CharlieLS

Thanks for the info! The only source I'm seeing for a difference between manual and auto is when I try looking up the part number, and how it's listed on various sites selling them. So yeah, I guess I don't *actually* know if there's a difference that matters. Looking at the ECU pinout diagram that wtdash linked below, there are 4 pins labelled for signal wires, shield, and power supply, and something just called "pin 5," so that might suggest that one pin is reserved for some other application, maybe something with turbo? (don't know enough about turbos to know). I'll try looking further using just that part number...thanks again!

Oof, thanks for the info! I've had the ECU swapped long ago, but my records don't show what it was swapped for....whether it was another ECU from a 90 or if it was from a compatible year! Is there a part number I should look for to tell me *that* info? Hate to contort myself and get up in there for nothing LOL! Looking at the pinout diagram, I see five pins for the MAF but one of them reading only "MAF pin 5"? What is this mysterious pin 5 - is there a chance that 4 pins would work as well as long as they match up to MAF power supply, the two MAF signal sensors, and the MAF shield? I did wonder whether it was a turbo thing, as you say that the 91-94 turbos used the same MAF. Maybe that pin is just not in use in my model year? Still going to keep searching for the One True MAF but in the meantime, after a cleaning, it's not doing the chug-and-die, sluggish acceleration thing anymore...though something's still just a little *off* and it does some RPM hunting when it's first turned on. But I drove it up to the mountains and back last weekend and everything was....OK? (Except the new whirring noise from the left rear wheel but that is...now on the list. Hoping it's not ANOTHER wheel bearing.) Anyway, thanks again for the info and everyone's prodigious knowledge! Coming here has helped me keep this baby running for 20 years (and counting)!

Well the part number is 22680 AA160F, but when I do a search for it on Subaru Parts, it always comes up "this item is not available," and the ones I see on EBay et al. say that it supposedly fits a 1990 Subaru Legacy, but with an *automatic* transmission...which is part of the confusion! Is it possible I had the wrong part on there all along, or wouldn't it just not have worked? I thought I finally had it solved with the one I got from PartsGeek, but it looks totally different (on the sensor part) and only has 4 pins...so basically I'm trying to do historical research and figure out what was *supposed* to be on the 1990 MT all along! 😂

Thanks for that, lmdew! I will give them a look.

Thank you, moosens! I know there's apparently a difference only as far as manual/automatic goes - so far, not sure there's anything different as to year, at least not between 90 and 93! But that's what I've been able to figure out so far.

I'm back! With more questions! So, the MAF sensor on my 1990 Legacy wagon (AWD 5MT) is bad, and I hunted all over to find a new one that fits my car. Finally found one on PartsGeek that said it fit my year, make, model, and was specifically for manual transmissions. Unfortunately there were no closeup pictures of it, and when it arrived, it doesn't appear to be the right one. The one that's been in my car forever is a hot film sensor with a 5-pin (female) connector. The one I just received has something else going on with the sensor and the connector has only 4 pins. I've got a partial FSM for the 1990, a FSM for the 1992, and hours of internet searching and I can't figure out if this thing will work in my car! So I come to the experts! Anyone know if this is the right sensor, or if it will work even though it doesn't look like the one I'm replacing? Thanks, as always, for everyone's help!

