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96 legacy 2.2 codes and problems


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#1 Pgh_Scoob

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Posted 04 July 2014 - 12:17 PM

Ok well as some of you know I was asking about oil leaks on my 96 legacy that I just picked up but after driving for a little while in it I gut a engine light.... Scanned it and this is what I got
Po170 lean bank 1 and po400 egr flow fault
I believe those were the descriptions but anyways I cleaned out the egr valve and ports going to the intake but was unable to remove the brass tube to try and clean that.... Is it common for that to clog? And I'm assuming that I am getting my lean code from that but any insight is always appreciated

The other issue is after paying it wound sit there and crank but not start... The guy said that if it gets low on fuel it won't want to start but he also out his jump pack on it and it fired right up... I did fill it up but only went like 40 miles and it says I used 1/4 tank already so could it just be due to it not being ran extensively and just running rich until it gets it's fuel trims in line ir is there a potential problem. I don't have any fuel smell like a leak and I did have a 96 impreza that had a wacky fuel gauge so could it just be lying and actually almost empty or is it the pump going bad... This is a vague description but I've only had it under a day so this is just off if what I'm seeing.

I hoping someone on here had these issues and can point me in the right direction as to what I should be looking at any other info needed please let me know.
Thanks
Greg

#2 Fairtax4me

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Posted 04 July 2014 - 02:28 PM

Lean code and an EGR code usually points to a vacuum leak. There are lots of old brittle vacuum hoses on that engine especially the 4-5 hoses that go to the BPT valve and EGR.
The EGR is vacuum controlled so any loose or broken vacuum hose can set the code you have.
Also failure of the BPT valve is common. A diaphragm inside ruptures which keeps the EGR valve from opening properly.

Hot restart problems can be caused by a bad ECT sensor. This will also send fuel mileage down the drain.
If your scanner can read live data, check the ECT reading. Generally if that sensor goes bad it will read -40° on data display.

#3 Pgh_Scoob

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Posted 04 July 2014 - 02:48 PM

Hey yes I did that already which checked good and it's not hot restarts but if fuel level gets too low like 1/4 tank.... Supposedly.
With just about a 1/4 tank yesterday when trying to drive away it didn't want to start but since filling up it fires right up and all it was doing was cranking and cranking well not like a weak battery but after he put the jump box on it fired right up

Also what's the BPT valve??? Is it right next to the EGR if so that had been changed already... Much cleaner than other components under the hood.

Oh and for my questioning torque bind.. Driving into work it's seemed good but I did a tranny flush and fill and doing tight turns in the parking lot and on test drive seemed to drive fine.

#4 Pgh_Scoob

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Posted 04 July 2014 - 03:32 PM

So after a quick run to the store I discovered this is a hot not start as well... After sitting for a bit I ran a block down the street started fine leaving and coming back into the shop then few moments later tried to start.... Only cranking put the jump pack on it started but cut out a moment later but started back up looked at live steam and
ECT READING GOOD
RUNNING IN OPEN LOOP NO o2 activity..... Completely ignored.... Not sure what's going on.. My cam seal us leaking on Driver side head and cam sensor is there correct... Could I be losing that signal didn't see an option to check that live stream. Yet again any insight helps

#5 Fairtax4me

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Posted 04 July 2014 - 04:12 PM

Possible the O2 sensor is unplugged or could just be dead.
Need to figure that out and get it running in closed loop. In open loop its dumping fuel in and that may be causing the hard restart.

No way to check crank and cam sensor signals with a regular scanner. Need a SSM scanner or o-scope. Doubtful these are an issue or you would have codes for them.

BPT valve is the black thing with the shiny sticker on top by the EGR. If that has been replaced make sure the vacuum hoses are properly connected. Check the hose routing diagram on the hood.
Could have also been replaced with a faulty part, or just removed and cleaned. There are several hoses that attach to it though, so make sure they're all in good shape.

