 AM
fishadventure A fuel injector is the epitome of engineering and service-life testing. They are amazing!! or can be...

The only reason “service life” has gone down in recent years (or claims that it has gone have become more frequent) is to sell products and services. Imho

I don’t know the nozzle specs for an ls but I suppose that if the spray ports are smaller (potential for better atomization) on an ls more frequent service may be needed. But they can engineer in whatever they want to; fuel injectors are a matured product.
05-26-2020 03:46 PM
NHfireLJ
Quote:
Originally Posted by FergiesJeep View Post
first question was about power and that is a hard one to answer i feel like is has more power after doing injectors but not much so i dont know if it is mostly wishfull thinking or not but i have noticed is shakes under load now which i believe is axle warp that i wasnt getting before. ladder bars or 4link here i come.



As for the injector swapping time line i have seen it several places an many different answers "We recommend cleaning fuel injectors at least every 36 months or 45,000 miles. Consider it a tune up for your fuel system- it's really amazing the difference people experience after having a fuel injection and throttle body cleaning on a car that has gone more than 60,000 miles without those services." So i figure mine has around 200k on it and i doubt they have ever been done it is probably time.


Waternut, I upgraded to a autometer programmable speedometer it would work with those tires.

I'm still calling BS.... all the LS trucks / engines out there and I have never heard , nor seen them going in for injector "cleaning" . Just saying... If it was a thing, the dealers would be sending emails and letters like crazy for the service work... And I have owned multiple 5.3 -6.0 GMs
05-26-2020 08:23 AM
FergiesJeep first question was about power and that is a hard one to answer i feel like is has more power after doing injectors but not much so i dont know if it is mostly wishfull thinking or not but i have noticed is shakes under load now which i believe is axle warp that i wasnt getting before. ladder bars or 4link here i come.



As for the injector swapping time line i have seen it several places an many different answers "We recommend cleaning fuel injectors at least every 36 months or 45,000 miles. Consider it a tune up for your fuel system- it's really amazing the difference people experience after having a fuel injection and throttle body cleaning on a car that has gone more than 60,000 miles without those services." So i figure mine has around 200k on it and i doubt they have ever been done it is probably time.


Waternut, I upgraded to a autometer programmable speedometer it would work with those tires.
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