CEL issues, idle issues, MPG issues

[Mizzat508]

So I got my dsm a few months ago, and the check engine lights been on for awhile. Its the same codes that always appear, and they havent really affected anything so I havent been in a hurry to fix them.

1. p0170 - Fuel Trim Malfunction bank 1.

I've searched and this could be an 02 in bank 1, but ive seen some threads where this isnt an o2. An o2 shall be ordered this week. Could this be because my boost is up to 15psi, like the maf is telling the ecu too much air is getting sucked in? I've also been seeing TERRIBLE mpg. like 13-14ish

2. p1400 - Manufacture Specific - I've found that this is a manifold differential pressure sensor. Mostly people are saying that this is just a little sensor that doesnt do much and doesnt affect performance.

3. p0125 and p0128 come on SOMETIMES.

I have checked my codes and these do not always come on with the p1400 and p0170. When this code is thrown though, my car will idle anywhere from 1200-2000 rpms randomly. Could this be just dirty coolant? I'll hit up a radiator flush asap if thats it. But if its a thermometer i'll order one.

I've looked around and read alot of different answers, so I figured I'd ask if my set up could be the reason for any of these before i go and replace a bunch of parts that might actually be fine. I did a boost leak check today and found the TB leaks where it meets the intake mani, but couldnt hear a leak anywhere else.

One last note, I am running the stock recirc 2ga BOV. The plastic one that leaks with added boost. Could this be causing an issue?

 

[poonman]

0170 could be many things, Volume Air,Injector,Fuel Pressure, Intake Air leak, CTS, IAT, Barometric, O2, or Exhaust mani crack.

P1400 Harness Issue or MDP sensor

P0125 FRONT o2, or connection.

After looking at the full picture, I would start by checking your engine harness's for Burns, Melts and so on.

Replace your Vacuum hoses, Clean your T/B and Intake Mani, Clean all your sensors. Clear codes and start over so we can narrow down.

 

[spyderturbo007]

Start with the front O2 sensor, clear the codes and see what comes back. Front O2 sensors can cause a variety of other, seemingly unrelated codes to be thrown.

You might want to check the front O2 voltage before throwing parts at the car, though.

 

[Mizzat508]

I'll follow the harness throughout the bay for any burns tomorrow.

As for the voltage, by buddies got a code scanner/OBD2 reader and it said no readings for the 02 sensors. To be frank, not much other then code reading worked...or atleast I couldnt get it to work. I'll check some sensors, look for cracks in the mani.

I just checked all the vacuum lines, intake tube, IC pipes (hoses rather), BOV lines...everything is in place, secured, etc.

Everywhere I've looked it seems the p0170 is a wild goose chase. I'll do some serious investigating in my engine bay this weekend.

 

[Blaze2gDSM]

I second the o2 sensor replacement. My car idled like crap, got horrible mileage and had a host of other little issues before i changed mine. Oxygensensors.com sells the denso replacements the cheapest i found. Don't use some crappy autozone o2 sensor, bosch and denso both make good sensors.

 

[spyderturbo007]

Blaze2gDSM is correct. Always go with an OEM style O2 sensor. The extra couple dollars is worth the investment so you don't have to go hacking up the harness and worry about the accuracy of the sensor reading.

Anyone in the Londonderry New Hampshire area that can help this guy out with access to a logger?

 

[Mizzat508]

Alright, and I'm sold on the OEM sensors. Why go cheap?

Also, my buddy has a scanner that reads o2 voltages. It just wasnt working on my car. We tried it on his RSX and it worked fine.

 

[Mizzat508]

Quick question, is it possible that I have a faulty temp gauge? Its the stock cluster, but it doesnt read like I'm overheating. But then when i get out of the car, i can FEEL the heat coming out of the wheel well when i walk past my front wheel. I pop the hood and it feels like I just ran a le mans under my hood. This happened tonight shortly after my car was idling at 1600-2000 consistently. I pulled over at mcdonalds, afraid i was over heating.

It only does this now and then, then it'll idle fine (800-900) and it wont feel unreasonably hot after driving.