P0100, P0101 - Replaced MAF, Still Won't Start

[beaconhillkilla]

Okay, this is copied and pasted from my NASIOC post. After a few weeks of no response, I thought I would ask you guys - you've been more helpful than anyone on nasioc has ever been.

Trying to fix my dads beater 95 OBD2 Legacy. It's been having lots of idle and ignition problems lately because of the MAF sensor. For example, some days it would sputter like crazy and you would need to hold your foot on the gas for a few minutes and let it idle at about 3k before it would idle on its own. Otherwise it would just sputter out and die. HUGE loss in MPG overall even when it would idle on its own.

Well, we ignored it for long enough and it died totally. He was driving down the street when it cut out, and it had to be pushed back to the house.

Pulled out two codes, a p0100 and a p0101; both of which are MAF related codes. I replaced the MAF sensor with the one out of my impreza and it still won't start. However I should note that when I took the faulty MAF from the legacy and put it into the impreza it would at least start, just not idle correctly.

We have fuel and spark. Can you think of anything else we should check? Keep in mind I have another car with the same motor that I am willing to temporarily cannibalize to figure this out. Thanks! Below is a video.

http://youtu.be/E-i1Q3CnTDM

[Flatfourced]

Pretty sure both of these codes can be thrown from vaccum leaks. If the car was still start and run bad i would say it is the case. Still may be.

So a few questions of how you are trying to start it?

Are you giving any pedal when you try to start it? May be your IAC or TPS

Something that makes me think is the fact you have no CEL immediatly after reset. In my experience a circuit failure will throw an immediate CEL. Also on this note the maf works on the impreza. Not great, but works. By the way, have you cleaned it with MAF cleaner yet?

Anyway all that being said, it may be unrelated to the maf. On both my ej25d and my ej22t i can make them run (horribly) with the maf unpluged, by playing with the throttle. another point to me thinking you may have a seperate issue and have been living with a vaccum leak.

If you havent already try the carb cleaner down the throttle body. Spray a good couple seconds into it and see if it fires up for a second. This process is a basic for fuel / fire diagnosis.

If it does start and run normal for a second then you know you have a fuel problem, if not it's spark or compression. It seemed to crank at normal speed so i wouldent think any major compression issues.

also i have no detail, but i hear the 95 ecu's were a bit quirky. The obd2 standard wasnt in effect till 96 so they are early and quirky. Might not be telling the whole story.

anyway yea.. see what effect the ether start has and we'll know more.

hope any of this helps.

[wtdash]

For future reference (from HERE):

P0100 OBD-II Trouble Code

Technical Description

Mass Air Flow (MAF) Circuit Malfunction

What does that mean?

Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. Other MAF sensor circuit DTC trouble codes are P0101, P0102, P0103, and P0104.

P0101 OBD-II Trouble Code

Technical Description

Mass Air Flow (MAF) Circuit Range/Performance Problem

I read your NASIOC post .......

Our pals @ USMB have this related POST.

I also think that if the wiring is intact, the CTS is suspect. You can pull the one off your Impreza to test b4 buying new.


GL,
td

[beaconhillkilla]

Okay, i'll be heading back down to town tomorrow and i'll check a few things:

1. Try to induce a start by spraying cleaner down the throttle
2. Swap the CTS
3. Swap the MAF
4. Swap the TPS and IACV

and...hopefully something fixes it.

[Flatfourced]

Well i dont know if i would go too crazy on taking my working car apart. Simple sensors yea, but the tps and iac are probably eliminated with easier tests.

Most of the mentioned things will throw a code. But not always, making it tough.

So the iac (idle air control valve) simply opens when the throttle body is shut allowing enough air for steady idle. When you move the plate in the throttle body (hit the gas) it turns off and air flows through the throttle body. That being said it can be tested simply by pressing the pedal and trying to start it. If the car dosent start then it's probably irrelevant.

The TPS may have something to do with it but, its not really a "no start" problem on these cars. it's major function is to control the iac. fuzzy on if this can cause a no start or not. i'm still kinda fuzzy on the full functionality.

Try just unpluging the maf and starting it, if it is at fault it should start and run poorly.

Across the board though it goes back to the 3 basic functions. Squirt, Squish, Bang. The engine dosent start because it lacks fire, compression or spark.

