Annoying Fuel trim problem

[tljohnson1]

Hello Everyone,
I have done my research on this Problem and it always seems to come back to a bad oxygen sensor.
MY 97 Talon TSI has a CEL that shows the code p0170 which is a "Fuel Trim Malfuntion" (Bank 1).
My vehicle: -can barely make it up hills or slight inclines
-Has a slow accelleration
-Will not boost past 5psi
-Has a rough idle (missing biss screw?)
-Spits and sputters when i try to accellerate hard
-Then feels like it hits a brick wall and looses all acceleration power.
Things i have done to try and correct this:
-Replaced both oxygen sensors
-Replaced my leaking factory BOV with HKS SSQV
-Replaced plugs and wires (NGK plugs, Bosch wires)
-Vacuum tests
-Fixed my exhast leaks
-Snap on scanner showed TPS, MAF, Injectors, and IAC all functioning properly.
-Tested fuel pressure and changed fuel filter

At an Absolute loss. Please help.

 

[95dsmgsx95]

Did you gap the plugs? And do a boost leak test.

 

[muscle187]

i have a 98 tsi talon auto awd that used to hesitate quite a bit under hard excelleration and i couldn't figure it out for the longest time. then my alternator went and the new alternator basically fixed the problem. i doubt this is your problem but you never know

 

[tljohnson1]

I gapped the plugs to .032 as recomended by the manufacturer and the boost leak test held up to 30psi.

also the alternator is less than a month old.

 

[Hesh724]

but did u put the spark plug wires back on in the proper order? um, make sure your coil pack or nothing isint arcing. check injectors for proper spary could be a bad wire in the harness for a sensor or injector or something. make sure you bov is adjusted, does it ever fall into closed loop? bad fuel regulator, biss unless u pluged the hole is gona make it run bad of course. dyin pump, lots of carbon in the cylinder, clogged cat if it seems like the o2 sensor is weird? but thats just some friendly ideas.

Good luck!!

 

[dsmpat95]

Your spark plug gap should be between 0.028 - 0.031. Redo your gap on your plugs.

 

[tljohnson1]

but did u put the spark plug wires back on in the proper order? um, make sure your coil pack or nothing isint arcing. check injectors for proper spary could be a bad wire in the harness for a sensor or injector or something. make sure you bov is adjusted, does it ever fall into closed loop? bad fuel regulator, biss unless u pluged the hole is gona make it run bad of course. dyin pump, lots of carbon in the cylinder, clogged cat if it seems like the o2 sensor is weird? but thats just some friendly ideas.

Good luck!!

The Plug wires are back in the right order and there is no arcing anywhere. The electrical aspect of the injectors and my sensors were checked with my friends scanner I did a visual inspection of my sensor connectors and my injector spray ports. The BOV is new and im not quite sure what to do to adjust it properly. I pulled the vacuum line off of the fuel pressure regulator and there is no gas in it so the diapham is still in working order. My cylinders seem to be visualy clean and i hallowed out the cat after this problem started.

Well this is probably an important piece of information and probably the cause of all the problems. I took my spark plugs out to re-gap them to .028. While i had the plugs out i decided to do a compression test. from passenger side to driver side i got 130, 130, 130, 140. My manual says that the compression should be about 178. Could this cause all my problems?

 

[brian102]

Not surr if its related or not but im throwing same code. No cat converter and my alternator just went bad.. put a reman on anf two days later its bad again.. maybe its not supplying the ignition system the voltage it should?

 

[Black-Out]

Did you make sure that the solenoid that controls the fuel pressure regulator is in good working order?
If its stuck mechanically but fine electrically then it can cause that....
What were the long term and short term fuel trims? post em up and I can better bet you can find a few things that you may have not thought of before.....also post up your injector pulsewidth at idle in milli seconds....

You've replaced 0/2's, plugs,wires, and you checked your maf but you didn't mention what your readings are in GPS (grams per second air flow) these are the little things that we need to know to help aim you in the right direction because if you say everything is in working order but your air flow meter is showing a reading at idle thats less than 3.2-3.5gps then you've got a restriction in the air flow path or a contaminated maf that may have debris caught in it causing all your headaches.... post up a freeze frame of your fault code showing all your real time data at the time of the fault and we should be able to help out.....otherwise this may all be a massive waste of brain energy trust me.....Ive seen master certified techs tell customers they need an engine when a house fly stuck in the airflow meter is whats causing the car to run like absolute crap...............

 

[Hesh724]

if your rear bumper isint covered in black then ## rings should be ok, u will notice any issue with those quickly. there are a few steps to doing a compression test like it should be done once with car cold then hot. and after u do a compression test pour a tiny bit of oil into each cylinder as u do them the 2nd time and if the copression raises drasticaly then there may be some issue. and make sure the gas pedal is pressed in so the trottle body doesnt affect the reading if there is bad enough blow by the tb will still hold a litle pressure. also if u have aftermarket pistons it may lower the compression a bit but not 10s of psi's i dont think . I would pay special attention to timing and electrical/ sensors etc. but again just my 2cnts. oh and like black out said too maf can really give u some weird symptoms. timing for the compression cause compression can only be affected by the condition of the parts like bad rings etc. or timing being off. and with the electrical thats like maf, tps, make sure your ecu is free of any leaks on the caps.well let us know!

Good Luck!,

 

[brownfinger]

Dude, I promise it's your fuel pump. Just 'cause it makes the right pressure in a static test at idle doesn't mean it's able to make that pressure while actually driving the car. As the consumption rises with acceleration, the pressure is dropping. Trust me. Besides, what's the only thing you haven't replaced or triple-checked with a computer?

 

[tljohnson1]

Thanks for the ideas guys. I will do some more testing and try to get my hands on a logger or have my friend come over with his scanner and post the actual readings. I should be able to have it all posted within the next day or so. Back to testing for me

 

[talondude4]

Was this problem ever fixed? If so what was the peoblem, I'm having some similar problems.

 

[Aanathan]

Same here any word from op what is wrong?