snw blue by you Posted September 3, 2008 Share Posted September 3, 2008 I have this truck that has a returning DTC 343, excessive exhaust backpressure. This should be easy enough to figure out, however I am not familiar with the MD diagnostics and I am having a problem interpreting the PIDS, what little there are. The EBP sensor has been previously replaced, I installed a new connector yesterday and replaced a severely coked MAP sensor, a recal was performed last month so I am sure that, that is not it. Drive symptoms include a loss of power on a long incline, say cruise at 70-75 and scrub off 10 to 15 mph all the while depressing the accellerator to the floor with no increase in power or speed until leveling off. I also noticed that if stopped at a light idling for a minute or so, when going to accellerate, the engine stumbles and has no power, then suddenly it seems to be alright. Looking through history, the 343 has reared it's ugly head at least 4 previous times, and it's pretty obvious that the root cause has not been repaired. It may be something stupid, and I know I can fix this if I could only interpret the PIDS, and know which ones offer the most info. Thanks for any help. Stephen Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 3, 2008 Share Posted September 3, 2008 Been there, see THIS TOPIC. You will need the jumper harnesses for diagnosing certain things on these engines and observe voltages. Long story short, it seems like you have eliminated any electrical malfunctions therefore if nothing is clogged either think performance... turbocharger... sticking. Your hesitation and stumbling sounds exactly like the one I ran into with a 343. I also had another 650 with a bad turbo doing the same thing but no DTC. It's the same turbo, same warranty coverage, same problems. Quote Link to comment Share on other sites More sharing options...
Alex Bruene Posted September 4, 2008 Share Posted September 4, 2008 Same here... I've had the same concern caused by a bad turbo... but the kicker is, the turbo I replaced was also bad... turns out that some of these turbos are subject to "shelf-rot" because of slow turn around... a second turbo and all was well. Quote Link to comment Share on other sites More sharing options...
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