#6 Pgh_Scoob

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Posted 04 July 2014 - 05:06 PM

Yeah I was thinking an o2 sensor or possibly fuel pump but I can hear it priming but haven't gotten a fuel pressure tester on it but want it to be acting up to see what the PSI reading is.
And for the o2 I'm assuming it's going to be the front one brcayse that's what does all the fuel metering

#7 Pgh_Scoob

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Posted 04 July 2014 - 05:08 PM

Oh and I did check the hoses not routing though but did spray starter fluid to try and get an idle spike but nothing happened

#8 Pgh_Scoob

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Posted 13 July 2014 - 01:15 PM

Ok I could really use some help with this please!!!!!

This is getting frustrating.....

so I am constantly having the stored codes

PO400 Exhaust Gas Recirculation Malfunction

PO170 Fuel Trim Malfunction Bank 1

 

What I have done so far.

Smoke tested Intake to check for apparent leaks... only found leak from EGR... Replaced with New and same result...

Checked/Replaced questionable vacuum hoses

Checked for flow through all ports and tubes

Checked and cleaned brass tube going to intake

Cleaned and Ran intake cleaner through ENG.

Cleaned EGR and accompanying ports to ensure flow... Code came back

Replaced EGR... Code was gone for a few days but came back on... Replaced with original EGR after checking for proper vacuum on diaphragm and ensuring it held.

Replaced EGR solenoid... Thinking that it was not clicking allowing back pressure. $90 later light was on next day.. same codes

Tried to test the BPT (looks like its been replaced) by applying simulated(shop air) back pressure and hooking up vacuum gauge on the other tubes to pull vacuum with no avail... while blocking off any other ports.

Is there supposed to be vacuum held through the BPT.... or is there a way of testing that I missed?

There are no procedures for testing individual components that I was able to find... the only one was with eng up to operating temp going from 3500-4000 rpm and looking for EGR valve to move.... Which isnt happening.

I am going through gas terribly... I believe but could possibly be the gauge lying... Need to run a little longer to find out... worst comes to worst run out of gas and see how far I get or try and see how long I can go while on E..... Feels like Seinfeld....

 

I am also getting an intermittent no start as well.... usually happens on short trips like 2-3 miles and quick shut off and restart where it will just crank... I have done fuel pressure tests and everything checked perfectly... but the car wasnt acting up with the no start while checking... not sure if it is a possible fuel pump and unrelated or could be part of the problem.....

Also my Long Term Fuel trims are extremely high... makes sense with the fuel trim code.. correct?

The LTFT was between 18%-20% and pegged rich on the numerous times of checking...

I also was watching my 02s on live stram and they seemed to be reacting correctly... B1S1 pegging righ when snap throttled holding higher RPM's and B1S2(Down Stream) reacting properly

Thats all I can think of for now.. I have really been scratching my head on this one but is it most likely the BPT thats causing all this grief?

I dont want to and cant afford to just throw parts at this... so could I possibly get away with a junkyard BPT or off a parts car... or is there a high failure rate with these...

I read one thread from 05 with a 97 outback and extremely stupid owner who supposedly had this same issue and after all parts thrown at it and system cleaned the code came back on intermittently and that was the end of it....

Im looking to actually fix this so if there is any input I would greatly appreciate it.

Thanks,

Greg


Edited by Pgh_Scoob, 13 July 2014 - 01:17 PM.


#9 Fairtax4me

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Posted 13 July 2014 - 07:22 PM

Fuel trims are way up there.

Like I said before, a vacuum leak can cause both of these codes. You need to check ALL of the vacuum lines, not just the ones for the EGR. If any of them are hardened or have a loose fit they should be replaced.

The BPT has a diaphragm in it that is supposed to hold vacuum and they're known to rupture, and this will prevent proper operation of the EGR. I don't recall which port is supposed to hold vacuum but one of them is. The other is a pass through to open and the EGR valve.


If O2 readings are both normal then the high fuel trim may be due to a fouled sensor. Need to sort out the vacuum issue first though.

The new EGR valve was leaking? Or were you saying that is didnt cure the issue?

