I have searched and searched and it seems like all of the threads that I have found are old and never end up posting a cure of what they ended up finding, so here is my situation:

I just bought a 2000 Civic EX. The exhaust was completely ruined, the check engine light was on (O2 Sensor Bank 1 low voltage), it needed a new positive power wire due to corrosion, and a few other things like suspension. There were minor dings and dents throughout the car so I bought it. The car, when it is cold, would not go over 3k rpm without a feel of misfire. Once the car warmed up (after about 10-15 minutes of driving), it would run perfect. Full RPM range including the VTEC all work but would still have the check engine light. I replaced the entire exhaust system, including header, installed a new Bosch upstream O2 sensor, replaced the fluids and reset the ECU.

So, guess what? No change for the most part. Now, when I get in the car on a cold start, no check engine light. However, still no revs over 3k rpm (and it's not easy attempting to merge on the interstate when you're having a hard time doing 60). BUT if I go over 3k and it starts sputtering, the check engine light comes on. Once the car warms up, the light goes off and it runs normal. If I stop somewhere for about 5-10 minutes and start the car, after about 30 seconds, the car will lose all engine power, but once I push in the clutch and give it a little gas, it revs up and doesn't do it again.

The car has a brand new distributor including cap, rotor, plugs, plug wires all from the previous owner. I'm starting to figure out why they traded it in. I'm going to go through and check/replace the ground wires today that are attached to the motor to see if that's the problem, but I'm running out of ideas of what it could be. Compression tested fine, there are no vacuum leaks, no alternative warning/problem noises, head gasket is good, and it's not blowing any smoke.

Any help or ideas would be greatly appreciated. I'm racking my brain trying to figure out any other possible issues that could be causing it before I order a chipped P28 and go that route.

****** SOLUTION FOR THIS PROBLEM IS AT THE TOP OF PAGE 4

 

is there any other code now? the light doesn't have to be on to have stored codes. what brand plugs are in the car?

 

no code as of now, the previous code was the Bank 1 O2 low voltage. The plugs & plug wires are straight from Honda; Honda Plug Wires and NGK plugs, I didn't check which model yet as the previous owner had them put in at the dealership. His receipt just shows "NGK SPARK PLUGS" so I'm not sure.

 

So after you replaced the o2 sensor you get a low voltage? As in reading to lean? Or heater code? Be specific

 

Clogged catalytic convertor?

 

Before and after replacing the O2 sensor it shows low voltage. Cat was replaced before replacing O2 sensor.


Edit: cel came back on tonight. Bank 1 O2 sensor low voltage again.

 

That means you are running lean. Look for vacuum leaks. Spray brake cleaner around the intake manifold gasket and tbody gasket. Make sure all vacuum lines are hooked up with no holes. You probably having a surging idle too or it runs rough. Pull injector plugs to make sure each injector is working. Pull the vacuum hose off the regulator to make sure its no leaking

 

Sounds like possibly an exhaust leak. This would cause your oxygen sensor to foul fairly quickly. Also, I would dump that Bosch junk and get a Denso.

 

I honestly dont think a o2 sensor will make you sputter all over the place and not be able to go passed 3000 rpms. LIke stated above you should look for vaccum leaks. Get brake cleaner,carb cleaner. Start your engine let it idol and spray the intake manifold along were it meets with the cylinder head,along all the lines,along the throttle body. If you notice a change in idle there is a vaccum leak there.

 

Ive had it happen to me. I would sputter like crazy and would throw me a fuel supply code (obd 0). I couldnt pass 3k rpm. No b.s. But the problem is not the o2 sensor right now. Its reading correct and its reading lean.

 

There are no vacuum leaks, it is not idle surging nor idling high. I'm getting plenty of fuel pressure, all 4 injectors are working properly and there are no exhaust leaks.

But again, once the car is warm (after about 10 minutes of driving) it will run normal, just will have the check engine light on. When I first replaced the upstream O2 sensor, the check engine light would actually turn off after about 10 minutes of driving. But not it's just on all the time again.

This is why I'm running out of ideas. All the normal things that would lead to the fix, aren't broken.

 

Sounds to me like a bad map/vacumm leak. When i was getiing my build done on my current hatch it would not rev past 3k EVER turned out the map sensor plug was loose fitting on the sensor its self, so i zip tied (around plug clip) to make snug fit. Works like a charm.

