Rich idle, lean boosting problem
Aug 19, 2013, 09:53 AM
#1
Rich idle, lean boosting problem
I just got my car running after installing my new transmission and notice a strange intermittent a/f problem.
Car is an 03 Evo 8, 3.5" straight pipe to muffler, hard intercooler piping, synapse recirculated bov, walbro 255, and a boost controller set to 21psi. Previous owner had a shop street tune it a while back.
Sometimes the car drives just fine and the wideband shows normal 14-15 a/f during cruise and 11's during boost. Randomly, it sometimes runs in the 10-11 area at cruise and idle, then started to lean out to 15-16 under boost until I realized what was happening and let off. It had a major power loss at the time of that also. I checked the vacuum hose going to the fuel pressure regulator and it looked fine. I plan on replacing the fuel filter and checking my plugs and i'm going to check it for boost leaks.
But seeing how its intermittent, it makes be believe its maybe a faulty sensor. Maybe CTS? My check engine light is not on, but I'm going to check on my evoscan unit and double check. I'll record some datalogs and check for weird voltages from sensor.
Any ideas what I should be looking for and what might be causing this? What voltages are normal for the 02, CTS, and any other sensor that affects a/f?
Thanks for the help
Car is an 03 Evo 8, 3.5" straight pipe to muffler, hard intercooler piping, synapse recirculated bov, walbro 255, and a boost controller set to 21psi. Previous owner had a shop street tune it a while back.
Sometimes the car drives just fine and the wideband shows normal 14-15 a/f during cruise and 11's during boost. Randomly, it sometimes runs in the 10-11 area at cruise and idle, then started to lean out to 15-16 under boost until I realized what was happening and let off. It had a major power loss at the time of that also. I checked the vacuum hose going to the fuel pressure regulator and it looked fine. I plan on replacing the fuel filter and checking my plugs and i'm going to check it for boost leaks.
But seeing how its intermittent, it makes be believe its maybe a faulty sensor. Maybe CTS? My check engine light is not on, but I'm going to check on my evoscan unit and double check. I'll record some datalogs and check for weird voltages from sensor.
Any ideas what I should be looking for and what might be causing this? What voltages are normal for the 02, CTS, and any other sensor that affects a/f?
Thanks for the help
Aug 19, 2013, 10:24 AM
#3
I've heard of fuel pressure regulators going bad causing what your describing. However, since I'm the first to respond ill ask the obligated first question of evom.... did you do a boost leak check?
Just read again and saw you were going to do that.
02 numbers should very from .1V to .9V. And contenue to go back and forth while engine is idleing or cruseing. It should peg at .9v when getting on it.
Just read again and saw you were going to do that.
02 numbers should very from .1V to .9V. And contenue to go back and forth while engine is idleing or cruseing. It should peg at .9v when getting on it.
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