dwalker Posted March 7, 2005 Share Posted March 7, 2005 Greetings fellow Subaru Owners: I have just rebuilt my 96 subaru outback EJ25 2.5L engine. It had leaking head gaskets and I had to pull the engine and replace all. Since I had it apart I put in all new bears, cleaned the pistions,, new rings, oil pump, water pump, all new gaskets, new ignitor, new spark coil, new Intake camshaft sprocket on left side, new crankshaft and camshaft sensors, all wires checked for proper ohms and the list goes on.. We'll to the point.. No Start !!! No Spark !! Computer keeps coding a P0340 or camshaft sensor circuit malfuntion. I even replaced the computer.. So anyone have any ideas? Please help if you can.. Dan Chicago Link to comment Share on other sites More sharing options...
85Sub4WD Posted March 7, 2005 Share Posted March 7, 2005 Ummm... you are in the Older Generation forum - that means 1990 model or older, with the exception of the Loyale - you want to put this in the newer generation forum Link to comment Share on other sites More sharing options...
frag Posted March 7, 2005 Share Posted March 7, 2005 Greetings fellow Subaru Owners: I have just rebuilt my 96 subaru outback EJ25 2.5L engine. It had leaking head gaskets and I had to pull the engine and replace all. Since I had it apart I put in all new bears, cleaned the pistions,, new rings, oil pump, water pump, all new gaskets, new ignitor, new spark coil, new Intake camshaft sprocket on left side, new crankshaft and camshaft sensors, all wires checked for proper ohms and the list goes on.. We'll to the point.. No Start !!! No Spark !! Computer keeps coding a P0340 or camshaft sensor circuit malfuntion. I even replaced the computer.. So anyone have any ideas? Please help if you can.. Dan Chicago Just trying to guess. Is the camshaft sproket that you replaced the one that triggers the camshaft sensor? If so, may be it's the wrong one and does'nt have the metal spiggot (not sure if it's the right word) that triggers the sensor. My .0002 cent. Good luck! Link to comment Share on other sites More sharing options...
Tiny Clark Posted March 7, 2005 Share Posted March 7, 2005 You should also be able to ohm out the sensor. I don't know what the resistive value will be, but it is just a coil of wire (a few to a couple hundred ohms?). Measure from the ECU plug out to the sensor if you can. If the sensor coil is OK, make sure the tang on the cam sprocket is there to "trigger" the coil, like frag suggested. I don't know what the clearance should be between the coil and the tang, but it has to be fairly close. Link to comment Share on other sites More sharing options...
dwalker Posted March 7, 2005 Author Share Posted March 7, 2005 The cam sprocket does have the little metal tabs in it. It's OEM, so I hope that its' correct. Also checked the ohms on both the crank and cam sensors. Suppose to be around 1,000 - 4,000 ohms and reads about 1,900 - 2,015 ohms. So I am assuming it is correct. Have never looked at the cranksprocket to see how close it is... Never thought about that one because only goes on one way and I figured,, has to be on there right. I'll check that one next.... Thanks Dan Link to comment Share on other sites More sharing options...
frag Posted March 7, 2005 Share Posted March 7, 2005 Getting my inspiration from the FSM, here are some more tests that you could do. 1) Check the connexion on the ECM side. 2) Redo your resistance check of the sensor, but at the ECM end of the circuit : disconnect at the ECM and check at the wires ends. You'll see if the harness is good. 3) Check resistance between sensor connector and ground. If you look at the sensor connector face on with the part devoid of tabs at the bottom, it's the contact to your left. The resistance should no be over 100 K ohms. If it is, the circruit is open. The resistance should not be under 10 ohms, if it is, the circuit is shorted. I'm not very good at reading wiring diagram, but the diagram shows the sensor coupling to the ECM at B84 contacts 28 and 7. Hope that means something to you. Link to comment Share on other sites More sharing options...
dwalker Posted March 7, 2005 Author Share Posted March 7, 2005 For Frag; So let me clearfy this. I should check the cam shaft sensor connector to the ecm ? I know the schematics say 28 & 7 but actually it's not.. I trace them out and found out to be different. number 28 on schematic is actaully #2 and #7 is actually #70. When I tested it was .2 ohms resistance.. what does this mean? Problem? if shorted what to do...? same for the crankshaft sensor. ohms out from the connector for the sensor to itself.. to the ecm connector at .2 ohms... Again is this bad..? If so How to correct ??? If shorted out.. Maybe I need to buy a new wiring harness (the one that goes or is attached to the intake manifold. The wires inside the engine compartment were just cleaned and I put new tape on them to better protect them) cost ... @ 156.00 USD... What do you think ? Dan (Chicago) Link to comment Share on other sites More sharing options...
