I get in my car and turn it on. I begin driving and with in the 1/4 or 1/2 mile, the car stumbles under acceleration. It gets so bad that with the accelerator depressed the car will still slow down, RPMs also getting lower as this happens. Occasionally the car will accelerate but only for a brief second before "loosing power" so to speak.

So my CEL was on for my after cat/downstream/secondary/whatever you want to call it O2 sensor. After a little searching I read that the downstream O2 does not affect the drive-ability of the car, and if the CEL light was on for the 2nd O2, that it was actually because of a bad cat.

Ok, so my poor self can't afford a new cat or exhaust system. And since this is an offroad use only '96 Accord, I figured I would take my chances.

I carefully knocked out the majority of the inside of the cat (that nasty grey brick of platinum and other fun stuff), leaving one thin-ish layer (maybe an inch thick) still there. I punched a marker size hole in it for safe measures then reassembled the exhaust.

I then searched for how to emulate the O2 sensor signal and came across a mechanical method in which 2 spark plug "non-foulers" are used to space the O2 sensor further from the exhaust in essence making it think the air is cleaner simply because less is reaching it.

whew, ok, all the hard work is done. A quick reset of the ECU and I start her up. Sounds quiet, no fire or smoke. Take it around the block and the problem is still there. Disheartened (read: pissed) I stumble home. What do i do now? Could it really be just a bad O2 sensor? Was all the work for nothing? Is it a clogged muffler (then sure the CEL wouldn't be on)?

Just looking for advise,
-Alex

 

I would have Deathzone autoparts scan the ecm again for any codes that may have been reset. It sounds like a fuel enrichment problem which could be brought on by several things.
Insufficient Fuel Flow (Clogged inline fuel filter)
Insufficient Fuel Flow / pressure (Pump)
Bad Map sensor
Bad Throttle position sensor

The only way the muffler might cause a problem is by rattling from all the debris sent it's way by your wayward Catalytic Converter. There's enough volume in there that it would be near impossible to clog it.

P

 

hmmm...can I do it with a personal code reader? Or does theirs do something mine won't?
Also, it won't tell me if any of those things you mentioned are bad will it.

Thanks,
-Alex

 

The scanners I've delt with were capable of calling out system values (voltages / resistances) as well as archived events and most recent set codes. Most useful when something is out of range, but not setting a code.
Let's give yours' a try and see what pops up.

P

 

Hey, back from school now and I just read the code. It's the bank 1, sensor 2 O2 heater circuit. I assume that that is the o2 sensor? If I buy a new one will that remedy my problems? Will I now have more problems because I gutted the cat?

Thanks for the help,
-Alex

 

Update: I bought the rear o2 sensor from TAS auto which was smaller, but significantly more shiny than the OEM one. I installed it about an hour ago and went through my voodoo ritual of unhooking the battery for about 30 minutes or so then started her up. No check engine light, no catastrophic engine failure, things are good.

Backed it off the ramp and took it for a spin around the block and it accelerated nicely, more so than I thought. Stopping for the final turn to home, I press in the clutch, the rpms drop to zero but it doesn't stall. No biggie I thought, the car hasn't officially been driven in a while. I turn onto the main road and about 75 feet from my driveway I mash the accelerator and nothing...just like before.

What is it now? My first thought was that I didn't let my car idle long enough after I had the battery unplugged to reset/recalibrate all the new settings. Second thought is that I merely bought the o2 sensor to fix the check engine light and my problems exist elsewhere.

Any pointers?

-Alex

 

Well, you did accomplish solving the underlying computer system problem, now we have to concentrate on those things the ECM has nothing to do with.
If the car has been sitting for a good while with the tank partially empty, fresh gas and some dry gas" should help (particularly if you're almost empty). During the cool Fall and Winter evenings; water can condense on the insides of the tank. Have this happen enough times and water starts puddling on the bottom. Since gas floats on top of water, guess what your fuel pickup is sitting in? Dry gas (Methol Alcohol) binds with the water and allows it to be burned.
I'd start there first.

P

 

hmmm, how exactly do I do that/where do I get it?

And that is exactly the case, it has been sitting for a month or so (though it has been started briefly during that time) and in on a near empty tank.

 

You may have also sucked up enough crap to stress out* your inline fuel filter (Firewall mounted, below the master cylinder(s))

*partially clog

P

 

I guess I'll swing by one of those places sometime tomorrow and pick up the methol and a filter and give those a shot. By the time I'm done with this thing it'll be new.

Thanks again for all the help! Glad one of us knows what they are doing.


-Alex

 

If you scanned the PCM and it found your secondary 02 is bad, you are correct, it's not going to affect your performance. That puppy is only there for emission reasons. Replace it and move on. It sound like a possible TPS problem. I would look into replacing that and see if you still have problems. If it's not the TPS i would go with insufficiant fuel pressure somewhere. Check those lines as well.

