P0440 and P0172 mystery

Lolvolol · Post by **Lolvolol** » 06 Dec 2019, 20:44

97 850 T-5 here, I have a troublesome strand of issues that I assume are related. First off, I’m getting two codes: P0440 and P0172, and I have a mystery hose that I assume is apart of the EVAP system that I cannot seem to figure out. It’s sitting on the drivers side of the fan shroud and is hooked up to nothing (see photo, and I have honestly no clue where it’s home is. Also my idle is around 950-1100. I’ve tried taking apart and cleaning the MAF with no luck, and I just did the complete pcv system replacement (cel lights were on beforehand), and my average gas mileage will suddenly drop to around 12-13 for no apparent reason and then go back to normal after a day or so. I’ve also had what sounds to be an air hiss that I can mainly hear when the hood of the car is down, it seems to be coming from around the battery/driver wheel area that I can’t figure out (and no it’s not the mystery hose, the sound remains even when the hose is plugged). Any advice would be much appreciated, since I don’t have money to just throw at new 02 sensors and MAF’s.

ashvolvo · Post by **ashvolvo** » 06 Dec 2019, 21:56

Can you check the canister purge valve near the fan shroud. There should be 2 connections to it- one coming from under the car ( from the charcoal canister) and other going to air intake near the MAF sensor. It could be that one of those has come off. The size of the hose gives an impression that it is an EVAP hose.

Lolvolol · Post by **Lolvolol** » 06 Dec 2019, 22:07

The one coming from the underside of the car is connected, and the hose I’m holding is the one that is coming out of the other side of the purge valve. So does that mean this hose routes all the way to the air intake? If so I’ll have to get some more hose, this one won’t reach near that far. Also it’s probably worth mentioning the guy i bought the car from said he had a new engine put in after the previous one quit, and it seems like the mechanic who did it didn’t quite put everything back together correctly, or the new engine and it’s components weren’t compatible with some aspects of the car so he just had to “make do”.

Lolvolol · Post by **Lolvolol** » 07 Dec 2019, 15:55

So I figured it out somehow. The cruise control vacuum hose was hooked up to the evap purge valve and then led to nothing, and the hose that was supposed to be hooked up to the purge valve was plugged into the intake manifold. So I unplugged the cruise control hose and plugged it into the the cruise control nipple under the battery, and took the evap hose that was connected to the manifold and plugged that up to the evap purge valve (where the cruise control line was) and then plugged that up to the intake manifold. It’s now idling at about 850 rpms, not 1100. Gonna check my codes in a bit

Post by **misha** » 07 Dec 2019, 16:03

Hose from purge valve goes to metal nipple at intake manifold...that's correct routine.
Remove negative battery terminal for about 10-15 min in order to clear the codes and reset fuel trims.
Then....do a re-learning procedure for ecu and see which codes are coming back.

Lolvolol · Post by **Lolvolol** » 07 Dec 2019, 16:56

misha wrote: ↑07 Dec 2019, 16:03 Hose from purge valve goes to metal nipple at intake manifold...that's correct routine.
Remove negative battery terminal for about 10-15 min in order to clear the codes and reset fuel trims.
Then....do a re-learning procedure for ecu and see which codes are coming back.

Gotcha. Will update

Post by **abscate** » 07 Dec 2019, 18:17

On a turbo car there are two suction routes from the purge valve to the engine

One runs to the intake manifold, the other to the intake snorkel just in front of the turbo. By front, I mean the air path front, not the location.

There is a check valve in each path after the T connection

Lolvolol · Post by **Lolvolol** » 08 Dec 2019, 14:04

All connections are good, acts like a different car now. Codes are gone. Thanks for all of the help guys.

VTs70T5M · Post by **VTs70T5M** » 08 Dec 2019, 23:19

Here's a stumper lol...
My 98 s70 t5 has an 04 b5234t9 rn swap with 62k.
Car runs amazing but I'm maxing out the maf.
So i get a 960 3" maf housing put my element in, tuner sends new bin scaled for 3" maf.
Now runs little sloppy but eventually smoothes out.
Heres the thing after about 30 miles I get efi-231 long term fuel trim part load.
Car is complete dog...
Swap bin and housing back runs amazing again.
Tuner has tuned a ton of these 960 housings on p80 m4.4 cars so i know its not tune...
Clearly my element is fine because in stock housing is perfect.
I have a 2.75 to 3" 90° coupler looks identical to my snabb one just larger diameter on one end for larger maf.
Runs 20 h.g at idle clearly no vacuum leaks.
Plus when I did rn swap last month I put all new silicone lines, new pcv lines, new fpr line, new plugs, new wires, new cap, new rotor, new intake gasket (snabb spacer/gasket), new turbo to manifold gasket, drain pipe gasket, tb gasket, cam seals, etc etc.
Car doesnt leak drop of anything anywhere..
Also running aem x series wideband full lambda regulation no stock o2.
Has the snabb rip kit, snow wmi kit, green injectors, even all new motor mounts including upper poly bushings for torque rod and firewall, ipd hd tcv, ipd hd cbv.
Anyway you guys get the point it's clearly not a vacuum issue or sensor issue.
Its either element isnt oriented right or maybe coupler has to tight of a bend idk has me stumped!!

VTs70T5M · Post by **VTs70T5M** » 08 Dec 2019, 23:21

ps efi-231 is vol-fcr code corresponds to p0171 or p0172 unsure...
Essentially o2 saying its lean and adding fuel maf is saying to much fuel for air and cutting it the 2 combat each other til ecu says ok time out! Limp mode... Lol..
When that happens wont boost over 8psi on a 16psi tune...
Afr are lean at part load until wot..
And pops a lot when downshifting.