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2000 Forester Ltd S Manual
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Discussion Starter · #1 ·
2000...5speed 160000km engine swapped in last year, recent timing belt replacement, sparkplugs less than a year.

Kept the plug wires that came with this new engine changed the plugs as I said.


Recently the engine has random hesitation that lasts half a second anywhere in the 2-4000 thousand rpm range... Other than that no other issues it doesnt always happen but when it does it feels like it runs out of gas for half a second anyone have a hint where to start looking?
 

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2012 Forester 4 speed auto
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Perhaps, not a DYI

How can I be 100% certain
Have the pressure check with a fuel pressure gauge or have the electric fuel pump checked with an oscilloscope. Both are not tools most people have in their garage, so take it to a shop that can check it for you. Replacing a fuel pump isn't cheap for the part and labor.
 

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Discussion Starter · #5 · (Edited)
I connected my bluetooth OBDII with TORQUE...


I seem to get stable readings on most sensors but curiously even though I replaced it the Bank1 sensor 1 shows a blank reading and B1S2 shows stable 1.3v.... Why is that?

Also without a CEL the ECU has curiously stored a Knock sensor malfunction....


Thanks for your input

EDit : Basically can any of these inputs have an impact on my initial problem? Hasn't done it yesterday and today the car seems to have good power just wondering your input on my O2 sensor? Anyone ever have issues with cheaper OBD scanners?
 

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Discussion Starter · #6 · (Edited)
Car's still been running fine, and randomly hesitates on start up, nothing really serious just annoys me because of my daily spirited driving I enjoy a car to respond to throttle as it should.

Thing for sure is its INTERMITTENT does not ALWAYS happen, seems to happen MORE when car is completely warmed up...


Things I Have noticed since my last posts : My CEL light has burned out it seems as it does not light up on my dash with the KEY @ON position..(Which would explain why I had stored codes without CEL)

Another thing is I had ERASED all pending faults on the ECU last time I plugged it on my OBD Bluetooth scanner, and the same codes appeared again :
B1S1 Circuit Malfunction, B1S2 malfunction, and Knock sensor mal function..

Where I need your help is : Ever since I have the car the B1S1 never has shown ANY voltage on my OBD scanner, I changed it for a brand new one, still no voltage but now it says malfunction but I just changed it (really!) another thing now my B1S2 shows a permenant 1.3V before it would FLUCTUATE and work is it now dead???

I've done some reading on the Knock sensor issues, does anyone think this could be causing my "hesitation" "loss of power" issues??

Thanks for your input!
 

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Discussion Starter · #7 ·
Well to those who still are reading and want to help out, I changed my knock sensor today after testing mine it had an intermittent bad connection in the wire from what I could tell and the resistance was bouncing out of range from the bad contact.. swapped in a working one from an old engine I had here... Hesitation/powerloss seems to have disappeared..

I still would need some advice to understand my oxygen sensor problem and where to start looking...

As I stated earlier on my Bluetooth OBD2 reader I always had 0V reading on my B1S1 sensor, and the B1S2 would fluctuate normally. But no CEL... Recently I swapped in a new sensor thinking that the 0V was caused by a dead part, to my surprise the brand new sensor displayed 0V also, and is now throwing a "bad sensor" code "Sensor 1 circuit"

I verified the connector it is clean free of corrosion where could the problem be? Can the wiring from the connector TO my ECU be damaged? How can I test this. Lastly why is my B1S2 stuck at 1.3V is this caused by the failure of the first? Or is there something fishy with my whole Oxygen sensor situation?

Thanks...
 

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Discussion Starter · #9 ·
Could any of you point me to the most efficient way to check this as when I work on my car (I'm a student) its -20 degree celsius here I try to make it efficient haha!

Thanks
 

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Discussion Starter · #10 ·
I visually inspected both my sensors there seems to be no exhaust leaks, my REAR O2 has a bit of corrosion on the connector on "one" of the wires a bit of "green" corrosion can be seen extending outside the connector on the sensor side.

The front one still looks brand new nothing seems bad about it,

So a simple reminder :

My scan tool has always indicated 0V on the front sensor ever since I had the car (even the old sensor)

My scan tool used to allow me to see fluctuations on the rear sensor now stuck at 1.3V and doesn't budge from there.

Can a bad rear offset a mistake on the front?
 

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Discussion Starter · #11 ·
Update on my problem :

So the knock sensor truly has ruled out the bogging haven't felt any so far.

Since I was getting P0136 and P0130 (Sensor 1 and 2 malfunction) I decided to pop my old Sensor 1 that I had changed thinking I was getting 0V on Sensor 1 on my reader for this reason and it still does it (My mom's 2010 impreza also shows 0V on the 1x1 sensor)
Atleast if my Sensor 1 malfunction does not come back I can guess that my replacement sensor is already bad...

