2009 c6z, texas speed ls7r cam, 285cc prc heads, 1 7/8 texas speed headers, cai, monster clutch. I have had this issue ever since I put the cam, heads, and headers on. ive had the car tuned by two tuners and I bought hptuners now so I can learn and make calibrations myself. 1 with second maf cal with cai pe on.hptpop2.hplpop5.hplno pop.hpl I posted my tune along with a few logs. the pop is intermittent. I attached a few logs with the pop and one without. any help will be greatly appreciated.
I just went through a lot of grief with a similar issue. If you can tell me a specific time that if happened in one of the logs you attached then I will see if its anything I encountered. The good news is, mine also went to two reputable tuners in Houston and all said "its just a big cam, nothing we can do about it" yet mine runs nearly like a stock one now.
In my opinion, there is just not enough money in tuning street cars to justify someone really digging in and solving minor drivability issues that are not necessarily detrimental to the engine or performance.
First of all, thanks for taking a look and responding. Ill attach another log that's short so its easier to look at. The stumble is happening pretty much during the whole log. The fact that its intermittent makes me feel like it can be fixed. Sometimes the car runs really well with no stumble at all. Ive taken the injectors out and sprayed them to watch spray patterns, Ive swapped them from bank to bank due to running 3-7 percent leaner on bank 1, Ive swapped the coils from bank to bank, Ive tried different plugs and gaps, Ive checked for vacuum leaks several times, fuel pressure is good, and Ive checked all the grounds on the whole car. Im going to swap o2 sensors today and see if that makes bank 2 the lean bank. Ive been working on cars for nearly 20 years although Im very new to calibrating ecu's. I agree that its not lucrative for a tuner to track down problems like these, it just doesn't make sense. I bought the software because I find calibrating interesting and Im planning on building more ls based vehicles so it just makes sense for me to learn it. I lived in Houston for 8 years before moving to Austin but I don't know of any tuners there other than pat g. Ive never met him but I heard he was the best. Did he look at your car? What was the issue with your car and what fixed it?
pop3.hpl actually that pop5 log is the short one I was thinking of but heres another short one
I would rather not say who looked at my car. They are both good shops that I would trust to work on anything I have, this was just an unusual issue.
My stumble/hesitation was a combination of several things. Not enough timing at light throttle(you should be good there), Torque management tables causing it to pull more timing when AC compressor turned on, and one cracked spark plug.
Im pretty sure that its not the torque management in your case because I dont see any fluctuations in timing.
Im sure you have checked this stuff before, but I would verify that you have a good ground to the coil packs, no bad spark plug wires, and no cracked plugs and that all plug gaps are pretty close to the same. I believe the cracked spark plug was probably my biggest issue. Mine only had the stumble/miss on certain days as well, and I was ready to give up. I finally caved and just got plugs and OE spark plug wires to rule them out, during the process found the cracked plug that was probably like that since the header install. It all made sense then because it was worse on days when humidity was high and more resistance to fire the plugs.
Sorry i couldnt be more help, but i dont see anything odd with tune compared to mine, and your cam specs are very similar.
Again, thanks for your time. I have checked all those things but will double check them again. It does seem as though higher humidity causes the issue to intensify.
Did you figure this out? I have the same issue. L92 TS 416 stroker, TS stroker cam, PRC heads.Originally Posted by crewscontrol
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