Alright.
I have a 97 SE. Since owning the car I had a series 1 supercharged motor in it (ran great) and over the summer I just put a new series 2 supercharged in it (ran awesome...for a while). Also, the throttle body has been replaced with a larger/milled out one, 3" downpipe has been installed, and cat has been removed (gotta love living in michigan).


After fixing up various electrical problems, I have a new issue that I can't seem to figure out.
Under light acceleration, it'* fine. Under mid-full throttle, I get misfires on ALL cylinders. This generally happens around 3500-4000 rpm. Occasionally though, it will get past the "bogging down" and let the RPM'* go all the way to 6000+ and run like a bat out of hell. Also, if I floor it from a stop, it usually won't misfire...it'* most noticeable when accelerating to pass someone for example. Note - this just started happening a few weeks back. Aside from having bag plugs/wires which were recently replaced, it ran awesome up to this point after putting the motor in.

Also, I'm getting a consistent rich condition with the only code thrown is p1133 - my scanner tells me this is from the front O2 sensor not toggling.

Could it be a fuel issue? Due to it running so rich, (and judging by my black exhaust tips), I can only assume it'* an A/F ratio problem. I'm going to change my fuel injectors - one could be leaking, or maybe they just can't keep up under boost? MAF, MAP, TPS, etc,. sensors all checked out to be fine when redoing the wiring.

or

Could it still be an electrical issue? If all cylinders are misfiring, but showing no codes to relate to this, maybe the battery cables are dirty not allowing sufficient power under heavy load...I don't know...I'm frustrated and taking that loan out for a 92' Typhoon is looking all the more tempting


Any insight would be greatly appreciated.

Thanks a lot!
-CP

What plugs did you use? If they were Bosch, they could be causing a problem. We have had many members have problems with the Bosch plugs not having a very long life and causing misfires.

Have you ever replaced the O2 sensor? While a bad O2 sensor won't cause misfires, it could probably be contributing to your rich condition.

Where do you live in Michigan? We have quite a few members here and one of them might be close by and be able to help diagnose the problem

As far as the injectors go, they would be more then sufficient with just a larger TB and a 3" downpipe.

Can your scanner read the sensor voltages while driving? that would probably be the best way to tell if you have any bad sensors.

You also mention the battery cables... it is never a bad idea to clean the cables on our cars, we have members join up all the time with random wierd problems that are fixed easily by removing the cables at both ends and cleaning the crap out of them, including underneath the boots at the battery.


One more thing.. you really should get a cat back on it. While it is pretty common in Michigan for people to run without a cat, it is still illegal by federal law. Not to mention that not having a cat could also be messing with stuff also with the rear O2 sensor. You can pick up a Magnaflow HI Flow cat on E-Bay for around $50 - $60 shipped. Another downfall of running without a cat is that our cars actually lose low end torque without one.

I second the cat advice, you are also contributing to greenhouse gases.

I plan on getting a high-flow cat because of the O2 problems...though I am confident my lack of a cat is not causing global warming (yea, I don't believe in that riff-raff)...that'* a topic for another day hah...


Anyway - I changed my injectors out and, what do ya know, the car runs awesome again. It'* still relearning it'* steps because I reprogrammed the computer, but it'* looking like it isback to normal.
I think the injectors were just worn out...probably leaking - whatever the case, it'* fixed now.

Now it'* time to drop a pully and advance the timing...

Thanks!

-Chad

Out of curiosity, what did you use for injectors?

Tell me more about this. What TB and MAF were used? What sort of milling was done to it? What injectors were in and what did you swap in(bigger or the same?)? I think it'* fairly clear where I am going with this, but it doesn't add up that you would have no miss under light throttle and miss on all cylinders past that.

The throttle body I used is a different style L67 than the one I had - It had a large metal "casing" with a hole in it for the MAF to read. It also had a lot of excess metal around the inner diameter which was milled down to open it up - I also milled off the large metal "casing" for the MAF to sit in and now it sits exposed. A lot of metal was taken off and I could tell an immediate change in performance after installing it - I didn't take any before/after pics unfortunately, but I'm sure someone has the same TB on here. The casing for the MAF probably took up 1/4 of the opening, it was silly.

The injectors were off a different L67 that is going to be used in my parents SLE. I honestly didn't check what brand they were - I just did a quick swap to see if it helped any, and it did. Though by looking at them, they have a tighter composition of the injector holes, and they are smaller than the ones I had as well. I think my old ones were leaking fuel/letting out too much fuel under heavy load causing an overabundance of fuel, which caused the chugging/bogging, poor fuel economy, and contributed to the extremely rich condition. I can get back to you on exactly which injectors they are.

Whether it "adds up" or not, this is how it went. New injectors fixed all my problems. I've ran the car through it'* paces over the last few days and it hasn't shown any similar symptoms - just lots of speed

Before it gets too cold to have fun on the roads (well, going fast anyway), I've got the capability to go 3.33 ratio, going to drop a pulley size (or 2, depends on if I start getting any KR), and I want to advance the timing slightly. Gotta love the speed of such a big comfy car, eh?

On milling the TB, it'* most likely that your MAF tables need to be updated to show more flow at the same frequency. Otherwise your pcm is probably compensating via the O2 reading, which is a little late in some ways.

All S2 L67 flow the same, as long as they were all S2 L67'*..you should be ok there.

Which PCM are you running?

I'm currently running a stock pcm - I've been checking out intense at their performance pcm'* but am currently undecided as to what I should do...

Stock as in the 97 SE pcm...

It'* no wonder you are having many issues. Your pcm is for an entirely different type of engine.