steve56

Thanks for the input guys. I did drop the heads off this afternoon at my usual machine shop. I think it will be $100 well spent. I'll check out GDs thread on getting the correct RA for DIY head resufacing. I have an 2005 Legacy 2.5 to JDM 2.0 swap coming up as my next project and will be doing head gaskets on the 2.0. Will also look up the new torque procedure 2005 and newer 2.5s. Didn't know there was a differnt torque procedure for those engines. One thing that I picked up from a Subaru buddy of mine that seems to reduce head bolts creaking.That is to use Permatex Ultra Slick engine assembly lube on head bolt threads and washers. Dont know if its better than using regular oil, but no bolt creaking on last head gasket job I did.

I'm using Six Star head gakets for the first time on a 2004 Impreza 96k miles with external oil and water leaks. On previous non Six Star head gasket jobs I got the mating surfaces on deck and heads prepped by razor blade then block sand with 250 then 400 grit sand paper. Used Felpro Perma Tourque head gaskets.Talked to local machine shop that said if I was going to have them resufaced there, they would use a milling machine rather than resurfaing machine to get the correct RA (roughness average). Checked heads with machinest straight edge and heads have no warpage. Is my previously mentioned head gasket prep method good enough for Six Star head gaskets, or do I need to take them to machine shop and have them milled?

Yes it was just a bad O2sensor. Replaced sensor and engine went into closed loop and both fuel trims and O2 sensors started showing live data. The live data voltage on this wide band sensor doesn't vary between .1and .9 volts. llike the narrow band sensor. The wide band sensor sends small amp changes to ecm to change fuel trims and sends an interpretive voltage reading to the meter of around 3 volts. Before changing the sensor I was getting an upstream voltage reading of 3.797 (v) and a heater circuit ok message. Like you said though the Fluke doesnt lie. It tested the bad sensor which had an OL reading on heater circuit and the new sensor with 1(v) reading on heater circuit. I went through the whole diagnosic process to learn how to trouble shoot more effectively. Thank for eveyones input.

I wish it was a plain 02 Sensor, but the FSM calls for a A/F sensor and they are over $100. I had never even heard of an A/F sensor.

Disconnected the upstream O2 sensor, tried clearing the P1133 code but the OS11(v) of 3.797 is still on the Actron. It looks like a permanent code is being stored in the ecm until a new O2 sensor is installed or...?

Yes, I will unplug the upstream sensor to verify. With every other Subaru using my Actron meter my asumption was that OS11(v) was the upstream sensor and OS12(V) was the downstream sensor. I thought OS11(v) stood for bank one sensor one (pre cat. converter voltage), and OS12(v) stood for bank one sensor two (post cat. converter voltage). Also I'm learing that with A/F sensors the (v) displayed on my Actron meter is interpretive data and that the ecm is actually reacting to micro amp changes in the sensor. The Actron interprets the micro apm changes as volts to make it (easier) to read.

One more unresolved issue. Just talked to GTC which is a Canadian Co. that makes O2 test equipment. Their tech said the heaters circuit in A/F sensors just speed up the heating process and the Cat. Converter would have the A/F sensor to operating temp. even if the heater circuit was broken. I already thought that ws the case, just got it confirmed. Now I need to know if a bad heater cicuit would trigger a CEL light and not let the fuel system go into closed loop even when the A/F sensor is up to temp. He also thought that my O2S11(v) being statisc at 3.797.on a live data screen on my Actron monitor looked like another circuit in the sensor might ultimately be the cause of my P1133 trouble code. Didnt know how Subaru software was set up though.

Appreciate your help. A/F O2 sensors are new to me. I've only dealt with Subaru narrow band sensors.

Thanks for your input. Im getting conflicting data from my Actron meter saying heater circuit good and my Fluke saying heater circuit is bad. I can see the Actron data meter being more ambiguous than the Fluke data.I'm still looking a known good used four wire A/F sensor that I can put in the car to verify whats going on.

Thanks for your imput. I am getting conflicting data from my Actron meter and my Fluke meter. I think your correct. The Actron data might be too generic, however an amp reading from a Fluke meter is pretty unambiguous.

Yes They have the correct A/F sensor at local auto parts store. Thats a four wire for my MT car. The AT cars use a five wire.They were nice enough to take it out of the box and let me test it with my Fluke 115 True RMS multimeter. The new one has 1 ohm resistance between the two black heater wires. Mine tests OL between the two black heater wires.To further muddy the waters, my Actron "Quick Test Resuls" screen shows Oxygen Sens Mon inc. and Oxygen HTR ok. I was looking back at a previous post on here Titled "P1133 DTC Tough to Solve". I know your were helping him also. The bottom line with his issue was, he did all the ECM ground and harness tests. Bought a new ECM and A/Fsensor and still had the P1133. As I remember, he finally just jiggled the right part of wiring harness and his P1133 went away.

