Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

03 ram 5.7 2500 - TPS/APPS driving me nuts- been struggling for months!

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1 year 1 month ago - 11 months 2 weeks ago #60129 by fstarocka.burns
Hi all - I have been trying to figure out a low power issue on my 03 ram for going 2 years now.. traded it at 100k miles and tore engine down and miced everything, new rings bearings timing set, plugs. Ive since put about 10k miles on it.

NO CEL / No Codes EVER / Passes smog every time
New CAT last year
New Torque converter
New ECU
New Coils (today)
New plugs
New sensors
New NTK o2 sensor (today)

Im still getting 8.5 mpg and this thing cannot tow for its life.. embarrassing - however i can get up to 80mph on the highway, starts idle fine every time-

o2 sensor i removed today was tan brown, i also confirmed no exhaust backpressure pre-cat/upstream.

Here is a pic of my APPS readout (under battery box / 6pin inline connector) AND my ignition analyzer on the plugs-

Apps/TPS readout - me slowly pressing pedal down - car on NOT running (yes i did a tps reset)

https://www.allpar.com/attachments/20230208_152221-2-jpg.93006/

Random drops on plug wires (new coils)
https://www.allpar.com/cdn-cgi/image/format=auto,onerror=redirect,width=1920,height=1920,fit=scale-down/https://www.allpar.com/attachments/20230208_122645-2-jpg.93007/
Last edit: 11 months 2 weeks ago by fstarocka.burns.

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1 year 1 month ago - 1 year 1 month ago #60130 by fstarocka.burns
Now I have the pin out diagram for the APPS here:



and I believe the correct C2 pinout:

My plan is to measure and compare the wires between APSP,ECM and TB (if thats possible at the TB) -

Specs i found are APPS1: Idle .45v, WOT 4.5v, APPS 2: idle .22v, WOT 2.3v. Which wires on the APPS do i check for these voltages - RETURN or SIGNAL?

Thanks
Last edit: 1 year 1 month ago by fstarocka.burns.

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1 year 1 month ago - 1 year 1 month ago #60131 by juergen.scholl
The signal wires carry the mentioned voltages. Be aware that Chrysler/Dodge products may show a periodic dip in app signal voltages without any fault. It's a circuit integrity check thing.

productforum.autorepairdata.com/forum/showthread.php?t=8186


An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Last edit: 1 year 1 month ago by juergen.scholl.
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1 year 1 month ago - 1 year 1 month ago #60134 by Noah
Please forgive me, I don't think I fully understand the problem.
Poor-ish mileage and doesn't tow well?
My Navigator weighed 8000lbs with 300hp, 350lbs torque, got 9 miles to the gallon and really wasn't happy with even an empty U-Haul utility trailer.

"Ground cannot be checked with a 10mm socket"
Last edit: 1 year 1 month ago by Noah.
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1 year 1 month ago - 1 year 1 month ago #60136 by fstarocka.burns
ok thanks - mine seems alot worse though.

My friend took me in a drive on his same model 2004 and it was night and day, his acceleration was unreal vs mine. His rear tires were smaller but yikes NIGHT and day difference.. Mine just feels mushy when u put the pedal down, part throttle accel is almost no existent.. also it shifts every 10 miles an hour at part throttle, so by the time u are doing 40 ur in 3rd gear or more = again no power.

Im going to reconfirm the sweep voltages at the apps and the ecu and go from there-
Last edit: 1 year 1 month ago by fstarocka.burns.

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1 year 1 month ago #60137 by Cheryl
Is it starving for fuel? Check fuel pressure on it?

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1 year 1 month ago #60141 by Noah
If you have a genuine low power issue, I wouldn't be going after tpp/app signals right off the rip. Not without some kind of high level indicator.Those circuits are very well monitored and any electrical issue will set a code and most likely put the engine in reduced power mode, with either a red lightning bolt warning lamp or a message displaying "reduced engine power". Then it would be REAL slow, barely get off the road slow. 3rd gear start and max 2,500ish rpm.
As Cheryl pointed out, low fuel pressure is a suspect in cases of low power.
During a wide open throttle pull through a 1-2 shift, upstream o2s should hang rich is fuel supply is good, and the load pid should hit very near 100%.
Just for the sake of argument, your friends truck could also have a different gear ratio. Two cars making the same power will feel very different with a 2:73 vs 4:10 rear end gears.

"Ground cannot be checked with a 10mm socket"
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1 year 1 month ago #60142 by Matt T

Hi all - I have been trying to figure out a low power issue on my 03 ram for going 2 years now.. traded it at 100k miles and tore engine down and miced everything, new rings bearings timing set, plugs. Ive since put about 10k miles on it.

Has the truck been low on power eversince the rebuild? Did it have power prior to the teardown?

Either ways I agree with Noah. Get some scan data at WOT and go from there. Aside from upstream O2s and load also grab MAP. That'll point to either fuel or breathing.

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11 months 2 weeks ago - 11 months 2 weeks ago #60967 by fstarocka.burns
yes - my friend has a 04 chevy with a 5.7 4wd, night and day difference in power and mileage. Pretty much the same truck/engine combo-

another friend took me for a drive in his 2004 ram 2500HD 2wd) - that thing ran like a freaking hellcat! Same truck/engine - 1 year apart.
Last edit: 11 months 2 weeks ago by fstarocka.burns.

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11 months 2 weeks ago #60968 by rpd1125
I had one with exact scenario a couple weeks ago. Purge valve was stuck wide open. You can remove hose going to purge valve from the fuel tank side which usually by radiator driver side,
With engine running you should not have any vacuum going across that purge valve with engine running. Thy fail allowing excess fuel vapors and sometimes raw fuel if the tank is completely full.
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11 months 2 weeks ago - 11 months 2 weeks ago #60970 by fstarocka.burns
Same symptoms as mine? bad mileage and loss of low end? Also - mine has an inline green switch (fuel line side i think), is that adjustable on/off or what?

Pulled my manifold hose, idle went up, reconnected and pulled tank side - no vac at the port so all seems good there.
Last edit: 11 months 2 weeks ago by fstarocka.burns.

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