check engine lighthelp please

[dale187]

Keep getting check engine code P0125 and P0170. The first code is coolant temperature sensor and the other one is fuel trim malfunction. Did a research and someone said it could possibly be thermostat. Change that. Someone also said it could be the coolant temp sensor. Changed that as well, reset the engine light by the battery and it came back on. Anyone have any idea what else this could be triggered from? Thanks guys

 

[Project2G]

P0125

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P0170

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[dale187]

Cool thanks, if anyone else has any cluem all suggestions will be great.

 

[jrohner]

You replaced the right temp sensor right? There is one going to the ecu and a different one going to the gauge.

 

[dale187]

We changed both... sigh this is such headache

 

[Auto RS T]

Post #2 is where it's at.

Check your front o2 sensor.

 

[dale187]

Now is it very well possible the 2 are linked together some how? Now mind you i have a afpr and injectors. How often do these trigger this code?

 

[Imback]

It's your front 02 it's the same stupid code that i just had not to long ago.

 

[Auto RS T]

PO125 is not a coolant temp code.

This code basically says that the Front o2 Sensor didn't start cycling (entering closed loop operation) within the alloted time after startup. (30 seconds).

The sensor operation has slowly degraded over time and is now out of spec when the car runs its self checks, that or it is completly dead.

Your secondary code is most likely a result of the poor o2 output to the ECU resulting in maxed out fuel trim values. The codes are organized in order of importance you could say. Notice "Heated Oxygen Sensor Failed" under "probable cause" for PO170.

If the front o2 sensor voltage doesn't sweep under 1 volt, crossing .5 continously after 30 seconds of starting the warm car. Replace it.

 

[dale187]

Just spent all day today and yesterday changing the o2 sensor what a job that was. I'm not going to get into that. But yeah changed the o2 sensor and the light came back on same codes. Anyone else got any other ideas what this could be. I also realize im fouling out plugs very quickly and burning gas. I do know im running very rich for some reason and i have the apfr set at 20 and still running rich. This has me stumped and extremely fustrated.

 

[Auto RS T]

Follow the steps in post #2, it's all there.

 

[dale187]

Yeah i know just seeing if anyone else had this and what worked out for them. Just tired of dumping money into this thing and gettng nothing outta it. Watch it be the last thing i try after trying everything in the post

Im having a funny feeling that it could be the apfr i'm not too sure because i dont have much experience with these. I have a stock fpr with a 6 bolt tsi. Would this work with my 2g ? If so, what about having bigger injectors will that have any effect with the fuel pressure the stock regulator is trying to manipulate?

 

[Auto RS T]

Pull the vacuum line off the AFPR and look in it, it should be dry, if it is wet the diaphram is leaking fuel and the regulator is bad. Verify that the AFPR is able to change the fuel pressure by hooking up an additional Fuel Pressure gauge and running the regulator high to low while watching the gauge.

The regulator won't have any issues because of the bigger injectors. The fuel pump and manifold vacuum can effect the regulator however.

Check for leaks in the intake tract, you are looking for unmetered air leaks.

Verify connections A-94, and B-56

Verify that the harness between the o2 sensor and the ECU is good. Look for the o2 signal voltage at the ECU.

 

[dale187]

The gauge i have on it now is reading pressure as i adjust, and is not wet inside. This is very confusing i dont understand how it coule still be running rich. Exhaust leak and no cat? Could this be throwing the engine light with those codes? Ill check the connection from the ecu for the o2 sensor and make sure that has juice. Im wondering if not having a working o2 sensor could be causing the car to be running rich regardless of fuel pressure? is this correct? As far as the a-94 and b-56 connections can you explain where these are? I'm having a hard time researching on this. I know this is fustrating you guys too trying to explain but im trying to eliminate the problem instead of dumping $100 here and there. Thanks guys

 

[Auto RS T]

Fuel pressure changes with AFPR adjustments and we have normal pressure.

Fuel Pressure Regulator-Check
Fuel Pump-Check
Fuel Filter-Check

Check the injectors resistances and compare to specs. It's not throwing any misfire codes or running on 3 cylinders so...
Safe to say injectors...-Check for now?

Have you had a chance to look at any engine data? Anything else besides the fuel trims look out of whack? Look at some of the parameters in the PO170 list and compare them to what they should be. They point to the MAS.

Baro
Intake air temp
Airflow Hz

If your car has been parked overnight, the Intake Air Temps (IAT) should be the same or only a few degrees off from the Engine Coolant Temps (ECT). I would need a wiring diagram for the connectors.

 

[dale187]

Hmmm fuel pump. See i bought this car and i keep finding different mods that have been done to it. What affectcould an upgraded fuel pump have on this if things were not done correctly? As far as the connectors i suppose i'll be doing more research as to what they are exactly,

 

[Auto RS T]

If the pump was bad or installed incorrectly I wouldn't expect to see normal fuel pressure. This also leads me to believe the filter is ok. You do have it at stock Fuel Pressure (43psi) correct?

 

[dale187]

I tried, i disconnect the vacuum line, set it at 43.5, and connect it and it adjusts accordingly. Typically dropping to about 32. Then i take it for a ride go WOT and it almost feels like it wants to shut off. Running extremely rich

 

[eclipsegsx224]

yup i got the same problem trouble codes p0125 and p0170 idk what going on i folloiwed my vaccum lines up and down 20 times but if i put my car pass like 2500 rpm and push my clutch in my car sometimes will either cut out and die or just got down to like 200 rpm and bounce back very annoying anyone got any ideas keep post going

 

[rush2252]

Just a suggestion but personally Ive seen different brands of code readers pull different codes. Kept getting a EVAP code on a 420 and it ended up being a CAM or CRANK sensor malfunction on another scanner. Problem was the CAM sensor. I cant explain it but Ive personally seen it. And I hooked them up back to back so I know it wasnt user error.

-Kolby

 

[stevo911]

I acually had this problem today on a 1G put the CAT back on and it went away something about airflow. Way I figured mine was to cover some of the muffler to restrict flow and it started to idle normal. Not sure if this will help you but I spent all day today rebuilding my exhaust because of it.