Anyone know how to read a data log? DTC help.

chrisv_10 · Apr 18, 2011

So my car is throwing codes right now and it runs like shit and idles like shit too. Here are the codes. P017-System too lean (bank 1) P0174-System too lean (bank2) P0402 Exhaust Gas Recirculation Flow Excessive Detected and I also get a Catalyst System Efficiency Below Threshold code for both banks. Here is the data log. Any other signals I should be reading that are more important?

I don't know how to upload a pic to the post so here is the link--
http://i72.photobucket.com/albums/i179/chrisv_10/datalog.jpg

JDwhite98gt · Apr 18, 2011

Do you have mill eliminators for that offroad x? If you do and those codes still come up your O2's are probably bad.

MadStang · Apr 18, 2011

You're running much too lean. the STFT should be at 1.00 which is perfect stoichiometric air/fuel. You're 11-13% too lean.

Datalog the o2's, the values should jump around if they are still good, if the values don't move then your o2's are bad.

Also sounds like your EGR valve is toast according to the code.

chrisv_10 · Apr 18, 2011

I don't have MIL eliminators right now. I'm also having trouble loading my 93 tune to my PCM. I keep getting a error that says that it failed to upload the stock tune. I will data log the O2 sensors and post the update.

vermilion · Apr 19, 2011

im leaning towards a bad gasket somewhere after the maf. your EGR could have worked itself loose. IE @ the headers (least likely), or at the nut on the back of the valve. also the 2 10mm bolts came loose on the valve. next the area under your plenum. if you removed this kitty cat you could have folded the gasket and weeps air in. next in line is runner gaskets. p0174 and p017xx is usually the gasket under the plenum. happens to be the largest opening in your intake and most prone to fail or leak because bolts are stripped or loose also. highly unlikely both sensors took a digger at the same time. EGR valves do randomly fail but trying to compensate for something else. its Vacuum assisted and electronically monitored. so in which id look at your intake gaskets.