Running terrible, limited codes

[Barto]

Hello All,

I'm new to the Forum and hope I'm not posting improperly. I have a 2003 Ram with a 2017 5.7 Hemi Crate motor. I've owned it since 2019 and its run pretty good with minimal problems. I use it very little - go to the dump, Home Depot and yard work...mostly it sits outside on a crushed stone parking area. It's a Hot Rod, Motor came with a Cam, Cold Air Kit, Headers and an OffRoad Use only ECU (unknown to me during the purchase). Bought it back in 2018 from a local garage! While looking at it, it needed to pass Emissions in the State of Connecticut. He said the Chip was preventing a good Emission but eventually it passed, and I've had zero problems with Emissions ever. 5 years later, I'm now having crazy issues with the truck.

Current situation: Started truck and it stumbled, ran very rough and stalled every time I put it into gear. Had to keep RPM's up while stepping on the brake to keep engine running while shifting into gear. Engine stutters, stalls when stopping (unless I keep the RPM's up) and it slips in and out of Limp mode. Rarely had a code!! Or sometimes it will run like a Champ!

Garage one, had it for three weeks Replaced Cam sensors and gave it back kinda frustrated - got 5 miles out of it, stalled and limped it back home.
Garage two, Changed the Throttle Body, Pedal Positioning Sensor, Engine Wiring Harness the MAP sensor and the Battery. My Tech also found that then previous owner installed spacers on the 0-2 sensor to get the vehicle through Emissions (???) Next option is the ECU - another $350.00 guess! Been with my Tech for 30 years - usually pretty good!
Only codes I received were me braking while applying throttle and also for a throttle body.

Any help would be a blessing - we're mostly out of ideas and now just swapping parts - no returns on electrical and I'm about to replace the ECU

Thx,
BARTO

[miniv8]

Hi Barto and welcome to the forum.
Yeah, you are right, this is basicly not a typical post around here, but we all have our daily drivers and work trucks, so I'm sure we can all relate to your frustration.

For starters, based on your symptoms, I would first make sure your fuel isnt old and stale, second, I would run over all the vacuum lines and make sure they are not loose, unplugged, cracked and leaking .and paying close attention to the big hose going to the brake booster along with its one way valve. And third, I would check the MAP sensor again, or atleast go over the plug connection and wiring and seeing if there is dirt plugged in the port where it reads its signal.
Not sure about your truck, but could be located in the front of the intake manifold, between the alternator and AC compressor.

Good luck with it.

[Racer71]

How’s fuel pressure and fuel trims? Sounds lean to me just given your observations. 02 spacers help eliminate catalyst codes but won’t typically affect driveability as downstream 02 only monitor catalyst on those engines. High positive fuel trims indicate lean condition, over 10-12% is an issue although it may not be enough to flag a code, or the codes could be disabled in the tune, depends on what who ever tuned changed. Along with adjusting many parameters when tuning we also have the ability to disable trouble codes of our choosing, that could be why it’s not flagging any codes. Data is important in any case but yours especially since you don’t specifically know what’s been altered

[Barto]

Thank you, gentlemen, Hope you don't mind, but I'm going to take your comments to my tech and see what they think! We're currently looking at the ECU but trying to find a replacement with the Mods I have is difficult.
Regardless, my truck is a bit junky, but I like it and want to keep and fix it up! Should I be using another site or thread for this post?

thx,

[V12MECH]

Like Racer stated, some more data stream info would be helpful, it sounds like your setup was functional for a while, many times double checking for clean and tight ground and power connections, and check ecm connectors for clean and tight connections and wire crimps at pins. Throw a DVOM at battery terminals, set on A/C volts with engine running at 2000 rpm, to make sure alternator is not allowing too much A/C ripple voltage into system, .300 millivolts is about max, (1/3rd of a volt) just so you can cross that of the list. You could also check Gearhead-EFI.com, interesting stuff that might help.

[V12MECH]

One other item I will mention, hopefully the various shops did the proper code clearing and resetting adaptions for component replacement, one thing you can try is to disconnect one of the battery cable ends, doesn't matter which one, connect them together with a jumper wire, turn key to on, wait 30 seconds, this will clear memory if you don't have a scan tool, reconnect battery and drive truck , record codes, worth a try.

[Barto]

Thanks for the note, I'll be discussing all this with my Tech this AM. Wish us luck!

[Kevin Johnson]

Maybe...

viewtopic.php?p=954978#p954978

[juuhanaa]

Hiya,

Sorry im not an electrician, but ive heard that 99% of electrical problems are actually caused by mechanical faults such as bad connections or cold joints, overheated parts, etc.. and the remaining one percent may be matter of faith.

Despite this things usually work out, but we should remember to look for answers to the warning lights from the user manual I hope this helped a little,



-juhana