Hi all! I'm back with New Problems! First off, thanks again to everyone who has helped me before. I love this forum for the wealth of knowledge and helpfulness here. I have searched extensively and read a bunch of topics from years prior that seem to relate to this issue, but I'm stumped on solutions! My 90 Legacy (2.2L LS AWD wagon MT), which has been a total trooper with very few major problems given its age, recently (within the last month) has sporadically (VERY sporadically) been acting "weird" (random bouts of sluggishness like it's not getting enough gas or something, lasting only a few minutes and then seeming normal) and randomly died in traffic a couple days ago. It wasn't a "chug chug die" like running out of gas or even alternator/battery death. It was just a silent power-down, Do Not Pass Go, we're done here sort of thing. Also, all the cab electrical stuff and the power seatbelt and door locks were still working fine. I was able to fire it up again after a few tries and panic-drive it onto a side street where it "powered down" again and would not restart. I grabbed some new gas from the gas station just in case it had anything to do with that (I was low on gas but not critically low - my gas gauge is intermittent but I always set the trip meter and have done so for years, so I know I wasn't - or SHOULDN'T have been - anywhere close to running out). Dumped in a gallon of gas, got the car to restart, drove it to the mechanic about three blocks away, they did some (cursory) diagnosis and couldn't find anything electrically wrong in the engine compartment. Drove it home, and just kept feeling that weird sluggishness like I wasn't getting enough (mechanical) power, but there was no (electrical) power loss, and it's been starting OK since (with caveats, will describe below). I'm just nervous to drive it if we're gonna do this mysterious-will-I-won't-I dance at random times. Here's my summary so far of what has been done recently and what has been looked at in this instance: Mechanic checked: Engine compartment wiring and grounds - said everything looked OK Alternator (which is new as of 2 months ago) - said output is great Battery (2 years old) - checks out fine. They also could not replicate the problem, but admittedly didn't do any highway testing or even very much driving beyond taking it around the block a few times. I never got a CEL when it died, but I checked for "hidden" codes anyway, and got: 13 - camshaft sensor 14 - crankshaft sensor and uh....4. Which doesn't appear to exist as a code. 😆 Started up for me OK this morning, with a little bit of hesitation to turn over which is fairly usual for me in cold weather when it hasn't run in a couple days. From reading previous posts about related issues, I tried: Thumping the MAF with a screwdriver to see if I could get it to stumble (Nope.) Checking the coil pack/coil pack wiring to see if there was any looseness/cracking (Nope) Wiggling/disturbing various parts of the wiring harness, mostly the camshaft and crankshaft sensor wiring to see if that caused any change (Nope) Checking all engine grounds for tightness/cleaning, etc - all looked OK and that had been confirmed by the mechanic a couple days ago anyway. Stuff that has recently been done on the car: - New alternator as mentioned - crankshaft sensor replaced last year, this is the first since then I'm seeing a code for it - camshaft sensor replaced twice within last year: first replacement due to recurring code, plug and play replacement by me, then when it coded again later due to mice chewing on the wiring, the harness was "repaired" by a shop. They hardwired it in, so when that sensor threw a code again six months later after timing belt replacement, I had to cut apart their wiring to replace it again. Not gonna say my wiring is the best, but I can't seem to get it to fault or cut out by wiggling it so idk? I'm very stupid when it comes to electrical though. - timing belt replacement six months ago due to the belt I bought and replaced a year previous breaking. New belt is a straight Subaru replacement part rather than aftermarket. Rollers/bearings replaced too. These were all double-checked in September when we had the engine block out for head gasket replacement, and they all move freely and smoothly. - fuel pump replaced last year - fuel filter replaced two years ago - spark plugs replaced in September Not strictly related, but - head gaskets/valve cover gaskets replaced back in September. (mentioned because having the engine block out did give us a chance to look at wiring and nothing jumped out as problematic) The only other things I can think to mention at the moment: - I do notice a much more significantly "gassy" smell when first starting the car than there should be, maybe? - I replaced the fuel pump relay earlier this year just because I was swapping out the HVAC/heater relay but it's not what one would call "new." (grabbed it from the junkyard) - clicking sound from under driver's side dash when I turn the ignition to "ACC." Would this be the fuel pump being primed? It's a slow click, and continues as long as I have the key to "ACC" (with none of the diagnostic circuits connected so not like when you have the green ones hooked up and it's the fan relay or something) - not sure how this would be related, but after the alternator replacement, my radioset digital display won't stay on with the unit powered off (aka, just showing the clock). I have to keep hitting the "DISP" button and after hitting it about 20 times it will sometimes stay on until I turn off the car, sometimes won't. Probably just old/something got messed up when the alternator died? Anyway, again, pretty sure that's not relevant to this. Anyway, thanks for reading and hope someone has some insight! This car is my only vehicle so it's a big bummer not to feel like I have reliable transportation this time of year, for sure... Hope everyone's having a great day!

