CEL woes + oil pressure light

[Hodges]

Okay. So I had a misfire in my engine. And I saw on the forums that most people seemed to fix that by changing their fuel injectors. I followed suite and changed my injectors and now I have these new CEL codes:

P0170 Fuel Trim Malfunction (Bank 1)
P0171 System too Lean (Bank 1)

And I've also had this one for a while:

P0411 Secondary Air Injection System Incorrect Flow Detected


Now, I've had the P0411 for as long as I've had the car. I'm guessing I might have a bad air pump or something going on there.

But I wonder what's going on with the other two codes? Do you think it might be possible that I didn't tighten the fuel line tightly enough when I reattached everything during the fuel injector replacement?

Also, an issue that I have when I drive the car. She lacks power now. And when I'm driving at a slow speed in first gear... the car jerks a little like the engine was dying. And now my idle rpm is sometimes low... around 500rpm, but only sometimes... it's usually at 1000rpm


And another thing I forgot. The oil pump light has been coming on since the start of the month (about two weeks before I changed my fuel injectors). However, for the same length of time. My engine has been making a rattling/tapping noise? The noise seems to rattle at a rate that is proportional to the engine's rpm... so the higher the rpm... the more the noise. Could this noise be related to my low oil pressure light? And the light only comes on when my engine's rpms are around 500-800. And the light usually goes out within a second or two of it coming on.

[repiv]

Although you have given some detail, there is still a lot of details lacking.

First, IMO, addressing the fuel injectors isn't what fixes "most" CEL misfire codes on this car. Next, you need to tell the story of the fuel injector work. Did you do it yourself? At a shop? Was the shop experienced in S2000 work? What kind of injectors? OEM? New? Used? Aftermarket? Those new codes would indicate that the fuel injector work was not done properly. Perhaps you substituted bad injectors for ones that were perfectly fine. Ordinarily, these codes can be associated with the MAP sensor, fuel pressure, O2 sensors, EVAP system, fuel pressure regulator. However, since they showed up after the fuel injector work, you would be best to target that first. The lack of power and related issues would be associated with this work.
There are a whole series of diagnostics and testing when misfire codes appear. Fuel injectors is but only one such area to test and one would do an injector random swap first. You didn't mention what those misfires codes were. Was it on one cylinder or all cylinders? The chances of all injectors being bad is very remote and thus, why the tests are a smart thing to do. Simply replacing all the injectors is taking a short cut that usually doesn't work. CEL for misfires can be attributed to spark plugs, fuel pressure, timing, valve adjustment, bad sensor readings or a bum ECU. There are ways to test all of these before spending money to replace stuff.

The P0411 has to do with this:
http://forums.s2kca.com/showthread.php?t=13773&highlight=secondary+air+injection
Do you have a CAI? You should trace all those items to make sure something isn't out of whack.

Low oil pressure can be caused by many things, one of which is the oil itself. Again, some details here would have been helpful. What kind of oil are you using? How long has it been since you changed it? Have you checked the level lately? Low rpm, low oil pressure can be a function of too thin of oil being used or really old oil or very low oil level or a pump going bad or the improper type of oil filter. What kind are you using? Yes, low oil pressure, low oil level, clogged oil journals or old, degraded oil can cause rattling. Rattling is usually associated with valve noise, timing chain tensioner noise, main bearings going bad, all of which can be attributed to oil, amongst other things.

[Hodges]

Wow, that was a lot of good information.

I don't remember the exact codes that the engine misfire was throwing out. But the misfire was happening in all 4 cylinders. I think there were 4 different codes, each one for a different cylinder.

I did the fuel injector replacement myself. I followed the directions in the Honda S2000 00-03 service manual (I have an '02). The fuel injectors that I used are new Python Injection fuel injectors that I purchased from the Auto Parts Warehouse online.

I originally tried replacing the spark plugs to see if that would help. But they hadn't. So, I figured I'd try the fuel injectors next. What are the tests for fuel pressure, timing, valve adjustment and bum ECU?

And also, the "(Bank 1)." Does that mean that the problem is only happening in cylinder 1?

I don't have a CAI, but I do have a K&N FIPK II air intake. The prior owner removed the OEM airbox and the P0411 and engine misfires were happening since before I purchased the vehicle. I installed the FIPK air intake hoping that that would prevent hot air from entering the intake and hopefully allowing the engine to run better. Plus there appeared to be a hole in the original intake.

The oil I use is Mobil 1 synthetic 10w-30. I replace the oil every 5k miles. But I don't know what oil filter I'm using... I usually just buy the cheapest. The oil level is also good, that was the first thing I checked when the light came on... but I am due for an oil change.... but I'm not yet over 5k miles (I'm within 100 miles of 5k miles though). And when you use synthetic oil you can go 6k miles before changing the oil?

Thanks for the help!

[repiv]

Sounds like you had a multiple misfire situation. Like I said before, it's not likely that all 4 injectors were bad. I suspect that those injectors you got may be the problem or that you didn't install something back the way it should have been when you did the job. You might want to begin by checking the fuel pressure at the fuel rail. You'll need a special gauge to do this, so if you don't have one, it might be time to let the dealer have at it.
If the fuel pressure checks out OK, then the next step is to randomly put the original fuel injectors back in.
Most people, when they put in new sparkplugs, can often times put in the wrong plugs or not even check the gap before they put them in. Did you use the correct plugs and did you check the gap first?
Timing can be checked with a timing light and valve adjustment simply has to be checked manually with feeler gauges. The ECU can be eliminated by putting in a known good one.
You should have also randomly rotated the coilpacks around to eliminate them as part of the problem.
I believe "Bank 1" is referring to the sensor reading in the primary O2 sensor (as opposed to the secondary sensor).
I'm somewhat surprised that if you have the service manual, you didn't go through the proper diagnostic sequence for a random, multiple misfire. Did you?