Yes the P1133 is for heater input high. With my Actron scan tool live data I'm getting an O2S11(V) that is stuck at 3.797V) and an OS12(V) that varies between .08(V) and .9(V). I cleared the codes and the P1130 for air fuel cicuit open erased.The P1133 stays. The scan tool shows 0.0 or all fuel trims. Still staying in open loop. The 02S11(V) stuck at 3.797 volts seem to be the key to the problem. I know that reading is just interpretive voltage and the ecm is really looking at micro amp changes. However thats the one reading that is unchanging. I have the FSM flow chart for the P1131 DTC. It instructs to test between ECM and Chasis ground. Depending on whether its more than 8(V) or less than 8(V) it says its either a bad ECM or short cicuit in harness between A/F sensor connector and ECM. That short circuit test has you look at an apm reading that my Actron scan tool doesn't display. The whole thing seems so confusing to me that replacing the A/F sensor seems to be a better first move. One reason for that is when I do a ohm test between the two black A/F heater wires with the connector unpugged from the harness Im getting OL reading on my multimeter. However I'm geeting a heater circuit good reading another test on my Actron meter. Alot of conflicting data. s

Wow AF sensors sure are expensive for a metal tube and a couple of circuits With this AF sensor having a bad heater element, will it alway stay in open loop, or when the engine heats up enough should it go into closed loop. Since I cant get mine to go into closed loop,I'm thinking the ecm must see the bad heater and just keep it in open loop.

My only test was an ohms test with the O2 sensor unplugged from the harness. To do a 12v test with ignition On, are you talking about plugging the O2 sensor back into the harness and backprobing the black wires? Im not sure how to safely do that without potentially shorting the ecm. What is the safe way to do this to find the 12v?

Yes its O.L. not 0.0 omms My Fluke 115 meter has auto range, so I think Im getting thee correct reading

Yes Cougar I saw that also. The two O2 sensor wires that are the same color are black. When I disconnected the the O2 sensor from wiring harness and did a resistance check between the two black wires I found no resistance. As you stated earlier, that implies an open circuit on the heater. I'm tring to decide if that is a conclusive enough test for a bad O2 sensor. I could just buy a new O2 sensor and check the resistance on the same color wires. However they are $140 with tax. I'm trying to avoid just parts swapping as part of my diagnosis at this point.

Thanks for clearing that up. How do I trouble shoot the O2 sensor? My current Actron live data info is: ST FTRM1 (%) 0.0 LT FTRM1 (%) 0.0 FUEL SYS 1 Open O2S12 (v) 0.915 ST FTRM12 (%) 0.0gr O2S11 (v) 3.797 20 min driving. Engine at operating temp. CEL P1133 Heater input high. Also it has a manual trans. The auto and manual trans have different upstream O2 sensors.

Yes I havn't absolutly varified that the two black wires are for the 02 heater. Its a 4 wire 02sensor so my statement on the two black wires being for the heater wires is just an assumption. My FSM doesn't seem to have a wiring diagram for the 02 sensor.

I thought the 02 voltage was supposed to vary between .01volts and .9 volts My 02 upstream stays at 3.70(v) and the downstream varies between,04(v) and .9(v).I dont see either Higher voltage, 3.5-4.0v, shows a lean reading. Lower voltage, 3.1-2.8v, shows a rich reading. I'm confused.

Update:FuelSys stays in open loop after 15 min of driving. The ST FTRM1 stays at 0% The LT FTRM1 goes betwween -9.0% and -4.0% 02S11 (v) Stays at 3.79 02S12 (v) goes between .04 and .90 Pulled the connector to the upstream 02 Sensor and the resistance betweed the two black heater wires is unlimited (no resistance) That should be enough info to diagnose whats going on. However it still insn't clear to me what the malfunction is.

Have 2000 OBW with CEL P1130 and P1133. Image is live data. How do I read and trouble shoot 02 malfunction.

Finally got it off with 1/2 IR air wrench with 3/8 wobble socket. My 3/8 Earthquake impact wouldnt budge it.

Having trouble getting the bottom 14mm nut removed that holdes on the starter. There is no access from the top of engine. From underneath the engine there doesnt seem to be enough room to get a socket and ratchet square with the bolt to be able to turn the ratchet. Ive tried a 14mm 3/8 wooble impact with Dewalt impact gun and nut still not loosening. Heated nut with torch also. The nut doesnt look corroded. It seems to be a problem with getting the right angle with wrench. Looking for solution.

Now that I have the head and timing belt back on, and have rotated the engine a few times from crank bolt, it looks like I just didn't have the exhaust valves set correctly while doing it on the bench. It sure was alot easier to get to them on the bench though.