#10 Pgh_Scoob

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Posted 13 July 2014 - 08:19 PM

It was leaking after smoke testing the intake... I smoke tested the intake to search for any apparent vacum leaks but the only place smoke came from was the Egr shaft end going to the intake... There was a fair amount f smoke coming out so thats why my coworker and I figured it was the EGR... When I replaced with the new one we went ahead and smoke tested again to see what would happen... There was still a leak coming from the New EGR but not as much of a leak as the Old one... So I decided to leave it on and see what happened... with in two days the light was back on.

 

I did check all of the vacuum lines... numerous times and the ones That looked questionable and then some I did replace.... I also made sure that all of the tubes that connected my vacuum lines were all free and clear...

I am almost positive that I dont have a vacuum leak due to checking and rechecking and testing everything... I guess I am gonna have to go ahead and dish out a few more bucks for the BPT and hope this solves the issue...

Also does anyone have any info on how the ECM controls/monitors the EGR??? I did do the proper checks for power and ground but couldnt really find any information pertaining to how it is controlled.



#11 Fairtax4me

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Posted 13 July 2014 - 11:43 PM

BPT valves fail often enough that they're the first suspect for EGR problems after ruling out the simple things like split vacuum hoses.

If you're sure you have no other vacuum leaks (including all of the breather and PCV hoses) then the high fuel trims are likely due to a fouled O2 sensor. But more diagnosis on that can wait until the EGR issue is straightened out.

As far as I know the the EGR valve won't be 100% sealed until there is vacuum in the manifold. It should be all the way closed though, with no chunks of carbon buildup on the valve pintle or the seat. A small amount of smoke leakage from the valve can be considered normal. More than likely there was nothing wrong with the old valve that a little brake cleaner and a nylon brush wouldn't have taken care of.

It has to go through a pretty lengthy process to determine if the EGR is not flowing properly.
The ECU looks for slight changes in vacuum (MAP), load calculation, MAF, and O2 sensor signals to determine if the valve is opening when its supposed to. It's not something that it can tell immediately because there is no good way to directly monitor exhaust flow through the EGR. The monitor for the EGR meeds a certain set of conditions to be met during a drive cycle before it can run. Then the checks for the monitor have to run overthe course of several miles of steady driving. This is why it takes a day or two for the EGR code to recurr. The conditions necessary for the EGR monitor to complete may not be met on every drive.

Control of the valve is entirely vacuum and pressure based with the exception of the EGR solenoid, which the computer will open at certain times such as when the engine is at above idle speed, or it will close the valve if you open the throttle more than about 95% to keep the EGR valve from opening and decreasing engine power.

#12 Pgh_Scoob

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Posted 14 July 2014 - 05:31 AM

Ok great thanks... yeah I was reading that it has to be through two consecutive key cycles ( full warm up, full cool down) before it will set the mil.... And for the ECM communication thanks for clarifying.. I was over thinking it... or thinking it was more involved with the ECM....

 

And for the EGR itself... I did figure it was good and I am going to go back a clean it more and make sure it has good flow.... and like I said when hooking up a vacuum gauge to the EGR port it did hold vacuum... so EGR should = Good

 

Also if the Diaphragm is bad and not allowing vacuum for the EGR itself will that also pick up the PO170 Fuel Trim fault Bank 1 or is that something different... such as a failing o2... and after driving around a little more I have noticed

1) Definitely get a no start after quick drives... went two blocks and forgot something turned around ran inside and when I came back out it was just cranking... after a few tries it did start though....

2) My fuel mileage might not be as bad as I thought... I still need to keep and eye on it though.

 

Thanks Again,

Greg

Oh and is there any way to open up the BPT after replacing to try and confirm the diaphragm is torn/split


Edited by Pgh_Scoob, 14 July 2014 - 05:36 AM.


#13 johnceggleston

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Posted 14 July 2014 - 07:17 AM

a few good reads. hopefully helpful?

did you check the wiring?

 

http://www.obd-codes.com/p0400

what i found interesting there is that it said you would not notice any drivability issues??????? whatever?