frag Posted March 7, 2005 Share Posted March 7, 2005 I'm really not an expert at electrical circuit testing, just trying to help. But if you are sure that you traced the sensor wires to the ECM correctly (with a continuity tester?) and that you get .2 ohms when you connect both wires to your ohm meter, it means that there is a short somewhere, that's sure. I guess you now have to find where. That's the limit of my competence. Probably someone else on this board can take the relay. Do you think you could make a direct connection from the sensor to the ECM and see if your can then start your engine?. You would at least know for sure that IT is the problem. I just hope you figure it out. Link to comment Share on other sites More sharing options...
dwalker Posted March 7, 2005 Author Share Posted March 7, 2005 Yep.. I'll make two long leads and put it from the camshaft sensor to the proper leads on the ECM connector.. Yes.. I put one lead (black) from the ohms meter and connected it to the correct wires on the ECM Connector and then the red one to the end which connects to the sensor it'self. So... From those two points... the .2 ohms resistance. It is a solid reading too. No fluctuation in the meter.. I am thinking that when I took the harness off of the intake manifold and cleaned it I probably did something.. So If the by pass test works.. I'll buy a new harness ..... Dan In Chicago Link to comment Share on other sites More sharing options...
Cougar Posted March 8, 2005 Share Posted March 8, 2005 Another test you might want to try is checking the resistance of the sensor leads to ground. You may have a short to there also. Place one of the meter leads to either of the sensor leads and the other meter lead to engine ground. You should see a high resistance on the meter. Be sure to remove the plug that connects the sensor to the ECU while doing this so you don't get a bad reading on the meter. I assume you did this also for the reading you took already. Using you meter as a guide it should be pretty easy to find the short and repair it. Link to comment Share on other sites More sharing options...
dwalker Posted March 8, 2005 Author Share Posted March 8, 2005 Glen (Cougar) I did an ohms test on the wiring harness that is under the intake manifold. I disconnected the lead that further connects that harness to the ECM. When I did the ohms test on the camshaft sensor leads. I read .2 -.3 ohms resistance on the wiring harness only. Starting to sound like a bad harness.... I'll try the test to bypass the wiring harness for the camshaft sensor. Just a note, but I did the same test for the Crankshaft sensor. Got 00.3 ohms there.... on both leads. Tomorrow I have a few things to test.. I'll let you know.. Thanks... Dan Link to comment Share on other sites More sharing options...
Cougar Posted March 8, 2005 Share Posted March 8, 2005 It sounds like you did things correctly. Let us know what you find out, and your welcome for the help. Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Q: I was doing reading on ohms resistance and just wondering,, if the resistance of a circuit / wiring is very low.. ie .2 ohms.. Doesn't that mean that there is no resistance in the wire itself? I took abouut a 3' foot section of wire and ohms resistance tested it.. go .1 ohms. No short or anything a brand new wire.. So... if the resistance in the connection from the camshaft sensor connection to the ECM connector is only .2 ... would that not indicate that it is a good connection and not a shorted out connection? Just really curious about this.. Really cold here in chicago today ... so I was not able to perform the bypass "surgury" test... But will do so over the next few days and report the findings.. Dan Link to comment Share on other sites More sharing options...
Cougar Posted March 9, 2005 Share Posted March 9, 2005 Dan, In answer to your question about the wire resistance, yes the resistance should be low. When you measured the wire resistance you were measuring a short really. The wire will have some measureable resistance but it is so low that it really is a short. From your question about the resistance you saw in the sensor wire it sounds like you just measured the wire resistance from the sensor to the ECU, is that correct? If so, you need to measure the resistance between (across) the two sensor wires with the ECU end disconnected. You should see a real low resistance in each of the wires to the ECU but it is the resistance across the sensor that we need to know. Hope it warms up there. Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Glen; Guess I'm confused & dazed at this point. I disconnected the connector on the ECM and ran an ohms test from the connector of the camshaft sensor to the proper ping on the ECM Connector. That is were I got the .2 ohms resistance. So when you mean test the resistance "across" the sensor.. What would be the procedure? I know I must disconnect the ecm.. then what? jump the two connectors on the sensor end then test the resistance between the two on the ecm connector ?? I'll have to buy more propane for my garage heater... Thanks again... Let me know the right process for this test.. ok ? Thanks Alot Dan in :-\ chicago.. email address: muwew@hotmail.com Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Glen;; Maybe this........ Keep the camshaft sensor connected... disconnect the ecm harness and measure the resistance between the two wires from the ECM connector.. In other words ... put one probe on #2 pin and second probe on #7 and measure the restance there.. am I correct ?? Dan:confused: Link to comment Share on other sites More sharing options...
