Need help! 67' Camaro with 6.2 & E38 ECM. Mild cam, cold air intake, LS3 intake.
When doing partial throttle cruising car is breaking up bad in the 2,500-4,500 range and then smooths out and picks up power.
Attached last data log and tune that is currently loaded in the car. Any suggestions is greatly appreciated.
The first thing I notice is your throttle is all over the place? There is one semi consistent pull near the end of the log but its only 60ish percent throttle. Why did you flatten out most of the spark table to 15*? Also, your maf has a huge dip in at above 26 lb/min.
I have only been working on the partial throttle and idle tuning right now. I have not started any WOT tuning yet. The owner of the car is who did the passes, I wasn't with him when he did it. I did the 15* in the spark table based off the training I got from The Tuning School. I welcome any recommendations for that spark table for the application I am working on. I am fairly new to tuning, have successfully tuned about 10-12 vehicles , but have never ran into the issue I am having now. It is a 6.2 engine out of a Cadillac Escalade, the ECM is for 2008 GMC Sierra truck, LS3 intake with LS3 MAF, MAP sensor, and injectors. Mild cam. Can you help me with what you do would do with the spark table? In the scan file I see the spark drops way down low to like 6-8* when the issue is happening. What could be pulling timing down to that low? Again, any help is greatly appreciated!
If it truly is a 6.2L then your cylinder displacement is wrong the ECM is set up as a 5.3L. Not the end of the world but might as well characterize that correctly from the start.Originally Posted by kcarruth25
What you have for your injector data is not LS3 injector data. They flow 42lb/hr at 58PSI. You need to upload all the correct injector data first before anything else happens.
What is the part number for the MAF sensor or do you know what application it came from?
Do you have a wideband connected? I don't see one in your log.
Have you updated the intake manifold volume and injector data to the LS3 specs? I pulled up a 2010 ls3 and it looks like you have not but I am unsure of exactly what injectors you have.
Wow, I can't believe I missed the cylinder displacement - it's always the first thing I do, but apparently not here.
I had went and put in the injector data from a LS3 stock file, and then the car ran like crap, backed it back out. I can put that back in and then from there should I adjust the idle airflow and spark tables because of the new inejctor data?
The part # for the MAF is 213-4222.
No wideband at this time.
Thank you for taking a look at this and for your help! It is greatly appreciated.
I did have the LS3 inejctor data in there but the car ran like crap and wouldn't idle anymore with it.
As for the intake manifold volume - what table in HP Tuners is that and I can tell you if I updated it?
Do you think this could be causing my sudden drops in spark and causing it to break up in that RPM range?
Hit CTRL + N to pull up the navigator, type in "intake manifold volume" and it will pull up that parameter. You need to put the correct inj data in or all the fueling math will be incorrect. In the log you provided I dont see a real sudden drop in spark in the 1 section that has semi consistent throttle input. The throttle input being all over the place make its impossible to tune correctly.
The owner of the car is who did the drive. Throttle may be all over the place because he was letting out when it started popping and breaking up.
Put the right displacement in it.
Put the right injector data in it, ALL of the injector data just not flow rate.
What are you cam specs? Idle airflow, idle spark and idle RPM will need to be changed depending cam specifications. This will be a bit of trial and error.
You may need to modify your injection timing depending on cam overlap.
You need a wide band to calibrate it correctly for PE fueling at the least.
One question about the injector flow rate. The LS3 stock file I?m using to get the injector data from, the column axis labels are different the those in the tune file I?m using. It will not let me edit those labels. How do I get the flow rates to copy and paste correctly if the column labels are a bit different?
just wondering if you have gotten this figured out yet im having the exacte same issue
You can find corresponding delta pressures between the two tables and interpolate between those. That is the fast and easy way to do it. Not the most accurate way but you can also use excel and some math to get it more accurate.
Your delta pressure shouldn't change much on this set up so as long as you get the flow rates right for the delta pressures your engine will encounter it should be ok.
Just make sure that the offsets, short pulse adder and all the other injector tables are copied as well.
Last edited by cadillactech; 10-13-2021 at 10:13 AM.
Hey - sorry for the late reply. Unfortunately, I did not, the guy bricked his computer messing with some grounds on his car, got a new computer and had him up and running. Car was running even better, and the range of the backfiring in the exhaust got shorter to around 3,000-3,400 RPM's. Fuel trims were excellent, no misfires, he replaced spark plugs just in case. He decided to drive it for a few days and then never brought it back after I spent lots of time researching this issue. Later found out that he took it to another tuner local to us, that guy said my latest tune looked great, just that "I didn't disable something in the VVT but he didn't go into detail. He also said that Gen IV are harder to tune and you have to know your way around them." Would love for anyone to chime in on what they think I could have left enabled on the VVT. Also, the guy lives a mile from us and we haven't seen the car out and about yet, so not even sure the other tuner fixed his problem.
Thank you for this! I'm kind of a nerd when it comes to Math and Excel, so that's the route I had taken to get the tables pretty dialed in.
Me too, Excel helps a lot!
just from that log in the first post, as your getting into wot, theres no fueling so its super lean, i would assume that has to be majority of the issue here, can you take a video of the issue? provided your still having this issue
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