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Discussion Starter · #1 ·
I did some testing today with the tuner and without. The conclusion I've come to is these engines defuel at 1500'F EGT. I tried with the tuner and egts got to 1550 then backed down to 1500 and stayed there or just below. Also a noticeable drop in acceleration when egts were staying right at 1500. Without the tuner it was the same story egts crept just over 1500 then backed down to 1500 or just below. IMHO a tuner is going to give you no added power towing up a long grade until other changes are made. Also noticed the tuner increased my egts only 50' climbing the same hill at the same speed. I'm thinking the high egts are the reason for the high coolant temps some are seeing pulling up hill also the defueling would explain losing speed at the top of a grade some people have talked about. This is just an observation I had. It was consistent every time I tried it. I think more air or some deletes are in order to get the most out of this engine.
 

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Discussion Starter · #3 ·
Racechip I don't think it matters though acted the same way stock egts would get just over 1500 then hold right at or drop just under.
 

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I know it is comparing apples to oranges, but my 2.8l VM EGTs increase with RPMs. Before my tranny tune, the RPMs would sore to 4000, engine temps would sore, and EGTs would sore. When climbing at 2700 RPMs now, it would reach about 1300 and the engine temps rose slower.

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Racechip I don't think it matters though acted the same way stock egts would get just over 1500 then hold right at or drop just under.
You are right. Doesn't really mater, but info is always good.

With the way the ED Jeep slowed down on the tow test, I was suspecting that the engine was defueling.
 

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You are right. Doesn't really mater, but info is always good.

With the way the ED Jeep slowed down on the tow test, I was suspecting that the engine was defueling.
If that is the case I expect the RAM to do much the same before the end of the test, hopefully they'll be reporting EGT's for the test.
 

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Discussion Starter · #8 ·
On my cummins the longer spray without adding some timing was a recipe for high egts. Also maybe someone should try to get TFL truck to get an obd2 adapter and the torque program to give us some egt and boost numbers. I forgot to look at my boost while it was defueling. 17-18PSI seems to be where it runs under full power it spikes over twenty five then settles down to the 17 or 18 psi.
 

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Discussion Starter · #10 ·
The only plug my module plugged into is the rail pressure sensor it has no affect on any other sensor.
 

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That shouldn't matter. If the rail and injectors are being told to deliver more fuel, and do so, the engine performance changes along with dynamics like heat and pressures, but the ECM brains that tell the comoutr about parameters think that everything is stock. Someone here should know which sensors can be trusted via the on board computer versus those that can't.
 

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I'm guessing there is a pyrometer probe in the exhaust manifold. If it's defuel at 1500F no doubt more timing and or air is needed with the pressure box. A boost fooler can be used to fake out the ECM on the actual boost level so the electronic waste gate will stay closed longer.
 

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I'm guessing there is a pyrometer probe in the exhaust manifold. If it's defuel at 1500F no doubt more timing and or air is needed with the pressure box. A boost fooler can be used to fake out the ECM on the actual boost level so the electronic waste gate will stay closed longer.
I have owned several diesels, and never heard of an "electronic wastegate". Please, enlighten me on this.
 

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Discussion Starter · #14 ·
I believe he is referring to an electronically controlled wastegate
 

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Wastegates aren't needed on a vgt. Vanes are opened/closed on a vgt to control boost and excess manifold pressure is vented through the egr in some cases.
 

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In most contexts "defuel" means to remove fuel from something like a car or boat. When you defuel it you remove fuel from the boat's fuel tank. You guys are using the word defuel to mean precisely what?
 

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reduce the amount of fuel per injection cycle until temps are within limits. Ecu defuels from what it would normally call for in that given situation
 

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That's a good sign for us. The tuners we are using are keeping our Egt's at a safe level. Race chip and Bluespark both recommend turning off the tune when towing. That's probably why they cannot guarantee a sustainable temperature range for our egt's. Excellent info.
 
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