Electrical Gremlins

[Sholtby]

Need a gremlin troubleshooting guru for some advice. 2014 Ram 1500 4x4 162,000km with a new long block at 80,000, had the EGR cooler fail(dropped 4” in my coolant reservoir in one drive with no external coolant leak or coolant in oil) and at the same time threw an underboost code and went into limp mode. Take it to the dealer and they say the EGR recall should take care of it, was told 10 or so months ago that they didn’t have access to the part and would call me when available but now they can do it in a couple weeks with a part from sister dealership. Get it done and it’s still throwing underboost code. Pressure test and smoke test and say I need a new turbo that they want $4700 CAD for. Have a buddy use 2 cans of turbo cleaner, shoots black smoke and up she spools, turbo is spinning free and clear. Drives fine and then intermittently goes gutless and staggers then throws more codes. Hook up to buddy’s scan tool and see that Lambda voltage and duty cycle are at zero and don’t budge and start throwing rich condition codes along with underboost. We also see that target MAF shoots up to 3000+ at low load(usually 400-600 at idle and low load and 1500-2000 full pin) and target boost shoots way up when target and actual in both parameters initially are matching and appropriate. Pull and clean MAP sensor and it’s beyond clogged with crap, Pull the o2 sensor and it looks like a black crayon, throw a new one in and instantly we are getting proper duty cycle wave forms and the mV we are expecting to see. Target and actual MAF and boost are bang on. Go through the entire graph screen and everything is perfect for 50km of highway driving, suddenly with no rhyme or reason target MAF shoots through the roof again, every other sensor reading either starts going bonkers or flat lines, limp mode, stored underboost and pending o2 sensor deceleration codes implying low voltage return, and yes we did an o2 sensor replace command on the scanner. Have disconnected and cleaned out/dielectric greased every harness and knuckle we can see. Through how many times we have had it drive perfectly with graphic information showing everything is working to spec, and then the whole system seeming shitting the bed all at once, and sometimes even correcting itself mid drive before having the chance to throw a code and being fine again with all graphs instantly returning to normal we have effectively said the turbo is fine as a matter of our opinion. Are we needing to embark on an endless ground fault wiring search, did the lame o2 sensor cause all the problems and it now has shown us it has a harness or wiring fault,or has the ECM just started to crap out or has an internal wiring fault? What information tells this ECM how much target MAF it needs? Did the coolant leak into the intake wreck every single sensor downstream? (Swirl valves although caked deep in crap report proper position and actuation) or are we reading way too deep and a bad turbo can cause this headache of data issues? Anyone with experience and advice on this bizarre problem? It would be greatly appreciated if you could help out. Thanks so much. Have read about some people getting a GDE tune and fixing problems like this before. Were those tunes done on your ECM, or a replacement and yours sent back as a core?

 

[ryansch7926]

I am having the same problems found and repaired damaged wire under the air cleaner box and still throwing codes never the same codes except low boost