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R-Dub
12-03-2005, 12:07 AM
secondary O2 sensor!

So I gutted my cat, got the P0420 CEL - got tired of it pulling timing and clearing it so I did the restrictor diode fix as seen on AW.

Few days later though - Im getting P0171 - Engine Running Too Lean.

My thoughts are attributing this to the 02 sensor wire now getting NOT ENOUGH voltage going through it.

How, oh how, do I get this ting to fix permanently with no CELs?

Also - when I was driving today the computer started flashing with the 2:00h seeting even though I have it set on XXXmiles left setting.

Why would it randomly start flashing?

BranCKY3
12-03-2005, 12:12 AM
I'm pretty sure that the secondary o2 sensor won't affect timing...

My car always flashes 2:00h when I reach the 2hr mark. Is it possible to turn it off?

turbojunkie
12-03-2005, 12:28 AM
Originally posted by R-Dub

Also - when I was driving today the computer started flashing with the 2:00h seeting even though I have it set on XXXmiles left setting.

Why would it randomly start flashing?

After 2 hrs of driving, it automaticlly comes on....also after 4...6...ect. at least it does on mine.

R-Dub
12-03-2005, 12:39 AM
Originally posted by BranCKY3
I'm pretty sure that the secondary o2 sensor won't affect timing...

My car always flashes 2:00h when I reach the 2hr mark. Is it possible to turn it off?

I hope so. I found out from a VW tech that it does that to remind you to take a break and rest up.

Ive been told that if you gut your cat you pull timing to cut down on unused hydrocarbons in the system, the opposite true for a lower voltage level from my diode.

Still, even if its only an amber MIL going off - its driving me nuts.

turbow8
12-03-2005, 10:16 AM
Originally posted by turbojunkie
After 2 hrs of driving, it automaticlly comes on....also after 4...6...ect. at least it does on mine.

same here, just clicking the rocker arm @ the end of the, the, the stick thingy where you turn on your wipers @ and it goes away. [wrench]

offroader1006
12-03-2005, 10:56 AM
the second 02 sensor is just a check for the catalyst. it only tells the computer whether its working or not. just plug the hole and attach the 02 sensor somewhere warm

R-Dub
12-03-2005, 11:29 AM
Tried that, had 4 CELs that came on every time I started the car.

k0mpresd
12-03-2005, 11:35 AM
the secondary o2 doesnt tell your ecu anything about the a/f ratio, rich or lean

it only tells the ecu if the cat is "working" or not..your lean code is not due to the diode mod on the rear o2

R-Dub
12-03-2005, 11:51 AM
Thats strange...I havent touched anything else on the car - what would cause it to run lean?

k0mpresd
12-03-2005, 12:00 PM
since your dbw it could be the maf dying

offroader1006
12-03-2005, 12:02 PM
yep, sounds like it

R-Dub
12-03-2005, 12:06 PM
Originally posted by k0mpresd
since your dbw it could be the maf dying

Oh come on, are you serious?? The car doesnt even have 40k miles on it!

What would cause an MAF to die so early?

Also - Im definetly getting some hesitation at WOT and definate power loss. This would be from the system being lean correct?

k0mpresd
12-03-2005, 12:10 PM
vw maf's are known for crapping out early and randomly..you dont have a k&n or anything do you?

hesitation and power loss could be caused by the dead maf...try unplugging the maf and see if it runs any better..if it does, then you more than likely found your problem

offroader1006
12-03-2005, 12:10 PM
probably the bad maf there too.

