heartless Posted July 18, 2011 Share Posted July 18, 2011 (edited) 1990 Legacy LS wagon - EJ22, 4eat, AWD - 216k + ok, starting over here - turns out the intermittent running problem was not the fuel pump - car FINALLY threw a CEL.... Code 23 - Air Flow Sensor - Abnormal voltage input entered from air flow sensor. diagnostic tree goes like this: 1. Check voltage between ECU & body ~~~ - ok - ~~~ Repair ECU terminal poor contact ~~~ - Not ok - 2. Check harness connectors between ECU ~~~ - Not Ok - ~~~ Repair Harness/connector & air flow sensor, and between air flow sensor and ground ~~~ - OK - Replace air flow sensor ok, so following the FSM directions we tested all specified connections - the results are noted on a copy of the page below... text in red are my results on the ohm readings - there was absolutely no change of the meter in any way shape or form - and we do know the meter works, tested an injector and it read fine... if i am reading all of this correctly, i need to repair/replace my wiring harness??????? or will changeing the MAF take care of the problem??? Edited July 20, 2011 by heartless Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 19, 2011 Share Posted July 19, 2011 I would recheck your measurements and make sure you are checking the right pins and connectors, especially the step number two, checking continuity between the ECM and the MAF sensor connector. Unless the cable was cut in two, you would likely have continuity on some of those wires. It is possible that you are misreading the pin numbers on the ECM connector or the MAF connector, so that you are not checking the same wire at both ends, but putting one end of the meter on one wire, and one end on a different wire. Also, how are you connecting the meter? are you using a long piece of wire connected to one of your probes to reach the Air flow sensor connector, and the other probe on the ecm? Do you have someone helping you with the connections? It's often hard to keep a probe in a connector that's in the engine bay, while the other one is in the interior of the car. Quote Link to comment Share on other sites More sharing options...
heartless Posted July 19, 2011 Author Share Posted July 19, 2011 ok, tried to reply last night, had a great post all typed up, then our interent took a dive (storms in the area) - didnt get fixed until 9am this morning. anyway.... It is possible that you are misreading the pin numbers on the ECM connector or the MAF connector, so that you are not checking the same wire at both ends, but putting one end of the meter on one wire, and one end on a different wire. took about half an hour, 45 mins to figure out which box under the dash i needed to be looking at, and then which plug, and then which way the plug was numbered... wouldnt it be wonderful if they numbered the actual connectors the way they are numbered in the diagrams??? Do you have someone helping you with the connections? Yes, i had help taking the measurements - would be almost impossible for one person to do it alone. The other half (who is the owner of the meter) was helping. Well, went back out and took another look at this - and apparently I was looking at the connector backwards...so new readings... (B48) No. 8 - Body 10-13 V (engine off) = 12.22 13-14 V (at idle) = 14.05 (B48) No. 9 - Body 0 - 0.3 V (engine off) = 0.05 0.8 - 1.2 V (at idle) = 1.52 (B48) No. 10 - Body 0 V (engine off) = 0.02 0 V (at idle) = 0.0 Harness check between ECU & air flow sensor connectors (B48) No 8 - (B1) No 1 / 0 ohm = 0.4 (B48) No 9 - (B1) No 4 / 0 ohm = 0.4 (B48) No 10 - (B1) No 2 / 0 ohm = 0.4 Resistance between air flow sensor connector and body ** (B1) No 1 - Body / 1M ohm min = -0.003 (B1) No 4 - Body / 1M ohm min = 1.31 (B1) No 2 - Body / 1M ohm min = -0.003 (B1) No 3 - Body / 0 ohm = -0.003 ** please note - even tho the FSM does not specify to plug the ECU back in for this test sequence, that is the ONLY way we could get a reading - otherwise the previous readings stand... It is still VERY warm & humid here, and i know that those two things will affect readings, so.... opinions as to where i stand here?? Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 19, 2011 Share Posted July 19, 2011 Ok, The first two steps tested normally, it is the 3rd one I wonder about. Basically, they want you to see if there is a good ground on pin 3 of the connector. Is it a five-pin plug in a straight line like this: 12345? If so, then it is obviously the center pin no matter which way you look at it. If that center pin is measuring close to zero ohms, the ground is good. The other pins readings are off, they should be infinity (no reading or OL, or however your meter signifies an open circuit, but I believe they want you to check it with the ecm still disconnected. That may be why you got those unusual readings for the other pins. Go ahead, try disconnecting that ecm connector and check pin 3 of the MAF sensor connector to ground. It should still read close to zero ohms. If your sensor doesn't have a five pin connector like my 96 legacy did, then you need to figure out which one is pin 3. Also, If you are checking for a connection to ground, you have to make sure your test probe is properly connected to a good ground, not just touching some random bolt or engine piece, etc. I usually wedge the probe into the soft lead negative terminal of the battery to get a good connection. If there is a good ground to pin 3 of the maf connector, your diagnosis is over, and you need to get a new maf sensor. If not, then you need to find where that pin 3 wire grounds to and check the ground connection, or find a break in the wire. From the test results you posted, it looks like the pin 3 wire is grounded, (but the other pins should not have been.) However, that may be because you had it plugged into the ecu. I think it wants you do do it unplugged. A bad maf sensor will make the car run poorly if at all. The ecu will not be able to adjust the mixture. With my car, when the maf sensor was inadvertently left unplugged, it would not even start. Matt Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 19, 2011 Share Posted July 19, 2011 Another thing I noticed with the third section of measurements is that some of the values you listed were negative numbers. There is no such thing as a negative number on the resistance scale. Double check that you didn't mistakenly have it on a voltage range instead of the ohms. In fact, you should set it on the lowest ohm range you have. Also, test your meter to see how many ohms it registers when you connect the two probes together. Theoretically, it should be zero, but often it reads 0.03 or something like that due to resistance in the leads or internal components. You can subtract that value from your result to get the true measurement. But on the ohms scale, you should never get a negative number. Matt Quote Link to comment Share on other sites More sharing options...
