LesPaulGoth

SYMPTOMS:

I am having issues with my car running very poorly after a Comp XR270HR-10 and Brodix IK200 Head swap on my 1990 350 Speed Density TPI. I also had PCMforless burn me a chip.

I am getting poor idle, stalling, missing, backfiring, shuddering, hesitating, bogging, no power at all. So I adjusted the IAC and TPS to spec, and they are both in order. I am getting a code thrown at me as soon as the car starts up, but when I jump the ALDL connector A to B, I get no error code. I have checked, rechecked and rechecked vacuum line routing and quality, everything is perfect. I got new plug wires and are routed away from the headers, no burn-through. I also statically relashed the valves, and they are spot on.


DATALOG:

Here is my datalog, it's a little over a minute long, and I had the counting at 10 counts per second. If it's too long, I can redo another log with less counts:

http://www.showsinyourtown.com/Test2.xls

I idled for a while, revved to 3k, idled, and back to 3k, idled and cut it. I was holding an idle to 1200-1500rpm because it wont hold on its own. It went into closed loop at around one minute.

There are some values that I am unfamiliar with, but things such as TPS, Spark Advance, A/F ratio, ect all look in order to me. What do you guys think, anything at all that just jumps out at you that shouldnt be there?

Injuneer

There's not a lot to be learned from a log where you let it idle and periodically tweek the throttle. Driving it makes more sense. But there are some significant problems that are visible.

-running EXTREMELY rich. In closed loop its pulled the long term correction down as low as it can possibly go (108, -15.6%), and its still running rich, forcing the short term fuel correction to bottom out at 80. That means the ECM has pulled out almost 50% of the fuel, and the O2 sensor is still showing 890mV.

-were you intentionally holding the throttle open slightly to keep it running? The throttle % never goes to "0" until record 729. If you weren't holding it open, its not closing all the way on its own. Other times its always 2 to 3% open.

-its pouring in air using the IAC counts. Its almost always over 100 counts, and at the end, its running at 127+ just to hold the idle.

-MAP is extremely high. At the end, idling, its 75kPa (vs. a barometer of 103kPa). You're only pulling 6 to 7"Hg vacuum at idle. How huge is the cam? I haven't looked at many 3rd Gen data logs, but it seems odd that its always in fuel trim Cell 4. I thought it should be in Cell 16 at idle. Maybe the high MAP is moving it to a different Cell. Not sure on that one though.

Why didn't you record coolant temp????

First problem to solve would appear to be the fact its running so rich. Then figure out why the MAP is so high (unless you've got a 24x/25x 108LSA cam). I think if it wan't running so rich, the IAC wouldn't have to open up so much to keep it running.

When was the O2 sensor changed?

LesPaulGoth

Well I got a better datalog for you guys. This one is of me starting up and driving around my block. (Less record counts this time, should be easy to read =]) Let me know if I left out any really important info this time...I tryed to cut down on things that I knew were sending back a null signal, or I knew didnt pertain to my issue.

http://eden.rutgers.edu/~irocz28/Test3.xls






As for the IAC: I rasied this to try and coax the motor into idling on it's own. This still didnt work, so I just left it, but the TPS is adjusted to compensate for this. Remember I am still holding the motor at 1200rpm to keep it running.

As for the Coolant Temp: The sensor is not installed, I still need to find a place to put it since my new heads dont have provisions for it.

The o2 sensor was replaced last summer.

This better?

Injuneer

Which coolant temp sensor is not installed? The one for the gauge or the one for the ECM? The screen shot shows a coolant temp... how could it not be hooked up?

Its a waste of time to even make data logs until you get all the bugs that are causing the DTC codes out.

LesPaulGoth

It's the one for the guage. Oh and the DTC code that comes up is 46 - VATS, however, the car is starting up no problem...sometimes if I move some wires around it wont want to start, but after 10 minutes it will...its weird.