MAF sensor cleaning, Please Help!

[carlito]

Hi,

My car recently started showing code 23 in addition to the 32 that has always been flashing due to disconnected 02 sensor. It has been running fine apart from some sputtering and hesitation during acceleration in second gear. So I disconnected the maf sensor, put it in a ziplock bag with some 99% Iso-propanol alcohol. I swished it around and let it sit in the bag fully submerged for 15 minutes. I then transfered it to another bag and swished some more, then I finally rinsed it in another bag full of the alcohol. I then left it to dry overnight. However in the morning I picked it and instinctively shook it around close to my ear and I could hear some sloshing sound somewhere inside the square part with female connector, upon looking closely I noticed a tiny hole on the cylindrical tubing near the base of the stem that holds the bulb like fillament. I hear there is another sensor inside this tiny aperture. It seems like the alcohol sipped into the hole and only a little amount seeps out after shaking. So I let it dry out in the sun shaking it regularly, a little fluid would ooze out then let it dry some more and repeat. Now this is the second morning and just tried shaking it and still some sloshing sound. However the fluid does not ooze out anymore. So i want to know. Is it safe if i reconnect the maf sensor and start the car? It doesnt seem like the fluid will dry completely. Every story I have read online using this method the maf was reconnected after one hour of drying or overnight and no one seemed to have issues. However do all subaru maf sensors have the tiny hole like mine maybe thats the difference?. Please help.

PS: My MAF is made by JECS #22680 AA160 A36-000R60

[Legacy777]

All you can do is try to hook it up and see if it works. Honestly, I've never necessarily heard of cleaning a Subaru MAF sensor like how you described. Usually MAF cleaner is just sprayed in the body housing.

[carlito]

The aparture is very close to the other sensors and spraying especially from the direction of air flow (through the wire gauze) would still soak the sensor in the tiny hole albeit with less fluid. I think I will put it off for atleast a week to see if it will dry completely. I dont want to connect it too soon and short it out or something. By the way what does this sensor in the small hole do? I am assuming there are three sensors, IAT which is very visible,then maf sensor hidden, then the one in the tiny aperture.

[cj91legss]

I dont believe there's an IAT sensor in these MAFs.

[Legacy777]

CJ is correct, there isn't a IAT in these MAF sensors.

The different pieces on the MAF sensor are all related to the MAF sensor measuring the air correctly. I don't recall if the JECS sensor is a hot wire or not. I've got a tech article at home that talks about the differences. I'll see if I can find it.

[carlito]

Thanks guys, Josh would very much appreciate the technical info or a diagram..I understand its the same maf used in subarus between 1990-1999 so thats ten years without IAT and we fine. However ironically I saw an IAT for the 1990-1994 justy online.

CJ is correct, there isn't a IAT in these MAF sensors.

The different pieces on the MAF sensor are all related to the MAF sensor measuring the air correctly. I don't recall if the JECS sensor is a hot wire or not. I've got a tech article at home that talks about the differences. I'll see if I can find it.

[Legacy777]

However ironically I saw an IAT for the 1990-1994 justy online.

Was it just an IAT sensor or a MAF with integrated IAT for the justy?

If it was just an IAT, more than likely the Justy used a MAP based ECU.

[Legacy777]

Sorry for the delay in responding. The JECS MAF sensor is a hot film type sensor. I looked at the article and it really doesn't give any additional information. However, if you haven't already done so, you can d/l the engine & wiring sections from me, which may be beneficial.

http://www.main.experiencetherave.com/s ... and_Elect/

[carlito]

Thanks Josh. My MAF sensor is Trashed.I had to wait two weeks for it dry completely!. I guesse thats not the way to clean a subaru sensor. Oh well ive learned my lesson.

I have tried three used sensors already and none worked. The car would bog down once accelerator is pressed and I couldn't drive past 30 km per hour, so it looks like am in the market for a brand new sensor. Its too much of a ripoff to buy it new here cause it costs $ 330!.