 

Thanks mavvrik, I'm assuming TPS is the throttle position sensor? If so, then wouldn't it all be off, not just at certain times? Because sometimes it drives fine, then it proceeds to spaz out.

Also Adams, I got a little antsy and went out tonight and picked up the filter and alcohol additive ("iso-heet"). The filter is big and metal and the alcohol is isopropyl, but the sales person assured me that it did the same thing as methol. Since my tank is near empty, he said put in the little bottle of isopropyl and put in a couple gallons of gas and it should work.

Sound right?

Thanks as usual,
-Alex

 

It will do just fine.

The TPS can intermittantly fail, yes; it measures throttle angle.
It's no more than a mechanical variable resistor which varies the voltage the ECM 'sees".
Being mechanical, they are prone to wear; and can act like a dash mounted gas gauge. Ever have one that stayed on 'full' yet you've drove 80 miles and then suddenly it drops to 'half'. Same thing.
They form wear patterns where they commonly range, and cold weather in particular can make it more apparent.
The only crevat to all this, it may/may not set a code. THAT"S what makes it tough to diagnose.

P

 

Update again: I removed my filter according to the FAQ section, well for the most part. I'm go out to install new one and I notice 2 things different. 1st the 19mm part on the bottom (the "in" I believe) is a little bit shorter, but it's really no big deal. The second thing is that when I look into the old filter, there is a metal plate of some sort (on the "out" side I believe) blocking my view, where as on the new one I can see all the way into the filter. Is this a bad thing? I'm assuming it's just a different filter design.

Thanks,
-Alex

 

The important thing is that both ends bolt up ok and do not leak.
The plate you saw in the original filter was a block-off plate which directed fuel from inside thru the filter element to the outside where it collected and continued to the engine. With the new one, the fuel flows from the outside, thru the filter element to the inside where it collects and continues on to the engine.
effectively the same conclusion.

P

 

Well I'll be darned if that didn't seem to be the problem. The idle is still really low, but maybe an ecu reset will solve the problem.

Knowing that the problem was about $20 away kinda frustrates me, but at least with 2 new o2 sensors, new spark plugs and wires, and cleaned IACV, FITV, and TB the car should be running like a champ for a while, and getting superb gas mileage!

Thanks again for all the help (especially P_Adams, and ghostaccord from a while back), and hopefully that was the problem!!

-alex

 

Sometimes it's the simplest things....

Warning: Boreness Zone. Read at your own risk

I was working as a SM at a Chevy Dealer in Milford, Mass when GM introduced the first EFI systems and I had a slew of mis-diagnosed drivability complains in which my techs kept diagnosing bad ECM's. After 8500$ in warranty claims disallowed (because said ECM's tested good) everyone went back to school.
Because of the "newness" of EFI, they were forgetting the basics and doubting themselves.

Thank You. you are now leaving the Boreness Zone

P

 

Well I'll be darned if I don't just T-bone the next car that pulls out in front of me and collect insurance....the problem persists!!! While it is probably 100x better (for now), it seems to be getting worse. (tonight was the worst so far).

What could it possibly be? Do I need a new TPS? Clean the EGR ports? Clean my injectors? New fuel pump? New intake filter and exhaust? New engine? I'm running out of time and patience with this car. I'm about to leave for school again and it can't just sit in the driveway broken.

EDIT: Also, after warm up, the idle is at the lowest tick mark on the tach or lower every time the clutch is in or car is in neutral.

 

(also, where do I go in the options to make it so the site sends me a notification every time someone posts up after me or on one of my threads?)

EDIT: under "Default Thread Subscription Mode" I selected instant email notification?

 

See if you can get a fuel sample. I know you replaced the fuel filter but something's not right here. I shouldn't have gotten better and then started deteriorating again.

I'm trying to avoid the "send it to a dealer to have it scanned" suggestion. That's rather $$$, and I know you're on a budget (like the rest of us)

 

A fuel sample? How exactly do I do that? I've never been around my car when it decided to take a leak!

 

...and when I do get a fuel sample, what do I do with it?

Should I give cleaning the egr ports a try even though I highly doubt it is the problem? Possibly take my injectors to be cleaned?

 

You can disconnect the inlet pipe to the fuel filter, attach a length of fuel hose to the pipe and put the other end in a good sized clean dry glass jar. Turn on the key so that the pump energizes. It won't have to be on long, it's under a bit of pressure.
Have someone watch the progress and call out when it's full. Reattach the pipe.
If you have any remaining water in the fuel it will seperate out.
Clear water in the bottom
Tinted gas floating on the top.
When looked at from the side there will be a clearly defined seperation

P

 

The inlet?! That's the hard one to get to that goes into the filter correct?

It's doable though. So if there is water then that is my problem?

 

I'm concerned about not only the water that may be present, but the crap (I can say crap, yes?) that might be carried along with it. Get enough of it and you could clog that new filter. Bummer.
Be careful with this, the fuel is flamable and will come out quick!


P