Wtf?

[selavia]

I drive to school today and my check engine light goes on just as I am about to shut my engine. I turn my car off, and turn it back on, the light stays on. So I call up and make and appointment to get it looked at. So I'm driving the damn thing home later in the day and everytime I press the gas the car hesitates / chokes. I'm assuming this is why the check engine light was on. I find the way my car is driving very frustrating and agitating because if I slightly release pressure off the gas it feels as if someone is driving a stick for the first time (it's choppy and jerky) and it would keep doing that until I either depressed the clutch or gave it gas. Since this was frustrating me, when I got on an open stretch I depressed the clutch fully and revved my engine in my anger. I did like three revs, each time taking it to about 3750 rpms, and when it would drop to about 2000rpms I'd do it again (I do this right before I race any of my buddies, lol) And as soon as the rpm needle returns to its idle, the check engine light goes off and the car drives like new. WTF??????

Someone please help me.

I'm thinking of three possible things:

1) Bad gas / fuel injector cleaner
2)The cat converter is messed up when it's cold
3) O2 sensor / fuel filter


I'm getting really freaking frustrated. If anyone know what's going on or anything, please help.

Sean

 

[andreyiv]

Don't know if its the cat converter. I hear that they die suddenly and the engine just refuses to rev making you go only a little faster then 5 mph. O2 sensor, hmm, not sure if it would have that great of an effect but you never know. As you might have already figured it out, the engine probably has too much of unburned fuel mixture but is it because it is getting too much fuel or because it is not getting enough air or is it because it just doesn't burn everything in the lower rpms collecting more and more gas making it worse with time.

 

[selavia]

Andreyiv,

So what are you saying? Are you trying to confuse me man? lol. just kidding.

Here's another piece of the puzzle; all this started happening after I changed to synthetic oil and I changed the fuel injector cleaner I used.

I used to use BMWs, then I used redline; I think I'm going to go back to the BMW stuff. Also when it's choking, if I put my face near the muffler I smell sh!t loads of gasoline. I mean like serious gasoline; like I sitting in a rickshaw fumes. That also leads me to think that there is too much gas in there, but why? Is it the fuel injector cleaner? ANd I know when I take it to the mechanic he's going to be like "there's nothing wrong with it.

I'm thinking that next time I fill up gas I'm not putting anything in there; I'm just going to put premium good gas from Exxon and hopefully I will not have any more of these f----ing problems.

Sean

 

[andreyiv]

Wow, I was actually somewhat right. Here is an explanation for the whole thing, well at least what I think. Now, the redline stuff is not mixing with the gas properly (or is, just not the way you want it to) and makes the mixture less flamable, making it burn less and stop the engine from doing its job. There you go, stop using that injector cleaner and you should be good.

Edit: incomplete combustion is the term I believe. Your getting fuel in the exhaust pipe instead of exhaust fumes, watch out, if the exhaust gets hot enough and you might get a back fire. Then again if the mixture didn't burn up in the engine why should it burn in the exhaust.

 

[selavia]

Andreyiv, should I use up all the gas in the tank and then go and fill it up again? WIll that correct the problem? I've already scheduled an appointment for this coming MOnday, but if that's the case, then I'll empty my tank and refuel before I take it and see if it solves the problem.

Sean

 

[andreyiv]

It shouldn't be as bad even if you just go and fill up now, the concentration of the cleaner in the gas will be less and it should somewhat fix the problem. Of course you can experience the problem through the whole tank and then fill it up, that should fix it right up but if you keep coming back and get the tank refilled, it should go away slowly.
I don't think you can go wrong here except of course putting the same injector cleaner in. Tell us what happends.

 

[jrt67ss350]

I highly doubt it's the fuel injector cleaner. It isn't the cat - revving the engine wouldn't have fixed that. A bad O2 sensor is a possibility, but I would tend to lean away from it as the cause of this problem.