A K&N FIPK is a cold air intake. This information would have been useful in the original post. Anytime the stock intake is messed with, chances are the hoses got messed up. Go to that link I gave you and trace those lines. Another detail -- If the previous owner removed the stock intake, what was put on there that you have now replaced with a K&N? It sounds to me that the intake has been altered several times. It is not hard to see that something got messed up in the process. How many miles on the car? Injectors have been known to last over 120K miles without so much as a hiccup. Unless you've got a very high mileage car, I doubt there was anything wrong with the old ones. They probably just needed cleaning.

The cheapest oil filter may not be the way to go. This car has a fairly high pressure oiling system and uses a very specific type of filter. Using the wrong one can create pressure issues. Mobil 1 10W30 oil is a pretty common oil for this car. People have been using it successfully for a very long time. I doubt that's the problem. To reiterate, your oil pump could be getting "tired" or somewhere along the way, the oil level may have been left way too low and some damage may have occurred or oil maintenance had been disregarded. Lot's of bad things can happen when the oil is ignored. On the other hand, it's hard to say if your oil pump is suspect since you left out info about how many miles is on the engine.
There is no defined interval for oil changes just because you are using synthetic. If your engine had been abused or maintenance neglected at some point, only an oil analysis now can tell you if your interval is adequate. People have gone 10,000 miles between oil changes without any problems, but each case may be different. If something is wrong with your engine, the oil can take a beating and not last long at all.

[bimdub]

Bank one is typical default, OBD 2 standards separate into two banks, O2 sensors are divided into primary and secondary, pretty much if you have an OBD2 car with only one primary O2 sensor it will only report as one bank. Bank 2 is reserved for V8, V6 and some inline 6 engines. So any reference to bank one is linked to all four cylinders on an S2000.

As a thought I would go back to basics and since you have reported noise I would be concerned about the valve adjustment, if it is too sloppy (noise) it could cause idle quality issues, I also suspect you have a fuel system problem that could be diagnosed as Repiv stated by doing a fuel pressure check, maybe a bad regulator? or pump? as for the P0411 from what seems to be common there could be a bad vacuum hose somewhere? or incorrectly connected? also find out what the oil pressure is!

[Hodges]

I hadn't realized there was a diagnostic section in the service manual. What page is it on? I can't seem to find it.

The spark plugs I used were NGK platinum plugs. And I checked the gaping to make sure they were set to a 1mm spacing.

The prior owner removed the airbox around the intake. But that was it. The rest of the intake was original and it was just sitting there. They had the original filter tied to that bar between the radiator and the engine. I'll use that link to check the air hose lines tomorrow in the daylight. I'll let you know what I find.

Also the car is at 78k miles. I've had it for about 15k miles. And I always change the oil at 5k miles... but I'll start using a higher quality oil filter. Are there any oil filters that you'd suggest?

I'll take in the vehicle to the dealer sometime this week and have them check out all the things you've suggested, if they do that for free. I'm just a graduate student, so my monthly income is not very high.

bimdub, how do I check the oil pressure? Is that something I'm going to have to ask the dealer to check?

Thanks a lot for the help! I've learned a lot from reading these forums and it looks like I'm going to learn a lot more.

Oh and one last thing. The prior owner also replaced the OEM exhaust with an Invidia exhaust.

And why is a K&N FIPK considered a cold air intake? I thought that to be a CAI the intake had to suck air in from below the car.

Thanks again!

[repiv]

I hadn't realized there was a diagnostic section in the service manual. What page is it on? I can't seem to find it.
Diagnostics begins with each specific CEL code. You can find the codes by looking at the index. DTC (diagnostic trouble codes) section is listed near the beginning of the index. You'll want the section to do with emissions. Each code will tell you the page you go to and what to do.

The spark plugs I used were NGK platinum plugs. And I checked the gaping to make sure they were set to a 1mm spacing.

This is good.

Are there any oil filters that you'd suggest?
You can't go wrong with the OEM one. I use a Purolator Pure ONE myself.

if they do that for free
The dealer will do nothing for free. You have no warranty. You might be better off to find some S2000 owners in your area. One of them might be mechanically inclined and may help you. I understand your finances and I wish you luck in getting this resolved without too much outlay. However, sometimes, there is no other option.

And why is a K&N FIPK considered a cold air intake? I thought that to be a CAI the intake had to suck air in from below the car.

Any aftermarket intake or intake mod that eliminates sucking hot engine bay air, is considered a cold air intake. It doesn't matter the type or brand it is. The FIPK draws air from that hole near the fender and closes off the engine bay heat from getting in. That hole leads to the same area that the more conventional CAI lives.

[bimdub]

I hadn't realized there was a diagnostic section in the service manual. What page is it on? I can't seem to find it.

bimdub, how do I check the oil pressure? Is that something I'm going to have to ask the dealer to check?


yup there is a diagnostic section starting at section 11 page 6, as for the oil pressure test section 8 page 4.

[Hodges]

I found that section with the diagnostic info. I wish had known about it sooner. Thanks for letting me know where it is.

Because of the oil pressure light. I went ahead and changed my oil immediately. And this time I used the Mobil 1 oil filter. The oil pressure is back to normal now and the noise is gone. I had no idea that using a cheaper oil filter could cause such an issue. And I suppose I'll also have to change my oil more frequently than every 5k miles.