97 OBW Hesitates and misses after being warmed up.

[DarkPhoenix]

It runs great when it is cold, but the moment the warms up, it starts hesitating and missing, getting worse the warmer it gets. Now, I have changed a bunch of things that it probably needed, and some that it didn't, in hopes of tracking down the issue. I have replaced the following:

Plug wires
Ignition Coil
Spark Plugs
Front o2 Sensor
Crank Sensor
Cam Sensor
Fuel Filter
PCV

Now, I noticed that the green diagnostics cable was plugged in under the dash, but only after I took it to AutoZone to get the codes pulled. They pulled the following codes:

P0136 - o2 Sensor Circuit Malf. (B1, S2)
P500 - Vehicle speed Sensor A Malf.
P1101, P1121 - Manufacturer Control Fuel Air Metering -
P1540 - Manufacturer Control Veh Speed Idles Speed control Aux Inputs.

I know that the P1101 and the P1121 codes are actually Neutral Safety Switch codes. And my speedo works, so that P0500 and the P1540 codes have me baffled.

Thanks for the help!!

Craig

[decke48]

p0500 and p1540 are both vehicle speed codes. the green connection need to be disconnected when driving or not in being diagnostic for code with out a reader. its common to throw the p0500 and p1540 if you drive with the green diag connector plugged in. so they are probably false codes. you should fix the neutral safety switch, ive seen them make the cars run rough. and the p0136 you may have a dead rear o2 sensor

[DarkPhoenix]

Thanks for the help. I disconnected the green cable, and reset the the ECU yesterday. After driving the car for about 35 miles, the problem persisted, but not as bad as it was. I took the car to AutoZone again, to pull the codes, since the CEL in the dash is broken, and they were only able to pull cylinder 2 & 3 misfiring. I am going to pull the plugs later and replace them, and also get a set of Subaru plug wires to see if that changes anything.

[green97gt]

replace your CEL while your at it, only take about 15 minutes.

[DarkPhoenix]

15 mins to remove the Instrument cluster?

[mike-tracy]

Yeah, it's about 8 Philips screws to get it out. Another thing that might cause it to act funny upon warm up could be one of the temp sensors - they rarely go bad, but in the older legacys they can cause rough running.

[DarkPhoenix]

Yeah, it's about 8 Philips screws to get it out. Another thing that might cause it to act funny upon warm up could be one of the temp sensors - they rarely go bad, but in the older legacys they can cause rough running.

I was kinda thinking that way as well, but the only codes that are coming up are the misfire in Cylinder 2 and 3.

I am at a loss here as to what it is. I have changed just about everything that I could think would cause this, except the ECU, Temp Sensor, rear o2, and EGR.

The EGR whistles every time it misses too. And it really only does it under load. Cruising it runs ok.

[Miker104]

Here is another post about a misfire code of woe:

http://www.subaruoutback.org/forums/sho ... ht=misfire (http://www.subaruoutback.org/forums/showthread.php?s=&threadid=21451&highlight=misfire)

I had a similar issue, misfire at idle (P0304) after it reached operating temp. It went away but mech suggested to replace wires. I have heard that Subaru's are fussy and like OE or NGK wires.

You could try swapping the #1 and #4 fuel injectors and see if the problem moves?

[DarkPhoenix]

Hmm, the wire thing could be it, being I used a set of autolite wires from the local auto parts guys. I changed them and the coil because I noticed some black stuff, almost looked like soot, in the terminals of the coil. After changing that, it did get better, as long as I wasn't trying to accelerate to hard. It is running rich, so I know the injectors are firing properly.

I read thru the entire thread, and the only difference I see between the two, is I feel the misfire. I am going to check the plugs again, and get some NGK wires from my local parts guy.

[DarkPhoenix]

One thing I didn't mention, but might be relevant, is I have a Phase I coil. Should I be going to a Neon coil instead?

[mike-tracy]

My recommendation is to get it running good on stock parts before you do any upgrades

[DarkPhoenix]

My recommendation is to get it running good on stock parts before you do any upgrades

I wasn't thinking for upgrades, I was thinking the coil might be the cause of the problem.

I have a few more parts coming in next week, and I will be bringing it to my buddy's shop to further diagnose it, as I have exhausted every route I have.

Upgrades are the last thing on my mind. :smt021

[DarkPhoenix]

New fun in the quest for a good running Outback.

I got the codes pulled today, and two more codes came up. One for the Camshaft sensor, which is brand new, and the 0136, rear O2 sensor code came back. Now, I didn't think that the rear O2 really affected the way the car ran, but who the hell knows. I am bringing the car into my buddy's shop on Saturday to chuck it on the lift, and check the wiring underneath, because through all of this, I am blowing turn signal fuses like a hooker at the wharf during shore leave. And this happens the moment I turn on the car.

I am very close to driving the thing into a bloody wall!!

