Elusive p0171 and p0174 problems

[ryankokesh]

I wasn't too worried when these guys popped up on my code reader. Easy fix, I thought... replace an intake boot and you're good to go! Well, two boots and a bunch of other stuff later and the codes are still there. The code reader (I'm using Torque for this on an Android) even calls them "current" faults and they don't go away at all when cleared. From what I've been reading, it seems that normally people's CEL will go off for a short time when the codes are cleared.

So here's a list of stuff that I know isn't the problem:

Lower and upper intake boots replaced (there was a small rip in the lower, but the upper appeared fine)
MAF cleaned
Entire CCV system replaced
Intake boot "F" connector replaced
Oil cap is tight and appears to seal well
Fuel pump replaced with OEM a few months ago
Fuel filter has around 40k on it, so technically not due yet
DISA rebuilt last year (including a new seal)
VCG replaced when I did the Vanos two years ago


Anyone got any ideas? This is driving me up the wall.... :begging

[danewilson77]

You haven't replaced the dipstick tube yet! That has to be it. SAP? Throttle Body gasket?

The friendliest forum on the planet.

[ryankokesh]

You haven't replaced the dipstick tube yet! That has to be it. SAP? Throttle Body gasket?

The friendliest forum on the planet.

Hmmm, I didn't really think about the SAP... I'll have to check that!

The dipstick tube wasn't replaced, but I cleaned it and put a new gasket on it. Thinking that should be enough? I do still have to find the stupid new one. What kind of person loses a freaking dipstick?

And I forgot to mention I put in a new throttle body gasket when I did the CCV. Although the old one looked like it was in pretty good shape.

[danewilson77]

Sounds good. You should have this fixed by now. I thought you were Seth's mechanic!?

The friendliest forum on the planet.

[ryankokesh]

I thought you were Seth's mechanic!?


If you think about it, that explains a lot, doesn't it?

[danewilson77]

If you think about it, that explains a lot, doesn't it?

:rofl

The friendliest forum on the planet.

[derbo]

if you think about it, that explains a lot, doesn't it?

roflmao

[LivesNearCostco]

Last time I had one of these codes, I found my F-connector was not inserted into the upper intake boot! If you think oil dipstick is sucking air but you replaced the lower O-ring, could check that the dipstick itself has the two small O-rings at the top under the plastic pull ring. It may also be possible for the DISA to leak even with new flap and new O-ring, if it leaks air at the vacuum bulb.

Could do a smoke test with mechanic or spray the starting fluid/cleaner around the intake manifold while running to look for vacuum leaks. There are at least 3 or 4 vacuum hoses running around and connected to the intake manifold somewhere, so having any of them disconnected could cause this. Two connect to the F-connector so might track where they go to make sure they're connected on the other end. When you replaced the CCV, you replaced all 4 related hoses including the one on the intake air equalizer thingamabob, right? Leaving any of those hoses disconnected at either end could also result in vacuum leak.

Can these codes come from failing VANOS piston seals or failing pre-cat O2 sensors? I don't see how the SAP could cause these codes unless there is a vacuum line attached to the SAP and that line is cracked or disconnected. While many E46 have that line, I never could find it on the SAP in my car.

[ryankokesh]

Last time I had one of these codes, I found my F-connector was not inserted into the upper intake boot! If you think oil dipstick is sucking air but you replaced the lower O-ring, could check that the dipstick itself has the two small O-rings at the top under the plastic pull ring.

Could do a smoke test with mechanic or spray the starting fluid/cleaner around the intake manifold while running to look for vacuum leaks.

Lol, I actually also replaced the dipstick itself. :facepalm

Checked the SAP and all appears to be in very good condition actually. I was really hoping for a split hose...

Might have to go the smoke test route... This is ridiculous!


Sent from my iPhone

[derbo]

Lol, I actually also replaced the dipstick itself. :facepalm

Checked the SAP and all appears to be in very good condition actually. I was really hoping for a split hose...

Might have to go the smoke test route... This is ridiculous!


Sent from my iPhone

Hope you find the leak.

[ryankokesh]

Hope you find the leak.

Thanks man, me too...

I think I might bust out the 'ole Halloween fog machine.... :shifty


Sent from my iPhone

[ryankokesh]

When you replaced the CCV, you replaced all 4 related hoses including the one on the intake air equalizer thingamabob, right? Leaving any of those hoses disconnected at either end could also result in vacuum leak.

Can these codes come from failing VANOS piston seals or failing pre-cat O2 sensors? I don't see how the SAP could cause these codes unless there is a vacuum line attached to the SAP and that line is cracked or disconnected. While many E46 have that line, I never could find it on the SAP in my car.

I did replace four hoses for the ccv, but three went to the ccv itself and one is on the top side of the manifold attached to one going to the ccv.

The vanos seals were swapped out like 2 years ago so I hope they're still good. And it seems weird that the o2s would fail simultaneously. I dunno. I'm calling shenanigans on this car. There's nothing left to replace!


Sent from my iPhone

[Hornung418]

Intake manifold gaskets, injector o-rings, throttle body gasket.

Sent from my GS3.

[ryankokesh]

Intake manifold gaskets, injector o-rings, throttle body gasket.

Sent from my GS3.

Throttle body gasket is new, but I'm afraid to check the other stuff. I'll probably replace the MAF before those. Have to check the fuel pressure first though.

http://baltimoresportsreport.com/wp-content/uploads/2013/07/frustrated-meme-300x271.jpg

[ryankokesh]

Does anyone else find it strange that these codes aren't clearing at all? From what I'm reading most of the time they turn off when you clear them, and come on again shortly after.

[Avetiso]

All codes should clear because the engine would have to redetect the vacuum leak. For some reason, you're not actually clearing them.

Sent from my SM-G900T using Tapatalk

[ryankokesh]

All codes should clear because the engine would have to redetect the vacuum leak. For some reason, you're not actually clearing them.

Sent from my SM-G900T using Tapatalk

Freakin Torque.... ugh. Gotta boot up INPA or whatever. :facepalm

[Cadeez]

I had the same codes, I replaced the upper intake boot, codes went away for a couple months but came back. So then I replaced the thermostat, boom! Problem solved (well, the codes problem that is, the issue with the coolant dumping out will be handled this weekend). Anyhow, you might try the thermostat. It's a maint part, it's a relatively cheap and easy fix, and it worked on mine. Not to mention the car drives noticeably better now that it is replaced. Do you ever notice the temp actually going down while driving at a constant freeway speed? Just a little bad thermo tell tale. Good luck brotha

[rvariverguy]

Thanks for the group therapy. Mine threw these codes out of nowhere this week and I've been on top of maintenance, although now at 120k. So I'm hoping it's a tear in my intake or a thermostat ready to be put to pasture. Not looking for a longwinded detective case, but I appreciate the trouble shooting here.

[ELCID86]

Thanks for the group therapy. Mine threw these codes out of nowhere this week and I've been on top of maintenance, although now at 120k. So I'm hoping it's a tear in my intake or a thermostat ready to be put to pasture. Not looking for a longwinded detective case, but I appreciate the trouble shooting here.
I hope it's an easy to spot/fix item. I chased them for months on my '02 330Ci. Intakes are on my list to do this w/e on the new red car.