I have searched online and came across an aftermarket one going for 65 dollars and they confirmed to me its brand new. Is the deal too good? Should I be suspicious? Anyone here delt with a company known as Deluxe Auto Mall. Are they legit? The maf will cost me $93.5 shipped to my doorstep only downside is I have to wait almost two weeks to receive it becaise they dont have a faster shipping option. Please advice

[alexandermf]

3 mafs and no fix...? You may have a diff problem

Sent from your bathroom closet

[carlito]

Yeah the MAFs are not brand new so its understandable. The first two mafs were covered in dust when I got them so I think they were already damaged. The last one was in a better condition and when I push the accelerator I can complete race. However the car can't move fast it feels like its chocking. Almost feels like clutch is slipping but theres also sputtering.

I figured the sparkplugs may have been damaged from the first two attempts so I removed them and sure enough they were full of soot. I put new spark plugs and no improvement, however at one point it really picked speed briefly but was backfiring then it began to idle really low almost dying out before I shut the engine off.

I plan to do a ecu reset and see what happens before I order a brand new one. No one bought stuff from this deluxe guys?

[James614]

I have searched online and came across an aftermarket one going for 65 dollars and they confirmed to me its brand new. Is the deal too good? Should I be suspicious? Anyone here delt with a company known as Deluxe Auto Mall. Are they legit? The maf will cost me $93.5 shipped to my doorstep only downside is I have to wait almost two weeks to receive it becaise they dont have a faster shipping option. Please advice

I'd trust a 20-year-old junkyard genuine Subaru MAF sensor over any aftermarket MAF sensor any day of the week.

+1 on something else being the problem if you went through 3 other MAF sensors. Dirty or not, they don't just go bad that often. They're pretty resilient apart from the sensor element/wires being physically damaged, I know first-hand (mudding with a K&N filter... not the best idea).

If the ones you tried are dirty, just use a can of MAF sensor spray-cleaner, it works great and I guarantee you it won't damage the MAF (I've done it 4 times on my Touring Wagon). You can remove the screen with snap-ring pliers to clean it more thoroughly.

[cj91legss]

I have a hitachi turbo legacy maf for sale

[carlito]

Ok the first time I reinstalled the original maf after cleaning it with isopropanol, I first disconnected the batterys negative terminal for 40 minutes then I reinstalled the maf and started car. It idled rough for a good 15 minutes, I did not touch the throttle but it did not normalize as expected. I turned of engine and started again. This time I pressed accelerator but it bogged down and couldn't complete race thats when i realised my maf is gone. So I got a brand new aftermarket maf. I disconected battery before reinstalling the new aftermarket maf so the ecu can relearn but it just wont idle.

This is how the car behaves. Once I crank it, it starts right up and the needle goes to about 2,000 rpm maintains it there for about 3 seconds then drops steadily and dies. Could it be the ecu picked the wrong settings from the malfunctioning maf and is now damaged? I have disconnected the battery before reinstalling the new aftermarket maf so it can relearn but it just wont idle. Before I cleaned the maf the car was running fine but it seems I may have damaged something with the bad maf, what could have been damaged? Ecu, tps or what.

[Legacy777]

If you disconnected the battery for 40 minutes, the ECU will have lost any learned memory. If all you did was clean the MAF and try a new aftermarket MAF, I'd still say that's the problem. That or the wiring may have some sort of issue, but I don't think that's the problem.

Any chance you can borrow a MAF from another Subaru owner/friend in the area to test? The reason I suggest this is because the aftermarket MAF you got may not work with your car or may be bad.

[carlito]

Ok so you don't recon its the ecu? Before the aftermarket maf I had tried four used mafs and they all failed only one worked but not perfectly because the car was acting like it has a speed limiter set at 30 kph. But otherwise the car would idle well. The aftermarket maf looks cheaply made, the connector is four pinned rather than five like my original one. perhaps thats why it wont work. I will borrow a maf from a working car and test. Could the fuel filter cause this issue? The other thing the starter has a slight delay before it cranks and sometimes it just clicks without starting.

[Legacy777]

I don't see how using the different maf could affect the ECU, so it should be fine.

The fuel filter being clogged might be a cause, but I couldn't say for sure. If it hasn't been replaced in a while, it might be a good idea to replace it.

The starter issue sounds like the starter solenoid contacts may be wearing out....which shouldn't be related to you MAF/running problem.