Well I just wanna finish up the story of this issue, in case it will help anyone else coming across the same questions! Long story short, it ended up being a problem with both the timing belt AND the camshaft sensor. I don't know exactly how those two things may have been related to each other in the moment, but here's the longer version of what happened: I checked the timing belt shortly after it was suggested I do so, and laughably, that definitely seemed to be the problem as when I opened up the covers, the timing belt sorta...flopped out. It had broken in half. Which frustrated and confused me, since I had changed it less than a year ago! This time, I ordered an actual Subaru brand timing belt (I *had* done my research to buy the last one, and decided on getting the whole kit from a brand - I can't remember it now but I'll look it up - that was recommended to me as being just as good as getting Subaru parts!), and a friend and I put that belt in and also discovered that the tensioner roller seemed to have seized. That bushing that the bolt goes through was just....stuck, somehow. Crappy part? We're not exactly sure, but luckily I had a new one waiting, and we put that in along with the belt. The piston tensioner and everything else was fine. So we put everything back together and presto! The car started, sounded fine and normal, and I was ecstatic! My friend went on her way and I drove to the store later that evening -- where, halfway there, the same thing happened as back when all this started. Very suddenly, the car died, no rough running, no weird noises, just noped out and the engine shut itself off. Luckily I was on an only mildly busy street and managed to pull to the side as it was happening. Tried to start it again and it was an absolute no-go. Starter motor tried, but no crank. So this time, I didn't sit there with my heat-addled brain trying to get it to start over and over, and just got a tow back home. Once there, I notice the check engine light is actually on (a rarity in this particular car), and I get the codes for coolant temp sensor, camshaft position sensor AGAIN, and knock sensor. So my friend comes back over the next morning with all her toolkit and we look at the sensors. The wiring looks fine, and suddenly, she's able to start the car and it runs at idle without dying. We poke and prod the wiring harness, can't kill it. Then we wonder about the signal getting to the ECU, whether it's just weak, or intermittent, or what have you. The harness FROM the ECU to the sensor tests good (thankfully - my car for whatever reason does not have that big harness connector at the firewall - the harness goes through and into the dash and there's not a damn thing you can do about it LOL). We test the sensor itself but we don't have an oscilloscope so the best we can do is see that it IS getting some voltage when we swing it past a large piece of metal. Then we look into the wiring order itself, since neither the sensor nor the cobbled-together connectors I put in have the original wiring color scheme (according to various manuals.) We decide to swap colors (in this case, the sensor has red, white, and black. We know the black is the shielded one so that goes to yellow on the harness, which, incidentally, goes back to a large black wire where it pins into the ECU). Just for funsies. Because the other two colors on the harness are white and black, and the other two colors on the sensor are white and red, so what if white goes to white, like...ya know...makes sense? So we do that and immediately get some new information - car does not like that AT ALL. It starts, it runs, but it makes angry noises and won't go above 3000 rpm. So, just to be scientific, we take the sensor all the way out to confirm that yes indeed, the car will not start without the camshaft sensor (I mean, ya gotta try, right? LOL) So luckily, on a whim, I had ordered another sensor off of EBay (because parts stores want to charge me $300 for it and at this moment I'm not exactly made of money, which is why I'm doing all this myself with the help of cool friends). We manage to find a wiring diagram that includes the SENSOR wiring (I wish I could tell you where, I think my friend still had access to some super-secret mechanics' manuals from when she worked at an auto shop) and discover that it goes like this, for anyone interested who has this particular setup: ECU big black wire (shield) --> harness yellow wire --> sensor black wire; ECU white wire --> harness white wire --> sensor RED wire; ECU small black wire --> harness black wire --> sensor WHITE wire. So with the new (used) sensor wired in like that, we start the car up again, everything runs peachy keen, I drive around town a bit with my friend following me in case anything else happens, and the car runs like a dream, except the check engine light comes on again! I drive home, check the CEL code, and it tells me it's the knock sensor...........which I had forgotten to tighten down way back at the beginning and it was completely loose 😂 That was that, for now, in this saga! As of this moment my car is running like a champ with no check engine lights and we're hoping it stays that way! Hope any of this info ends up being helpful and/or interesting to someone, thanks to everyone here for their help and suggestions!