Back to basics, is the point of the carb cleaner. It answers 2/3 of the basic needs for combustion. If it starts for a sec the problem is fuel or air. If it dosent it's fire/timing

I really dont think the maf would be a reason for no start i have delt with 3 maf codes myself and all were just poor running condition. I can unplug mine and it still runs. You tried it on your impreza and got the same poor running condition. Known good one on the legy and still no start.

All of that stacked up brings me to reason that the maf is not the reason for no start. Without a CEL spotlighting the real problem it's back to basics to find the reason.

So, If it were me i would first start with unpluging the maf and giving about 1/2 throttle when trying to start it. 2 questions down.
Then carb cleaner as a starting point for testing without a resonable ecu code.

Good luck

[beaconhillkilla]

Back again with no luck.

-We believe that its computer related, it isnt getting spark. Plugs are new, wires are good, coil is good.
-Its doing the exact same thing that my 92 ss did when I had sensor issues, crank but not start.
-Tried spraying starter fluid down the throttle, no luck.
-Spark plugs are wet - indicating that the car is getting fuel
-Cranked the car with the fuel line removed, fuel flows freely. The fuel pump can also be heard from inside the car
-Changed the CTS, still nothing
-I don't believe that the timing belt slipped a tooth, it died the exact same way that it always has - flooding out and dropping in idle until it dies.

Does anyone have any ideas? Or, if your in Seattle and can come take a look at this car we will pay you for your time. I live in Bellingham and coming back and forth just to work on this car is a PITA. We just need it to be fixed so I can have my other car back.

Youtube Video - http://youtu.be/OX38UYnaeAU

[Flatfourced]

Ok, so its a certain no spark issue.

Next steps i would take is bringing a compression tester and a basic continuity tester with me next trip.

Comp tester just to clear up that timing belt slip, and all other compression issues, it's a solid yes or no and be done with it.

The continuity tester is to trace from the coil back for signal to fire. coil, ignitor, and ecu are the only components on that end. If your ignitor is 3 wire it's grounded through the case, 4 wire is wire grounded. May be some corrosion on the 3 wire setup.

Input to fire really only comes from cam and crank angle sensors. If one is broke or the belt is off then the ecu wont send signal. and will throw a code.

The ecu is somewhat working because your plugs are wet (inj firing) and the fuel pump is kicking on. And there are no codes, and no event to damage the wires to stop the codes from reaching the obd port. So bad ECU.. eh.. slim maybe.

So, that said and in my opinion (feel free to chime in and correct me) it's one of 4 things.

1. you have sliped a tooth, but not far enough to trigger a code, then why would it stop spark?). It dosent seem to be as rythmatic as it should be when it turns over and the wierd hit at 8 sec makes this hard to rule out. Curious enough to bring the comp tester.

2. Wire or component issue from ecu to coil. A knock sensor wire getting brittle, breaking and grounding to it's shield wire is common, and possibly something similar here. It was shaking alot in there i'm sure. And i dont think anything in this circuit would throw an obd code.

3. Check your grounds. Clean up everywhere a wire bolts to the body/frame or engine. Grounds have cost me pleanty of time and money.

4. Ecu wierdness. Full reset the ecu, disconnect batt for 1/2 hour?

Past those i'm throwing up the shoulders in shrug.

Hope some of this helps. Good luck, and let me know what happens.

[beaconhillkilla]

The ECU has been fully reset several times, no luck. I pulled the timing cover off and the belt is where it all should be. It's getting towed to the damn shop so they can figure it out. I tried all that I knew how to try, but I want my impreza back and my dad wants his wagon. Thanks for all the input everyone, but i'm throwing in the towel on this one.

[Legacy777]

Ok, well let us know what the shop finds out.

[beaconhillkilla]

So the car apparently had a blown head gasket and that head gasket caused one of the cylinders to lose compression totally. I don't know the specifics because I wasn't able to talk to the mechanic personally. But in any case, it looks like I'm going to have to haul all my tools and my hoist to Seattle and replace the engine. I'm just going to find an used ej22, I don't want to pull the block apart - this car isn't worth the time.

[Legacy777]

That sucks! At least you know what the problem is though.