 

I'll look at the sensors for the intake, but that'll have to wait til tonight. Went to get in the car this morning and there was a flat tire on the back. Looks like I'll be swapping tires from the stock rims the the BMW bottom caps for the time being. Had to drive the 350Z to work today.... shucks!

 

At this point u need to get yourself a scanner that can pull up a data list and look at all your parameters and see what the car is actually trying to do when it is running bad. If you are not familiar with this, you need to take it to a technician who can diag this car for you. Also have u checked your wiring for the o2 sensor going back to the ecu?

 

My brother is a tech at a dealership (not a mechanic, but a tech for about 12 years) and has looked it over as well, which is why we have tested just about everything on the car. A few of my friends that are also Honda Techs have looked over the car, but we still aren't finding anything.

 

Many "techs" or mechanics (dealership or not) are not very good at interpreting scanner data. It is unfortunate, because the information is invaluable. Post up some scanner data at idle,2500 rpms (or cruise) and at WOT. I'll see what I can do.
* And no disrespect to your brother or friends, but maybe I'll see something they missed.)


(Dont use the HDS. There are too many PIDS that will not be relevant. Use generic OBD2 data. The refresh rate will be faster.)

 

It most certainly can and it did to me.

Mine through a code 1 which is basically the same.

 

I'm going to have to post a video just to show how it's running. The car is getting its suspension put on tonight as well as some new tires on the bottle caps. I ordered all of this stuff when I first got the car and figured I might as well put it on rather than just letting it sit.

DCFIVER: I'll talk to him about that, but I don't think we'll have a chance to do that til next week. I'm a vendor at a meet/cruise this weekend and he's off winterizing boats. Thanks for the info though.

 

Ok, so check engine light went off on its own yesterday, but then popped back on about 10 minutes later when it wasn't even running bad. It had 8 codes this time:

P0108 - MAP - Circuit High Input
P0420 - Catalytic Converter System - Efficiency Below Threashold (bank1)
P0301 - Cylinder 1 Misfire Detected
P0303 - Cylinder 3 Misfire Detected
P0302 - Cylinder 2 Misfire Detected
P0304 - Cylinder 4 Misfire Detected
P0300 - Random/Multiple Cylinder Misfire Detected
P1399 - Looks like another misfire code, but I don't have the Honda Book.

So I started looking into this deeper and deeper, using the P1399 as reference. Some people have issues with their injectors/fuel system and after cleaning/replacing their injectors, they no longer have the problem. SO... Although they were "reading" that they were fine, we're going to try doing a full system cleaning, as well as the EGR valve.

DCFIVER - BTW - I'm using the MacTools ET97 for the code reader and it wouldn't give me live stream of data. Says it's "not supported on model car".

 

p0420 is usually a bad cat! but dont quote me on that.

If you replaced the o2 sensor already my only thought could be you installed the wrong o2 sensor and its peaked rich! causing the cat to melt and all the misfires.

Ive seen a 2008 odyssey come in with a cat that was glowing red. after talking to customer they had replace the upstream (precat) o2 sensor.

pulled it out cross refferenced it and it was a down stream o2 sensor so it was pinned at a rich condition.


just a thought.
might wana try another o2 sensor possibly from a dealer(were they KNOW parts) not autozone

 

Hondas of that era were really poor at identifying misfires. A misfire on one cylinder would usually set off DTC's for all of them. Try to find if you have one offending cylinder and ignore the rest of the codes for now.

 

I've actually replaced both of the O2 sensors twice now. Didn't make a difference. Moving onto the fuel system now that the ignition system is all new. Reading correct output from the alternate sensors as well (cps, tps, oil pressure, coolant temp etc). About to toss this motor and just swap the F20. I've had about enough.

 

how about map sensor? has that been inspected/replaced? have you check vaccum at idle?

 

Pulled the MAP sensor after the code and replaced it with OEM Honda MAP Sensor. There are no vacuum leaks at all but I have not checked the actually vacuum rate. When I replaced the MAP sensor, I cleared the codes yet again on Monday (10/8) and the CEL has not come back on yet, but hasn't ran any different than before, still misfiring until it's warm.

 

try spraying some brake cleaner around the vacuum lines and ports while the car idles, also check the fuel filter and for a clogged cat... shot in the dark but good luck