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Been dealing with defueling, any ideas? *edit I had the wrong screenshot

1K views 21 replies 5 participants last post by  Crashnburn 
#1 · (Edited)
Last year I put an 03 engine in my Super Duty. It runs great, but has a defueling problem. At almost exactly 2000 rpm, it falls on its face every single time. I datalogged it with HP Tuners and the problem is very obvious, but the reason is not.
I thought the problem was due to the swap, and the ECM not seeing feedback from the transmission (I'm running the Ford transmission), but I loaded in a manual trans base file and there was no change. It seems to have properly loaded because the Editor Suite in HPT has a blank box for transmission, and the Scanner Suite shows only clutch depressed yes/no.

I have the Smarty Touch turned all the way up.
In the log, you can see that the Main Injector Pulse Width at 2003rpm is 2850. At 2004 rpm it drops to 1136.
Also at 1993rpm, the desired rail pressure is just under 19k, and at 2007rpm it drops to 14k.
Also the FCA goes from 30% to 19%. 30 seems low anyway, but I could be wrong about that.

So it seems to me that there is no mechanical issue, the ECM is pulling a ton of fuel on purpose. But why?
The only discrepancy I can see is that the "Stock File" that HPT provides (because the ECM is not readable) assumes I have 3.54:1 gears while my truck has 3.73, but at the same time, the datalog vehicle speed seemed correct. And again, it ran the same with the auto trans tune and the manual trans tune.

Anybody have any ideas?

I attached 2 datalog screenshots.






Product Computer Font Screenshot Software


Product Font Screenshot Software Parallel
 
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#2 ·
what are modifications to the engine/turbo/fuel system?
Any codes ?
What happens with stock tuning?
stock tuning check
What is RP demanded vs actual at idle, +/-5400psi
Pull FCA, what is RP demanded vs RP actual? should go +23k otherwise most common cause HP fuel issue, ie injectors prv or CP3.
 
#3 ·
4" exhaust turbo back, Airdog 150, Smarty Touch. Otherwise stockity stock.
No relevant codes
Happens with stock tune, just less obvious
Actual RP follows commanded nicely
5-6k at idle
RP will go as high as 23k sometimes. When it drops, the commanded RP drops.
It really does not seem like a mechanical issue, but an electronic one.



what are modifications to the engine/turbo/fuel system?
Any codes ?
What happens with stock tuning?
stock tuning check
What is RP demanded vs actual at idle, +/-5400psi
Pull FCA, what is RP demanded vs RP actual? should go +23k otherwise most common cause HP fuel issue, ie injectors prv or CP3.
 
#4 ·
If you pull FCA should always go to max RP or something is wrong.
at idle should hold steady +/- 100 psi

With out specific codes
On electrical side should double check good grounds, ECM does not monitor them well.
double check RP sensor and its wiring , AC compressor wiring, fan wiring , IAT sensor, they share 5 volt feed from ECM
Double check FCA wiring
Measure APPS voltages
 
#5 ·
You mentioned the fan wiring. My fan is not working properly, I do have a clutch on order. What am I looking for and what that would cause? I do have a fan speed code and my data log shows 0 rpm for the fan. I didn't mention it because I didn't think it was relevant.

I'm pretty sure I checked the FCA and all that before but I can check again...
RP fluctuates probably 200 at idle
I ran a ground wire direct from the ECM to the battery
Throttle position is accurate on the data log, so I wouldn't think APPS





If you pull FCA should always go to max RP or something is wrong.
at idle should hold steady +/- 100 psi

With out specific codes
On electrical side should double check good grounds, ECM does not monitor them well.
double check RP sensor and its wiring , AC compressor wiring, fan wiring , IAT sensor, they share 5 volt feed from ECM
Double check FCA wiring
Measure APPS voltages
 
#6 ·
APPS voltage is very critical less then 0.1 volt difference can cause issues, with control.
03 APPS is POS, has issues on stock truck, best to use 05 APPS. Info here to convert.
As far as fan and other sensors, with no codes
Can look in FSM for 2003 ECM engine wiring found here .
 
#7 ·
Looks like a tuning issue. You are hitting a limiter. One thing I noticed... MAP of 235.8 kpa and 44 pounds of boost at 2000 rpm? Nah. What were EGTs during this?
 
#8 ·
Yeah the boost is strange. The Smarty and the Ford factory boost gauge work off 2 different MAP sensors and they say more like 32 psi. HPT seems to be counting atmospheric pressure and boost pressure combined for some reason.
EGTs never go high unless I am towing uphill in overdrive/lockup at very low rpm.
What could the tuning issue be? I don't have custom tunes, just the canned Smarty tunes. Is there a parameter I can change in HPT? The bummer about the 03 ecm is that it is not readable. It's writable but not readable. How that makes any sense is beyond me. So I can't see what it has, but I can change it if needed.
 
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