MAF's are just sent here to do one thing, then they pass on. some go early, some never go. sad really . . .

offroader1006
12-03-2005, 12:11 PM
Originally posted by k0mpresd
you dont have a k&n or anything do you?

here we go, . . .

k0mpresd
12-03-2005, 12:13 PM
Originally posted by offroader1006
here we go, . . .
what?

the oil from a k&n filter is known to get sucked into the engine and getting stuck on the sensor itself, causing premature failure or if youre lucky, you can just take it out and clean it

that may also work here, removing the maf and cleaning it w/ some electric parts cleaner

offroader1006
12-03-2005, 12:17 PM
i know, just bustin your chops for starting the k&n scare again.

they only risk damage if over-oiled, which they dont come from the factory. ive fun a properly oiled K&N on two vehicles for over 50k combined, with perfectly clean MAFs

k0mpresd
12-03-2005, 12:24 PM
i have a k&n too....just no maf [;)]

R-Dub
12-03-2005, 12:26 PM
Had a K&N for about 10 minutes; didnt like it and took it out.

Now Im running a Weapon R SW1 that is not oil lubricated.

Well Im going to unplug the sensor, see if my power loss continues.

EDIT: Wtf? $90 the best price on ECS? Goddamit.

k0mpresd
12-03-2005, 12:39 PM
i might could get you a deal on a maf..ill have to check on monday...shoot me a PM

R-Dub
12-03-2005, 03:22 PM
Well, I get off work and as I am driving I notice that my car is EXTREMELY gutless and is driving like a 91 civic.

Then I started watching my boost gauge - nothing past 6psi.

So I as limped home in limp mode, I check the engine - same thing P0171, Lean.

Cleared the CEL, drove and got it out of limp mode.

Is there ANY thing other than a MAF that would do this?

goldenchild
12-03-2005, 03:45 PM
what r u boostin? i had that problem in my 01 with a k04 when id hit a high boost pressure it would throw that code and put me in limp. u might wanna get a mbc and turn it down a bit. i just say this bc of the year car u have and the known shitty tuning for the cars. yes i know giac is a good one but they did have problems untill now being the new updated software. just a thought

R-Dub
12-03-2005, 04:34 PM
This would be a first.

I usually spike at 20 but that never set me in limp before.

goldenchild
12-03-2005, 05:39 PM
i didnt know what ur chips psi was and plus ur probally seeing more than 20 psi in the charge pipes bc im guessin ur gauge is off the intake manifold

R-Dub
12-03-2005, 08:49 PM
Well its been a day that I havent gotten the code thrown at me, if it doesnt turn up Im going to assume it was a fluke.

However, is it still safe to drive it under the circumstances? I know leaning the turbo may hurt it but as long as my CEL isnt on it should be ok.

Confirmation?

offroader1006
12-04-2005, 11:06 AM
if it gets too far lean, it SHOULD throw a code, just make sure it doesnt run hotter than usual.

i doubt its really going lean though

alen
12-04-2005, 12:06 PM
did you try unplugging the MAF?

Yuikio
12-04-2005, 12:20 PM
Don't the later DBW cars have a throttle cut past 19psi that makes them go into limp mode?

I never really paid attention to those threads, since I'm not DBW, but you might check those out, because this sounds like you have a similar issue to those guys.

R-Dub
12-04-2005, 07:47 PM
Damn! This thing is like the herpies!

So I keep going into limp, getting my P0171 CEL, clear it and afterwards it runs fine.

But, just like herpies it keeps comming back - based on time not on my PSI.

I havent tried disconnecting the MAF - but thats my next step.

Anything I should be worried about?

b00st
12-04-2005, 08:38 PM
man after all these headaches...i don't think i want to run the ATP TEST PIPE.

R-Dub
12-04-2005, 10:30 PM
I disconnected the MAF after I hit limp again, I hope this solves my problem.

But, my question is, wont there be a problem with running no MAF sensor? If air flow isnt monitored what other kinds of problems am I looking at?

offroader1006
12-04-2005, 10:35 PM
its got a MAP to lean back on.

at least it should.

R-Dub
12-04-2005, 11:13 PM
Here's hoping man.

bitterchild
12-04-2005, 11:16 PM
Originally posted by b00st
man after all these headaches...i don't think i want to run the ATP TEST PIPE.

us DBC guys have it easy. be sure to chase the threads in the flange before you put the studs in though.

