Ever since I bought my 2004 Rubicon in July 2018, I have been disappointed in power production. It was not an issue around town, 2 lane highways or on the trail, but found myself trying to keep up with traffic on the interstate with even the smallest hill. It got better when the heat and humidity gave way to much cooler air.
I hooked up a scan tool to see if anything was odd. I noticed that timing was low at cruise on level ground and went lower as the accelerator pedal was pressed further the timing continued to drop. When the skinny pedal was pinned the timing dropped as low as 16* btdc. I could tell little difference on the interstate between half and full throttle. It seemed like power dropped beyond 3/4 throttle. Any more power that could be made by more air going in was negated by reduced ignition timing. That 16* btdc above is roughly half of what I would think the motor needed.
After seeing this I started shopping for ways to tune the stock ECU. Most handheld tuners are not worth the cost for negligible at best gains. I will likely end up turbocharging my 4.0 before my trip out west this summer. I don't have a lot of EFI tuning experience but have tuned several cars, both N/A and power adders. B&G tuning software was the first I saw that supported my 2004 TJ. After more than 2 months of not being able to contact B&G I gave up. In the meantime, I saw another option, Syked.
I received my Syked hardware 2 days ago and installed my first modified tune today. Basically, I added 5* to the bottom right corner of the timing table. With the modded tune, on a road I have traveled many times, I can say it has no trouble accelerating on hills that it struggled to maintain 70mph before. There is more in it and I have started the next round of changes. More to come as I get familiar with it.
I hooked up a scan tool to see if anything was odd. I noticed that timing was low at cruise on level ground and went lower as the accelerator pedal was pressed further the timing continued to drop. When the skinny pedal was pinned the timing dropped as low as 16* btdc. I could tell little difference on the interstate between half and full throttle. It seemed like power dropped beyond 3/4 throttle. Any more power that could be made by more air going in was negated by reduced ignition timing. That 16* btdc above is roughly half of what I would think the motor needed.
After seeing this I started shopping for ways to tune the stock ECU. Most handheld tuners are not worth the cost for negligible at best gains. I will likely end up turbocharging my 4.0 before my trip out west this summer. I don't have a lot of EFI tuning experience but have tuned several cars, both N/A and power adders. B&G tuning software was the first I saw that supported my 2004 TJ. After more than 2 months of not being able to contact B&G I gave up. In the meantime, I saw another option, Syked.
I received my Syked hardware 2 days ago and installed my first modified tune today. Basically, I added 5* to the bottom right corner of the timing table. With the modded tune, on a road I have traveled many times, I can say it has no trouble accelerating on hills that it struggled to maintain 70mph before. There is more in it and I have started the next round of changes. More to come as I get familiar with it.
