Car running horribly - 91 L

[realfinn]

But would a MAF pose a only when warm issue?

Do you have a vaccum/pressure gage you can hook up to the intake to watch whats happening inside the manifold during your crazy idle? -This is definitley where I would start.

Also another thing you should definitley do is pull the plugs and inspect them. Make sure they look normal. If there glazed or appear that they may have been foweled this could provide some good info to. This is a really quick and easy check. Just don't take the plugs out when the motor is warm.

Or if you can use the scan tool on this site it would provide a lot of good info.

[Manarius]

But would a MAF pose a only when warm issue?

I think that when the engine gets warm, the ECU goes to correct the A/F ratio and it gets a crazy reading from the MAF and then over corrects the ratio and timing and causes the car to act crazy.

I don't have a vacuum meter and I guess I could build the scan tool...

I did notice though, plug 4's wire plug (like the red boot around the plug itself) was very black. This follows the trend that cylinder 4 is the lean cylinder.

[realfinn]

Ok, I can see what your saying about the MAF. But the boot makes me wonder. Your saying that the rubber boot is being discolored? Being that it is not internal to the engine it just sounds strange. Do you have a extra soob sitting around that you could try the plug wires off of? One thing I would definitley check is if the plugs are in tight. If you are getting blowby the spark plug it will definiley cause problems. If you need some wires I have some old ones sitting around you can have...and probably some old plugs (still in good shape). Wouldn't cost that much to ship to PA from NY.


If there is an advanced auto or autozone around they probably have a cheap vaccum/pressure meter you can pick up. I bought a cheap-o for $24 but its one of the nicest instruments you can have when a car is doing crazy things.

[Manarius]

Both my new set of plug wires and stock set of plug wires have a similar coloring trend. The boot on plug 4 is pretty black. The boot on plug 1 is not really that black, but it has some scoring. Plug boots 2 and 3 show barely any signs of use.

The stock wires were on the car for 14 years and it never saw this kind of problem before, and they have the same coloration. The plugs are a year old and so are the new wires.

I was talking to a few people over the SVX board and they said that if the MAF doesn't fix it, that it may be a clogged cat. I certainly hope it's not that, but it's definitely a possibility (although, I don't really smell anything to tell me that).

[quicklook]

check for clogged cat or exhaust with a vacuum gauge.

[realfinn]

I've only ever seen one clogged CAT and the guy had CEL for the O2 sensor. But I suppose that it could be a possibility. The ECU on most cars runs an internal loop on the O2 sensor before the exhaust comes up to temperature. Once the exhaust is up to temp it runs to the O2 sensor. Not sure if the Subaru's are the same as GM in this aspect. But it might be running the internal loop until you start having problems. If you suspect a blocked CAT there is one little trick I learned on my buddies car. Dropped the pipe off the car dumped a bunch of gas in it and set it in the middle of my drive way and dropped a match to it. I just let it burn all the junk out of the CAT. I then blew the CAT out with 140 psi from my compressor and put the pipe back on. No problem since then. Other than that BlackBart probably has a cat you can buy cheap.

[Manarius]

Well, today I moved it to wash the car. Even cold it wouldn't hold an idle. Between my garage and my yard, it stalled out probably 5 or 6 times (It took me 3 restarts just to get it out of the garage and it stalled as I started the turn to roll down the hill). As soon as I dropped it into drive or reverse and the RPM dropped, it just dropped out. Going back up the hill to the garage I pushed it hard and it just dropped out from under me....I was at 3k in 1st and it just dropped out. 2000, 2200, 2400 (me still pushing on pedal), car drops to 1500, drops to 0 (I'm sitting on the hill going "WTF!?")

It's throwing a constant CEL now when the car is on...even if it's cold. CEL is for the airflow sensor, which was mailed to me this morning (Should be here on or before Wednesday).

I did an "at home" exhaust test...basically me sticking my hand behind the exhaust pipe. There was a full flow which was warm. I don't smell anything funny, just regular exhaust fumes.

Hell hath no fury like a car that's pissed at you.

[Brat4by4]

I did an "at home" exhaust test...basically me sticking my hand behind the exhaust pipe. There was a full flow which was warm. I don't smell anything funny, just regular exhaust fumes.

I surely hope you don't think this tells you anything about a clogged cat... Replace the MAF and then see what happens. I don't think there is much else to post until then.

[Manarius]

I surely hope you don't think this tells you anything about a clogged cat... Replace the MAF and then see what happens. I don't think there is much else to post until then.

I figured that if the cat was clogged, I would either get the typical "rotten egg" smell or I'd get really restricted exhaust flow.

Maybe I'm mistaken? Remember, I'm here to learn. I'm all into learning the correct way to tell if things are broke. I'm also into not spending money, so if it requires buying a tool, fine, but I'd rather know how to do it if a tool isn't absolutely necessary.

[quicklook]

i had a corvette with blocked cats, no smell, exhaust still coming out the pipes.

get the vacuum gauge and test the car.

[Brat4by4]

Hit the cat (when its cold) with the palm of your had and listen for what sounds like gravel in there. If you hear gravel, that's bad. If you don't, the cat might still be good or bad - you can't really tell for sure unless you hear the gravel sound or take the cat off.

[realfinn]

I know you say you don't want to spend money but the vaccum/pressure gage will do wonders for just about any car you buy in the future. Its pretty easy to diagnose a blocked exhaust with a gage. Basically hook the gage up to the manifold and start the car in park. Rev the engine and watch the gage. When you let off the throttle the needle should drop back to normal manifold pressure relatively quickly. If it floats there for a while or if the needle drops really slowly there is probably a backed up CAT or something else in the exhaust.

But if you have a different MAF on the way try that first.

[Manarius]

SOLVED!!!!!!

MAF did it for sure this time. I drove it around at op temp and it ran like a brand new car. Thanks to subyluvr2212 for 2nd Day'ing me a JECS MAF.

[realfinn]

Awsome

Add this one to the old archive of strange subaru occurances.

[entirelyturbo]

Wow! They told me it wouldn't be there until tomorrow! Cool!

I do think we overanalyzed the problem a little bit , discussing fuel pump connection problems and what not. But this is good that we dragged this out into specific details, so we know EXACTLY what happens when a MAF sensor kicks the bucket.

It's not exactly a strange occurrence, Josh had the same thing happen to him pretty much, and I'm sure others have as well.

[Manarius]

Wow! They told me it wouldn't be there until tomorrow! Cool!

I do think we overanalyzed the problem a little bit , discussing fuel pump connection problems and what not. But this is good that we dragged this out into specific details, so we know EXACTLY what happens when a MAF sensor kicks the bucket.

It's not exactly a strange occurrence, Josh had the same thing happen to him pretty much, and I'm sure others have as well.

Plus, I have some cool videos of it bucking and stalling out.