94jedi
12-05-2005, 07:30 AM
Originally posted by bitterchild
us DBC guys have it easy. be sure to chase the threads in the flange before you put the studs in though.

yep or else you get an exhaust leak.

b00st
12-05-2005, 11:51 AM
yeah i remember you posting that info up bitter,
just not sure I want to go through the CEL code problem...dunno if diode trick is worth it. better shot with the spacers i think. not sure...i really want to get my stock cat out...its a huge restriction on my system here...and testpipe would be ultimate...but CEL code is an issue for me....or the IL state of emissions.

R-Dub
12-05-2005, 12:55 PM
The diode mod is about 4 minutes and easy as pie.

I would recommend it over the spacer as a first try.

k0mpresd
12-05-2005, 01:31 PM
Originally posted by offroader1006
its got a MAP to lean back on.

at least it should.
the map sensor only tells the ecu the actual boost level, not how much air is going into the engine...that is monitored by the maf w/ the o2 sensor to fall back on

b00st
12-05-2005, 02:23 PM
Originally posted by R-Dub
The diode mod is about 4 minutes and easy as pie.

I would recommend it over the spacer as a first try.

so is it 3 diodes that you need? black, brown, green IIRC?

offroader1006
12-05-2005, 02:38 PM
Originally posted by k0mpresd
the map sensor only tells the ecu the actual boost level, not how much air is going into the engine...that is monitored by the maf w/ the o2 sensor to fall back on

i know this is how a lot of other new cars work, figured they do it on audis as well.

k0mpresd
12-05-2005, 02:50 PM
stop hanging out w/ honda boys..its poisoning your brain [;)]

offroader1006
12-05-2005, 03:39 PM
i dont hang with hondas, i go to a toyota sponsored school[up]


and how does it monitor air flow? watch the heater voltage?

R-Dub
12-05-2005, 04:00 PM
Originally posted by b00st
so is it 3 diodes that you need? black, brown, green IIRC?

I just did it for the black wire connected to the green O2 connector.

1 diode, then I whipped out the multimeter and monitored the voltage while a friend revved the engine - worked like a charm.



Oh and BTW - diconnected the MAF sensor - havent gone into limp mode yet BUT now I am getting P0102 MAF Sensor low voltage.

Is there any way to fix this without having a bloddy CEL???

k0mpresd
12-05-2005, 04:24 PM
buy a new maf..of course youre going to get a maf code when its not plugged in...the ecu isnt getting a signal from the maf so it throws a code

R-Dub
12-05-2005, 04:36 PM
Originally posted by k0mpresd
buy a new maf..of course youre going to get a maf code when its not plugged in...the ecu isnt getting a signal from the maf so it throws a code


Yeah I knew that but my question is; I seem to be damned if I do/dont.

Im going to try to get some CRC and clean the MAF with it - hopefully that will do the trick.

If not, Im getting a new MAF I suppose.

R-Dub
12-06-2005, 02:35 AM
Ok, so now the disconnected MAF is sending me into limp mode as well.

I am convinced at this point that it has to be my secondary O2 sensor.

The voltage reading is so low that my engine thinks I am running a lean mixture and sends me into limp so I dont blow my engine.

I talked to a few guys and they gave the same information.

If anyone has any ideas that doesnt involve me pulling the diode and getting back the P0420 CEL would be greatly appreciated.

k0mpresd
12-06-2005, 07:37 AM
how much boost is the car making??

the rear o2 has nothing to do w/ rich or lean

R-Dub
12-06-2005, 09:17 AM
I run about 14-16, peak at 20 and hold 18.

b00st
12-06-2005, 09:56 AM
ok so i'm not doing to diode trick....its either spacers or i gotta drop coin on a real HFC.

k0mpresd
12-06-2005, 11:41 AM
Originally posted by R-Dub
I run about 14-16, peak at 20 and hold 18.
not to sound like a dick...but you did diode the 4 wire sensor correct?...not the 6 wire..

R-Dub
12-06-2005, 12:11 PM
Not a dick-ish comment at all.

When I did the diode mode the DIY says to only tap the brown connector, I did so.