[carlito]

Thanks I will test with another maf but I Just thought of something. I have been getting some rattling sound on the right side of the car during startup I thougt it could be the heatshield but now suspect the catalytic convertor because car cant idle and when I last drove it felt severly restricted or maybe it is a failed muffler. One question. If I find the cat is the issue can I just remove it and drive like that? Or do I have to adjust the exhaust to work without it?.Hope it wont make car louder. Cause I dont plan to spend money on a new one.

[James614]

The 02 sensor is before the catalyst, so you'll be fine with removing it, although I doubt it's the cause of your idle/power issues. Restricted exhaust flow reduces power, but from my experience not in the manner you're describing. But you could rule out the possibility if you have the tools to do it without blowing too much money on it.

A failed muffler would make it louder, but wouldn't restrict flow significantly unless you hit something that dented the pipes closed.

[Legacy777]

Yeah, you could drop the exhaust and see if that helps, I'm not sure it will, but you can give it a shot.

[carlito]

Ok guys after importing an aftermarket maf which made my car misfire badly. We finally discovered the problems were apparently being caused by a dead alternator. The explanation I got from my mechanic is that the fuel pump and spark plugs were not getting enough juice from the battery hence the rough idle and stall on startup. Luckily I still had a spare alternator from the engine I swapped out. After installing it all symptoms disappeared. Even the click -but- no- start behavior of the starter which I attributed to a worn solenoid disappeared.

I would have never guessed the alternator was the issue. Aren't Cars just funny. The car was working perfectly. The only reason I removed the MAF to clean it was because I had noticed a check engine light which indicated code 32. Anyway I didnt anticipate the alternator would die right after that and thus I was mislead into buying useless parts which I can't return even though seller has offered to refund cause I will loose too mjch to shipping and taxes Grrr! Anyway atleast the car is running with my old Maf.

I also removed my patched up, beat up muffler. Which was just a straight pipe with some baffle material. I then installed an sti axelback from my friends bug eye STi. The car is very quite now. In the process I discovered I do not have a cat. The previous owner must have deleted it for louder exhaust noise. With the sti axelback I noticed some sound seems to escape from where the cat should be which indicates he did not put a straight pipe. Now exhaust fumes seem to waft into the cabin, I guesse due to the more restrictive muffler. My questions
1. Is it safe to weld in a straight pipe where cat was?
2. Are there any negative effects? On engine if i remain catless?

I am trying to avoid buying the cat because I will also need to purchase an oxygen sensor. But if theres no harm in staying catless then I will just weld in a pipe to stop the exhaust leak and raspy exhaust noise.

Sorry for the long post. Thanks in advance for your advice

[mike-tracy]

I'm not sure about the non turbos, but I was running without an o2 sensor for a while on my turbo. Fuel economy was reduced to about 220-240 per tankful down from the usual 300. Also the throttle wasn't nearly as sharp without the sensor. After replacing the wire I'm back to the usual economy.

What surprised me is that no check engine code came up for not having the o2 sensor plugged in.

I'm also unclear about where the o2 sensor(s) are located on the n/a first gens. On the SS, it is before the cat so not having a cat wouldn't make a difference in how the ecu makes decisions. My 96 n/a has a pre and post cat o2 sensor.

[cj91legss]

The N/A O2 sensor is in the Y pipe right infront of the cat. Mike, I wish i got 300 on a tank...

[Alphius]

My 96 n/a has a pre and post cat o2 sensor.

The '96 is OBDII and as such is required to monitor catalyst system efficiency. The pre-cat sensor is used to adjust fueling by the ECU, the post-cat sensor simply checks to see if the cat is still working, and if not, throws a CEL. It doesn't affect fueling at all. In order for a pre-OBDII system to properly adjust fueling, it needs to have an O2 sensor pre-cat so it can measure the true AFR in the exhaust instead of the modified AFR post-cat.

[Legacy777]

Glad you got the car fixed and running. Sucks you bought a part you didn't need.

You can just weld a straight pipe in there.

As Alphius indicated, the O2 sensor is to make fine fueling adjustments so if you don't have one, your car would benefit from one. Generic type O2 sensors work and can be spliced into the old O2 sensor wiring harness to keep "plug & play" compatibility.