Sounds to me like the car is running rich - not that the gas won't burn because you have fuel injector cleaner in there, but because the engine is getting too much gas. The smell of potent gas fumes out the exhaust obviously means that the gas isn't burning properly, but the fuel injector cleaner shouldn't do that. For some reason, your engine was getting too much gas and not all of it was burning. This would cause the plugs to be fouled with fuel (when plugs get wet from either fuel or oil, they can't create a spark), resulting in misfiring, causing the hesitation/choking you were talking about, and finally causing the check engine light to come on. When you revved the engine 3 times, you in effect cleaned off the plugs, and they began firing properly again. I am surprised the check engine light went off right away, though.

The flip side of this could be that for some reason, spark was weak (failing coils, bad plugs, etc), resulting in the fouling situation I described above.

How far had you driven it this morning when it started? How cold was it up there in Maryland? Another possibility is that the coolant temp sensor the engine computer uses (probably not the same one that is connected to the gauge in the dash) is bad and the computer didn't ever go into closed loop mode. When you start a cold engine, the computer rusn in open loop mode, basically bypassing the oxygen sensors, and richens the mixture to "choke" the engine so it'll actually start and run. If the ECM coolant temp sensor is bad, the computer doesn't ever see the engine is heating up, so it never goes into closed loop mode where it uses the oxygen sensor to lean out the mixture and modulate an optimum air/fuel mixture. If your car operates only in open loop mode, that can shorten the life of your plugs and even result in fouling, because it's kind of like you are driving around with your choke on all the time. It'll also eventually destroy the oxygen sensors.

If it keeps doing it, I'd get it checked out.

 

[selavia]

Justin, everytime that it's choked or any of this nonsense happens, it's cold (at least windy) outside, and the engine is completely cold; none of these issues creep up once the engine is warmed up.

That morning when all this started to happen I had probably driven it about 1 / 1.5 mile/s; so not far at all.

I'm taking it in on Monday and just limiting use to absolute necessity. I figure if the light came on, then it must have set off some code, which would give them a clue as to what the hell is going on. Also, Inspection due is about 3200miles away; I know the O2 sensor, plugs, and half the stuff that was mentioned that could be wrong gets replaced; would this rectify the problem?

Sean

 

[newguy]

You did say you replaced the air filter...take it out and see if it changes anything...not enough air going in will make it rich...possibly a wrong filter...in backwards..its a possibility. It won't hurt to try it for 10 minutes or so..good luck.

 

[wood_e]

Your engine has a stored code... get the trouble code pulled before you do anything else. Usually thats your problem and you can fix it and not spend money on needless things.

 

[selavia]

The Verdict.....

I got a call from the shop about 45 minutes ago....

Andreyiv, you were somewhat correct...not enough oxygen, causing the gas to not mix properly and not burn.

The lack of oxygen was caused by a faulty air flow meter and boot. He said judging by the way the boot was ripped, it looks like someone was tampering with my engine!!?!??!!!!! He also said someone tried to remove the air flow meter (or whatever it's called); he siad those things do not come off by themselves, even under hard driving conditions. That made me mad. I explained to him that I have some a**hole neighbors and that my car had been broken into; he then took a look at other hoses, pipelines, etc. and said that several other lines look like someone is cutting them slightly with a knife so that under pressure it breaks on it's own accord. TO replace all the messed up hoses and pipes is costing approximately $150. On a positive note, he said once it's all done the car will be much more peppy...which is always a plus. lol. And I guess $150 isn't too bad; I'm just getting worried now, cause I keep thinking what's next? And I know as soon as I tell my parents, they're going to forbid from driving it. Whatever.

Sean

 

[andreyiv]

I figured it was the injector cleaner since thats the only thing that changed but I guess not. If I were you, I would pull an all nighter, just sit there with a baseball bat or something, when the stupid idiot comes out, I would silently come over and smash him/her over the head or at least the back. Then again its you not me. Thank god though that you got/getting everything fixed.

 

[poboyis]

sit out with a pellet gun or crank up a paintball gun to about 400 ft/sec (400 is about all the way up on most guns) and wail on hit ass. paintballs are nice because it makes a mess, it not easily cleaned off, and hurts enough to leave marks and break skin, but no serious injuries.