There are 3 wires, black, white, grey. The DIY shows a spliced black wire and doesnt touch the grey or the white - I did the same.

After that I didnt have any problems for..oh about a week. So I have no F'ing clue whats going on.

I dont think my harness is identicle to the DIY so there may have been a mis-communication.

Let me know what you think.

b00st
12-06-2005, 01:01 PM
Originally posted by R-Dub
I run about 14-16, peak at 20 and hold 18.

shit...i can't even hold 18...more like 14-15psi.....spike to 21psi. but this is in the summer.

now i hit 14psi and hold at redline 10psi maybe 11...but i doubt it. it was 11 degrees last night and it said it felt like 1 degree. either way it was freezing balls.

k0mpresd
12-06-2005, 03:09 PM
Originally posted by R-Dub
Not a dick-ish comment at all.

When I did the diode mode the DIY says to only tap the brown connector, I did so.

There are 3 wires, black, white, grey. The DIY shows a spliced black wire and doesnt touch the grey or the white - I did the same.

After that I didnt have any problems for..oh about a week. So I have no F'ing clue whats going on.

I dont think my harness is identicle to the DIY so there may have been a mis-communication.

Let me know what you think.
ok..i just didnt want to sound like i was insulting your intelligence or anything..

anyways...it should be a brown connector w/ 4 wires, 2 white, 1 black, and 1 gray

the black wire is the one you splice, its the 0-1v signal to ecu, the 2 white are for the heater and the gray is a ground i believe...so sounds like you did all that right

01.5 should be an awm engine (this when VW switched to the awm engine), which also should have a 6 wire, wideband front o2 sensor

widebands use a 0-5v signal to the ecu, which is a lot more accurate than the older, narrowband 0-1v sensors

your front, wideband 0-5v o2 sensor is what sends a signal to the ecu for a rich or lean condition

the rear o2 sensor ONLY deals w/ the efficiency of the catalytic converter..this is why all cars in the usa made '96 and up have atleast 2 o2 sensors, 1 front and a rear sensor

if you spliced the black wire on the brown connector then your lean code is NOT because of the diode mod, just a coincedence

if a dbw car is throwing a lean code most of the time it is because of a bad maf..and most of the time unplugging it is a good good/bad test because with it unplugged the ecu is going off fuel maps and the o2 sensor reading and not taking the signal from the maf into consideration...since you are still going into limp w/ the maf unplugged then i dont really have any other suggestions for you [confused] if you have a vagcom i would suggest clearing the codes to reset the ecu and logging spec/actual boost and see whats going on there since you are still hitting limp mode...i bolded "most" because anything w/ a german car can happen [:p]

R-Dub
12-11-2005, 07:13 PM
Update:

Cleaned the MAF last night using 99% alcohol in a bag and swished it around, let it soak for a few hours and dried it overnight.

Put it in and hoped for the best:

Not getting the Lean CEL yet or going into limp....

BUT: definate power loss at WOT - engine is hesitating and acceleration is dead in the water.

At this point I am leaning toward a dead MAF and probably going have to buy a refurb.

Now lets say the refurb MAF doesnt work - what else am I looking at? IE: Diverter Valve?

b00st
12-11-2005, 07:24 PM
hmmm...when i cleaned mine...my rpms were all over the place at idle. bouncing as i would come to a stop, didn't feel right and then about 80 miles later and it cleared up. though I think my MAF is on the way out too...just holding off.

AB18
12-11-2005, 07:36 PM
I have never oiled my k&n, i just clean it out. Don't be afraid of the testpipe, somepeople have issues and some don't. I have a labree shotgun on my stage3 have no cel.

R-Dub
12-11-2005, 08:24 PM
My idle and all RPMs up to 3200 are fine - after that the engine hesitates badly.

offroader1006
12-11-2005, 11:43 PM
not a misfire is it?

thats what mine did when it lost a cylinder, cant notice it until midway through the rpms

R-Dub
12-12-2005, 12:31 AM
I can tell a missfire though...plus it would throw a CEL for the cylinder - but no, no misfire.