 

http://www.obd-codes....php?f=1&t=6376

 

http://forums.nasioc...d.php?t=1453414


Edited by johnceggleston, 14 July 2014 - 07:20 AM.


#14 mikec03

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Posted 14 July 2014 - 03:36 PM

You should not be able to suck any air out the BOTTOM of the BPT.  If you can, the diaphragm is cracked.



#15 Pgh_Scoob

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Posted 14 July 2014 - 08:51 PM

REPLACED BPT= WORKING EGR!!!!!!

I am so sorry fairtax for not initially listening to what you said... I dont know why I was so hell bent on the fact that it had been changed already.... none the less thanks again.

 

Johnceggleston thanks for those llinks... Wish I would have come across those earlier... that was my big issue not knowing how to test the BPT.

 

Now I need to give it a few days to see how it goes.. Oh but while checking that the EGR was working and snapping throttle it was moving significantly but while holding the throttle at higher rpms according to AllData the EGR shaft should move and hold... Mine moves and holds momentarily but will go back down after a few moments... Is that correct or is there something else I might be missing... I also went ahead and gave all components another thorough  cleaning and scrubbed out the EGR really well.

Thanks for all the help yet again.. I will post with new details in a few days.

Greg



#16 Pgh_Scoob

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Posted 16 July 2014 - 06:36 AM

Well the fun continues.....
PO170 fuel trim bank 1
Is that a potential o2 going bad or could a possibly clogged/stuck Pcv be the culprit???

#17 Pgh_Scoob

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Posted 16 July 2014 - 02:02 PM

Checked my PCV and it was stuck open... Gave it a good cleaning and cleaned the hoses/ports associated with it. So hopefully I am in the clear

#18 heartless

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Posted 17 July 2014 - 06:42 AM

new PCV is under $10 - if the problem persists, maybe try replacing it before moving on to something else.



#19 Pgh_Scoob

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Posted 17 July 2014 - 07:09 AM

Light popped back on while driving into work... Scanned it and same code. I just don't want to put more money into it unless it's necessary

#20 Fairtax4me

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Posted 17 July 2014 - 08:44 PM

PCV can cause problems but it wont knock fuel trims off by 20%.

That's probably a bad front O2 sensor. Dirty MAF can throw off fuel trim but usually causes other problems.

#21 Pgh_Scoob

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Posted 17 July 2014 - 09:54 PM

yeah thats where Im leaning.... I was reading through my diagnostic book from my one instructor who is an absolute genius with Diag on a vehicle, but it is all based around a pico scope... which I dont have access to... 

Also if I go after the front o2 would you suggest using a wire in one??? I have used them as downstream o2's on subarus and in either spot front or rear on different makes...

I checked the maf to be clean and it all looks good and I would assume there would be tons of performance/running issues as well.

Are there any good test for the MAF besides using a scope???



#22 Pgh_Scoob

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Posted 17 July 2014 - 09:57 PM

Oh and after replacing the o2 do you know how long it should take for the fuel trims to start leveling out?

I was checking my LTFT earlier and it was up to 22.3%!!!!!



#23 Fairtax4me

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Posted 17 July 2014 - 10:01 PM

96 you could probably use a universal fine, but Rockauto carries Denso direct fit for under $50 last I checked.

To reset fuel trims unhook the battery - for ten minutes. Otherwise it takes 3-4 drive cycles and in the meantime you're still burning up a ton of fuel.

#24 Pgh_Scoob

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Posted 17 July 2014 - 10:37 PM

Ok yeah why I ask is because I can get a universal for cheap through my shop... I am also a huge fan if immediate gratification with purchases.... One of my pet peeves, waiting on packages to arrive...

Thanks Again... and Hopefully this is taken care of.

Greg



#25 Olnick

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Posted 17 July 2014 - 10:44 PM

If you're considering a "universal" sensor--the wire-in type--check out Bosch sensors on Amazon.  Last time I looked they ran about $25--and Bosch is generally good quality (they invented the O2 sensor!)






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