Cougar Posted March 9, 2005 Share Posted March 9, 2005 Yes, that is correct. We are trying to determine the resistance of the sensor. I assume there is two leads from the sensor that tie to pins 2 and 7 of the ECU and that will allow the meter to read the resistance of the sensor. The wire leads to the sensor will be included in the measurement but that resistance will be insignificant as we saw previously. By disconnecting the harness from the ECU that will isolate any error to the reading if the connector was tied to the ECU. Your meter will see the resistance of the sensor that the ECU sees when the connector is normally in place. Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Sounds good, I'll put the ole heater on tomorrow and see what I can see.. I'll keep you posted.. and thank you very much for your time in responding... Dan Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Glen if you want I can send you a document I put together during the rebuild of this engine.. A word document.. Dan Link to comment Share on other sites More sharing options...
Cougar Posted March 9, 2005 Share Posted March 9, 2005 Your welcome for the help Dan. Keep us posted. You can send me the document by PM if you want. Link to comment Share on other sites More sharing options...
frag Posted March 9, 2005 Share Posted March 9, 2005 Quote «But if you are sure that you traced the sensor wires to the ECM correctly (with a continuity tester?) and that you get .2 ohms when you connect both wires to your ohm meter, it means that there is a short somewhere, that's sure.» Sory if that was not clear. By «both wires» i meant the wires disconnected from the ECM et leading to the sensor. If almost no ohms there it certainly would mean a short of some sort. Link to comment Share on other sites More sharing options...
dwalker Posted March 9, 2005 Author Share Posted March 9, 2005 Got the heater out... Here's the results. Between Pin#2 and Pin#70 I got 1.914 K Ohms Resistance. Don't know if that is right, but sounds right because if you ohms test just the camshaft sensor you get close to that resistance value. Also, I thought I would see if there is voltage to the sensor when the key is turned. Yes there is 12.+ volts. Is that to be there? I also got resistance from pin#2 to pin #16, #44 & #96. Have no idea why.... but at this point I am getting rally confused.. So there you have it.. Next step is to have it towed.. but I also have a neighbor who works for Chrysler and it still could be a timing issue. If the timing is off just a little, then it's possible that it is the timing still.. I'll try the timing again tomorrow.. Dan :-\ Link to comment Share on other sites More sharing options...
Cougar Posted March 10, 2005 Share Posted March 10, 2005 We can probably assume that the resistance you read is normal. The real test would be to see if there are pulse signals coming from the sensor while cranking the engine. The other pins you mention and took readings on may have no bearing at all on this problem. I'm not sure what is tied to those pins. The main thing is, you want those pulse signals from the sensor getting to the ECU. You may be able to see the pulses by setting a digital meter to AC volts and take a reading across the pins. An analog meter would see the pulses also. The 12 volts you are seeing is normal. That voltage will pulse as the sensor sees the tabs of the pulley go by. Link to comment Share on other sites More sharing options...
dwalker Posted March 10, 2005 Author Share Posted March 10, 2005 So.. what would be next? How to see if the signal pluses as the intake cam sprocket goes by the camshaft sensor? I'll look at the timing belt again... and try it again to see If I can get it perfect. Something for the next few days. this whole thing is really perplexing... sure seems like the wiring is ok.. so again.. Is it the timing.? Is this motor so sensitive that if it's off that little it won't fire? The hunt goes on.. Dan Link to comment Share on other sites More sharing options...
Cougar Posted March 10, 2005 Share Posted March 10, 2005 I kind of doubt that the timing would do this (unless it is way off). Even though the sensor had a presumably good resistance reading it is possible that it may not work still. The proof will be seeing those pulses while cranking the engine. An oscilliscope would be the best thing to look at the pulses with but not many people have one of those handy. An analog meter would be the next best choice or a dwell meter should work also. A digital meter that has a frequency mode would also work. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now