However, I did disconnect the MAF and now I no longer go into limp mode...so now I am 99% sure its the MAF.

My engine still hesitats a LITTLE bit at WOT but other than that Its working.


So after Christmas its time for a new MAF - Ill send you a PM kOmpressed.

offroader1006
12-12-2005, 10:44 AM
Originally posted by R-Dub
I can tell a missfire though...plus it would throw a CEL for the cylinder - but no, no misfire.

you'd think it'd throw a CEL, mine never did.

but no use in doing anything until you get the new MAF.

R-Dub
12-12-2005, 12:23 PM
Yeah, I just need to get my hands on a new MAF.

For now, running with a disconnected MAF is working fine.

R-Dub
12-16-2005, 08:18 PM
Ok...so I repalced the MAF.

I took it for a run for about 10 minutes and up to ~80mph and although I did feel quite a bit of hesitation at WOT - no CEL...yet.

I fear that I will still get the lean CEL soon.


So now I fear it is something other than the MAF - what else could it be?

I keep thinking that it could be a loose Vac line....but I dont know.

What are the other causes of a lean engine other than a MAF?

R-Dub
12-17-2005, 10:21 AM
Update :

Started up the car this morning, nothing fishy going on until I started to drive it. Car is hitting a max of 10PSI, when I used to tap out at 20.

Now I know its winter and my PSI will drop a little, but HALF??

So now as I am driving along with NO CEL, I boost up to 10 PSI - and (usually in 3rd gear) after I hit 3kRPM exactly, my car starts to shake!

Not alot, but the more I progresse toward 4kRPMs the more it shakes!

No CELS, no misfires, nothing! All I did last night was replace the MAF (which I suspect was not the problem now, but no matter), I just need to know what the HELL is going on with my car!



- I suspect a damaged/dead Vac line so I am going to replace them all to insure that I fix that problem if it is the source - does anyone have a diagram of ALL Vac lines in the engine bay?


Thanks to anyone who can help me with this serious problem - I will owe you a 12 pack.

bitterchild
12-17-2005, 03:02 PM
how far are you from LA? What codes are you getting now? What plugs, gap and how old are they? How's your idle? speed? smooth? Does the engine start right up and hit idle speed immediately or does it hunt around?

R-Dub
12-17-2005, 03:07 PM
422 miles from LA.

I got 2 missfire codes - C1 and C4 missfired twice.

The plugs are (to my knowledge) stock and now 39,455 miles old.

It is my thought that they are at fault.

Idle is ok, 1.2k then down to 900 after warming up, though it is not a smooth start up.

Speed - lacking heavily.

Smooth - about as smooth as a bed of nails.

I am also talking to Ian (kOmpressed)

k0mpresd
12-17-2005, 03:28 PM
problem found [;)]

R-Dub
12-17-2005, 03:33 PM
http://i4.photobucket.com/albums/y103/EternalVash/FUCK002.jpg


Everything looks ok right?

http://i4.photobucket.com/albums/y103/EternalVash/FUCK003.jpg


WRONG!!!!

http://i4.photobucket.com/albums/y103/EternalVash/FUCK004.jpg


THE CAUSE OF LEAN ISSUE AND MISSFIRE.

bitterchild
12-17-2005, 04:07 PM
your welcome :p

change those plugs

R-Dub
12-17-2005, 05:27 PM
So Ian had me replace the piping with 1/2'' rubber heater piping and it seems to be working just fine.

I am still experiancing some boost issues - for example my boost still seems a tad low and my acceleration is absolute crap after ~4k rpms when WOT.

I think I need to VAG this bad girl and see whats going on.

R-Dub
12-17-2005, 10:37 PM
Also in a semi-realted issue, ever since this lean code has been going on - my gas mileage has gone from a combined 25mpg to 18mpg with no change in my driving style.

Would this be an effect from the blown suction hose as well?

R-Dub
12-17-2005, 11:16 PM
New problem!!

1st gear - fine, I dont usually boost past 0PSI so thats normal.

