Reprogramming JTEC for Timing Curve Change?

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Neuner
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Reprogramming JTEC for Timing Curve Change?

Post by Neuner »

I had posted earlier in the year about Decreasing the Timing by altering the Hesco CPS position. This worked some but I still have some pinging in the upper end and it has decreased my performance in the lower end. To adjust it correctly, I would like to change the timing curve for the PCM but not sure if I'm able to. Most of the research I've done has led me to products or posts that have changed like the STC units.

I would like to be able to just reprogram the JTEC if possible but a piggy back system would be fine as well. I'm trying to keep the cost within reason since I'm only wanting to make this change.

I have a friend that programs PCMs/ECMs for a living but only has the tools required for their engines. If I can get just the required hardware and programming software, he'd be able to teach me how to make the changes. Is it possible to DIY with this PCM?

I've come across EFI Analytics and TurboStudio Lite. Wish I could find a used MegaSquirt already built for cheaper.
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Neuner
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Re: Reprogramming JTEC for Timing Curve Change?

Post by Neuner »

Digging even further I can see what a PITA and costly option this would be. Appears it would be cheaper to run a higher octane. Oh well.

Would be nice if I could install an aftermarket ECM but for now I don't think I'll waste the effort. I'll scratch further if something happens to my PCM.
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jeepxj3
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Re: Reprogramming JTEC for Timing Curve Change?

Post by jeepxj3 »

You should be able to do it with a AEM FIC where you only use the timing portion but that is like $350.
Neuner
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Re: Reprogramming JTEC for Timing Curve Change?

Post by Neuner »

jeepxj3 wrote:You should be able to do it with a AEM FIC where you only use the timing portion but that is like $350.
I had briefly looked at those not sure if it would work with the JTEC? I couldn't find confirmation. Do you know if it drops the entire curve by a certain amount or are you able to adjust the curve based on RPM, etc?


Just dug up my Torque Pro data and my timing advance has been around 40-44 at 2000 -2500 which appears excessive and why I would be getting pre-detonation? Also saw that the timing advance drops when the MAP pressure increases. Thought I read about a modification boosters were doing to change the MAP sensor input?

MAP Pressure readings are at 54 when Timing is at 40 and at 64 when Timing is at 35. All sensors are new as of the swap which was completed early Spring of this year.
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SilverXJ
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Re: Reprogramming JTEC for Timing Curve Change?

Post by SilverXJ »

The AEM FIC6 works fine for the JTEC PCM. I am using one on my 2000 XJ. You can adjust timing, fuel, map O2(not really working) and two additional sources. You can also log to a PC. The fuel and ignition can be setup for MAP or TPS input load. E.g. x axis is RPM, y axis is MAP or TPS. 21 points for RPM, 17 for Load. It has its own built in MAP sensor. It doesn't modify the stock map sensor unless you want it to. It directly intercepts the cam sensor, crank sensor, and fuel injectors. It can not increase timing, only decrease.

Just be sure to get the Neon version so it works with the injector drivers.
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