[DarkPhoenix]

I think me may have a resolution!!!

I brought the car to my buddy's shop for some help troubleshooting this thing that has plagued me since I bought the car. It appears that one of the previous geniuses that worked on the car decided that it would be a great idea to use a solder-less butt connector on the pigtail for the cam sensor. Now the code I was getting was the cam sensor circuit malfunction, not the cam sensor malfunctioning. So What I need to do now is find another pigtail connector for it since the guy left me less than an inch to work with ti try to resolder this thing together. The rear O2 sensor stems from the fact that the guy used a universal, unheated O2 and then used butt connectors on that. My buddy says that once I figure out the bad wiring with the cam sensor, I should be good to go.

So no mechanical issues with the engine, just an I Dee 10 Tee error from the previous retard to own the car.

[DarkPhoenix]

Ack!!! The trouble continues.

I took apart the old connector and resoldered the wires to it, and it is still doing the same thing. It isn't as bad as it was, but what my mechanic told me is that it isn't missing, but the engine is turning off while it is under load. So he thinks it is an electrical issue. I tried to get it to do it by moving the wires under the hood for the coil, cam and crank sensors, etc, but nada.

I may just take it to the stealership to get it diagnosed.

[DarkPhoenix]

I just had a Eureka moment!!

When I was pulling into my parking space at my karate school, I put the car into reverse, and then it started missing like a mofo!!

Now one of of the two constants in this struggle have been that P0136 code (rear o2 sensor). The other was the fact that I keep blowing turn signal fuses. Being that it really only happens when it is cold, and even moreso when I go into reverse, I am beginning to think that those two wires are shorting each other out. The previous owner chopped out the rear o2's harness and truly made a ghetto fabulous connection with tape and I know my back up light switch is covered in grease and maybe shorted out as well.

Does this make sense to anyone, or am I just trying to talk myself into this as being the solution?

[DarkPhoenix]

Okay that wasn't it. I fixed the short for the back up switch and that is good now, and I also disconnected the rear o2. I am still getting the same results. It feels like the engine is just shutting down, and then picking up again, like someone is killing the spark.

I am going to get another ECU to see if that fixes the issue.

[DarkPhoenix]

Had my mechanic check everything out. He said the O2 sensors, TPS, ECT, Cam and Crank, etc, are all showing good. I changed the plugs, as the previous owner put in Bosch Platinums +2s in three cylinders and there was a loose Motorcraft copper plug in the driver's side back cylinder. I am assuming that with how difficult it was for me to get it out and back in, he loosened it and then decided not to change it.

It runs better, but still feels like the spark is cutting out, as it runs really rich and I see the unburned fuel on my rear bumper and tailpipe. When I took the plugs out, they were all black, showing a rich condition.

So far the things that I have changed are:

Spark Plugs
Wires
Cam and Crank sensors
Ignition coil (Phase 1)
O2 Sensor (front)
Fuel Filter
PCV
Air Filter
MAF
ECU (98 5 speed ECU)
Resoldered wire for cam sensor.

He did mention seeing a Fuel Temp Sensor Code. He didn't tell me whether it was a 0181, 0182, or 0183.

Any other ideas out there?

[green97gt]

have you gone thru and replaced all your vacuum hoses/rubbers?

when i bought mine the vacuum lines were way messed up, i ripped it all out and put it back together according to the diagram.

there are check valves/filters/switches in there and if its not hooked up properly, your FPR may not be functioning, etc.

worth a look, and as long as your touching it, might as well replace them if theyre old.

[DarkPhoenix]

^^ But wouldn't the vacuum leak affect it all the time, not just while the car is warm?

[green97gt]

there was no vacuum LEAK. just improperly hooked up hoses, going where they shouldnt, etc.

worth a look.

[DarkPhoenix]

Very true. I will check that out when I get home.

[DarkPhoenix]

After changing all of my hoses and a few other things, the issue was still persisting. I dropped it off at my friend's shop on Monday for a look over, and he mentioned at the previous owner may have messed up the reluctor ring when he did the TB. At least I know the TB is pretty new.

Anyone have the link for the Subaru parts catalogue?

[green97gt]

i have never heard of a reluctor(spelling?) ring in the TB.

as far as i know a reluctor ring is on something like an ABS sensor, or crank sensor, or distributor. it is the cogged wheel that gives the sensor its position/rotation speed

could he be referring to the TPS sensor resistor sweep?

but just cause i havent heard of it, doesnt mean it doesnt exist. have you downloaded the FSM for your car?

EDIT: ok, read another post on here you posted. you said TB i thought throttle body. haha.

having done timing belts on these cars, i dont off hand know what reluctor ring there is to screw up when doing the timing belt...?

[DarkPhoenix]

Sorry, TB=Timing Belt.

Whatever gives the signal for timing to the crank sensor.