2nd gear - after 4.5k I hit a brick fuckin' wall. My car just plain stops accelerating while boosting 16-17PSI.

My boost is irregular, rough boost and spikes SUDDENLY into 21PSI randomly at WOT.

Ive NEVER gone past 20PSI, ever.

HELP! Ian! Bitter!

SFexBOY
12-18-2005, 05:14 PM
MAF.

R-Dub
12-18-2005, 11:55 PM
MAF is brand spaking new.

Car will now randomly missfire, sometimes at WOT in 3rd after 4k....sometimes not!

Im going nuts over this, and I have carbonation build up (like more than usual, it looks almost like unused fuel leaking) on the intake manifold side of the engine.

Im going to try to fix this before Tuesday when I have to drive 250 miles.

My fuel economy is now at a combined 14mpg vs. 27 before, what is going on?

bitterchild
12-19-2005, 01:45 AM
have you changed your plugs yet? do it

fuel build up is injector seals/seats or intake manifold gasket. check em

i need either codes or a car. show me one

R-Dub
12-19-2005, 01:58 AM
Only missfire codes from OBD; 300, 301, 302, 304.

Car - 2001.5 1.8T.

I have pics of the engine, AIM me to see them.

Aim = R To The Dub.

R-Dub
12-19-2005, 09:12 AM
So heres the deal.

I am running rich - why? We need to find out.

Too much fuel in the cylinder is causing a missfire (it feels like late detonation, but I could be wrong).

This only occures in 3-5th gear after 3.8k RPMs.

Boost is still not 100% back to normal.

Feul economy is 120 miles short of what it used to be.


What would cause these problems?

onemoremile
12-19-2005, 10:38 AM
seriously, did you ever change those plugs?

shit, just throw another 8 bucks at the problem already!

k0mpresd
12-19-2005, 10:45 AM
you need to change your plugs and reset your ecu

R-Dub
12-19-2005, 01:06 PM
No Kragens/Pepboys/Autozone around here carry the plugs so I have them ordered.

Meanwhile, some IDIOT nailed my front end so now I cant get my fucking hood open!

So even if I wanted to fix my plugs I couldnt!

Goddamn this first day of vacation has sucked.


Oh and still throwing lean code after the accident [=(] [=(] [=(] [=(] [=(] [=(] [=(]

R-Dub
12-19-2005, 04:45 PM
Got the hood opened, found a small shop that sold BKRs.

Gapped at 0.028, put them in, torqued to 22ft/lbs.

Switched the coilpacks around for good measure.

Also replaced the FPR vac line for good measure (the braided cable was looking trashy).


But, still after all that I am still missfiring in cylinders 1 and 4.

So I know its not the coilpacks, plugs, or FPR/FPR line.

What else should I be looking at to discern the missfire?

Also - fuel economy is still 70-90 miles short of its original map.

I still suspect I am running rich because the ECU thinks I am running lean for some reason when my mixture should be ok.

k0mpresd
12-19-2005, 04:49 PM
what is the part # of the plug you got?

R-Dub
12-21-2005, 04:44 PM
Still having problems:

Missfires - 3rd-5th gears under WOT after 4k RPM.


Lean - Still recieving lean code.


Fuel Economy - Still 50 or 60 miles less than normal.


Boost - Will loose boost even with throttle still open, not just during shifting. Example : In 3rd gear will punch it up to 12-14PSI, but without letting off the throttle at all the boost will go down to 0.


Tony, Ian, Daft - you guys have helped so well in the past, please help with this mysterious problem.