Secondly :
Got a brand new Bank 1 sensor 2 off Ebay (Rear/Downstream) installed that in the exhaust

When I came to UNHOOK the old one the connector's pins broke from corrosion and stayed stuck in the old sensor's connector, so I Went to the scrapyard and had the "car side" connector cut atleast 7-8 inches away from the plug to have some play.

Cut out my broken connector, and stuck this one in twisted the wires together and shrunk wrapped them.. Plugged in the new sensor and started up the car now previously Torque Application on my Android Phone via my Bluetooth OBD2 would give me 1.3V STATIC and it was bugged there (not good) with my old sensor, and now I get "no data" 0V....with a new connector and sensor... when I remove the sensor from the circuit while the car is running I get 0.3V static on my reader... what could be up?

Really need help on this one!

Mat
 

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Discussion Starter · #13 ·
Is the wiring on the front A/F O2 sensor also rigged like the rear sensor, or is it a direct-fit connection?
The current sensor (I'm trying my old one) I rigged its wires onto its connector because I had cut them to test it thinking it was bad now I put it back in to see if the "New" A/F is bad by elimination..

Today I drove about 10-15 km on the freeway mixed city stop and gos also... got NO DATA most of the way then all of a sudden it changes to 0V as if it catches something, once in the parking lot at school I reved watching my OBD scanner and was getting response on my Sensor 2, shut the engine off restarted the car NO DATA... and then nothing again after a couple minutes..

Left later in the day NO DATA for a good part of the distance than once almost at home 0V appears and it starts fluctuating at very small values (between 0 and 0.1) and then I get some random peaks when I'm not watching i see the software leaving a red "Max" mark on the dial where it's been at during the road.

So far today the ECU has not thrown any codes in about 50km of mixed driving does this help anyone pin point my problem?

I did notice there was TINY exhaust leak you can barely hear a little whistle on a weld behind the cat (So after the O2 sensor) would this have an effect as I understand it exhaust leaks only affect O2 readings "Before" sensors not after them..

Thanks for your help!
 

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Discussion Starter · #14 · (Edited)
Correct me if my hypothesis is bad:

I'm thinking maybe what onset the initial code for circuit malfunction on both sensors could have been brought on by the short circuit or damaged wiring from corrosion in the sensor 2 plug? Could the ECU be confused? Maybe I didn't need to swap in my old A/F with the connector and rear sensor replacement... I'm just wondering if the fact I Got a cheaper rear sensor than the original ( A chinese PRIME PARTS ) from Ebay (With OEM plug ) could that play into factor its bad response or is something else up?


EDIT : Just did some more work on the problem : Two things and a few anothers :

First : Removed the new rear sensor from the exhaust and tested it using a Propane torch and multimeter on Volts. Waited til it was well heated up, and it was a very fast reacting to approach and removal of the torch. (Ranging from 0.1-0.9V) which seems good to me...

Second : I realized the oxygen sensor connectors are both jointed into one main connector for both of them only (Nothing else is on this connector) under the hood next to the cruise control which can easily be disconnected which allowed me to remove that whole harness that has the plug for the rear and the front sensor. I tested continuity on all wires and everything adds up good...

Third : Put the rear sensor back in exhaust stream and while car was running measured its voltage directly off my multimeter, started really low and gradually seems to have went up... the highest I've seen was 0.60 but what I found peculiar is reving the engine left a static voltage or atleast didn't seem to change much (0.5-0.6) and the more I Checked it the more it ended up going down to 0...

I also checked the voltage for the heating element, there was 13.9V on the wires and the sensor does have about 6 ohms of resistance on it's element...


I'm thinking either the plug FROM the engine bay to the ECU might have bad wires? How probable could this be... would I Have these symptoms?

Or else the exhaust leak 'BEHIND' The cat (AFTER THE REAR SENSOR) is playing with the data?

I did realize that this sensor needed quite a lot a bit of heat to start reacting to the torch, once it it did it was running fine but is the exhaust maybe not allowing enough heat to heat up the element? Is its element not strong enough? What are your thoughts?

Thanks a lot
 

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Discussion Starter · #15 ·
Drove around so my sensor 1 has not came back (have my old one in) for the circuit malfunction...


The sensor 2 just popped my P0136 again... "Circuit malfunction" As I said I did test the sensor OUTSIDE exhaust and it responds quite well to a flame torch, tested it with a multimeter INSIDE the exhaust and don't get quite the same voltages (is that normal considering it is post cat?)

The wiring from the sensor all the way to the engine bay is GOOD, from the engine bay to the computer I do not know how to test, one thing I do find peculiar is that when measuring voltage on the ECU side wires in the engine bay for the SENSOR 2 signal I get 0.26V (Which explains why I get 0.3V on my scanner when I disconnect the rear O2 sensor)


Any thoughts? Other than that the car runs really well...

Could the exhaust leak behind the cat (after sensor) be causing my rear O2 to be responding badly?
 
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