Thanks for the info! The OG cam sensor (I guess it must have been modified itself at some point?) in my car did have one of those rounded connectors hooking it up to the wiring harness...so I ordered just the connector to see if I can reattach it in a way that makes sense LOL. It does have three wires, but one of them definitely is shielded, so idk how careful I have to be in making sure there's shielding the whole run? If it isn't meant to get voltage at the harness, then lmdew might be right and it's a timing belt issue...in which case, thank gods for non-interference engines! Cuz I definitely instinctively tried to restart it a bunch of times when it died. XD For now, everything is on hold cuz I have to ship off on a boat for work for a few weeks...will continue looking into things when I get back! Thanks again!

Also, is there a fuse or something for the ECM/ECU? I'm still getting no voltage reading on the engine wiring harness for this sensor, and I'm pretty sure I should be getting *something* with the ignition turned on. ....? Just wondering/dreading the thought that I accidentally shorted something out when trying to resolve this connector mess...

They sure did! It's causing me such a headache, wish I'd never taken it to them I don't have an oscilloscope but I did get little voltage bumps from holding the sensor near a metal tool and moving it around? My biggest question at the moment is if it's actually the *harness* that's causing the problem - since I can replace the sensor pretty easily if need be - because I tried testing the harness wires for voltage with the power turned on and got nothing. I don't know if I did it wrong, or if the wires in the harness are fried. From what I've been researching, I think the ECM is supposed to output some kind of signal/voltage through the reference wire and the signal wire...? (sorry if I've got the terminology wrong, like I said, anything electrical is my downfall, which is why this is turning into a kind of nightmare scenario for me 😆) Gonna check the timing belt tomorrow though, thanks for the tip!

Hi everyone, Longtime reader, first time poster...I have done a lot of reading/searching the last few days, and I'm still struggling with a sensor problem. I have a 1990 Legacy wagon, and it's really been a helluva trooper. But recently, it suddenly died in traffic, and when I checked OBD, it gave me the code for the camshaft position sensor. I have gotten this code before, about a year prior, and replaced the sensor and ended up taking it to a shop for the coolant temp sensor and what turned out to be a fuel pump issue. They fixed those things, but in the process, ended up hardwiring in my camshaft sensor and my crankshaft sensor, because I guess there was old/fragile wiring at the connectors? Anyway, fast forward to a couple weeks ago when it dies and I get the camshaft sensor code. I have had to cut apart the shop's hard wiring to test the sensor/harness, and after a lot of hair-pulling have tested the sensor (it's good), and now am trying to hunt down the problem in the harness wiring. I am getting no voltage readings from the harness wires with the key in the ignition and accessories turned on (i.e., I believe, no signal/power from the ECM?) Before I tear apart the dash and everything trying to chase faulty wires in the harness...is there anything else that I could be missing? I'm kind of an idiot when it comes to electrical stuff so maybe I wasn't doing the reading right? Maybe there's some other "x" factor that could be causing all of this? I haven't even gotten to checking the timing belt yet because of mucking around trying to re-wire this sensor, and kinda feel stopped cold with the no-voltage-in-the-harness thing. The weird thing is how suddenly it failed - I had been doing a lot of driving recently, longer trips too, and it performed perfectly (well, as perfectly as a 34 year old car that I haven't always had the $ to perfectly maintain can!) No stumbling, weird noises, power fluctuations, misfires, anything. The only thing that happened between then and when it died was that someone tried to steal it (!??) and had jammed half a pair of scissors into the ignition, but afaik they didn't mess with anything else except jacking a bunch of my stuff out of it. I don't think that has anything to do with this, though, honestly. Anyway, sorry for being long-winded! Like I said, I'm a long-time reader and admirer of this forum and I just hope I can keep this car going! Thanks in advance, hope everyone is having a great day. (better than mine anyway LOL)