R-Dub
12-22-2005, 01:32 AM
VAG-Codes
VAG-COM Version: Release 504.1-UD

Control Module Part Number: 4B0 906 018 CH
Component and/or Version: 1.8L R4/5VT G 0001
Software Coding: 16201
Work Shop Code: WSC 06435
5 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16685 - Cylinder 1: Misfire Detected
P0301 - 35-00 - -
16688 - Cylinder 4: Misfire Detected
P0304 - 35-00 - -
17584 - Bank1: O2 (Lambda) Correction Behind Catalyst: Control Limit Reached
P1176 - 35-00 - -
17522 - Oxygen (Lambda) Sensor; B1 S2: Internal Resistance too High
P1114 - 35-10 - - - Intermittent




I have the VAG Logs for blocks 32,34,10,20, and 115 if anyone wants them to help me with this problem.

bitterchild
12-22-2005, 11:01 AM
did the misfires follow the coilpacks when you swapped them?

sounds like you may have a leak after the maf

R-Dub
12-22-2005, 02:40 PM
No, missfires contintued at the same cylinders even after switching the packs.


Also - I tried switching the spark plug wires and my car wouldnt even turn on? Is that normal?

bitterchild
12-22-2005, 02:58 PM
what spark plug wires? Are you talking about the ground straps? Stop randomly doing shit. It's not helping at best and may be adding issues.

it's very difficult to help you without looking at the car.

R-Dub
12-22-2005, 03:38 PM
Local Audi tech advised the switch to see if the wires are to blame.

bitterchild
12-22-2005, 04:38 PM
what do you want me to say? have the local tech fix it :p

R-Dub
12-22-2005, 06:18 PM
Well his 'fix' only made my car not start up.


Heres the things though:

While having the diode for the second 02 sensor in - I ran lean.

Well I took it out last night when I was running the VAG and sure enough - no more lean code.

So I would theorize that the secondary O2 sensor not only works as a check for the cat but also have a plan in the fuel trim.


But that still wouldnt explain my missfires, bitter, would you like to see the logs I ran during the missfires? Maybe those could help somewhat?

bitterchild
12-22-2005, 07:16 PM
replace your plugs. usually the secondary sensor is only used to monitor catalyst efficiency. That doesn't make any sense. maybe it's b/c you're dbw and have a wideband primary. still doesn't make any sense.

R-Dub
12-22-2005, 07:26 PM
Thats what I thought too but I am now almost 100% positve that the secondary sensor also trims the fuel.

But then my question is - those DBWs that are running test pipes - shouldnt they be having the same problems as me?

ECS has the rear O2 sensor listed as 150 bucks for AWM engines - fuck that, there has to be a way to fix this without me spending another 150.

offroader1006
12-22-2005, 09:26 PM
buy a regular bosh 4 wire and splice the wires

offroader1006
12-22-2005, 09:38 PM
have you tried switching the 02 sensors and clearing the codes and seeing if the code follows the sensor or stays?

R-Dub
12-23-2005, 12:08 AM
I havent tried that, but its a good idea.

Would that work even with my wideband front?

Also, as mysteriously as my missfires came, they seem to have almost vanished.

I only get one if I am in 5th gear WOT over 4.5k RPM. But I seldom go that high anyway so its of little to no concern for me.


But I am back to where I was before, CEL is on from the gutted cat and I now know that the diode mod doesnt seem to work on a 01.

Would the spacer that seems to be popular work with my set up?

bitterchild
12-23-2005, 01:09 AM
It could. So basically you're saying everything is fine now that you took the diode mod out?

Change your spark plugs. I swear I'll slap you upside the head if you don't.

R-Dub
12-23-2005, 01:11 AM
I did! I swear![:D]

There are still some issues, I am loosing boost even if I dont let off the throttle which makes me raise my eyebrow.

But my fuel economy is back to normal and my lean code is gone.

But, still have a CEL glaring at me again.

R-Dub
12-24-2005, 02:12 AM
Missfires are completely gone, but what does concern me is that I am not boosting to save my life.

I can boost up to 20 easy but it doesnt hold at all, it slids down slowly to 0.

Are those symptoms of a dying DV? Even though its a 710N that has less than 10k miles on it?

bitterchild
12-24-2005, 03:11 AM
possibly, usually you don't get a spike to full pressure w/ a ruptured DV. It's pretty easy to get under and look at it...

R-Dub
12-24-2005, 04:19 AM
True, I pulled it and it seems ok.

What else would cause boost to slide off with no throttle let off?