heartless Posted July 19, 2011 Author Share Posted July 19, 2011 ok - went and took another set of readings for that last group with meter set to lowest ohm setting - and i did unplug the ECU for this. and yes, it is a 5 pole plug, straight line 12345 no 1 - body = no reading no 4 - body = no reading no 2 - body = no reading no 3 - body = 0.5 test leads together yields a 0.2 reading. Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 19, 2011 Share Posted July 19, 2011 Excellent! So basically all your tests were normal, which leads to the conclusion that the MAF sensor is whacked out. I am not sure if this is one of the types of MAF sensors that can be cleaned, maybe post a new msg about it, or better yet, search the forums because I know it's been discussed. Does your parts car have one you can swap over? Matt Quote Link to comment Share on other sites More sharing options...
heartless Posted July 19, 2011 Author Share Posted July 19, 2011 hehe, have 3 parts cars - would hope that at least one of them would be good I think this one can be cleaned - looks like to little pins with a coiled wire between them - i dunno - it doesnt look dirty at all, tho... thank you once again, Matt. For ALL your help. Quote Link to comment Share on other sites More sharing options...
heartless Posted July 19, 2011 Author Share Posted July 19, 2011 well, swapped out one of the parts car MAF sensors & went for a little test drive - seems to be running fine at this point. will have to see how it does tomorrow - supposed to be the hottest day yet and with storms coming thru later tonight should be good and soggy out too...oh yay. keep your fingers crossed for me! Quote Link to comment Share on other sites More sharing options...
TheLoyale Posted July 20, 2011 Share Posted July 20, 2011 Gonna keep my Fingers and Legs crossed (To be a proper lady) for you and hope it works out! Quote Link to comment Share on other sites More sharing options...
KaraK Posted July 20, 2011 Share Posted July 20, 2011 Gonna keep my Fingers and Legs crossed (To be a proper lady) for you and hope it works out! We're rootin for ya!!! ^^^TheLoyale^^^ You may be the only "proper lady" here!!! Quote Link to comment Share on other sites More sharing options...
heartless Posted July 20, 2011 Author Share Posted July 20, 2011 We're rootin for ya!!! ^^^TheLoyale^^^ You may be the only "proper lady" here!!! Glad you said that and not me, Kara! :lol: Well, i am gonna call it fixed - drove it today with no issues - wasnt even able to get more than a mile before...put about 25 on today. lesson learned - make SURE you are reading the connectors correctly!!!! Quote Link to comment Share on other sites More sharing options...
KaraK Posted July 20, 2011 Share Posted July 20, 2011 Glad you said that and not me, Kara! :lol: Well, i am gonna call it fixed - drove it today with no issues - wasnt even able to get more than a mile before...put about 25 on today. lesson learned - make SURE you are reading the connectors correctly!!!! Flippin Awesome!!! Extra very glad for ya!!! As for the comment- just had to be said!!! Still ing!!! Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted July 20, 2011 Share Posted July 20, 2011 I know, I know, I'm the best, everyone wants to hang out with me, etc.... I am just glad I was able to help you get that thing fixed without having to spend a ton of money. Now enjoy the hottest day of the year... Matt Quote Link to comment Share on other sites More sharing options...
heartless Posted July 20, 2011 Author Share Posted July 20, 2011 you are da bestest, Matt! as for the hottest day of the year (so far) well, had to drive to school, sit for 3 hrs listening to a lousy prof, then drive home in this lovely stuff.... currently soaking up the AC at home! Quote Link to comment Share on other sites More sharing options...
gbianchi Posted July 20, 2011 Share Posted July 20, 2011 I successfully cleaned a fouled MAF from the SVX with no res break cleaner no issues since, darn K and N oil so they are cleanable and sometimes resolderable also, cheers.................G Quote Link to comment Share on other sites More sharing options...
BigMattyD Posted August 15, 2011 Share Posted August 15, 2011 Wait, Now hold on a sec, are you a lady, Heartless? If I'd have known that, I'd never have helped you out!!!! Just Kidding, If you are indeed a female, I am glad to have helped. In fact, I have two young ladies of my own who sometimes help me with the cars, but far too infrequently, as they are both absorbed in princess stories and boys and the like. Props to all the ladies out there who are brave, smart, and cool enough to work on their cars! I only hope I can get my little ladies (5 and 6 yrs old now) to develop a love for wrenching on the vehicles! Matty D And Emilee and Bethany! Quote Link to comment Share on other sites More sharing options...
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